Journal articles: 'Process adsorption mechanisms'

1

Huang, Fei, Lu Zhang, Ren-Ren Wu, Si-Ming Zhang, and Rong-Bo Xiao. "Adsorption Behavior and Relative Distribution of Cd2+ Adsorption Mechanisms by the Magnetic and Nonmagnetic Biochars Derived from Chicken Manure." International Journal of Environmental Research and Public Health 17, no. 5 (March 2, 2020): 1602. http://dx.doi.org/10.3390/ijerph17051602.

Full text

Abstract:

The present study investigated the adsorption of Cd2+ by nonmagnetic and magnetic biochars (CMB and M-CMB) derived from chicken manure, respectively. The adsorption characteristics were investigated as a function of initial pH, contact time, initial Cd2+ concentration and magnetic separation. Adsorption process of both biochars were better described by Pseudo-second-order kinetic equation and Freundlich isotherm model, which were spontaneous and endothermic in nature. It was found that maximum capacities were 60.69 and 41.07 mg/g obtained at the initial Cd2+ concentration of 180 mg/L for CMB and M-CMB, and the turbidity of adsorption-treated solution was reduced from 244.3 to 11.3 NTU after magnetic separation of 0.5 min. These indicated that M-CMB had lower adsorption capacity of Cd2+ than CMB, though it was successfully separated from the treated solutions. Furthermore, both biochars before and after adsorption were analyzed by SEM-EDS, XRD and FTIR. Adsorption mechanisms mainly included precipitation, ion-exchange, complexation and Cπ-coordination, in which precipitation and ion-exchange dominated the adsorption process by CMB, while in M-CMB, precipitation was always predominant mechanism, followed by ion-exchange. The two other mechanisms of complexation and Cπ-coordination were trivial in both biochars, jointly contributing 7.21% for CMB and 5.05% for M-CMB to total adsorption. The findings deepen our understanding of the mechanisms governing the adsorption process, which are also important for future practical applications in the removal of heavy metals from wastewater by the biochars.

APA, Harvard, Vancouver, ISO, and other styles

2

Asaduzzaman, Abu Md, Slimane Laref, P. A. Deymier, Keith Runge, H. P. Cheng, Krishna Muralidharan, and M. J. Drake. "A first-principles characterization of water adsorption on forsterite grains." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 371, no. 1994 (July 13, 2013): 20110582. http://dx.doi.org/10.1098/rsta.2011.0582.

Full text

Abstract:

Numerical simulations examining chemical interactions of water molecules with forsterite grains have demonstrated the efficacy of nebular gas adsorption as a viable mechanism for water delivery to the terrestrial planets. Nevertheless, a comprehensive picture detailing the water-adsorption mechanisms on forsterite is not yet available. Towards this end, using accurate first-principles density functional theory, we examine the adsorption mechanisms of water on the (001), (100), (010) and (110) surfaces of forsterite. While dissociative adsorption is found to be the most energetically favourable process, two stable associative adsorption configurations are also identified. In dual-site adsorption, the water molecule interacts strongly with surface magnesium and oxygen atoms, whereas single-site adsorption occurs only through the interaction with a surface Mg atom. This results in dual-site adsorption being more stable than single-site adsorption.

APA, Harvard, Vancouver, ISO, and other styles

3

Tang, Yu Bin, Fang Yu, Fang Yan Chen, and Cheng Chen. "Research on Adsorption of Pb²⁺ on to Microspheres Prepared by Rectorite and Humic Acid." Advanced Materials Research 233-235 (May 2011): 1972–80. http://dx.doi.org/10.4028/www.scientific.net/amr.233-235.1972.

Full text

Abstract:

Rectorite (REC), humic acid (HA) and polyvinyl alcohol (PVA) were used to prepare microspheres. Batch adsorption experiments of Pb2+ion on to the microspheres were performed. The results obtained indicate that adsorption time, the microspheres dosage and temperature were the main factors influencing the adsorptive capacities. The adsorption data for Pb2+ion were well described by the Freundlich, Langmuir and Temkin models. The kinetic experimental data properly correlated with the pseudo-first-order model, pseudo-second-order model and Elovich equation. The adsorption process is spontaneous, endothermic and out-of-order. The whole adsorption process is mainly controlled by entropies. The adsorption can be classified as chemical adsorption. The mechanisms for the adsorption of Pb2+ion on to the microspheres involved ion-exchange adsorption of Pb2+or the formation of complex compound. Under the experimental conditions employed, the removal of Pb2+ion attained value of 96.05%.

APA, Harvard, Vancouver, ISO, and other styles

4

Strawn, Daniel G. "Sorption Mechanisms of Chemicals in Soils." Soil Systems 5, no. 1 (February 24, 2021): 13. http://dx.doi.org/10.3390/soilsystems5010013.

Full text

Abstract:

Sorption of chemicals onto soil particle surfaces is an important process controlling their availability for uptake by organisms and loss from soils to ground and surface waters. The mechanisms of chemical sorption are inner- and outer-sphere adsorption and precipitation onto mineral surfaces. Factors that determine the sorption behavior are properties of soil mineral and organic matter surfaces and properties of the sorbing chemicals (including valence, electron configuration, and hydrophobicity). Because soils are complex heterogeneous mixtures, measuring sorption mechanisms is challenging; however, advancements analytical methods have made direct determination of sorption mechanisms possible. In this review, historical and modern research that supports the mechanistic understanding of sorption mechanisms in soils is discussed. Sorption mechanisms covered include cation exchange, outer-sphere adsorption, inner-sphere adsorption, surface precipitation, and ternary adsorption complexes.

APA, Harvard, Vancouver, ISO, and other styles

5

Ketratanakul, A., S. Ohgaki, and K. Yano. "Comparative Study on Adsorption Mechanisms of RNA-F-Specific Coliphages and Poliovirus in Activated Sludge Process." Water Science and Technology 24, no. 2 (July 1, 1991): 407–12. http://dx.doi.org/10.2166/wst.1991.0100.

Full text

Abstract:

The adsorption mechanism of RNA-F-specific coliphages, Qβ, and poliovirus 1 in the activated sludge process was studied experimentally. The mechanisms of Qβ and poliovirus associated with microbial flocs were attributable to the pH change in the system which was caused by either microbial activity during glucose uptake or the added acids/alkalis. The adsorption mechanisms of them seemed to be similar, and the only difference was the pI level of each other. In addition, Qβwas found to be more tolerant of environmental stress than was the case for poliovirus because of Qβ being stable for a week in a batch activated sludge reactor. By contrast, poliovirus was reduced about 0.8 log in three days in the identical reactor.

APA, Harvard, Vancouver, ISO, and other styles

6

Munkhbat, Dolgormaa, Tamiraa Ganbold, Ariunzul Naranbaatar, Koichiro Shiomori, and Ochirkhuyag Bayanjargal. "Pb(II) Adsorption of Composite Alginate Beads Containing Mesoporous Natural Zeolite." Journal of Nanoscience and Nanotechnology 20, no. 8 (August 1, 2020): 5267–75. http://dx.doi.org/10.1166/jnn.2020.18530.

Full text

Abstract:

Natural zeolite beads were prepared by encapsulating mesoporous zeolite into alginate beads via egg box method and its adsorption properties of Pb(II) ions were investigated in aqueous solution. Crystallinity and size reduction of natural zeolite were enhanced by mechanic modification of the ball milling process. FTIR and SEM-EDS analyses confirmed that mechanically modified zeolite particles were incorporated into alginate hydrogel. The highest adsorption amount of zeolite alginate beads was 87.47 mg/g after 20 h adsorption process. SEM-EDS result confirmed that the adsorption process has occurred on the surface of zeolite alginate beads. Adsorption kinetic data were fitted with Langmuir adsorption isotherm which showed that Pb2+ cation adsorbed into monolayers of adsorbent material. Moreover, we observed that calcium ion released after the Pb2+ adsorption process in the feed solution. Therefore, the adsorption mechanism of zeolite alginate beads explained by complex mechanisms including surface sorption and ion exchange of Pb2+ and Ca2+ in beads.

APA, Harvard, Vancouver, ISO, and other styles

7

Jia, Miao, Ji Wei Hu, Jin Luo, Su Ming Duan, Zhi Bin Li, and Chun Liu. "Comparison Study on Adsorption and Removal of Antimony from Acidic Aqueous Solution by Activated Carbons and Machine-Made Charcoal." Advanced Materials Research 779-780 (September 2013): 1600–1606. http://dx.doi.org/10.4028/www.scientific.net/amr.779-780.1600.

Full text

Abstract:

Adsorption effects of three kinds of activated carbons and a type of machine-made charcoal on the removal of antimony from acidic aqueous solution were investigated and compared. With an initial antimony solution concentration of 1000 μgL-1, the antimony adsorption by selected adsorbents were found to descend in the following order: machine-made charcoal (52.4%) > coconut activated carbon (42.6%) > coal based activated carbon (31.1%) > apricot stone based activated carbon (24.6%). The machine-made charcoal has the best adsorption capacity with a maximum adsorption values of 523.76 μgL-1. Five kinetic models were used for the fitting of the process of antimony adsorption, including Elovich, parabola diffusion, second order, first order and double-constant. Results showed that parabola diffusion and double-constant rate equation were the most suitable models in describing the relationship of antimony adsorption with time in acidic aqueous solution, implying that the adsorption kinetics of the antimony by the selected adsorbents in water might be a surface diffusion. Three adsorptive capacity indicators (iodine number, methylene blue number and phenol number) were determined in this paper. However, machine-made charcoal, which has a relatively high adsorption capacity, is of the lowest levels of the adsorptive capacity indicators. Thus, some complex mechanisms might be involved for the antimony adsorption by the machine-made charcoal, consequently considering the mechanism for the adsorption of antimony by the charcoal has not been verified, a further study still needs to be done.

APA, Harvard, Vancouver, ISO, and other styles

8

Mohanty, Saismrutiranjan, and Sanjoy Kumar Maji. "Adsorption/photodegradation of methylene blue from synthetic wastewater on titanate nanotubes surfaces." Water Science and Technology 82, no. 11 (November 5, 2020): 2562–75. http://dx.doi.org/10.2166/wst.2020.535.

Full text

Abstract:

Abstract Titanate nanotubes (TNTs) were hydrothermally synthesized from commercially available TiO2 powder and were characterized by XRD, SEM/EDX, and TEM. The as-prepared TNTs were used to remove organic dye, Methylene Blue (MB) from aqueous media by batch mode at 25 ± 2 °C, at pH 6.8 ± 0.2. The MB removal process followed two mechanisms of adsorption (absence of UV light) and photodegradation on precursor's surfaces. Photo-illumination study revealed the ∼98% MB removal with the dose of 3 g/L TNT with an initial concentration of 10 mg/L. Adsorptive capacity of TNT was evaluated from the Langmuir isotherm and found to be 151.51 mg/g. Dimensionless equilibrium parameter RL value suggested the favourable but the free energy changes (ΔG°) value (10.752 kJ/mol) suggested the non-spontaneity of the adsorption process. Adsorption followed the pseudo-second order kinetics model best. MB adsorption onto TNT surfaces followed neither pore diffusion nor film diffusion. Studies conducted in the presence of different foreign ions as well as varying pH of the media to understand their effects in the process if any. Turnover studies were also conducted. A probable photodegradation mechanism was proposed. Finally, TNT was used to remove MB from spiked pond water collecting from the KISS University, including pre- and post analysis of water quality.

APA, Harvard, Vancouver, ISO, and other styles

9

Xu, Nan, Hong Wei Yin, Zhi Gang Chen, Ming Chen, and Shou Qing Liu. "Mechanisms of Phosphate Removal by Synthesized Calcite." Materials Science Forum 743-744 (January 2013): 597–602. http://dx.doi.org/10.4028/www.scientific.net/msf.743-744.597.

Full text

Abstract:

Calcite was synthesized through different drying processes, and characterized by X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). By bath experiments, the mechanisms of phosphate removal by synthesizing calcite were investigated. It showed that synthesis calcite had a strong capability to remove phosphate from solution. The adsorption of phosphate mainly depended on the total concentration of phosphate and pH in solution. Magnesium tended to the phosphate adsorption during pH range of 8-13.5; while it inhibited the adsorption at around pH 7. The experimental results suggested that the synthesized calcite with aged process could effectively remove the phosphate from an alkaline aqueous solution.

APA, Harvard, Vancouver, ISO, and other styles

10

Pinisakul, A., C. Polprasert, P. Parkpian, and J. Satayavivad. "Arsenic removal efficiency and mechanisms by electro-chemical precipitation process." Water Science and Technology 46, no. 9 (November 1, 2002): 247–54. http://dx.doi.org/10.2166/wst.2002.0250.

Full text

Abstract:

This research was conducted to investigate the efficiency and mechanisms of arsenic (As) removal from a contaminated water by using the electro-chemical precipitation (ECP) process, with the operating conditions as follows: initial As concentration of 0.5-5 mg/L, 0.1 M KCl, electrical gradient of 200 V/m and initial pH higher than 3. The laboratory-scale ECP unit was able to reduce As to within the WHO drinking water standard of 0.01 mg/L in 20 min. The ClÐ salt was found to yield better As removal efficiencies than the NO3− salt probably because NO3− ions interfered with the production of OH− and Fe(OH)3, important for As removal. X-ray fluorescence and X-ray diffractometric analysis revealed maghemite (Fe2O3) and angelellite (Fe4As2O11) to be the major compounds present in the precipitated sludge. The percent Fe2O3 and Fe4As2O11 contents of the dried ECP sludge were 98.29% and 0.26%, respectively. From a mass balance analysis, As removal in the ECP process was due to: incorporation in and adsorption on the ECP sludge - 64.9-94.9%, conversion to arsine (AsH3) gas - 10.5-15.6%, adsorption on the electrode plates and reactor walls - 0.03-1.1%, residual in the supernatant - 0.2-0.4%, and unaccounted for - 1.2-19.8%.

APA, Harvard, Vancouver, ISO, and other styles

11

Nacke, Herbert, Affonso Celso Gonçalves, Marcelo Angelo Campagnolo, Gustavo Ferreira Coelho, Daniel Schwantes, Marcelo Gonçalves dos Santos, Dionir Luiz Briesch, and Juliano Zimmermann. "Adsorption of Cu (II) and Zn (II) from Water by Jatropha curcas L. as Biosorbent." Open Chemistry 14, no. 1 (January 1, 2016): 103–17. http://dx.doi.org/10.1515/chem-2016-0010.

Full text

Abstract:

AbstractThe objective of this work was to evaluate the removal of Cu2+ and Zn2+ in water by means of the adsorption process using three biosorbents derived from jatropha biomass (bark, endosperm and endosperm + seed coat). The experiments were performed in batch and evaluated the effect of solution pH, adsorbent mass, contact time, different initial concentrations of the metals Cu2+ and Zn2+, and the temperature of the solution during the adsorptive process. By kinetics, the adsorption isotherms and thermodynamics the mechanisms that control the adsorptive process were evaluated. The optimal conditions for the realization of the adsorptive process for both metals were: solution pH of 5.0 and 8 g L-1 of adsorbent mass per volume of solution, with a contact time between adsorbent and adsorbate of 60 min. According to the Langmuir model, the maximum adsorption capacities for the bark, endosperm and endosperm + seed coat of Jatropha were, respectively, for Cu2+ 11.541, 20.475 and 22.910 mg g-1, and for Zn2+ 14.852; 15.888 and 14.674 mg g-1, with the predominance of chemisorption in monolayer. The three biosorbents derived from the biomass of Jatropha have potential for the remediation of water contaminated with Cu2+ and Zn2+.

APA, Harvard, Vancouver, ISO, and other styles

12

Aquino-Torres, E., F. Prieto-García, J. Prieto-Méndez, O. A. Acevedo-Sandoval, and R. A. Canales-Flores. "Experimental and DFT Study of Reaction Mechanisms in Removal of H2S in Ferrites." Asian Journal of Chemistry 31, no. 8 (June 28, 2019): 1693–703. http://dx.doi.org/10.14233/ajchem.2019.21931.

Full text

Abstract:

The objectives of this work were to synthesize and characterize manganese ferrites via hydrochemistry under optimized conditions to evaluate the adsorption capacity and removal of H2S; calculation of the structural and electronic parameters involved in the process of adsorption between H2S and Fe3O4 surfaces as majority phase ferrites in manganese and discern the process of physisorption or chemisorption. Relating experimental and theoretical on the mechanism of adsorption data allow us to conclude the interaction of H2S with Fe3O4 and ferrites of manganese. The XRD patterns showed the majority of ferrites obtained magnetite phase. The adsorption capacity of H2S on Mn ferrites indicate that the adsorption depends on the amount of iron and temperature. The XRD patterns after adsorption of H2S show two corresponding to crystalline phases Fe3O4 and FeS2 orthorhombic. Estimates of the volume of magnetite surfaces and adsorption of H2S with Fe3O4 (111) with CRYSTAL09 code using the PBE0 functional and the data bases were performed using a modification of an iron base that improves the results of volume and surface adsorption H2S on Fe3O4 (111) in FeO-Fet termination. BSSE results in the calculation of the energy of adsorption of H2S were bridged site -17.50 kcal/mol base using Fe(III), -12.51 kcal/mol using the Fe(III) and Fe(II) bases simultaneously and -4.99 kcal/mol with the modified base. The energy of chemisorption process on octahedral iron was -48.42 kcal/mol, where the rupture of the -SH bond in the molecule and the formation of H2S and O-H bond occurs at the surface. The experimental and theoretical evidence suggests that the adsorption capacity of the ferrites is limited to 50 %, as is the majority magnetite phase and it has two ends Feo-Fet and Fet-O energetically favoured. However, the former is reacted with hydrogen sulfide.

APA, Harvard, Vancouver, ISO, and other styles

13

Kol'tsov, Nikolay I., and Vladislav Kh Fedotov. "STUDY OF CARBON DIOXIDE ADSORPTION ON CHROMOXIDE CATALYST ON NON-STATIONARY CONCENTRATIONS." IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 61, no. 7 (June 18, 2018): 37. http://dx.doi.org/10.6060/ivkkt.20186107.5714.

Full text

Abstract:

Investigation of the regularities of chemical processes, not only near but also far from the stationary state, gives additional information on their mechanisms. In this paper, we present a new method for estimating rate constants of adsorption-desorption processes from the experimentally measured values of the nonstationary concentrations of an adsorbed substance, based on calculating the instantaneous rates of the adsorption (or desorption) process. This method allows to connect unknown kinetic parameters of adsorption (desorption) of a substance on the catalyst surface for various most probable assumed mechanisms with the calculated values of the instantaneous rates of adsorption-desorption processes. As a consequence, the method makes it possible to solve two types of inverse problems of chemical kinetics: calculate point and interval values of rates constants of adsorption and desorption; determine the most likely mechanism from several proposed mechanisms of implementation of these processes. Using this method, point and interval values of the rates constants of adsorption and desorption of carbon dioxide were determined on the base of nonstationary experimental data on adsorption on the assumption of carbon dioxide adsorption on a chromoxide catalyst to three proposed mechanisms: linear, bimolecular and dissociative. Based on the results of calculations, the corresponding non-stationary dependences of carbon dioxide adsorption were restored, which were compared with the experimental data. The obtained results confirm that the previously established dissociative mechanism of adsorption of carbon dioxide on the chromoside catalyst is the most probable. The developed simple method does not require the use of complex optimization calculations and can be used to solve the inverse problem of chemical kinetics associated with the determination of mechanisms and the estimation of the rates constants of adsorption and desorption of substances on various catalysts.Forcitation:Kol’tsov N.I., Fedotov V.Kh. Study of carbon dioxide adsorption on chromoxide catalyst on non-stationary concentrations. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 7. P. 37-42

APA, Harvard, Vancouver, ISO, and other styles

14

Peng, Chen, Peng Shiyang, Yang Tao, Chen Xuexi, Liu Yongjie, and Wang Pengfei. "Study on the law of coal resistivity variation in the process of gas adsorption/desorption." Open Physics 17, no. 1 (November 29, 2019): 623–30. http://dx.doi.org/10.1515/phys-2019-0064.

Full text

Abstract:

Abstract In order to detect coal and gas outburst disasters by means of electric exploration technology, the characteristics of gas adsorption/desorption electrical response were studied. The law of resistivity variation of different coal samples was investigated under different gas pressures with the aid of a self-built real-time test system of coal resistivity during gas adsorption/desorption. In addition, the mechanism of coal resistivity variation was studied. The research results indicate that coal resistivity decreases during gas adsorption and increases during gas desorption, but generally it cannot return to the initial value. Gas influences coal resistivity through a variety of mechanisms. In the gas adsorption process, coal resistivity decreases under the combined effect of surface energy decline, skeleton expansion, free gas pressure and adsorption swelling stress. In addition, as the gas pressure rises, the resistivity varies in a wider range. The coal resistivity shares the relation of y = a + b ln(x + c) with gas pressure and the relation of y = ax + b with the content of adsorbed gas. This study lays a foundation for the application of electrical prospecting technology to gas hazard prediction and provides technical support for safe production in coal mines.

APA, Harvard, Vancouver, ISO, and other styles

15

Yin, Danyang, Zhengwen Xu, Jing Shi, Lili Shen, and Zexiang He. "Adsorption characteristics of ciprofloxacin on the schorl: kinetics, thermodynamics, effect of metal ion and mechanisms." Journal of Water Reuse and Desalination 8, no. 3 (March 10, 2017): 350–59. http://dx.doi.org/10.2166/wrd.2017.143.

Full text

Abstract:

Abstract In this study, schorl was used as an effective adsorbent for ciprofloxacin removal from wastewater. The adsorption performance, mechanism and effect of metal ion on sorption were investigated. Adsorption capacity reached a maximum (8.49 mg/g) when the pH value was 5.5. The pseudo-second-order kinetic model and Freundlich model could better describe the experimental data. The negative ΔH (–22.96 KJ/mol) value showed that the adsorption process was exothermic. The results also indicated physical adsorption existed on the adsorption process, which was in agreement with the analysis of X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy. The desorption rate could reach 94%, which suggested that schorl had a good desorption and regeneration performance. Coexisting ions, such as Cu2+ and Al3+, could obviously inhibit adsorption, and the inhibition from Al3+ was significantly higher than that from Cu2+. However, the additional Zn2+ could slightly promote the adsorption.

APA, Harvard, Vancouver, ISO, and other styles

16

Licsko, I. "Coagulation mechanisms - nano- and microprocesses." Water Science and Technology 50, no. 12 (December 1, 2004): 193–200. http://dx.doi.org/10.2166/wst.2004.0713.

Full text

Abstract:

Possible coagulation mechanisms were studied in relatively high alkalinity model systems and surface waters. On the basis of available information, original laboratory experiments and simple calculation ere performed in order to show that the adsorption of Al3+ and Fe3+ ions is not the dominant process in decreasing the stability of suspended particles. The ions of the feeding coagulants hydrolyse within short time and form positively charged water soluble aluminium- or ferric hydroxides. Adsorption of these water soluble hydroxides onto the surface of colloids and quasi-colloid particles are restricted because of the quick completion of the hydrolysis process in relatively high alkalinity (>1.2 mmol/L) water. The result of complete hydrolysis of Al3+ or Fe3+ ions are slightly positively charged poorly water soluble aluminium or ferric hydroxide sols. The positively charged hydroxides and the associated water molecules are connected to each other by hydrogen bonds, providing a stabile structure. The hydrogen bonds provide the aggregation of slightly positively charged sol aggregation into flocs. Considering the repulsing forces among the sols, high numbers of individual sol particles (having nm sizes) are able adsorb onto the surface of suspended particles, changing their electrical charge and decreasing the stability of the colloids and quasi-colloid particles. This process is dominant in the destabilisation of suspended particles.

APA, Harvard, Vancouver, ISO, and other styles

17

Zhu, Wen, Junsheng Liu, and Meng Li. "Fundamental Studies of Novel Zwitterionic Hybrid Membranes: Kinetic Model and Mechanism Insights into Strontium Removal." Scientific World Journal 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/485820.

Full text

Abstract:

A series of zwitterionic hybrid membranes were prepared via the ring opening of 1,3-propanesultone with the amine groups in the chains of TMSPEDA and a subsequent sol-gel process. Their kinetic models for strontium removal were investigated using three two-parameter kinetic equations (i.e., Lagergren pseudo-first order, pseudo-second order, and Elovich models). Adsorption mechanism was evaluated using intraparticle diffusion model, diffusion-chemisorption model, and Boyd equation. It was found that the adsorption of strontium ions on these zwitterionic hybrid membranes fitted well with the Lagergren pseudo-second order model. Mechanism insights suggested that diffusion-chemisorption was one of the main adsorption mechanisms. Boyd equation exhibited that film-diffusion mechanism might be the control process during the starting period. These findings are very useful in strontium removal from the stimulated radioactive wastewater.

APA, Harvard, Vancouver, ISO, and other styles

18

Elqahtani, Zainab, Mohamed Ben Yahia, Nada Alfryyan, Shatha Aldaghfag, and Fatma Aouaini. "Statistical Physics Modeling of Sorption Isotherms of Aluminum, Iron, and Indium on Tetraphenylporphyrin (H2TPP) and Tetrakis(4-tolylphenyl)porphyrin (H2TTPP): Phenomenological Investigation of Metalloporphyrins at the Molecular Level." Adsorption Science & Technology 2021 (April 21, 2021): 1–14. http://dx.doi.org/10.1155/2021/5540517.

Full text

Abstract:

A quartz crystal adsorbent functionalized with two promising porphyrins (the 5,10,15,20-tetrakis(4-tolylphenyl)porphyrin and the 5,10,15,20-tetraphenylporphyrin) was applied for the investigation of the adsorption phenomenon of aluminum chloride, iron chloride, and indium chloride. The aim is to prove new insights about the appropriate adsorption materials for metalloporphyrin fabrication. The equilibrium isotherms were measured at five adsorption temperatures (from 290 to 330 K) through the microbalance (QCM) method. The discussion of the experimental observations indicated that the adsorption of the aluminum chloride and the iron chloride was performed via a monolayer process. On contrary, the participation of the chloride ions in the double-layer adsorption of the indium chloride was explained by the layer-by-layer process. Overall, the statistical physics modeling of the experimental curves indicated that the number of ions per adsorbent site n was found inferior to 1 for all the adsorption systems (multi-interaction process for the three ions). Interestingly, the physicochemical investigation of the three adopted models showed that the complexation mechanism of the tested porphyrins was an endothermic process since the two steric parameters ( n and P M ) increased with the rise of the temperature. The FeCl3 curves were discussed via a monolayer adsorption model which includes the parameters a and b (lateral interaction description), indicating the lowest stability of the formed iron-porphyrin complex. The energetic study showed that the adsorption energies ∣ − Δ E 1 / 2 ∣ of AlCl3 on H2TTPP and H2TPP are superior to 40 kJ/mol (chemical adsorption mechanism), whereas the adsorption mechanisms of FeCl3 and InCl3 took place via a physical process since they presented adsorption energy values lower than 40 kJ/mol.

APA, Harvard, Vancouver, ISO, and other styles

19

Deng, Hua, Qiuyan Li, Meijia Huang, Anyu Li, Junyu Zhang, Yafen Li, Shuangli Li, Caiyan Kang, and Weiming Mo. "Removal of Zn(II), Mn(II) and Cu(II) by adsorption onto banana stalk biochar: adsorption process and mechanisms." Water Science and Technology 82, no. 12 (November 10, 2020): 2962–74. http://dx.doi.org/10.2166/wst.2020.543.

Full text

Abstract:

Abstract Low-cost banana stalk (Musa nana Lour.) biochar was prepared using oxygen-limited pyrolysis (at 500 °C and used), to remove heavy metal ions (including Zn(II), Mn(II) and Cu(II)) from aqueous solution. Adsorption experiments showed that the initial solution pH affected the ability of the biochar to adsorb heavy metal ions in single- and polymetal systems. Compared to Mn(II) and Zn(II), the biochar exhibited highly selective Cu(II) adsorption. The adsorption kinetics of all three metal ions followed the pseudo-second-order kinetic equation. The isotherm data demonstrated the Langmuir model fit for Zn(II), Mn(II) and Cu(II). The results showed that the chemical adsorption of single molecules was the main heavy metal removal mechanism. The maximum adsorption capacities (mg·g−1) were ranked as Cu(II) (134.88) > Mn(II) (109.10) > Zn(II) (108.10)) by the single-metal adsorption isotherms at 298 K. Moreover, characterization analysis was performed using Fourier transform infrared spectroscopy, the Brunauer-Emmett-Teller method, scanning electron microscopy with energy-dispersive X-ray spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The results revealed that ion exchange was likely crucial in Mn(II) and Zn(II) removal, while C-O, O-H and C = O possibly were key to Cu(II) removal by complexing or other reactions.

APA, Harvard, Vancouver, ISO, and other styles

20

You, Hanyang, Wenying Li, Yi Zhang, Zilin Meng, Zhenxiao Shang, Xuedong Feng, Yanfei Ma, Jie Lu, Menghong Li, and Xiaoyin Niu. "Enhanced removal of NO3-N from water using Fe-Al modified biochar: behavior and mechanism." Water Science and Technology 80, no. 10 (November 15, 2019): 2003–12. http://dx.doi.org/10.2166/wst.2020.033.

Full text

Abstract:

Abstract To remove NO3-N from water, coconut shell biochar (CSB) was modified by a solution of FeCl3, a solution of AlCl3 and a mixture solution of FeCl3 and AlCl3 respectively. The obtained modified biochar with the best effect of NO3-N adsorption was screened out to explore the adsorption behavior and mechanism of NO3-N removal by batch experiments and kinetics and thermodynamics and correlated characterization. The results indicated that the mixture solution of FeCl3- and AlCl3- modified CSB (Fe-Al/CSB) showed the best adsorption performance for NO3-N removal. Iron and aluminum elements existed on the surface of Fe-Al/CSB in the form of FeOOH, Fe2O3, Fe2+, and Al2O3 respectively. The adsorption process could reach equilibrium in 20 min. An acidic condition was favorable for NO3-N adsorption. The presence of coexisting anions was not conducive for NO3-N adsorption. The quasi-second-order model and Freundlich model could be well fitted in the adsorption process. The maximum adsorption capacity of Fe-Al/CSB fitted by the Langmuir model could reach 34.20 mg/g. The adsorption of NO3-N by Fe-Al/CSB was an endothermic and spontaneous process. Ligand exchange and chemical redox reaction were the NO3-N adsorption mechanisms which led to NO3-N adsorption by Fe-Al/CSB.

APA, Harvard, Vancouver, ISO, and other styles

21

Villabona Ortíz, Angel, Candelaria Nahir Tejada-Tovar, and Rodrigo Ortega Toro. "Adsorption Thermodynamics of Cr(VI) Removal by using Agro-Industrial Waste of Oil Palm Bagasse and Plantain Peels." Ingeniería e Investigación 40, no. 3 (September 17, 2020): 22–28. http://dx.doi.org/10.15446/ing.investig.v40n3.83709.

Full text

Abstract:

The effect of temperature on the adsorption of Cr (VI) was determined with waste materials from the agroindustry, such as palm bagasse and plantain peels, by determining the thermodynamic parameters which allow to establish the mechanisms that control the process. The methodology included an initial preparation of the biomass, its characterization, and subsequent adsorption tests by setting the initial concentration of the metal to 100 ppm, a particle size of 0,5 mm, a biomass amount of 0,325 g, pH 2, and a volume of 100 mL. The process temperature varied between 303,15, and 352,15 K. The concentration of the remaining metal in the solution was performed using the diphenyl carbazide colorimetric method through a UVVis spectroscopy at a wavelength of 540 nm. The results show that the effect of temperature does not present a defined trend for palm bagasse, whereas it is linear for adsorption using plantain peels. Furthermore, the process of adsorption of Cr (VI) with palm bagasse is more favorable at higher temperatures, since it is a spontaneous process with a physical adsorption mechanism. On the other hand, the adsorption process with plantain peels is thermodynamically feasible at temperatures from 40 to 55 °C and not spontaneous at higher temperatures. Also, a physicochemical adsorption mechanism was evinced. It is concluded that the use of the studied materials is possible in the removal of the Cr (VI) ion in aqueous solutions.

APA, Harvard, Vancouver, ISO, and other styles

22

Yang, Zhe, Wenyong Hu, Bin Yao, Liangchen Shen, Feifeng Jiang, Yaoyu Zhou, and Avelino Núñez-Delgado. "A Novel Manganese-Rich Pokeweed Biochar for Highly Efficient Adsorption of Heavy Metals from Wastewater: Performance, Mechanisms, and Potential Risk Analysis." Processes 9, no. 7 (July 14, 2021): 1209. http://dx.doi.org/10.3390/pr9071209.

Full text

Abstract:

A novel manganese-rich pokeweed biochar was prepared at different temperatures from manganese-rich pokeweed plants collected at manganese tailings, resulting in materials identified as BC300, BC400, and BC500. The synthetized biochar materials were investigated as regards their potential for removing Cu2+, Pb2+, and Cd2+, specifically in terms of adsorption performances, adsorption kinetics, adsorption isotherms, and potential environmental pollution risk. The results showed that the sorption process fitted well to the pseudo-second-order kinetic and Langmuir models, and the maximum adsorption capacities of BC500 were 246, 326, and 310 mg·g−1 for Cu2+, Pb2+, and Cd2+ respectively. The physicochemical characteristics of the biochars, and the adsorption mechanisms, were revealed by using scanning electron microscopy-energy spectrometer, elemental analysis, Brunauer–Emmett–Teller techniques, X-ray diffraction, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The sorption mechanism of these three heavy metal ions onto biochars included ion exchange, electrostatic adsorption, chemical adsorption, and precipitation. Besides, the potential pollution risk of manganese-rich pokeweed biochars was significantly reduced after pyrolysis. Therefore, it is feasible to transform manganese-rich pokeweed biomass into manganese-rich pokeweed biochar with potential for heavy metals removal, showing high adsorption capacity, recyclability, and low environmental pollution.

APA, Harvard, Vancouver, ISO, and other styles

23

Ragadhita, Risti, and Asep Bayu Dani Nandiyanto. "How to Calculate Adsorption Isotherms of Particles Using Two-Parameter Monolayer Adsorption Models and Equations." Indonesian Journal of Science and Technology 6, no. 1 (January 19, 2021): 205–34. http://dx.doi.org/10.17509/ijost.v6i1.32354.

Full text

Abstract:

Adsorption isotherm is the most important calculation to predict and analyze the various possible mechanisms that occur in adsorption process. However, until now, most studies only presented the adsorption isotherm theory, and there are no studies that explain the adsorption isotherm thoroughly and in detail from theory to calculation. Therefore, this study contains guidelines for selecting the type of adsorption isotherm to describe the entire adsorption data set, which is featured by the ten most common adsorption isotherms. The steps of how to analyze the two-parameter monolayer adsorption are presented. This study is expected to provide clear and useful information for researchers who are working and studying on the adsorption process.

APA, Harvard, Vancouver, ISO, and other styles

24

Yue, Jiwei, Zhaofeng Wang, and Jinsheng Chen. "Dynamic response characteristics of water and methane during isobaric imbibition process in remolded coal containing methane." Energy Exploration & Exploitation 37, no. 1 (September 13, 2018): 83–101. http://dx.doi.org/10.1177/0144598718798083.

Full text

Abstract:

Addition of water to the coal is actually an isobaric imbibition process. To study the dynamic response characteristics of water and methane, the isobaric imbibition process was stimulated by a self-designed experimental device which can eliminate the reabsorbing phenomenon. The results indicate that adding water can displace absorbed gas. The displacement mechanism is attributed to the capillary effect and competitive adsorption during isobaric imbibition process. A competitive adsorption phenomenon exists between gas molecules and water molecules. Since oxygen-containing functional groups in coal and the hydrogen bond of water, water can easily occupy high-energy sites and only the low-energy sites are available for methane. The imbibition quantity increases with increasing water content or adsorption equilibrium pressure. Moreover, the imbibition quantity would reach a maximum value. The relationship between water content and maximum imbibition quantity or the maximum imbibition rate can be described by a Langmuir function under the same adsorption equilibrium pressure. The maximum imbibition quantity increases with increasing adsorption equilibrium pressure under the same water content, which also can be described by a Langmuir function. However, the maximum imbibition rate decreases with increasing adsorption equilibrium pressures under the same water content, which can be described by an exponential function. Compared to the adsorption equilibrium pressure, the water content has a greater effect on the imbibition quantity and imbibition rate. This study revealed the mechanisms of the dynamic response characteristics of water and methane during isobaric imbibition process based on the transformation form of Hagen–Poiseuille equation, adsorption force of coal and gas and adsorption force of coal and water, which can provide a new method to control gas in deep coal seams.

APA, Harvard, Vancouver, ISO, and other styles

25

Chi, Lin, Zheng Wang, Yuan Sun, Shuang Lu, and Yan Yao. "Crystalline/Amorphous Blend Identification from Cobalt Adsorption by Layered Double Hydroxides." Materials 11, no. 9 (September 13, 2018): 1706. http://dx.doi.org/10.3390/ma11091706.

Full text

Abstract:

In this study, the adsorption behavior of CaAl-Cl layered double hydroxide (CaAl-Cl-LDH) with a controlled pH value (pH = 6) on Co(II) ions ([Co] = 8 mM) is investigated. The comprehensively accepted mechanism of cobalt adsorption on LDH is considered to be co-precipitation, and the final adsorbed products are normally crystalline Co-LDH. One unanticipated finding is that crystalline/amorphous blends are found in the X-ray diffraction (XRD) pattern of Co-adsorbed LDH. To shed light on the adsorption products and the mechanisms in the adsorption process of Co(II) in an aqueous solution by CaAl-Cl-LDH, a series of testing methods including Fourier-transform infrared spectroscopy (FT-IR), Scanning electron microscope (SEM), High-resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma (ICP) are applied to clarify the interaction between cobalt and CaAl-Cl-LDH. According to the comprehensive analysis, the formation of the crystalline/amorphous blends corresponds to two adsorption mechanisms. The crystalline phases are identified as Co6Al2CO3(OH)16·4H2O, which is attributed to the co-precipitation process occurring in the interaction between Co(II) and CaAl-Cl-LDH. The formation of the amorphous phases is due to surface complexation on amorphous Al(OH)3 hydrolyzed from CaAl-Cl-LDH.

APA, Harvard, Vancouver, ISO, and other styles

26

Yang, Chao, Deqing Niu, Fujie Zhang, Yilong Zhong, Tianqi Cao, Lei Li, and Yang Liu. "Absorption mechanisms of lead in aqueous solutions with hydrous manganese dioxide." Water Science and Technology 77, no. 10 (April 30, 2018): 2454–62. http://dx.doi.org/10.2166/wst.2018.197.

Full text

Abstract:

Abstract Hydrous manganese dioxide (HMO) has been synthesized through a facile method. It is found that HMO has an excellent Pb(II) adsorption performance, and an equilibrium adsorption capacity of 127 mg g−1 is expected under room conditions. The sorption capacity is strongly dependent on pH when pH < 7.0, but is not affected by ionic strength, suggesting a mechanism of inner-sphere surface complexation confirmed by X-ray photoelectron analyses (XPS) and Fourier transform infrared spectroscopy (FTIR). The adsorption capacity of Pb(II) in the presence of coexisting negative ions is higher than positive ions. The best fitting of adsorption kinetics and isotherm data are simulated by pseudo-second order equation and Langmuir model, respectively. An endothermic and spontaneous nature in the adsorption process of Pb(II) can be deduced from the obtained thermodynamic data (ΔG < 0, ΔH > 0, ΔS > 0).

APA, Harvard, Vancouver, ISO, and other styles

27

Shen, Tingting, Chengcheng Jiang, Chen Wang, Jing Sun, Xikui Wang, and Xiaoming Li. "A TiO2modified abiotic–biotic process for the degradation of the azo dye methyl orange." RSC Advances 5, no. 72 (2015): 58704–12. http://dx.doi.org/10.1039/c5ra06686g.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

V. Sales, Rafael, Heloise O. M. A. Moura, Anne B. F. Câmara, Enrique Rodríguez-Castellón, José A. B. Silva, Sibele B. C. Pergher, Leila M. A. Campos, Maritza M. Urbina, Tatiana C. Bicudo, and Luciene S. de Carvalho. "Assessment of Ag Nanoparticles Interaction over Low-Cost Mesoporous Silica in Deep Desulfurization of Diesel." Catalysts 9, no. 8 (July 30, 2019): 651. http://dx.doi.org/10.3390/catal9080651.

Full text

Abstract:

Chemical interactions between metal particles (Ag or Ni) dispersed in a low-cost MCM-41M produced from beach sand amorphous silica and sulfur compounds were evaluated in the deep adsorptive desulfurization process of real diesel fuel. N2 adsorption-desorption isotherms, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM) and scanning transmission electron microscopy coupled to energy-dispersive X-ray spectroscopy (STEM-EDX) were used for characterizing the adsorbents. HRTEM and XPS confirmed the high dispersion of Ag nanoparticles on the MCM-41 surface, and its chemical interaction with support and sulfur compounds by diverse mechanisms such as π-complexation and oxidation. Thermodynamic tests indicated that the adsorption of sulfur compounds over Ag(I)/MCM-41M is an endothermic process under the studied conditions. The magnitude of ΔH° (42.1 kJ/mol) indicates that chemisorptive mechanisms govern the sulfur removal. The best fit of kinetic and equilibrium data to pseudo-second order (R2 > 0.99) and Langmuir models (R2 > 0.98), respectively, along with the results for intraparticle diffusion and Boyd’s film-diffusion kinetic models, suggest that the chemisorptive interaction between organosulfur compounds and Ag nanosites controls sulfur adsorption, as seen in the XPS results. Its adsorption capacity (qm = 31.25 mgS/g) was 10 times higher than that obtained for pure MCM-41M and double the qm for the Ag(I)/MCM-41C adsorbent from commercial silica. Saturated adsorbents presented a satisfactory regeneration rate after a total of five sulfur adsorption cycles.

APA, Harvard, Vancouver, ISO, and other styles

29

Miller, Mark W., Jose Jimenez, Sudhir Murthy, Dave Kinnear, Bernhard Wett, and Charles B. Bott. "Mechanisms of COD removal in the adsorption stage of the A/B process." Proceedings of the Water Environment Federation 2013, no. 16 (January 1, 2013): 2472–81. http://dx.doi.org/10.2175/193864713813673721.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

Zolfaghari, Mehdi, Patrick Drogui, Satinder Kaur Brar, Gerardo Buelna, and Rino Dubé. "Insight into the adsorption mechanisms of trace organic carbon on biological treatment process." Environmental Technology 38, no. 18 (November 28, 2016): 2324–34. http://dx.doi.org/10.1080/09593330.2016.1259355.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Li, Lixin, Wanmeng Liu, Taojie Liang, and Fang Ma. "The adsorption mechanisms of algae-bacteria symbiotic system and its fast formation process." Bioresource Technology 315 (November 2020): 123854. http://dx.doi.org/10.1016/j.biortech.2020.123854.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Wang, Jiao, Guijian Liu, Tanfu Li, Chuncai Zhou, and Cuicui Qi. "Zero-Valent Iron Nanoparticles (NZVI) Supported by Kaolinite for CuII and NiII Ion Removal by Adsorption: Kinetics, Thermodynamics, and Mechanism." Australian Journal of Chemistry 68, no. 8 (2015): 1305. http://dx.doi.org/10.1071/ch14675.

Full text

Abstract:

This research concerns the adsorption of CuII and NiII using zero-valent iron nanoparticles supported by kaolinite (nZVI-Kaolinite). The characterization studies indicated that the surface of kaolinite or the kaolinite fragments were filled with nZVI particles. The kinetics of CuII and NiII adsorption were evaluated for various contact times. The adsorption of CuII and NiII at different initial concentrations was examined by injecting 0.5 g of adsorbent to achieve equilibrium. The adsorption of CuII and NiII was a chemisorption process, which fitted well with the Freundlich and the Temkin isotherm models. The low value of activation energy suggests the occurrence of a redox process and both physical and chemical processes for CuII and NiII adsorption respectively. The negative values for the Gibbs free energy (ΔG0) and enthalpy of adsorption (ΔH0) revealed that the adsorption process was spontaneous and exothermic. Both surface diffusion and pore diffusion were involved in the rate-limiting step. The possible removal mechanisms involved redox, adsorption, precipitation, and co-precipitation, depending on the adsorption process studied (CuII or NiII adsorption).

APA, Harvard, Vancouver, ISO, and other styles

33

Satlaoui, Yosra, Mariem Trifi, Dalila Fkih Romdhane, Abdelkrim Charef, and Rim Azouzi. "Removal Properties, Mechanisms, and Performance of Methyl Green from Aqueous Solution Using Raw and Purified Sejnane Clay Type." Journal of Chemistry 2019 (August 21, 2019): 1–15. http://dx.doi.org/10.1155/2019/4121864.

Full text

Abstract:

Adsorption of cationic methyl green (MG) on nontreated (AB) and purified (AP) natural Sejnane clay type was studied in an equilibrium batch process. This work reported the application of kaolinite-rich heterogeneous clay for the removal of a cationic dye. Effects of contact time, initial dye concentration, mass adsorbent, pH, and temperature on the MG removal were checked. The adsorbent before and after adsorption processes was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR), and atomic adsorption spectrophotometer. Equilibrium data were mathematically modeled using the Freundlich, Langmuir, and intraparticle diffusion models. Kinetic of adsorption was determined by pseudo-first-order and pseudo-second-order models. The free energy (ΔG°), standard enthalpy (ΔH°), and standard entropy (ΔS°) were calculated. A fast increase in the equilibrium removal of the cationic dye was obtained at a pH ranging between 3 and 11 and moderate temperature. This rapid MG adsorption proved the efficiency of kaolinite clay in cationic dye removal. Decolorizing yields were 73.3% for AB and 99.8% for AP. Thus, the adsorption capacity of purified clay was clearly higher than of H2SO4 and thermic activated clays. The data more closely resembled a pseudo-second-order model process, and the clay had reasonable Freundlich adsorption capacity. Adsorption process was endothermic and spontaneous chemisorption. SEM analysis showed that the adsorbed MG had remarkably changed the morphology of raw and purified clay surface. The low desorption rates confirmed effectiveness of this type of material for the retention of methyl green molecules. Thus, tested clays have no environmental impact.

APA, Harvard, Vancouver, ISO, and other styles

34

Wang, Ying, Hui He, Nan Zhang, Kazuya Shimizu, Zhongfang Lei, and Zhenya Zhang. "Efficient capture of phosphate from aqueous solution using acid activated akadama clay and mechanisms analysis." Water Science and Technology 78, no. 7 (October 15, 2018): 1603–14. http://dx.doi.org/10.2166/wst.2018.441.

Full text

Abstract:

Abstract In this study, akadama clay, a kind of volcano ash, was activated with sulfuric acid and then evaluated for the adsorption of phosphate from aqueous solution via batch experiments. The effects of adsorbent dose, initial pH and coexisting anions on phosphate removal by natural akadama clay and acid-activated akadama clay were investigated. Based on the pH effect, the modified adsorbent could efficiently capture phosphate over a wider pH range of 3.00–6.00 than natural akadama clay. Competitive anions showed negative effects on the phosphate adsorption, especially citrate and carbonate. The adsorption process followed the pseudo-second-order kinetic equation and the intra-particle diffusion. Langmuir isotherm model was found to fit the data better than Freundlich model, and the maximum adsorption capacities of phosphate onto the natural akadama clay and acid-activated akadama clay were 5.88 and 9.19 mg/g, respectively. Furthermore, thermodynamic studies confirmed that the adsorption of acid-activated akadama clay was a spontaneous process. The mechanisms of phosphate adsorption on the clay could be ascribed to electrostatic attraction and ligand exchange. These results suggest that after modification, acid-activated akadama clay could be used as a promising adsorbent for phosphate removal from wastewater in real application and then further used as fertilizers.

APA, Harvard, Vancouver, ISO, and other styles

35

Giri, Balendu Shekher, Mandavi Goswami, Prabhat Kumar, Rahul Yadav, Neha Sharma, Ravi Kumar Sonwani, Sudeep Yadav, et al. "Adsorption of Patent Blue V from Textile Industry Wastewater Using Sterculia alata Fruit Shell Biochar: Evaluation of Efficiency and Mechanisms." Water 12, no. 7 (July 16, 2020): 2017. http://dx.doi.org/10.3390/w12072017.

Full text

Abstract:

Biochar prepared from Sterculia alata fruit shell showed a better performance for dye removal than the biomass from Sterculia alata fruit shell. The important process parameters—namely the pH, the amount of biochar, the initial dye concentration and the contact time—were optimized in order to maximize dye removal using biochar of Sterculia alata fruit shell as the bio-sorbent. The results from this study showed that the maximum adsorption of dye on the biochar was obtained at a biochar dosage of 40 g/L, at a contact time of 5 h, and an initial dye concentration of 500 mg/L (pH 2.0; temperature 30 ± 5 °C). The increase in the rate adsorption with temperature and the scanning electron microscopic (SEM) images indicated the possibility of multilayer type adsorption which was confirmed by better fit of the Freundlich adsorption isotherm with the experimental data as compared to the Langmuir isotherm. The values n and R2 in the Freundlich isotherm were found to be 4.55 and 0.97, respectively. The maximum adsorption capacity was found to be 11.36 mg/g. The value of n > 1 indicated physical nature of the adsorption process. The first and second order kinetics were tested, and it was observed that the adsorption process followed the first-order kinetics (R2 = 0.911).

APA, Harvard, Vancouver, ISO, and other styles

36

Edet, Uduakobong A., and Augustine O. Ifelebuegu. "Kinetics, Isotherms, and Thermodynamic Modeling of the Adsorption of Phosphates from Model Wastewater Using Recycled Brick Waste." Processes 8, no. 6 (June 3, 2020): 665. http://dx.doi.org/10.3390/pr8060665.

Full text

Abstract:

Phosphates in wastewater at elevated concentrations cause eutrophication of water bodies and their removal from treated wastewater is essential before effluents are discharged to the environment. Phosphates are predominately removed during wastewater treatment by chemical precipitation which is usually expensive and has a significant environmental footprint. The purpose of this study was to investigate the effectiveness of waste recycled bricks as adsorbent for phosphate removal during wastewater treatment. The kinetics, isotherms, and thermodynamics of adsorption were investigated to establish the mechanisms of adsorption. The results showed that adsorption capacities increased with an increase in contact time, adsorbent dosage, and initial phosphate concentration. The kinetic study indicated that adsorption was governed by several mechanisms with various processes dominating different stages of the adsorption. The adsorption process was better represented by the pseudo-second-order kinetics and the Langmuir isotherm adequately described the adsorption of phosphates onto brick particles with a maximum adsorption capacity of 5.35 mg/g. The thermodynamic studies showed that the adsorption process was exothermic and proceeded spontaneously, demonstrating that waste bricks can be used as a sustainable alternative for the effective removal of phosphates from wastewater.

APA, Harvard, Vancouver, ISO, and other styles

37

Wei, Jia, Yitao Liu, Jun Li, Hui Yu, and Yongzhen Peng. "Removal of organic contaminant by municipal sewage sludge-derived hydrochar: kinetics, thermodynamics and mechanisms." Water Science and Technology 78, no. 4 (August 23, 2018): 947–56. http://dx.doi.org/10.2166/wst.2018.373.

Full text

Abstract:

Abstract In this work, a microporous municipal sewage sludge-derived hydrochar (MSSH) with relatively high surface area and abundant surface organic functional groups was produced through hydrothermal carbonization. Based on the adsorption results over a wide range of conditions, the prepared MSSH was suggested as a promising adsorbent for CV because of its high and efficient adsorption capability. The experimental data were fitted to several kinetic models. Based on calculated respective parameters such as rate constants, equilibrium adsorption capacities and correlation coefficients, the pseudo second-order model proved the best in describing the adsorption behavior of MSSH. Through kinetics, thermodynamic modeling studies and material characterization, a plausible adsorption process was discussed under the conditions used in this study. It can be confirmed that the adsorption of CV onto MSSH is via both physical interactions (electrostatic interaction and Van der Waals' force) and chemical interactions (formation of H-bonding).

APA, Harvard, Vancouver, ISO, and other styles

38

Refino, Andam Deatama, Mohammad Kemal Agusta, Hermawan Kresno Dipojono, and Nugraha. "First Principle Study of Hydrazine and OH^- Co-Adsorption on Ni(111) in High Coverage System." Advanced Materials Research 893 (February 2014): 35–38. http://dx.doi.org/10.4028/www.scientific.net/amr.893.35.

Full text

Abstract:

Theoretical investigation of co-adsorption process between hydrazine (N2H4) and OH- on Ni(111) is performed using density functional theory. OH- adsorption mechanisms at various adsorption sites as well as its interaction with hydrazine in various conformations (anti, cis, and gauche) are studied. The stability of OH- adsorption on nickel surface is significantly influenced by the presence of hydrazine molecule. Among the three conformations of hydrazine, OH- adsorption on nickel surface doesn't occur in cis conformation. Otherwise, co-adsorption occurs in system with gauche and anti conformation. In anti system, hydrazine conformation is transformed during relaxation process and forms gauche conformation as the most stable configuration of the system.

APA, Harvard, Vancouver, ISO, and other styles

39

Long, Jianyou, Xiaona Huang, Xiaoli Fan, Yan Peng, and Jianrong Xia. "Effective adsorption of nickel (II) with Ulva lactuca dried biomass: isotherms, kinetics and mechanisms." Water Science and Technology 78, no. 1 (June 14, 2018): 156–64. http://dx.doi.org/10.2166/wst.2018.253.

Full text

Abstract:

Abstract This study aimed to evaluate the Ni2+ ions adsorption capability of Ulva lactuca. The isotherms, kinetics and mechanisms for the adsorption of Ni2+ from aqueous solution by Ulva lactuca were also investigated. Influencing factors including initial pH, initial Ni2+ concentration, biomass, contact time were examined. The results indicate that the maximum Ni2+ adsorption capacity of 38.28 mg/g was obtained at pH 5, initial Ni2+ concentration 250 mg/L, biomass dosage 0.5 g/L and contact time 30 min. The adsorption can be well fitted with Langmuir isotherm, and the kinetics were well described by the pseudo-second-order model. The parameters of thermodynamics verified that Ni2+ adsorption on Ulva lactuca was a spontaneous and endothermic process. Analyses of FT-IR, SEM-EDS and XPS indicate that carboxyl and hydroxyl groups on the surface of biomass are involved in Ni2+ adsorption. The dried biomass of Ulva lactuca can be a cost-effective and eco-friendly adsorbent for the removal of Ni2+ from wastewater.

APA, Harvard, Vancouver, ISO, and other styles

40

BIZI, Mohamed. "Sulfamethoxazole Removal from Drinking Water by Activated Carbon: Kinetics and Diffusion Process." Molecules 25, no. 20 (October 13, 2020): 4656. http://dx.doi.org/10.3390/molecules25204656.

Full text

Abstract:

Sulfamethoxazole (SMX), a pharmaceutical residue, which is persistent and mobile in soils, shows low biodegradability, and is frequently found in the different aquatic compartments, can be found at very low concentrations in water intended for human consumption. In conditions compatible with industrial practices, the kinetic reactivity and performance of tap water purification using activated carbon powder (ACP) are examined here using two extreme mass ratios of SMX to ACP: 2 µg/L and 2 mg/L of SMX for only 10 mg/L of ACP. In response to surface chemistry, ACP texture and the intrinsic properties of SMX in water at a pH of 8.1, four kinetic models, and two monosolute equilibrium models showed a total purification of the 2 µg/L of SMX, the presence of energetic heterogeneity of surface adsorption of ACP, rapid kinetics compatible with the residence times of industrial water treatment processes, and kinetics affected by intraparticle diffusion. The adsorption mechanisms proposed are physical mechanisms based mainly on π–π dispersion interactions and electrostatic interactions by SMX−/Divalent cation/ArO− and SMX−/Divalent cation/ArCOO− bridging. Adsorption in tap water, also an innovative element of this study, shows that ACP is very efficient for the purification of very slightly polluted water.

APA, Harvard, Vancouver, ISO, and other styles

41

Ma, Jinzhen, Liyuan Hou, Ping Li, Shumin Zhang, and Xiangyu Zheng. "Modified fruit pericarp as an effective biosorbent for removing azo dye from aqueous solution: study of adsorption properties and mechanisms." Environmental Engineering Research 27, no. 2 (February 19, 2021): 200634–0. http://dx.doi.org/10.4491/eer.2020.634.

Full text

Abstract:

To explore cheap, easily available and high adsorption performance bioadsorbent is still an important task for azo dye pollution control. In this study, the Methyl orange (MO) adsorption capacity by a novel bioadsorbent obtained from lychee and longan pericarps via simple modification was investigated. Prepared pericarps were modified by PEI at 30˚C and 65˚C, which improved the adsorption performance confirmed by batch adsorption experiments. The characteration of modified pericarps by X-ray diffraction, scanning electron microscopy and zeta potential indicated that the enhanced adsorption performance may be due to the abundant amines and imines and stronger electropositivity. The maximum adsorption capacity (349.37 mg/g) was observed for LC@PEI-65 at 45˚C and pH 4. Freundlich isotherm model fitted pretty well with the isotherm experiment data, and the isotherm experimental data were preferably described by pseudo-second order model indicating the chemical adsorption process, and the intra-particle diffusion also involved in the adsorption process. Characterization and adsorption tests suggested electrostatic interaction played a key role in MO removal, accompanied by intermolecular hydrogen bond, π-π dispersion interaction and pore filling collectively. The present study show that the cost-effective PEI modified pericarps could possess a hopeful application for azo dye removal from wastewater.

APA, Harvard, Vancouver, ISO, and other styles

42

Karimi, Samira, Mohammad Tavakkoli Yaraki, and Rama Rao Karri. "A comprehensive review of the adsorption mechanisms and factors influencing the adsorption process from the perspective of bioethanol dehydration." Renewable and Sustainable Energy Reviews 107 (June 2019): 535–53. http://dx.doi.org/10.1016/j.rser.2019.03.025.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Chen, Lingyun, Zhigang Li, and Qian Liu. "Treatments of produced water in oilfield: A comprehensive review." E3S Web of Conferences 300 (2021): 02011. http://dx.doi.org/10.1051/e3sconf/202130002011.

Full text

Abstract:

Substantial produced water in oilfield need to be treated. Treatment mechanism such as adsorption, flotation, filtration, desalination, etc. are described. Based on the mechanisms, process and technology, tools and facility for produced water treatment are compared. Technology selection method and requirements are discussed. Multiple processes combination is discussed and considered as promising.

APA, Harvard, Vancouver, ISO, and other styles

44

Rajan, M., and G. Alagumuthu. "Study of Fluoride Affinity by Zirconium Impregnated Walnut Shell Carbon in Aqueous Phase: Kinetic and Isotherm Evaluation." Journal of Chemistry 2013 (2013): 1–8. http://dx.doi.org/10.1155/2013/235048.

Full text

Abstract:

This paper examines the kinetics of fluoride removal from water by the adsorbent zirconium-impregnated walnut-shell carbon (ZIWSC), exploring the mechanisms involved. The dependence of the adsorption of fluoride on the pH of the solution has been studied to achieve the optimum pH value and a better understanding of the adsorption mechanism. The presence of bicarbonate ions in aqueous solution was found to affect the fluoride removal indicating that these anions compete with the sorption of fluoride on adsorbents. The kinetic profile has been modeled using pseudo-first-order model, pseudo-second-order model, and intraparticle diffusion model. The kinetic sorption profiles offered excellent fit with pseudo-second-order model. Adsorption isotherms have been modeled by Langmuir, Freundlich, and Temkin equations, and their constants were determined. The equilibrium adsorption data were fitted reasonably well for Freundlich isotherm model. XRD and SEM patterns of the ZIWSC were recorded to get better insight into the mechanism of adsorption process.

APA, Harvard, Vancouver, ISO, and other styles

45

NELSON, MARK I., RUBAYYI T. ALQAHTANI, and FAISAL I. HAI. "MATHEMATICAL MODELLING OF THE REMOVAL OF ORGANIC MICROPOLLUTANTS IN THE ACTIVATED SLUDGE PROCESS: A LINEAR BIODEGRADATION MODEL." ANZIAM Journal 60, no. 2 (October 2018): 191–229. http://dx.doi.org/10.1017/s1446181118000226.

Full text

Abstract:

Before wastewaters can be released into the environment, they must be treated to reduce the concentration of organic pollutants in the effluent stream. There is a growing concern as to whether wastewater treatment plants are able to effectively reduce the concentration of micropollutants that are also contained in their influent streams. We investigate the removal of micropollutants in treatment plants by analysing a model that includes biodegradation and sorption as the main mechanisms of micropollutant removal. For the latter a linear adsorption model is used in which adsorption only occurs onto particulates.The steady-state solutions of the model are found and their stability is determined as a function of the residence time. In the limit of infinite residence time, we show that the removal of biodegradable micropollutants is independent of the processes of adsorption and desorption. The limiting concentration can be decreased by increasing the concentration of growth-related macropollutants. Although, in principle, it is possible that the concentration of micropollutants is minimized at a finite value of the residence time, this was found not to be the case for the particular biodegradable micropollutants considered.For nonbiodegradable pollutants, we show that their removal is always optimized at a finite value of the residence time. For finite values of the residence time, we obtain a simple condition which identifies whether biodegradation is more or less efficient than adsorption as a removal mechanism. Surprisingly, we find that, for the micropollutants considered, adsorption is always more important than biodegradation, even when the micropollutant is classified as being highly biodegradable with low adsorption.

APA, Harvard, Vancouver, ISO, and other styles

46

Wang, Tao, Kun Ge, Kexian Chen, Chenglong Hou, and Mengxiang Fang. "Theoretical studies on CO2 capture behavior of quaternary ammonium-based polymeric ionic liquids." Physical Chemistry Chemical Physics 18, no. 18 (2016): 13084–91. http://dx.doi.org/10.1039/c5cp07229h.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Ugbe, Fabian Audu, Patrick Onuh Anebi, and Victoria Abiola Ikudayisi. "Biosorption of an Anionic Dye, Eosin Yellow onto Pineapple Peels: Isotherm and Thermodynamic Study." International Annals of Science 4, no. 1 (February 4, 2018): 14–19. http://dx.doi.org/10.21467/ias.4.1.14-19.

Full text

Abstract:

Eosin Yellow (EY), an anionic dye (acid dye) was adsorbed using an agricultural waste, pineapple peels (PP) as bio-sorbent in order to investigate its suitability as an alternative adsorbent, and to give insight into the mechanisms of binding. The study includes: equilibrium isotherms and thermodynamics studies. The adsorption isotherm and thermodynamics experiments were conducted using batch equilibrium techniques. The adsorption data were fitted into Langmuir, Freundlich and Temkin isotherm models; as a result, the data fitted well into the Langmuir model from which the adsorption capacity, qe was obtained as 11.76 mg/g. Experimental values of the thermodynamics parameters (ΔH, ΔS and ΔG) and separation factor (RL) in combination suggested that the adsorption process was endothermic, feasible, spontaneous, and had high degree of freedom. Combined results of the isotherms and thermodynamic study suggested a physisorption-chemisorption mechanism for the adsorption process. Therefore, the results of the study could provide useful information to evaluate the raw pineapple peel powder as a cheap source of adsorbent for the removal of EY from waste water.

APA, Harvard, Vancouver, ISO, and other styles

48

Xu, Hao, Kang Xiao, Jinlan Yu, Bin Huang, Xiaomao Wang, Shuai Liang, Chunhai Wei, Xianghua Wen, and Xia Huang. "A Simple Method to Identify the Dominant Fouling Mechanisms during Membrane Filtration Based on Piecewise Multiple Linear Regression." Membranes 10, no. 8 (July 29, 2020): 171. http://dx.doi.org/10.3390/membranes10080171.

Full text

Abstract:

Membrane fouling is a complicated issue in microfiltration and ultrafiltration. Clearly identifying the dominant fouling mechanisms during the filtration process is of great significance for the phased and targeted control of fouling. To this end, we propose a semi-empirical multiple linear regression model to describe flux decline, incorporating the five fouling mechanisms (the first and second kinds of standard blocking, complete blocking, intermediate blocking, and cake filtration) based on the additivity of the permeate volume contributed by different coexisting mechanisms. A piecewise fitting protocol was established to distinguish the fouling stages and find the significant mechanisms in each stage. This approach was applied to a case study of a microfiltration membrane filtering a model foulant solution composed of polysaccharide, protein, and humic substances, and the model fitting unequivocally revealed that the dominant fouling mechanism evolved in the sequence of initial adaptation, fast adsorption followed by slow adsorption inside the membrane pores, and the gradual growth of a cake/gel layer on the membrane surface. The results were in good agreement with the permeate properties (total organic carbon, ultraviolet absorbance, and fluorescence) during the filtration process. This modeling approach proves to be simple and reliable for identifying the main fouling mechanisms during membrane filtration with statistical confidence.

APA, Harvard, Vancouver, ISO, and other styles

49

Yang, Gordon C. C., Pei-Ling Tang, and Chia-Heng Yen. "Removal of micropollutants from municipal wastewater by graphene adsorption and simultaneous electrocoagulation/electrofiltration process." Water Science and Technology 75, no. 8 (February 7, 2017): 1882–88. http://dx.doi.org/10.2166/wst.2017.074.

Full text

Abstract:

In this work the optimal operating conditions for removing selected micropollutants (also known as emerging contaminants, ECs) from actual municipal wastewater by graphene adsorption (GA) and simultaneous electrocoagulation/electrofiltration (EC/EF) process, respectively, were first determined and evaluated. Then, performance and mechanisms for the removal of selected phthalates and pharmaceuticals from municipal wastewater simultaneously by the GA and EC/EF process were further assessed. ECs of concern included di-n-butyl phthalate (DnBP), di-(2-ethylhexyl) phthalate (DEHP), acetaminophen (ACE), caffeine (CAF), cefalexin (CLX) and sulfamethoxazole (SMX). It was found that GA plus EC/EF process yielded the following removal efficiencies: DnBP, 89 ± 2%; DEHP, 85 ± 3%; ACE, 99 ± 2%; CAF, 94 ± 3%; CLX, 100 ± 0%; and SMX, 98 ± 2%. Carbon adsorption, size exclusion, electrostatic repulsion, electrocoagulation, and electrofiltration were considered as the main mechanisms for the removal of target ECs by the integrated process indicated above.

APA, Harvard, Vancouver, ISO, and other styles

50

Pham Thanh, Minh, and Thuan Le Van. "Investigation of sorption mechanism of methylene blue, congo red and tannic acid from aqueous solutions onto magnetic composite sorbent obtained from alkaline pretreated spent coffee grounds." BIO Web of Conferences 30 (2021): 02008. http://dx.doi.org/10.1051/bioconf/20213002008.

Full text

Abstract:

In this article, a novel magnetic composite material obtained from alkaline pretreated spent coffee grounds was used for investigating of the sorption mechanism of methylene blue, congo red and tannic acid from aqueous solutions. In order to clarify mechanisms were analyzed the adsorption kinetics models (external and internal diffusion; chemical kinetics (pseudo-first order, pseudo-second order); intraparticle diffusion) and the adsorption thermodynamics. The results showed that the sorption of all studied sorbates was controlled by a mixed diffusion model and a pseudo-second order and diffusion rate revealed three stage of the mass transfer. The adsorption process of methylene blue, congo red and tannic acid onto Fe3O4/PVA/APSCGs sorbent was spontaneous and endothermic. Based on the results, it was concluded that the mechanism for removal of the studied sorbates by adsorption onto Fe3O4/PVA/APSCGs sorbent may be assumed both physisorption and chemisorption.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Process adsorption mechanisms'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles