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Journal articles on the topic 'Freundlich Isotherm'

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Published: 4 June 2021
Last updated: 31 January 2023

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1

Lan, Hui Xia, Xiao Feng Liu, Rui Chen, and Heng Zhang. "The Adsorption of Pentachlorophenol (PCP) on Aerobic Granules." Advanced Materials Research 599 (November 2012): 354–57. http://dx.doi.org/10.4028/www.scientific.net/amr.599.354.

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the adsorption of PCP using aerobic granules was studied. The static adsorption experiments were carried out and the Freundlich and Langmuir adsorption isotherms were applied to describe the biosorption processes and the isotherm constants were evaluated. The Freundlich and Langmuir isothermy adsorption equations obtained from the static experients were q=2.04ce0.82 and q=3.47ce /(1+0.56 ce), respectively. Both the adsorption isotherms described the static adsorption behavior of PCP well. Then the Freundlich adsorption isotherm was used to estimate the adsorption of PCP by aerobic granules in the dynamic state. The results showed that the adsorption mainly occurred in the initial periods during the operation of the reactor.
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2

Gong, Zheng Jun, Wenbo Zhou, and Zhong Ping Qiu. "The Study of Copper (II) Removal from Aqueous Solutions by Adsorption Using Corn Stalk Material." Advanced Materials Research 610-613 (December 2012): 1950–53. http://dx.doi.org/10.4028/www.scientific.net/amr.610-613.1950.

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In this study, removal of copper(Ⅱ) from aqueous solutions was examined using corn stalk. In the batch mode adsorption studies, the effects of initial pH and contact time on the copper(Ⅱ) adsorption by the corn stalk have been studied. The results show that: the pH 6.0 and contact time 8 hrs is optimum conditions of this absorption process when the dosage of corn stalk is 0.1g. In the isotherm studies, the Langmuir and Freundlich isotherm models were applied. The R2 of the Langmuir and Freundlich isotherm are 0.981 and 0.944 respectively. The Langmuir adsorption capacity Qmax is 54.05 mg/g. The goodness of fitness was obtained with the Langmuir and Freundlich adsorption isotherms.
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3

Hastuti, Budi, Mudasir Mudasir, Dwi Siswanta, and Triyono Triyono. "Preparation and Pb(II) Adsorption Properties of Crosslinked Pectin-Carboxymethyl Chitosan Film." Indonesian Journal of Chemistry 15, no. 3 (November 12, 2015): 248–55. http://dx.doi.org/10.22146/ijc.21192.

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A modified pectin has been synthesized by reacting/combining -OH group among pectin and chitosan with BADGE (Bisphenol A diglycidyl ether) crosslinker agent. The structure and morphology of the new material were characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and X-ray Diffraction (XRD) analysis. Thermogravimetric studies showed an improvement in thermal characteristic. Adsorption experiments were performed in batch processes; sorption isotherms and kinetics were also studied. The Langmuir and Freundlich adsorption isotherm models were applied to describe the isotherms and isotherm constants for the adsorption of Pb(II) ion onto adsorbent pectin-carboxymethyl chitosan-BADGE (pec-CMC-BADGE). The dynamic study showed that the sorption process followed the second-order kinetic equation. Result indicated also that Pb(II) ion uptake could be well described by the Langmuir and Freundlich adsorption model of pec-CMC-BADGE and CMC with DG° of 25.3 and 23.1 kJ mol-1,respectively, while that of pectin followed Freundlich isotherm with DG° of 16.6 kJ mol-1.
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4

Olafadehan, Olaosebikan A., and Alfred A. Susu. "Numerical Solution of Binary Liquid-Phase Adsorption onto Porocel Clay Using Linear, Freundlich and Langmuir Isotherms." Adsorption Science & Technology 23, no. 3 (April 2005): 195–213. http://dx.doi.org/10.1260/0263617054353627.

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A generalized mathematical model is presented to describe the process of multi-component adsorption onto porous media in fixed beds. The model was applied to the binary adsorption, without reaction, of aromatics and sulphur compounds onto a fixed bed of Porocel clay for kerosene deodorization using linear, Freundlich and Langmuir isotherms independently. A computational scheme for the solution of the model equations is presented. The scheme is based on orthogonal collocation for spatial discretization of the resulting set of coupled hyperbolic and parabolic partial differential equations for the macro-and micro-system, respectively. Michelsen's modified third-order semi-implicit Runge-Kutta method combined with step-size adjustment strategy was used to integrate the resulting 4N ordinary differential equations. Excellent agreement between the simulated results and pilot plant data was obtained for the breakthrough profiles for the non-linear adsorption isotherms of Freundlich and Langmuir. No agreement was obtained for the linear isotherm. Also, using the Freundlich and Langmuir isotherms, the exit concentration of the less preferentially adsorbed component (aromatics) exceeded its inlet concentration to the adsorption column for a certain period. This is indicative of the behaviour of competitive multi-component adsorption: relative to aromatics, sulphur compounds are selectively adsorbed onto Porocel clay. The relationship between solid- and liquid-phase concentration profiles for the Freundlich isotherm revealed the formation of multiple adsorption layers upon the primary mono-molecular layer. Again, for the Freundlich isotherm, the structure of the profiles exhibited a highly pronounced maximum for sulphur. An experimental breakthrough time of 8 h was also predicted for both aromatics and sulphur compounds using the non-linear Freundlich and Langmuir isotherms.
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5

Tewari, Hemlata, and Vivekanand. "Removal of heavy metals from industrial effluent using Pinus roxburghii leaves as biosorbent: equilibrium modelling." Water Science and Technology 67, no. 9 (May 1, 2013): 1894–900. http://dx.doi.org/10.2166/wst.2013.034.

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In the present study, biosorption capability of pine (Pinus roxburghii) leaves for the removal Cr6+, Cu2+, Fe2+ and Zn2+ ions, present in brass and electroplating industry effluent, were investigated with respect to different adsorbent doses, contact time and pH. Heavy metals concentrations were estimated by atomic absorption spectrophotometry. Initial concentration of Cr6+, Cu2+, Fe2+ and Zn2+ ions in the effluent were found to be 2.741, 4.551, 8.820 and 5.529 mg/L respectively. Biosorption studies revealed that Cr6+, Cu2+, Fe2+ and Zn2+ showed maximum removal of 99.85, 94.54, 97.10 and 89% at pH 4, 4, 4 and 8, respectively, with 4 g pine leaves when shaken at 150 rpm for 60 min. The applicability of the three equilibrium isotherm models was investigated and the data obtained fitted the three investigated isothermal models in the order: Langmuir > Temkin > Freundlich for all the studied metal ions. The adsorption isotherm coefficients, Qmax, b, Kf, n, at, bt were also calculated. Very high regression correlation coefficients (R2 > 0.9) were found for Cu2+, Fe2+ and Zn2+; Cr6+ (Temkin isotherm) when pH (2–8) was varied; Cr6+, Cu2+,Fe2+ and Zn2+ when contact time (15–60 min) was varied; Cu2+ (Langmuir isotherm) Fe2+ (Freundlich and Temkin isotherms) when adsorbent was varied from 2 to 5 g. Results also revealed that among all the studied ions Cr6+ at varied pH and Fe2+ at different adsorbent doses satisfy the Temkin and Freundlich isotherm models to describe the biosorption equilibrium by pine (Pinus roxburghii) adsorbent.
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6

Buaphean, Tanaree, Thamonwan Ketwongsa, and Kowit Piyamongkala. "Coagulation of Chitosan Solution in Commercial Detergent as Adsorbent for Sorption Methylene Blue Dye." Solid State Phenomena 266 (October 2017): 122–27. http://dx.doi.org/10.4028/www.scientific.net/ssp.266.122.

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The chitosan resin forming with commercial detergent solution was used as adsorbent for removal of the methylene blue. The effect of the amount of adsorbent was thoroughly investigated through batch adsorption system. The percent adsorption of methylene blue increased in the same direction as the amount of chitosan resin. The experimental result showed that adsorption capacity onto 0.4 g of chitosan resin was 9.1 mg/g. The Langmuir and the Freundlich adsorption isotherms were applied to describe the methylene blue uptake, which could be explained by Freundlich adsorption isotherm onto chitosan resin. Single-state batch adsorption design of methylene blue onto chitosan resin has been studied, using on the Freundlich isotherm equation.
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7

Hussain, Zainab, Zeyad Fadhil, Sameer Kareem, Salam Mohammed, and Emad Yousif. "Removal of Organic Contaminants from Textile Wastewater by Adsorption on Natural Biosorbent." Materials Science Forum 1002 (July 2020): 489–97. http://dx.doi.org/10.4028/www.scientific.net/msf.1002.489.

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In the present study, removal of safranin dye from water bodies was investigated using natural biosorbent (Thyme leaves (TEL)). The influence of multiple factors such as as contact time (15 – 105 mins), adsorbent dose (25 to 350) mg/l , adsorbate dose (5 to 40)mg\L, and temperature (25 to 55)o C were taken for investigation. The adsorption isotherms were described by utilized Langmuir, Freundlich and Dubnin-Radushkevich models, Freundlich isotherm model found to be best suited with experimental data out of 3 isotherm The adsorption process followed pseudo second order model.
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8

Dada, A. O., J. O. Ojediran, and Abiodun Paul Olalekan. "Sorption of Pb2+ from Aqueous Solution unto Modified Rice Husk: Isotherms Studies." Advances in Physical Chemistry 2013 (March 18, 2013): 1–6. http://dx.doi.org/10.1155/2013/842425.

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Investigation of the sorption potential of rice husk, an agricultural waste, as an adsorbent was carried out. The rice husk was modified with orthophosphoric acid and was used for adsorption of lead (II) ions (Pb2+) from aqueous solution. Physicochemical properties of the modified rice husk were determined. Equilibrium sorption data were confirmed with Langmuir, Freundlich and Temkin adsorption isotherms. On the basis of adsorption isotherm graphs, R2 values were determined to be 0.995, 0.916, and 0.797 for Langmuir, Temkin, and Freundlich isotherms, respectively, indicating that the data fitted well into the adsorption isotherms, but Langmuir isotherm is a better model. The maximum monolayer coverage from Langmuir studies, Qmax=138.89 mg/g, Langmuir isotherm constant, KL=0.699 L/mg, and the separation factor, RL=1.41×10−2 at 100 mg/L of lead(II) ions indicating that the sorption process, was favourable. The suitability of modified rice husk as an adsorbent for the removal of lead ions from aqueous solution and its potential for pollution control is established.
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9

Liu, Ming Da, Ge Tian, Liang Jie Zhao, Yao Sheng Wang, Lei Guo, and Yao Jing Wang. "Removal of Pb (II) from Aqueous Solution by Blast-Furnace Slags." Advanced Materials Research 726-731 (August 2013): 2736–41. http://dx.doi.org/10.4028/www.scientific.net/amr.726-731.2736.

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Five blast-furnace slags were used as adsorbents to remove Pb (II) from aqueous solution. Kinetic studies showed that the sorption process was best described by pseudo-second-order model. Among Langmuir, Freundlich and Temkin isotherms, the Freundlich isotherm had a better fit with the simulation of the adsorption of Pb (II).
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10

Ding, Wei, Shuqin Bai, Haorong Mu, and Gaowa Naren. "Investigation of phosphate removal from aqueous solution by both coal gangues." Water Science and Technology 76, no. 4 (April 25, 2017): 785–92. http://dx.doi.org/10.2166/wst.2017.241.

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Equilibrium studies were carried out for the adsorption of phosphate onto newly discharged coal gangue and spontaneous combustion coal gangue, which are industrial solid residues. The experimental data were fitted to the two-parameter equations of Freundlich, Langmuir, Temkin, and Dubinin-Radushkevich and the three-parameter equations of the Redlich-Peterson, Sips and Toth isotherms by non-linear method. All three-parameter isotherm equations have a higher correlation coefficient than the two-parameter isotherm equations. For new discharged coal gangue, the maximum phosphate adsorption capacity is over 2.504 mg/g (as P), and the best two-parameter isotherm is Freundlich, which indicated multilayer adsorption takes place on the surface. For spontaneous combustion coal gangue, the maximum phosphate adsorption capacity is 7.079 mg/g (as P), two times larger than new discharged coal gangue, and the best two-parameter isotherm is Langmuir, suggesting that the adsorption process occurs on a homogenous surface by monolayer adsorption. The three-parameter isotherm model of Redlich-Peterson shows the best fitting in both cases, but parameter g is 0.6138 in new discharged coal gangue (the parameter g is nearly 1, which means that the equilibrium isotherm behaves as the Langmuir, not as the Freundlich isotherm), g approaches to unity in spontaneous combustion coal gangue, suggesting that the two kinds of coal gangues have different adsorption properties.
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11

Jibin, Shi, and Liu Guojie. "The Derivation of Freundlich Adsorption Isotherm." University Chemistry 30, no. 3 (2015): 76–79. http://dx.doi.org/10.3866/pku.dxhx2010376.

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12

Zhao, Ling-Xi, Shu-E. Song, Na Du, and Wan-Guo Hou. "A sorbent concentration-dependent Freundlich isotherm." Colloid and Polymer Science 291, no. 3 (August 2, 2012): 541–50. http://dx.doi.org/10.1007/s00396-012-2742-7.

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13

Mwevura, Haji, Peter Nkedi-Kizza, Michael Kishimba, and Henrik Kylin. "Adsorption-desorption of chlorpyrifos in soils and sediments from the Rufiji Delta, Tanzania." Western Indian Ocean Journal of Marine Science 19, no. 1 (October 29, 2020): 77–97. http://dx.doi.org/10.4314/wiojms.v19i1.7.

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Batch adsorption-desorption equilibrium techniques were used to investigate the adsorption capacity and influence of salinity on partitioning of the insecticide chlorpyrifos between water and soil or water and sediments from the Rufiji Delta. The data were fitted to different adsorption-desorption models and the hysteresis index was calculated using the ratio between the Freundlich exponents for desorption and adsorption, and secondly, the difference in area under the normalized adsorption and desorption isotherms using the maximum adsorbed and solution concentrations. The data showed non-linear adsorption and that chlorpyrifos was strongly adsorbed to soil and sediments from the Rufiji Delta. The linearized adsorption coefficient (KD) and Freundlich adsorption coefficient (Kf) correlated significantly with organic carbon content. Chlorpyrifos adsorption as well as hysteresis calculated by both methods decreased with salinity (i.e. the sediment adsorbs increasing amounts of chlorpyrifos with decreasing salinity). This indicates that settling of freshwater sediments is among the major removal pathways of the chemical from the water column, but increased turbulence during high tides may resuspend settled sediment simultaneously increasing salinity and re-dissolve chlorpyrifos. However, discharge of fresh water, particularly during heavy rains, increases the trapping efficiency of the sediments. The theoretical approach developed showed that the Langmuir model describes the desorption data better than the Freundlich model, and that a better index of hysteresis is one that considers areas under the adsorption and desorption isotherms, provided the desorption isotherm is described by the normalized Langmuir isotherm and the adsorption isotherm by the normalized Freundlich isotherm.
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14

Abunowara, Mustafa, Usama Eldemerdash, Mariyamni Awang, and Hassan Mady. "Evaluation of Carbon Dioxide Adsorption on Malaysian Coals for Potential Sequestration." Applied Mechanics and Materials 625 (September 2014): 184–87. http://dx.doi.org/10.4028/www.scientific.net/amm.625.184.

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Adsorption experiments of carbon dioxide (CO2) were contacted on two coal samples from Sungai Buloh and Silantek mines in Malaysia. A fixed bed adsorption unit was used to determine CO2 adsorption capacity of the coal samples. The experiments were conducted at different pressure ranges (5-40 bar) and temperature at 25°C. The CO2 adsorption capacity of Silantek coal sample showed adsorption capacity of 4.178 mmol/g at 40 bars and 25 °C, which is higher than Sungai Buloh sample. Different adsorption isotherms were employed to examine the experimental results, Langmuir isotherm of Silantek coal sample illustrated better correlation than Freundlich isotherm for the same sample. In contrary, Freundlich isotherm of Sungai Buloh coal sample illustrated better fitting than Longmuir isotherm correlation for the same sample. This is related to the coal rank and moisture content and ash content.
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15

Syauqiah, I., D. Nurandini, N. P. Prihatini, and Jamiyaturrasidah. "Determination of rice husk activated Carbon capacity in adsorption of Cu Metal from Sasirangan liquid waste based on isotherm model." IOP Conference Series: Materials Science and Engineering 1212, no. 1 (January 1, 2022): 012019. http://dx.doi.org/10.1088/1757-899x/1212/1/012019.

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Abstract The process of manufacturing Sasirangan - a traditional fabric of South Kalimantan - has an impact that affects environmental pollution, namely the dyeing process of the fabric. The synthetic dyes used contain heavy metals and one of those toxic metals is copper (Cu). This study aims to determine the adsorption capacity of rice husk activated carbon adsorbent by adjusting the adsorption pattern based on isotherm models as the treatment to sasirangan liquid waste. The method consists of three stages: preparation of adsorbent by carbonization process, chemical and physical activation, then continued by adsorption process of Cu metal with carbon from rice husks with variations of adsorbent dose (2, 4, and 6 grams). This treatment was conducted by batch process. In this reseach, the adsorption capacity of rice husk adsorbent towards heavy metal Cu in sasirangan liquid waste was determined from the equilibrium state with the Langmuir isotherm equation and Freundlich isotherm equation. Based on isothermal studies of adsorption data, the correlation coefficient values obtained from the isotherm model approaches are: for dose of 2 grams adsorbent, Langmuir R2 = 0.9991 and Freundlich R2 = 0.9981; for dose of 4 grams adsorbent, Langmuir R2 = 0.9992 and Freundlich R2 = 0.9989; for dose of 6 grams adsorbent, Langmuir R2 = 0.9990 and Freundlich R2 = 0.9986. The results of investigation indicate that adsorption data correlated well with Langmuir isotherm model.
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16

Önen, V., and E. Yel. "Adsorption of ferrocyanide onto raw and acid-activated clinoptilolite and sepiolite: equilibrium modelling by error minimization." Clay Minerals 48, no. 4 (September 2013): 613–26. http://dx.doi.org/10.1180/claymin.2013.048.4.15.

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AbstractThe experimental data on adsorption of Fe and CN of a ferrocyanide complex onto raw and acid-activated clinoptilolite/sepiolite on the basis of detention time and particle size was modelled by a linear and a non-linear approach. The linearized best-fit isotherm selection method and non-linear error minimization was applied through Freundlich, Langmuir and Temkin isotherms. ERRSQ, MPSD, HYBRID and ARE error functions were minimized by a developed MATLAB script to determine the isotherm parameters in non-linear optimization. The complex was not adsorbed as whole anions but the Fe and CN were adsorbed separately. 0.65 mg Fe/L. min and 4.84 mg CN/L. min initial adsorption rates were achieved with acid activated clinoptilolite. The Fe adsorption was not as successful as CN. The adsorption of Fe and CN was described by Freundlich and Langmuir isotherms respectively. The differences between the predicted isotherm parameter sets of linear models and minimized error function models indicated that both the best-fit isotherm selection and the isotherm constant determinations can be performed properly by error minimization as well as by conventional linear best fit modelling approach.
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17

Zytner, Richard, Nihar Biswas, and Jatinder K. Bewtra. "Adsorption and desorption of perchloroethylene in soils, peat moss, and granular activated carbon." Canadian Journal of Civil Engineering 16, no. 6 (December 1, 1989): 798–806. http://dx.doi.org/10.1139/l89-123.

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Studies were conducted to evaluate the adsorption–desorption isotherms of a common dry cleaning solvent, perchloroethylene (PCE), in soils, peat moss, and granular activated carbon. The results obtained followed the Freundlich Isotherm, and the organic carbon content of the media was the most significant controlling factor in the adsorption–desorption process. The peat moss exhibited the highest residual saturation concentration for pure PCE amongst all the media tested. The desorption studies indicated that PCE had medium mobility in soil and was not significantly affected by moderate changes in pH. Key words: adsorption, desorption, Freundlich Isotherm, granular activated carbon, peat moss, perchloroethylene, soils.
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18

Hsiao, H. C., S. M. Yih, and M. H. Li. "Adsorption Equilibrium of Xylene Isomers and p-Diethylbenzene in the Liquid Phase on a Y Zeolite." Adsorption Science & Technology 6, no. 2 (June 1989): 64–82. http://dx.doi.org/10.1177/026361748900600202.

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The saturated adsorptive capacity, adsorption equilibrium constant and adsorption isotherms of p-xylene, m-xylene, ethylbenzene (EB) and p-diethylbenzene (PDEB) on a K–BaY zeolite with n-heptane as the solvent have been studied at 25°C. The adsorption isotherms of the six binary pairs of these solutes with n-heptane as the solvent have also been determined at 25°C. The data cover a concentration range of xylene isomers from 0.05–0.3 mmol/ml. The molar adsorption capacity of the K–BaY zeolite for the different sorbates was found to be in the order: p-xylene > EB > m-xylene ≈ PDEB. PDEB is normally used as the desorbent for the Parex process. Three types of isotherm model, i.e. Langmuir, Freundlich and Langmuir–Freundlich, have been used to fit the data. The results indicate that the Langmuir–Freundlich isotherm provides a reasonable representation of the equilibrium data for the xylene isomers on a K–BaY zeolite.
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19

Kuipa, Pardon K., and Olga Kuipa. "Removal of Pyrethrin from Aqueous Effluents by Adsorptive Micellar Flocculation." Journal of Chemistry 2015 (2015): 1–6. http://dx.doi.org/10.1155/2015/735631.

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The equilibrium adsorption of pyrethrin onto aggregates formed by the flocculation of micelles of the surfactant sodium dodecyl sulphate (SDS) with aluminium sulphate is reported. The experimental results were analysed using different adsorption isotherms (Langmuir, Freundlich, Redlich-Peterson, Sips, Radke-Prausnitz, Temkin, linear equilibrium, and the Dubin-Radushkevich isotherms). The Freundlich and linear equilibrium isotherms best describe the adsorption of pyrethrin onto SDS micellar flocs, with the Freundlich adsorption constant,KF, and the mass distribution coefficient,KD, of 64.266 ((mg/g)(L/mg)1/n) and 119.65 L/g, respectively. Applicability of the Freundlich adsorption model suggests that heterogeneous surface adsorption affects the adsorption. The mean free energy value estimated using the Dubinin-Radushkevich isotherm was 0.136 kJ/mol indicating that physisorption may be predominant in the adsorption process.
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20

Owabor, C. N., I. O. Oboh, and F. A. Omiojieahior. "Adsorption Isotherms for Naphthalene on Clay and Silt Soil Fractions: A Comparison of Linear and Nonlinear Methods." Advanced Materials Research 367 (October 2011): 359–64. http://dx.doi.org/10.4028/www.scientific.net/amr.367.359.

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Polycyclic aromatic hydrocarbons occur naturally in petroleum oil and coal and the burning of fuel and the activities of paper mills also release these compounds to the environment. Batch experimental adsorption study for both soil fractions was conducted in a soil slurry system at ambient temperature, using <0.02mm particle sizes. Comparison was made of the linear least-squares method and a trial-and-error nonlinear method of some widely used isotherm models for the adsorption of naphthalene on clay and silt fractions. The experimental results were fitted to the Langmuir, Freundlich, Radke-Prausnitz, Sips, Temkin and Redlich-Peterson isotherms to obtain their characteristic parameters of each model. The coefficient of determination obtained from the different models using the linear method showed that Freundlich isotherm had the highest values for both clay and silt soil fractions with values of 0.843 and 0.897 respectively. The equilibrium data did not fit the Langmuir isotherm with values of 0.287 and 0.021 for clay and silt soil respectively. Using the nonlinear method the equilibrium data gave good fit for Radke-Prausnitz, Sips, Temkin and Redlich-Peterson isotherms. Sips isotherm gave the best fit for silt soil with the r2value of 0.9779 and this was followed by Temkin isotherm for clay soil with the value of 0.9673.
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21

He, Shao Hua, Dan Wang, Qing Qiu Kong, and Xi Wu. "Thermodynamic Studies for Adsorption of Cd2+ and Pb2+ from Waster Water on Modified Walnut Shell." Applied Mechanics and Materials 737 (March 2015): 622–26. http://dx.doi.org/10.4028/www.scientific.net/amm.737.622.

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The adsorption isothermal curve and thermodynamic adsorption of Cd2+ and Pb2+ on modified walnut shell from waster water were investigated using batch technique. The equilibrium adsorption data are fitted to Langmuir and Freundlich isotherm models and the model parameters are evaluated. The Langmuir isotherm model shows a better fit to adsorption data than the Freundlich isotherm model for the sorption of Cd2+ and Pb2+ on modified walnut shell. The maximum adsorption capacity of Cd2+ and Pb2+ by modified walnut shell is found to be 32.68 mg·g-1 and 84.75 mg·g-1 at 298K temperature, respectively. The adsorption processes of Cd2+ and Pb2+ has feasibility and spontaneous nature. Thermodynamic parameters depict the endothermic nature of sorption and the process is spontaneous and favorable.
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22

Overah, L. C. "Nonlinear Kinetic and Equilibrium Adsorption Isotherm Study of Cadmium (II) Sorption by Dacryodes edulis Biomass." Nigerian Journal of Basic and Applied Sciences 28, no. 2 (April 26, 2021): 10–19. http://dx.doi.org/10.4314/njbas.v28i2.2.

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The kinetics and equilibrium adsorption isotherm of cadmium (II) adsorption onto Dacryodes edulis (native peer seed) biomass was studied using a nonlinear approach, which is unpopular but proven in some literature to be more reliable and easier. In optimizing the process, about 98% removal of the cadmium ion was achieved within five minutes at pH 7 by contacting just 30 mg of the Dacryodes edulis seed biomass with the adsorbate solution of a concentration of 100 mg/L. Non-linear investigation of the kinetics and adsorption isotherms of the process was done using the R console statistical and computing software. The results indicated that the Elovich mechanism and the Freundlich adsorption isotherm most suitably described the kinetics and adsorption isotherm, respectively, of the process as provided by their least values of the sum of squared residuals (SSR). This outcome implied a chemical adsorption (chemisorption) mechanism and a multi-layer coverage by the cadmium ions on heterogeneous active sites of the biomass surface with a Freundlich constant or capacity factor, Kf of 27.83 mg g-1, heterogeneity factor, 1/n of 0.2614 and Elovich constants, α and β of 7.0 mg g−1 s−1 and 1.0 g mg-1, respectively. These findings indicate that Dacryodes edulis seed biomass has a good potential for cadmium (II) adsorption. Keywords: Dacryodes edulis, Elovich kinetic model, Freundlich isotherm, Langmuir isotherm, Nonlinear
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23

Brdar, Mirjana, Aleksandar Takaci, Marina Sciban, and Dusan Rakic. "Isotherms for the adsorption of Cu(II) onto lignin: Comparison of linear and non-linear methods." Chemical Industry 66, no. 4 (2012): 497–503. http://dx.doi.org/10.2298/hemind111114003b.

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Equilibrium studies were carried out for the adsorption of Cu(II) onto Kraft lignin as an adsorbent. The experimental data were fitted to the Freundlich, Langmuir and Redlich-Peterson isotherms by linear and non-linear method. Comparison of linear and non-linear regression method was given in selecting the optimum isotherm for the experimental data. The coefficient of correlation r2 and Chi-square test ?2 was used to select the best linear theoretical isotherm. The best linear model is Redlich-Peterson isotherm model, where r2=0,985 and ?2=0,02. In order to predict the error ERRSQ, HYBRD, MPSD, ARE and EABS were used. Moreover, by minimizing these error functions the optimal values of parameters and also the optimum isotherm was found. The Redlich-Peterson isotherm was found to be the best representative for adsorption of Cu(II) on the adsorbent in the cases when ERRSQ, HYBRD, MPSD functions were used. There coefficients of determination are 0.986, 0.985, 0.984, respectively and Chi-square is 0.02 in all cases. Freundlich isotherms which were obtained by minimization of the ERRSQ, HYBRD, MPSD, ARE and EABS function showed very good agreement with experimental data. In all cases the coefficients of determination are greater than 0.91. Besides, it was observed that non-linear isotherm models were better for representation of equilibrium data than linearized models.
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Liu, Junsheng, and Xin Wang. "Novel Silica-Based Hybrid Adsorbents: Lead(II) Adsorption Isotherms." Scientific World Journal 2013 (2013): 1–6. http://dx.doi.org/10.1155/2013/897159.

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Water pollution caused by the lead(II) from the spent liquor has caught much attention. The research from the theoretical model to application fundaments is of vital importance. In this study, lead(II) adsorption isotherms are investigated using a series of hybrid membranes containing mercapto groups (–SH groups) as the hybrid adsorbents. To determine the best fitting equation, the experimental data were analyzed using six two-parameter isotherm equations (i.e., Langmuir, Freundlich, Dubinin-Radushkevich (D-R), Temkin, Harkins-Jura, and Halsey isotherm models). It was found that the lead(II) adsorption on these samples followed the Freundlich, Dubinin-Radushkevich (D-R), and Halsey isotherm models. Moreover, the mean free energy of adsorption was calculated using Dubinin-Radushkevich (D-R) isotherm model and it was confirmed that the adsorption process was physical in nature. These findings are very meaningful in the removal of lead(II) ions from water using the hybrid membranes as adsorbents.
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25

Stepova, K., L. Sysa, and R. Konanets. "Nonlinear Fitting of Iron Sorption on Bentonite to Theoretical Isotherm Models." Physics and Chemistry of Solid State 23, no. 2 (May 25, 2022): 270–76. http://dx.doi.org/10.15330/pcss.23.2.270-276.

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A comparative analysis of adsorption models application for the description of experimental isotherms of iron adsorption on two samples: natural bentonite and bentonite irradiated with microwave irradiation. Sorption isotherms are described using the theories of Langmuir, Freundlich, Redlich-Peterson and Langmuir-Freundlich. The constants and parameters of these equations are determined. Nonlinear fitting of experimental data to the theoretical models of isotherms showed that adsorption by native bentonite corresponds to the three-parameter Redlich-Peterson model, and microwave irradiated - to the Freindlich isotherm. This modeling allows to predict the maximum adsorption capacity, which is 37.7 mg / g of natural bentonite and 64.4 mg / g of the modified sample.
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26

Salahudeen, N., and A. Alhassan. "Adsorption of Crystal Violet on Rice Husk Activated Carbon." Journal of Engineering Sciences 9, no. 1 (2022): F11—F15. http://dx.doi.org/10.21272/jes.2022.9(1).f2.

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The need to develop effective technology for the treatment of liquid effluent of dye-intensive industries such as textile, rubber, paint, and printing is synonymous with the need to save the life-threatening risks posed by these carcinogenic and mutagenic pollutants on human and aquatic lives. Isotherms of adsorption of crystal violet (CV) on activated carbon (AC) synthesized from rice husk are presented herewith to elucidate the mechanism of the adsorption process of crystal violet dye contaminated water on rice husk activated carbon. AC was synthesized from rice husk via a phosphoric acid activating agent at low temperatures. Langmuir, Freundlich, Temkin and Dubinin–Radushkevich (D-R) isotherm studies were employed. The mean square values for Langmuir, Freundlich, Temkin and D-R models were 0.98, 0.91, 0.94, and 0.63, respectively. Analysis of the isotherms of the adsorption of crystal violet sorbate on the synthesized rice husk sorbent suggested that the adsorption process proceeded via a homogeneous monolayer mechanism. Langmuir isotherm gave the best fit of the adsorption process. Langmuir isotherm constant was –1.40 l/mg, and the equilibrium adsorption capacity was 13.53 mg/g.
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LAKSANA, SAGA DERMAWAN DWI, ERICK RYAN YULIANTO, and EDI PRAMONO. "The Chicken Utilization Of Α-Keratin Of Waste Chicken Feathers In Enviromental As Adsorben Of Procion Red And Remazol Yellow Dye." Science Proceedings Series 1, no. 3 (May 18, 2019): 12–14. http://dx.doi.org/10.31580/sps.v1i3.865.

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as the adsorbent. The adsorption characterization of activated chicken feathers by Na2S 0.1 N and non-activated chicken feathers was determined. Effect of variation experimental parameters pH, Contact time and variation dye concentration also being investigated in a batch adsorption method. Procion and Remazol Yelloow were characterized by UV-Vis spectroscopy VV The results show that the contact time and pH condition for adsorption equilibrium are 120 min for activated chicken feathers and 100 min for chicken feathers which were not activated by Na2S at pH 3. Procion red dye absorption by activated and not activated chicken feathers follows Freundlich isotherm and follow Langmuir isothrem. For remazol yellow dye absorption by activated and not activated chicken feathers follows Langmuir isotherm and Freundlich isothrem and the reaction kinetics follow the Ho equation. Keywords: adsorption, chicken feather, procion red, remazol yellow
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28

El-Aassar, Mohamed R., Tamer M. Tamer, Mohamed Y. El-Sayed, Ahmed M. Omer, Ibrahim O. Althobaiti, Mohamed E. Youssef, Rawan F. Alolaimi, et al. "Development of Azo Dye Immobilized Sulfonated Poly (Glycidyl Methacrylate) Polymer Composite as Novel Adsorbents for Water Treatment Applications: Methylene Blue Immobilization Isotherm, Kinetic, Thermodynamic, and Simulations Studies." Molecules 27, no. 23 (December 1, 2022): 8418. http://dx.doi.org/10.3390/molecules27238418.

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Methylene blue (MB) immobilized onto a sulfonated poly(glycidyl methacrylate) (SPGMA) polymer composite has been developed as a novel adsorbent for water treatment applications. The MB adsorptions onto sulfonated poly(glycidyl methacrylate) polymer characters have been studied. The adsorption isotherms, namely Langmuir and Freundlich, have been investigated. Other isotherm models. As a compromise between the Freundlich and Langmuir isotherm models, such as the D–R isotherm and the Temkin isotherm, have been compared. The results indicated that the adsorption process followed the Freundlich isotherm model, indicating heterogeneous surface site energies and multi-layer levels of sorption. This study selected three linear kinetic models, namely pseudo-first order, pseudo-second order, and Elovich, to describe the MB sorption process using SPGMA negatively charged nanoparticles (430 nm). The obtained data revealed that the adsorption process obeyed the pseudo-second-order kinetic model, suggesting that the rate-limiting step in these sorption processes may be chemisorption. Furthermore, the thermodynamic parameters have been evaluated. Moreover, the interaction of the MB molecules with SPGMA nanoparticles has been simulated using the governing equation that describes ion exchange resin derived from Nernst—Plank equations between two ion species. Finally, the developed MB-SPGMA composite adsorbent (27 mg/g) wastested for the first time for the removal of Cr6+ ions and Mn7+ metal ions from dichromate and permanganate-contaminated waters under mild adsorption conditions, opening a new field of multiuse of the same adsorbent in the removal of more than one contaminant.
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29

Vigdorowitsch, Michael, Alexander Pchelintsev, Liudmila Tsygankova, and Elena Tanygina. "Freundlich Isotherm: An Adsorption Model Complete Framework." Applied Sciences 11, no. 17 (August 31, 2021): 8078. http://dx.doi.org/10.3390/app11178078.

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The absolute majority of modern studies dealing with the interpretation of experimental data on the basis of the Freundlich isotherm ignore the fact that the data obtained for regions of low and moderate adsorbate concentration/pressure can be analytically continued within the Freundlich adsorption model to the adsorptive saturation area with coverages tending to 100%. Needless to say, this would give valuable extended information about the corresponding adsorption process. This message proposes a framework to comprehensively analyse experimental data first recognised as complying with the Freundlich adsorption model. An algorithm-driven method is presented which enables one to translate the data obtained in the area of small and moderate the coverages of the area of adsorptive saturation regime. As examples, three sets of experimental data for adsorption of mercury (II) on N-rich porous organic polymers and of protein on carrier nano-Mg(OH)2 have been processed and presented according to the framework developed.
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30

Nounou, M. N., and H. N. Nounou. "Multiscale estimation of the Freundlich adsorption isotherm." International Journal of Environmental Science & Technology 7, no. 3 (June 2010): 509–18. http://dx.doi.org/10.1007/bf03326160.

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31

Taba, Paulina, Miftahul Jannah, and Yusafir Hala. "Mesoporous Silica MCM-48 as Chloramphenicol Adsorbent." Indo. J Chem. Res. 8, no. 3 (January 31, 2021): 242–46. http://dx.doi.org/10.30598//ijcr.2021.7-mif.

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This study is aimed to determine the potential use of MCM-48 to adsorb chloramphenicol pollution. Chloramphenicol adsorption was conducted at various times contact and concentration. Adsorption isotherm was studied by comparing Langmuir and Freundlich adsorption isotherm. The results showed that chloramphenicol adsorption was suited to Freundlich isotherm with an optimum contact time of 80 minutes
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32

Akbar, Nor Azliza, Hamidi Abdul Aziz, and Mohd Nordin Adlan. "Iron and Manganese Removal from Groundwater Using High Quality Limestone." Applied Mechanics and Materials 802 (October 2015): 460–65. http://dx.doi.org/10.4028/www.scientific.net/amm.802.460.

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Several techniques are used for iron and manganese removal from groundwater. Among these treatments, adsorption has been proven to be a very effective in metal removal for groundwater treatment. Thus, limestone has been proposed as adsorption media because of its low cost. In this study, the mineral contents of limestone were detected using X-ray fluorescence (XRF). XRF results showed that limestone contains 97.93% CaCO3, 0.87% MgO, and 1.2% other elements. Groundwater sample was obtained from USM borehole located at 5° 08’ 50.5”N and 100° 29’ 34.7”E. A batch study was carried out for various dosages of limestone media (5–50 g) in 200 mL of groundwater sample. The highest iron and manganese removal was more than 90% and 70%, respectively, at optimum dosage of 40 g/200 mL sample. Adsorption data were modeled using Langmuir and Freundlich adsorption isotherms. The batch study result shows that monolayer Langmuir isotherm fitted the experimental data better than the Freundlich isotherm. The correlation coefficient (R2) in the Langmuir isotherm for both metals were 0.84 and 0.97, whereas 0.83 and 0.23 in the Freundlich isotherm, respectively. Based on the present results, application of limestone as adsorbent media can be a good alternative of groundwater treatment because of the low cost of the media. Thus, the use of limestone could help to overcome the excessive iron and manganese problem in water treatment plants.
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33

Agarwal, Ajay K., Mahendra S. Kadu, Chandrashekhar P. Pandhurnekar, and Ishwardas L. Muthreja. "Equilibrium isotherm studies for the sorption of Nickel ions onto coal fly ash." Environment Conservation Journal 15, no. 1&2 (June 18, 2014): 153–59. http://dx.doi.org/10.36953/ecj.2014.151220.

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The objective of the present study was to study equilibrium isotherm for the sorption of Nickel ions onto coal fly ash. In this study, BET adsorption isotherm was found to be best fitted among Langmuir, Freundlich, BET, Temkin and Harkins Jura adsorption isotherms using lest square fit method. The best fit adsorption isotherm is assessed by the linear coefficient of determination (R2) and non-linear Chi-square test. The theoretical value of qe calculated from the best fit linear equation of each adsorption isotherm and the experimental values of qe (0.08) are plotted against Ce, to compare the experimental and Theoretical value of qe.
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34

Chauhdary, Yusra, Muhammad Asif Hanif, Umer Rashid, Ijaz Ahmad Bhatti, Hafeez Anwar, Yasir Jamil, Fahad A. Alharthi, and Elham Ahmed Kazerooni. "Effective Removal of Reactive and Direct Dyes from Colored Wastewater Using Low-Cost Novel Bentonite Nanocomposites." Water 14, no. 22 (November 8, 2022): 3604. http://dx.doi.org/10.3390/w14223604.

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The present study was aimed to remove direct violet-51, reactive green-5, reactive red, and acid red dyes by novel bentonite clay nanocomposites prepared using sodium metasilicate and potassium ferricyanide. The effect of temperature, pH, adsorbent amount, contact time, and initial concentration were studied to optimize the removal process. Various adsorption isotherms (Temkin, Freundlich isotherm, Langmuir isotherm, Harkin Jura, and Dubinin Radushkevich models) and kinetic models (pseudo-first order and pseudo-second order) were applied to adsorption data to find out the best fit model, i.e., Freundlich isotherm and pseudo-second order model. The prepared samples of bentonite nanocomposites were characterized using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Bentonite treated with sodium metasilicate and potassium ferricyanide removed 96.6% of direct violet-51 dye, bentonite treated with sodium metasilicate removed 95%, bentonite treated with potassium ferricyanide removed 94%, and pure bentonite removed 80% of the dye from the solution.
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35

Shojaat, Rahim, Afzal Karimi, Naghi Saadatjoo, and Soheil Aber. "Dye removal from artificial wastewater using heterogeneous bio-fenton system." Chemical Industry and Chemical Engineering Quarterly 23, no. 4 (2017): 447–56. http://dx.doi.org/10.2298/ciceq160621058s.

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In the present study, GOx/MnFe2O4/calcium alginate nano-composite was prepared by the trapping enzyme/nanoparticles in calcium alginate. The prepared absorbent was applied for decolorization of artificial dye wastewater of acid red 14 (AR14) by heterogeneous bio-Fenton system. Kinetic and isotherm studies were carried out. The decolorization of acid red 14 followed the Michaelis- Menten, pseudo-first order and pseudo-second order kinetic models. Good correlation coefficients were obtained by fitting the experimental data to Michaelis- Menten and pseudo-second order kinetic models. The adsorption isotherms were described by Langmuir, Freundlich and Temkin isotherms. Among the three isotherm models, the Freundlich model was fitted with the equilibrium data obtained from adsorption of AR14 onto MnFe2O4/calcium alginate; while Temkin isotherm gave the best correlation for adsorption on MnFe2O4 nanoparticles. The effect of various parameters such as initial pH of solution, initial dye concentration, and contact time on the adsorption of AR14 on MnFe2O4 and MnFe2O4/ /calcium alginate as well as dye enzymatic decomposition was studied. The decolorization of AR14 with initial concentration of 10 mg.L?1 by using GOx/ /MnFe2O4/calcium alginate was 60.17%.
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36

Ali Fil, Baybars. "Investigation of adsorption of Basic Orange 2 dye on montmorillonite and error analysis." Bulletin of the Chemical Society of Ethiopia 37, no. 1 (October 26, 2022): 47–58. http://dx.doi.org/10.4314/bcse.v37i1.5.

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ABSTRACT. In this study, isotherm studies were investigated for the removal of basic orange 2 (BO2) dye on the montmorillonite surface. Two-parameter isotherm models such as Langmir, Freundlich, and Temkin isotherms and Three-parameter isotherm models such as Sips, Toth, and Khan isotherms were calculated by non-linear analysis method. The adsorption capacity at equilibrium was calculated by adding 0.035 g of adsorbent at 10-300 mg/L concentrations to 100 mL of synthetic dyestuff solution at room temperature. According to the results obtained, it was determined that the isotherm data matched the Langmuir isotherm with a regression coefficient of 0.995 from the Two-parameter models, and the Sips isotherm with a regression coefficient of 0.998 from the Three-parameter isotherm models. In addition, according to the results of error analysis, it was determined that the lowest error value fit the HYBRID model. SNE values support the HYBRID model. KEY WORDS: Adsorption, Basic orange 2, Isotherm models; Error analyses, Hybrid Bull. Chem. Soc. Ethiop. 2023, 37(1), 47-58. DOI: https://dx.doi.org/10.4314/bcse.v37i1.5
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37

Pratt, C., and A. Shilton. "Suitability of adsorption isotherms for predicting the retention capacity of active slag filters removing phosphorus from wastewater." Water Science and Technology 59, no. 8 (April 1, 2009): 1673–78. http://dx.doi.org/10.2166/wst.2009.163.

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Active slag filters are an emerging technology for removing phosphorus (P) from wastewater. A number of researchers have suggested that adsorption isotherms are a useful tool for predicting P retention capacity. However, to date the appropriateness of using isotherms for slag filter design remains unverified due to the absence of benchmark data from a full-scale, field filter operated to exhaustion. This investigation compared the isotherm-predicted P retention capacity of a melter slag with the P adsorption capacity determined from a full-scale, melter slag filter which had reached exhaustion after five years of successfully removing P from waste stabilization pond effluent. Results from the standard laboratory batch test showed that P adsorption correlated more strongly with the Freundlich Isotherm (R2=0.97, P&lt;0.01) than the Langmuir Isotherm, a similar finding to previous studies. However, at a P concentration of 10 mg/L, typical of domestic effluent, the Freundlich equation predicted a retention capacity of 0.014 gP/kg slag; markedly lower than the 1.23 gP/kg slag adsorbed by the field filter. Clearly, the result generated by the isotherm bears no resemblance to actual field capacity. Scanning electron microscopy analysis revealed porous, reactive secondary minerals on the slag granule surfaces from the field filter which were likely created by weathering. This slow weathering effect, which generates substantial new adsorption sites, is not accounted for by adsorption isotherms rendering them ineffective in slag filter design.
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38

Abdelhamid, Arwa A., Mogeda H. Badr, Ramadan A. Mohamed, and Hosam M. Saleh. "Using Agricultural Mixed Waste as a Sustainable Technique for Removing Stable Isotopes and Radioisotopes from the Aquatic Environment." Sustainability 15, no. 2 (January 13, 2023): 1600. http://dx.doi.org/10.3390/su15021600.

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In the current study, dried ground mixed waste of olive waste and water hyacinth was subjected to the treatment of wastewater contaminated with stable or radioactive cobalt and cesium. Contact time, temperature, amount of adsorbent, metal ion concentration and pH-value were evaluated as the most potent factors that affect the adsorption process. Concentrations of Co and Cs ions before and after treatment are measured using ICP-OES technique. Moreover, kinetic and equilibrium isotherm parameters were investigated by explaining the equilibrium data by induction of two isotherms, “Langmuir” and “Freundlich”. Experimental results indicated that more than 85% of 60Co and 134Cs were efficiently removed from spiked wastewater after one hour of contact time by using 0.2 g of dried mixed waste. The optimal time to remove Cs+ and Co2+ was 50 and 90 min, respectively. The kinetic study showed that the adsorption of Cs+ and Co2+ were better suited to the second order. The most favorable pH value was at a range of 6–7 for Cs+ and 5–6 for Co2+. R2 values were higher at the Freundlich isotherm, indicating that the adsorption process was taking place according to Freundlich isotherm at all temperatures for Co2+ and Cs+ ions.
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39

Shi, Wei Mei, Ye Chun Ding, and Long Huo Wu. "The Adsorption Properties of Ciprofloxacin by KMnO4 Modified Durio zibethinus Murr Shells." Advanced Materials Research 1104 (May 2015): 111–17. http://dx.doi.org/10.4028/www.scientific.net/amr.1104.111.

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Through the experiment of Ciprofloxacin (CIP) adsorption by KMnO4modifiedDurio zibethinusMurr Shell (KDS), the best condition, adsorption kinetics and thermodynamic characteristics were studied. The isotherm parameters were estimated by linear regression analysis with Langmuir isotherm model, Temkin isotherm and Freundlich isotherm model. The equilibrium process was described well by the Freundlich isotherm model, which indicated that the adsorption thermodynamics of CIP on KDS is a multilayer adsorption process．The kinetics of the interactions showed better agreement with the pseudo-second-order model (R2=0.9999). This study demonstrated that KDS could be used for the removal of CIP in water treatment.
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40

Wu, Chung Hsin, Chao Yin Kuo, and Meng Jia Chen. "Adsorption of Copper Ions from Aqueous Solutions by Chitin." Advanced Materials Research 550-553 (July 2012): 2424–27. http://dx.doi.org/10.4028/www.scientific.net/amr.550-553.2424.

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This study utilizes chitin to remove dissolved Cu(II) from aqueous solutions. The effects of the dissolved Cu(II) concentration, chitin dosage, and pH on adsorption of dissolved Cu(II) by chitin are determined. Adsorption capacity for 20 and 80 mg/L dissolved Cu(II) onto chitin (2 g/L) was 3.86 mg/g and 5.12 mg/g, respectively. The dissolved Cu(II) adsorption percentage increased from 39% to 70% when the chitin dosage was increased from 2 g/L to 4 g/L. The linear correlation coefficients of Langmuir and Freundlich isotherms were obtained. Analytical results demonstrate that the Freundlich isotherm fitted experimental results better than did the Langmuir isotherm. Enthalpy (ΔH0) and entropy (ΔS0) for dissolved Cu(II) adsorption were 8.46 kJ/mol and 123.1 J/mol.K, respectively.
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41

Anwar Mohamad Said, Khairul, Nor Zakirah Ismail, Ramizah Liyana Jama'in, Nurul Ain Mohamed Alipah, Norsuzailina Mohamed Sutan, Genevieve George Gadung, Rubiyah Baini, and Nur Syuhada Ahmad Zauzi. "Application of Freundlich and Temkin Isotherm to Study the Removal of Pb(II) Via Adsorption on Activated Carbon Equipped Polysulfone Membrane." International Journal of Engineering & Technology 7, no. 3.18 (August 2, 2018): 91. http://dx.doi.org/10.14419/ijet.v7i3.18.16683.

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The aim of this study was to investigate the application of membrane equipped activated carbon for heavy metal removal. An adsorption capacity of the activated carbon inside membrane matrix was performed against environmentally problematic ions specifically Pb2+, in aqueous solution. The adsorption process was examined by Temkin and Freundlich isotherm. From the SEM observation, membrane exhibit sponge-like structure with dense micro-void formation across the matrix. This phenomenon was usually observed with membrane mixed with polyethyleneimine. For the adsorption studies, it is shown that Freundlich isotherm show better fit based on R2 value of 0.9893 with Temkin isotherm fitted with R2 of 0.9009. Through the fitted model, the adsorption occur on the surface of activated carbon are possibly multilayer type adsorption based on theory by Freundlich isotherm and fall under non-ideal reversible adsorption.
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42

El maguana, Y., N. Elhadiri, M. Benchanaa, and R. Chikri. "Activated Carbon for Dyes Removal: Modeling and Understanding the Adsorption Process." Journal of Chemistry 2020 (September 14, 2020): 1–9. http://dx.doi.org/10.1155/2020/2096834.

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Batch adsorption experiments have been conducted to investigate the removal of methyl orange from aqueous solution by an activated carbon prepared from prickly pear seed cake by phosphoric acid activation. The adsorption process has been described by using kinetic and isotherm models. The kinetic of adsorption was examined by pseudo-first-order, pseudo-second-order, and intraparticle diffusion models. Adsorption isotherm was modeled using Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherms. The adsorption process of methyl orange was well explained by the pseudo-second-order model and Freundlich isotherm. Also, pseudo-n-order model has been applied to estimate the order of adsorption kinetic and it was found equal to 2 which confirm the good accuracy of the pseudo-second order. Moreover, Dubinin–Radushkevich isotherm reveals that the adsorption of methyl orange onto activated carbon was a physisorption process in nature. The adsorption capacity of activated carbon was found to be 336.12 mg/g at temperature 20°C and pH∼7. These results demonstrated that the prickly pear seed cake is a suitable precursor for the preparation of appropriate activated carbon for dyes removal from aqueous solution.
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43

Roring, Stero H., Mariska M. Pitoi, and Jemmy Abidjulu. "Isoterm Adsorpsi Rhodamin B Pada Arang Aktif Kayu Linggua." Jurnal MIPA 2, no. 1 (January 31, 2013): 40. http://dx.doi.org/10.35799/jm.2.1.2013.764.

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Telah dilakukan penelitian adsorpsi rhodamin B pada arang aktif yang dibuat dari kayu linggua. Penelitian ini bertujuan untuk menentukan koefisien adsorpsi arang aktif limbah gergajian kayu linggua terhadap zat warna rhodamin B dengan menggunakan isoterm adsorpsi Langmuir dan Freundlich. Penelitian dilakukan secara batch di mana 0,1; 0,2; 0,4; 0,7 dan 1 gram arang aktif dimasukkan ke dalam labu Erlenmeyer terpisah yang masing-masing telah berisi 100 mL larutan rhodamin B 100 ppm. Campuran kemudian diperlakukan di atas magnetic stirrer selama 50 menit dan selanjutnya konsentrasi larutan rhodamin B dianalisis menggunakan spektrofotometer UV-Vis. Hasil penelitian menunjukkan bahwa isoterm adsorpsi rhodamin B pada arang aktif kayu linggua lebih mengikuti isoterm adsorpsi Freundlich dengan koefisien adsorpsi 2,999x10-4 dan nilai intensitas adsorpsi 1,459.Adsorption isotherm of rhodamine B by activated carbon made from linggua wood waste was investigated. The adsorption isotherm was analyzed by Langmuir and Freundlich models. The isotherm was measured by batch experiment where 0,1; 0,2; 0,4; 0,7; and 1,0 grams where added into the separated Erlenmeyer flasks filled with 100 mL of 100 ppm rhodamine B. The mixtures were then treated on magnetic stirrers for 50 minutes followed by rhodamine B analysis using spectrophotometer UV-Vis. The result showed that the isotherm followed the Freundlich model better than Langmuir with the Freundlich adsorption coefficient of 2,999x10-4 and the Freundlich exponent of 1,459.
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44

Ahmadpari, Hedieh, Mohsen Eskafi Noghany, Behnam Rigi Ladez, Babak Mehrparvar, and Saeed Momeni. "Kinetics Modeling and Isotherms for Adsorption of Nitrate from Aqueous Solution by Wheat Straw." Tecnologia e Ambiente 25 (October 7, 2019): 203. http://dx.doi.org/10.18616/ta.v25i0.5301.

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Nitrate is a colorless, odorless chemical substance with a chemical formulation of NO3- and average mass of 62.0049 gr/ Mol. According to an announcement of the world health organization (WHO), the standard amount of Nitrate in potable water is at most 50 ml/ lit (based on nitrate). Nitrate enters into the body and is transformed to nitrite by digestive system’s bacteria, then enters to the circulatory system and oxides the exiting iron in Hemoglobin of blood which converts the iron capacity from 2 to 3. As a result of this process Hemoglobin is converted to Methemoglobin which has far more less capacity in oxygen delivery. Therefore, the tissues cannot receive sufficient oxygen and it causes a disease called “Methemoglobinemia”. The objective of this study was to investigate the nitrate removal using wheat straw and determining the adsorption isotherms and kinetics. In this study, nitrate solutions were prepared from potassium nitrate salt. The pH values of the solutions were adjusted by NaOH and HCl at a concentration of 0.1 molar. The pH of the solution was adjusted to different values (4 to 13). Kinetics models of Ho et al and Lagergren were used to describe the data. Isotherm models of Langmuir and Freundlich were used to describe the data. The results showed that the maximum capacity of wheat straw in nitrate adsorption occurred at pH=6 and contact time 140 minutes. Equilibrium models (Langmuir and Freundlich) and non-equilibrium (Ho et al and Lagergren) were used to investigate the adsorption process. Comparing the determination coefficients between measured data and obtained value from Ho’s model (R2= 0.97) and Lagergren model (R2= 0.91) showed that the Ho’s model describes experimental data better. Also, comparing the Langmuir and Freundlich isotherm for nitrate adsorption by wheat straw showed that Freundlich isotherm (R2= 0.98) was more proper than Langmuir isotherm (R2= 0.83) in describing adsorption process.
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45

Krishnaveni, S., and V. Thirumurugan. "A Study on Removal of Heavy Metal Chromium from Aqueous Chromium Solution Using Ipomoea carnea Root as Biosorbent." Journal of Drug Delivery and Therapeutics 9, no. 4-A (August 30, 2019): 409–14. http://dx.doi.org/10.22270/jddt.v9i4-a.3504.

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Pollution is the main problem due to heavy metal discharges from industries . In this study Ipomoea carnea (Family:Convolvulaceae) is selected to remove the heavy metal chromium from aqueous chromium solution using biosorbent . The present work focuses to evaluate the effectiveness of low cost absorbent Ipomoea carnea root powder. Various parameters like pH, biosorbent, dose, contact time and metal ion concentration are investigated using batch studies. A kinetic model study and isotherm model fitting study are studied using Langmuir and Freundlich isotherms. The Thermodyamic parameters ∆G, ∆H and ∆S are also seen. The results reveal that it follows pseudo first order kinetic model and also fit in the Langmuir and Freundlich isotherms. The results are very much encouraging. So, it can be used as low cost biosorbent in controlling the pollution. Keywords: Pollution, Heavy metal, chromium, Ipomoea carnea, Batch adsorption study, Kinetics Langmuir and Freundlich isotherms and Thermodynamic study.
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46

Phatai, Piaw, Songkot Utara, and Nantana Hatthapanit. "Removal of Methyl Violet by Adsorption onto Activated Carbon Derived from Coffee Residues." Advanced Materials Research 864-867 (December 2013): 710–14. http://dx.doi.org/10.4028/www.scientific.net/amr.864-867.710.

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The study aimed to investigate the adsorption efficiency of methyl violet (MV) dye on activated carbon (AC) derived from coffee residues. A batch adsorption study was performed to examine various contributory parameters including contact time, solution pH, adsorbent dose and initial dye concentration. The morphology of the AC was studied by means of scanning electron microscopy (SEM). The results showed that maximum adsorption of MV dye on activated carbon occurred with a contact time of 60 min, solution pH of 9.0 and adsorbent dose of 0.3 g. The equilibrium adsorption data were analysed using Freundlich and Temkin isotherms. The adsorption isotherm was found to follow the Freundlich isotherm. Adsorption behavior of MV dye follows mechanism of physical adsorption which is occurred by heterogeneous surface. The results indicate that the AC from coffee residues is a suitable adsorbent for the adsorption of dyes.
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47

Zhu, Min Cong, Wei Qi, Yan Jie Mao, Yin Hu, Xin Qing, Kan Zhu Li, Yuan Ye, Ying Chen Zhang, Deng Xin Li, and Hong Mei Chai. "Synthesis, Characterization and Adsorption Property of Expanded Graphite/Conducting Polymer Composite." Advanced Materials Research 322 (August 2011): 93–97. http://dx.doi.org/10.4028/www.scientific.net/amr.322.93.

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In the present work, expanded graphite (EG) was prepared by microwave irradiation. Then, the expanded graphite/polyaniline (EG/PANi) composite was synthesized in the typical method. The samples of EG and EG/PANi were characterized by SEM and IR analysis techniques. Adsorption property of EG/PANi composite for removing the dye, reactive brilliant red K-2BP, from aqueous solution was investigated. The effects of initial dye concentration and contact time, pH, sorbent dosage on the adsorption process were studied. Experimental data were modelled by Langmuir and Freundlich isotherms. Langmuir isotherm model fitted well the equilibrium data for EG/PANi composite comparing to the Freundlich isotherm model. The uptake capacity of EG/PANi for K-2BP was found to be 1.03047 mg/g. The results indicated that EG/PANi composite is not an ideal sorbent used for reactive dye removal.
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48

Senin, H. B., O. Subhi, R. Rosliza, N. Kancono, M. S. Azhar, S. Hasiah, and W. B. Wan Nik. "Role of Sawdust in the Removal of Iron from Aqueous Solution." ASEAN Journal on Science and Technology for Development 23, no. 3 (November 1, 2017): 223. http://dx.doi.org/10.29037/ajstd.107.

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Sawdust, inexpensive material has been utilized as an absorbent for the removal of iron from aqueous solution for their safe disposal. The adsorption experiments of untreated sawdust (SD) and treated sawdust (SDC) have been carried out at room temperature using the batch test. The Langmuir and Freundlich isotherms were used to observe sorption phenomena of sawdust in the removal of iron. The results indicate that the sawdust was capable in removing iron in aqueous solution. The results have shown that the Langmuir isotherm was found well fitted into the experimental data as compared to the Freundlich isotherm. It was found that, chemisorptions and physisorption were the prime mechanism for the process of adsorption to occur between the sawdust and iron. The results also proved that the acid sulphuric treated sawdust is much better than that of untreated sawdust as an adsorbent for iron.
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Zhao, Qing, Hui Lu, Liao Meng, and Shui Li Yu. "The Adsorption Performance of Hybrid PVDF Membrane by HA." Applied Mechanics and Materials 700 (December 2014): 298–301. http://dx.doi.org/10.4028/www.scientific.net/amm.700.298.

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Ultrafiltration test was carried out to simulate the pollution performance of humic acid (HA) solution. The HA adsorption properties on membrane surface was studied by static adsorption experiment. The influences of HA concentration on adsorption characteristics were taken into account. And Freundlich isotherm model was used to evaluate of adsorption isotherms.
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Liu, Yu Zhen, and Jie Min Cheng. "Adsorption Kinetics and Isotherms of Cu (II) and Cd (II) onto Oxidized Nano Carbon Black." Advanced Materials Research 529 (June 2012): 579–84. http://dx.doi.org/10.4028/www.scientific.net/amr.529.579.

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A new kind of sorbent, Oxidized Nano Carbon Black (OCB), was prepared with the acid potassium permanganate. The adsorption kinetics,isotherms of Cu (II) and Cd (II) onto Nano Carbon Black(CB) and Oxidized Nano Carbon Black(OCB) were investigated. The experimental data were analyzed by Langmuir, Freundlich isotherm, Pseudo first order equation and Pseudo second order equation. The results demonstrated that the Langmuir isotherm provided a better fit to the experimental data of CB and the OBC fitted well into Freundlich adsorption isotherm. The adsorption capacity of Cu2+ and Cd2+onto oxidized Carbon black was significantly enhanced after modification. The maximum amount of CB was 16.129mg/g for Cu2+, 5.747mg/g for Cd2+, the maximum amount of OCB was 83.333mg/g for Cu2+, 10.3097mg/g for Cd2+, respectively. The Freundlich parameters of OCB were KF, Cu = 0.360, nCu = 1.16, KF, Cd = 1.777 and nCd = 3.086. The values of n > 1 indicated a favorable adsorption process. The study of adsorption kinetic showed that the adsorption stage of Cu and Cd onto sorbents could be divided into two stages: fast reaction and slow reaction. The adsorption kinetic model of metal on OCB followed pseudo second order model well (RCu2=0.985, RCd2=0.987) and the data of CB fitted pseudo first order model well (RCu2=0.983, RCd2=0.998).
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