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Journal articles on the topic 'BET isotherm'

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Published: 4 June 2021
Last updated: 7 February 2022

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1

Cascarini de Torre, Lydia Ethel, and Eduardo Jorge Bottani. "BET Adsorption Isotherm and Surface Heterogeneity." Collection of Czechoslovak Chemical Communications 57, no. 6 (1992): 1201–9. http://dx.doi.org/10.1135/cccc19921201.

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The BET adsorption isotherm is modified in order to take account of surface heterogeneity. The adsorption isotherm is obtained following the statistical mechanics formalism, proposed by Steele, and the effect of surface heterogeneity is limited to the first layer. A Gaussian adsorption energies distribution function is used to describe surface heterogeneity. The variations of the C parameter, multilayer formation and the inversion of adsorption isotherms are analysed.
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2

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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3

Rachtanapun, Pornchai, and R. Suriyatem. "Prediction Models for Moisture Sorption Isotherms of Soy Protein Isolate/Carboxymethyl Chitosan/Oleic Acid Blend Films." Advanced Materials Research 506 (April 2012): 595–98. http://dx.doi.org/10.4028/www.scientific.net/amr.506.595.

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Soy protein isolate/carboxymethyl chitosan/oleic acid (SPI/CMCH/O) blend films were prepared by solution casting. The effect of various oleic acid content (0, 2.5, 5.0, 10.0, 20.0 pph of SPI and CMCH) on water sorption isotherm of SPI/CMCH base film was investigated. The sorption isotherm of SPI/CMCH/O blend films was evaluated at serveral relative humidity (0, 16, 35, 55 and 76% RH), at 25±1°C. The isotherms showed equilibrium moisture content (%EMC) of SPI/CMCH/O blend films decreased when oleic acid content increased. Understanding of sorption isotherms is an importance for prediction of moisture sorption properties of films via moisture sorption empirical models. Guggenheim-Anderson-de Boer (GAB), BrunauerEmmettTeller (BET) and Oswin sorption models were tested to fit the experimental data. The root mean squares (RMS) of GAB, BET and Oswin were in the range of 68.60-87.02, 22.86-79.38 and 694.78-3797.23, respectively. BET model was found to be the better-fitted model for SPI/CMCH/O blend films at 25±1°C.
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4

Yu, Wei, Kamy Sepehrnoori, and Tadeusz W. Patzek. "Modeling Gas Adsorption in Marcellus Shale With Langmuir and BET Isotherms." SPE Journal 21, no. 02 (April 14, 2016): 589–600. http://dx.doi.org/10.2118/170801-pa.

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Summary Production from shale-gas reservoirs plays an important role in natural-gas supply in the United States. Horizontal drilling and multistage hydraulic fracturing are the two key enabling technologies for the economic development of these shale-gas reservoirs. It is believed that gas in shale reservoirs is mainly composed of free gas within fractures and pores and adsorbed gas in organic matter (kerogen). It is generally assumed in the literature that the monolayer Langmuir isotherm describes gas-adsorption behavior in shale-gas reservoirs. However, in this work, we analyzed four experimental measurements of methane adsorption from the Marcellus Shale core samples that deviate from the Langmuir isotherm, but obey the Brunauer-Emmett-Teller (BET) isotherm. To the best of our knowledge, it is the first time to find that methane adsorption in a shale-gas reservoir behaves similar to multilayer adsorption. Consequently, investigation of this specific gas-desorption effect is important for accurate evaluation of well performance and completion effectiveness in shale-gas reservoirs on the basis of the BET isotherm. The difference in calculating original gas in place (OGIP) on the basis of both isotherms is discussed. We also performed history matching with one production well from the Marcellus Shale and evaluated the contribution of gas desorption to the well's performance. History matching shows that gas adsorption obeying the BET isotherm contributes more to overall gas recovery than gas adsorption obeying the Langmuir isotherm, especially at early time in production. This work provides better understanding of gas desorption in shale-gas reservoirs and updates our current analytical and numerical models for simulation of shale-gas production.
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5

Suriyatem, Rungsiri, and Pornchai Rachtanapun. "Prediction Modeling for Moisture Sorption Isotherms of Rice Starch/Carboxymethyl Cellulose from Durian Rind Blend Films." Applied Mechanics and Materials 431 (October 2013): 32–36. http://dx.doi.org/10.4028/www.scientific.net/amm.431.32.

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Rice starch/carboxymethyl cellulose from durian rind (RS/CMCd) blend films were prepared by solution casting. The effect of different ratios between rice starch and CMCd (100:0, 88:12, 67:33, 50:50, 33:67, 12:88 and 0:100) on moisture sorption isotherm of blend films was investigated. The sorption isotherm of RS/CMCd blend films was determined at various relative humidity (RH) at 25°C. The isotherm curves revealed that the highest equilibrium moisture content (EMC) was obtained from CMCd film, at aw=85. Knowledge of sorption isotherms is important to predict the moisture sorption properties of the filmsviamoisture sorption empirical models. The Lewicki, Peleg, Guggenheim-Anderson-deBoer (GAB), BrunauerEmmettTeller (BET), and Oswin models were tested to fit the experimental data. The root mean squares percentage error (%RMS) of Lewicki, Peleg, GAB, BET and Oswin was in the range of 5.3-83.1, 2.2-20.0, 6.9-20.2, 3.4-26.4 and 4.7-41.2, respectively. The Peleg model was found to be the best fitted model for RS/CMCd blend films.
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6

Bakaev, V. A., and W. A. Steele. "The Characteristic Curve in Physical Adsorption." Adsorption Science & Technology 10, no. 1-4 (March 1993): 123–36. http://dx.doi.org/10.1177/0263617499010001-411.

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The concept of the characteristic curve in physical adsorption and the rule of its temperature invariance is traced from the potential theory of adsorption by Polanyi to the Frenkel–Halsey–Hill equation, the theory of volume filling of micropores by Dubinin et al. and the theory of adsorption on heterogeneous surfaces. A computer simulation of an irregular atomic configuration at the surface of amorphous carbon is presented. In the submonolayer region, the isotherms of argon adsorption simulated on that surface are shown to correspond to the Freundlich equation and are close to the experimental isotherms on a diamond dust sample. Simulated isosteric heats of adsorption are also reasonably close to the experimental data for argon on a real carbon black. The BET C constant for the simulated isotherm is lower than for the real isotherm on untreated carbon black. However, the isotherms at two temperatures can be described by one absolute isotherm of adsorption.
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7

Chen, Qing, Yuanyuan Tian, Peng Li, Changhui Yan, Yu Pang, Li Zheng, Hucheng Deng, Wen Zhou, and Xianghao Meng. "Study on Shale Adsorption Equation Based on Monolayer Adsorption, Multilayer Adsorption, and Capillary Condensation." Journal of Chemistry 2017 (2017): 1–11. http://dx.doi.org/10.1155/2017/1496463.

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Shale gas is an effective gas resource all over the world. The evaluation of pore structure plays a critical role in exploring shale gas efficiently. Nitrogen adsorption experiment is one of the significant approaches to analyze pore size structure of shale. Shale is extremely heterogeneous due to component diversity and structure complexity. Therefore, adsorption isotherms for homogeneous adsorbents and empirical isotherms may not apply to shale. The shape of adsorption-desorption curve indicates that nitrogen adsorption on shale includes monolayer adsorption, multilayer adsorption, and capillary condensation. Usually, Langmuir isotherm is a monolayer adsorption model for ideal interfaces; BET (Brunauer, Emmett, Teller) adsorption isotherm is a multilayer adsorption model based on specific assumptions; Freundlich isotherm is an empirical equation widely applied in liquid phase adsorption. In this study, a new nitrogen adsorption isotherm is applied to simultaneously depict monolayer adsorption, multilayer adsorption, and capillary condensation, which provides more real and accurate representation of nitrogen adsorption on shale. In addition, parameters are discussed in relation to heat of adsorption which is relevant to the shape of the adsorption isotherm curve. The curve fitting results indicate that our new nitrogen adsorption isotherm can appropriately describe the whole process of nitrogen adsorption on shale.
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8

Smith, Kyla, Xiaodan Zhang, and Ron Hofmann. "Assessment of alternate characterization tests for prediction of taste and odour control by granular activated carbon." Water Supply 12, no. 4 (July 1, 2012): 531–39. http://dx.doi.org/10.2166/ws.2012.026.

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The acetoxime number test was recently identified by the American Society for Testing and Materials as a method to characterize activated carbon. This adsorption isotherm gives information about the number of high energy adsorption sites on the surface of an activated carbon. A similar test uses tetrafluoromethane for the same purpose. In contrast, the more common iodine number and Brunauer, Emmet and Teller (BET) surface area parameters are a measure of the total number of adsorption sites. 2-Methylisoborneol (MIB) is reported to require high energy sites for removal, so it was hypothesized that data from acetoxime and tetrafluoromethane isotherm tests for different activated carbons would be better correlated to MIB removal than iodine numbers or BET surface areas. MIB breakthrough was monitored in rapid small-scale column tests (RSSCTs) using four natural waters and five activated carbons. Results showed no correlation between acetoxime or tetrafluoromethane isotherms and MIB breakthrough.
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9

Mashile, Geaneth Pertunia, Kgokgobi Mogolodi Dimpe, and Philiswa Nosizo Nomngongo. "A Biodegradable Magnetic Nanocomposite as a Superabsorbent for the Simultaneous Removal of Selected Fluoroquinolones from Environmental Water Matrices: Isotherm, Kinetics, Thermodynamic Studies and Cost Analysis." Polymers 12, no. 5 (May 12, 2020): 1102. http://dx.doi.org/10.3390/polym12051102.

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The application of a magnetic mesoporous carbon/β-cyclodextrin–chitosan (MMPC/Cyc-Chit) nanocomposite for the adsorptive removal of danofloxacin (DANO), enrofloxacin (ENRO) and levofloxacin (LEVO) from aqueous and environmental samples is reported in this study. The morphology and surface characteristics of the magnetic nanocomposite were investigated by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) adsorption–desorption and Fourier transform infrared spectroscopy (FTIR). The N2 adsorption–desorption results revealed that the prepared nanocomposite was mesoporous and the BET surface area was 1435 m2 g−1. The equilibrium data for adsorption isotherms were analyzed using two and three isotherm parameters. Based on the correlation coefficients (R2), the Langmuir and Sips isotherm described the data better than others. The maximum monolayer adsorption capacities of MMPC/Cyc-Chit nanocomposite for DANO, ENRO and LEVO were 130, 195 and 165 mg g−1, respectively. Adsorption thermodynamic studies performed proved that the adsorption process was endothermic and was dominated by chemisorption.
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10

Bağcı, Safiye, and Ayhan Ceyhan. "Adsorption of methylene blue onto activated carbon prepared from Lupinus Albus." Chemical Industry and Chemical Engineering Quarterly 22, no. 2 (2016): 155–65. http://dx.doi.org/10.2298/ciceq150522030b.

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The adsorption of methylene blue (MB) from synthetic aqueous solutions in batch experiments using Lupinus Albus-activated carbon (LAAC) by chemical activation with zinc chloride was investigated. Prior to adsorption experiments, surface/physical properties of LAAC were determined using Scanning Electron Microscopy, Fourier transform infrared Spectroscopy and nitrogen adsorption isotherm. In the adsorption experiments, effects of adsorption time, solution pH, MB concentration and amount of LAAC were investigated. The isotherm and kinetic parameters were used to describe the experimental data. The BET surface area was 1254 m2/g while its total pore volume was found to be 0.484 cm3/g. Maximum adsorption capacity occurred at solution pH value 10 and was recorded as 109.89 mg/g. Adsorption data were modeled using Langmuir, Freundlich and Temkin adsorption isotherms. Langmuir isotherm and pseudo-second-order models fit to the process and reaction kinetics correspondingly.
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11

Chen, Jun Tao, Yue Xin Han, Shu Fang Ding, and Shui Lin Zheng. "The Adsorption Performance Study of Acid Leaching Residue of Asbestos Tailings." Materials Science Forum 685 (June 2011): 246–52. http://dx.doi.org/10.4028/www.scientific.net/msf.685.246.

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Acid leaching residue of asbestos tailings was calcined at 600°C. N2adsorption and desorption isotherms of this modified mineral material were measured at low temperature and the adsorption characteristic of acid leaching residue as well as the mechanism were discussed. The specific surface area of acid leaching residue was calculated by BET model, and meanwhile micropore and mesopore structural parameters were calculated by means of ‘t-Plot’ and BJH theory, respectively. The results showed that the N2adsorption-desorption isotherms of acid leaching residue were in line withⅠpattern of the IUPAC isotherm criterions. The residue contained well-developed micropore and mesopore system. The adsorption performance of of Pb2+in simulated wastewater for the acid leaching residue was also performed. The results indicated that a predominant chemisorption, which could be fitted by Langmuir isotherm, occurs on the materials.
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12

Kim, Daekyoum. "Better Refined Adsorption Isotherm than BET Equation." American Journal of Analytical Chemistry 07, no. 05 (2016): 421–33. http://dx.doi.org/10.4236/ajac.2016.75039.

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13

Rahman, Muttakin, Pal, Shafiullah, and Saha. "A Statistical Approach to Determine Optimal Models for IUPAC-Classified Adsorption Isotherms." Energies 12, no. 23 (November 29, 2019): 4565. http://dx.doi.org/10.3390/en12234565.

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Adsorption heat transformation (AHT) systems can play a major role in protecting our environment by decreasing the usage of fossil fuels and utilizing natural and alternative working fluids. The adsorption isotherm is the most important feature in characterizing an AHT system. There are eight types of International Union of Pure and Applied Chemistry (IUPAC) classified adsorption isotherms for different “adsorbent-adsorbate” pairs with numerous empirical or semi-empirical mathematical models to fit them. Researchers face difficulties in choosing the best isotherm model to describe their experimental findings as there are several models for a single type of adsorption isotherm. This study presents the optimal models for all eight types of isotherms employing several useful statistical approaches such as average error; confidence interval (CI), information criterion (ICs), and proportion tests using bootstrap sampling. Isotherm data of 13 working pairs (which include all eight types of IUPAC isotherms) for AHT applications are extracted from literature and fitted with appropriate models using two error functions. It was found that modified Brunauer–Emmet–Teller (BET) for Type-I(a) and Type-II; Tóth for Type-I(b); GAB for Type-III; Ng et al. model for Type-IV(a) and Type-IV(b); Sun and Chakraborty model for Type-V; and Yahia et al. model for Type-VI are the most appropriate as they ensure less information loss compared to other models. Moreover; the findings are affirmed using selection probability; overall; and pairwise proportion tests. The present findings are important in the rigorous analysis of isotherm data.
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14

Ribeiro, Luciana C., José M. C. da Costa, and Marcos R. A. Afonso. "Hygroscopic behavior of lyophilized acerola pulp powder." Revista Brasileira de Engenharia Agrícola e Ambiental 20, no. 3 (March 2016): 269–74. http://dx.doi.org/10.1590/1807-1929/agriambi.v20n3p269-274.

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ABSTRACT Powder products are characterized by their practicality and long life. However, fruit powders have high hygroscopicity and tend to agglomerate due to its hydrophilic nature. The isotherms of equilibrium moisture content apply to the study of dehydrated food preservation potential. Acerola is a nutritionally rich fruit, with great economic and industrial potential. The objective of this study was to analyse acerola powder adsorption isotherms obtained by lyophilization and characterize the powder obtained from lyophilized acerola pulp. Analysis of hygroscopicity, solubility and degree of caking were performed. Isotherms were represented by the mathematical models of GAB, BET, Henderson and Oswin, at temperatures of 25, 35 and 45 °C. According to the results, the obtained powder showed hygroscopicity of 5.96 g of absorbed water 100g-1 of solids, solubility of 95.08% and caking of 14.12%. The BET model showed the best fit to the adsorption isotherms of the acerola pulp powder obtained by lyophilization. The obtained isotherm was of type III, with a "J" shape. There was an inversion of the effect of temperature on the isotherms of acerola powders.
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15

Ge, Mingliang, Xubin Wang, Mingyi Du, Guodong Liang, Guoqing Hu, and Jahangir S.M. "Adsorption Analyses of Phenol from Aqueous Solutions Using Magadiite Modified with Organo-Functional Groups: Kinetic and Equilibrium Studies." Materials 12, no. 1 (December 28, 2018): 96. http://dx.doi.org/10.3390/ma12010096.

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Organically-modified magadiite (MAG–CTAB–KH550) was synthesized via ion-exchange method and condensation reaction in the presence of pure magadiite (MAG), cetyltrimethylammonium bromide (CTAB) and γ-aminopropyltriethoxysilane (KH550) in aqueous solution in this research. This new adsorbent material was studied using scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), and N2 adsorption/desorption isotherms process. It was found that the MAG–CTAB–KH550 has high Brunaur-Emmet-Teller (BET) specific surface area and mesoporous pore size distribution which enhanced its ability to remove phenol in aqueous solution; and, the value of pH has a relatively large impact on the adsorption behavior of the sorbent. Finally, the adsorptive behavior of the mesoporous material on phenol was followed pseudo-second-order kinetic adsorption model. In contrast, the adsorption equilibrium isotherm was better performed Langmuir isotherm model than the Freundlich isotherm model; in addition, the results also showed that the MAG–CTAB–KH550 had a better adsorption capacity and removal efficiency than MAG.
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16

Alamri, M. S., A. A. Mohamed, S. Hussain, M. A. Ibraheem, and Akram A. Abdo Qasem. "Determination of Moisture Sorption Isotherm of Crosslinked Millet Flour and Oxirane Using GAB and BET." Journal of Chemistry 2018 (December 11, 2018): 1–8. http://dx.doi.org/10.1155/2018/2369762.

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Epoxy resin was prepared by crosslinking epoxidized oil and millet flour. The reaction was carried out at three different temperatures (25, 40, and 55°C) and zinc chloride levels (1, 2, and 3%). Moisture sorption isotherms were determined at 0.1 to 0.9 water activity (aw) using a gravimetric sorption analyzer (Q 2000). The sigmoidal shape (type II) of the resin isotherms exhibited lower equilibrium moisture content (EMC) at higher temperature. The experimental data were modeled using GAB (Guggenheim–Anderson–de Boer) and BET (Brunauer–Emmett–Teller). The EMC of the resin was significantly lower than that of the flour, which could be attributed to the decrease in the number of water-binding sites due to the creation of dense areas during crosslinking. The low root-mean-square error (RMSE) indicates that GAB and BET were suitable for predicting the water sorption isotherm for millet flour resin. The heat of sorption of the resin was large at low moisture content and increased at higher relative humidity. It is recommended that millet flour resin be used at relative humidity below 60%.
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17

Luo, Li Jun, Ping Bao Ban, Xue Jiao Huang, and Jun Hong Li. "Functionalized Mesporous Silica with Ethylenediamine for Removal of Pb(II)." Applied Mechanics and Materials 395-396 (September 2013): 610–14. http://dx.doi.org/10.4028/www.scientific.net/amm.395-396.610.

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Amine-functionalized mesporous silicas ((referred as NH2MS)) were synthesized by grafting with ethylenediamine. The obtained materials have been characterized by N2 adsorption desorption measurement (BET). Adsorption behaviors of the adsorbent for lead (containing effects factors, kinetics, isotherms, thermodynamics) were investigated. The result indicated that the obtained particles possessed mesoporous structrure. The Pb (II) adsorption isotherm and kinetic data fit Freundlich model and the pseudo second-order kinetic model respectively. the adsorption of Pb (II) onto NH2-MS was an enothermic nature.
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18

Bottani, E. J., J. R. Zarate, and L. E. Torre Cascarini De. "Argon and Nitrogen Physical Adsorption on Boron Nitride." Adsorption Science & Technology 4, no. 1-2 (March 1987): 121–30. http://dx.doi.org/10.1177/0263617487004001-211.

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Physical adsorption isotherms of N2 and Ar on boron nitride are analysed and the behaviour of the adsorbed phase is discussed. Different models are used to interpret the adsorbed states. The behaviour of the BET C parameter suggests that a phase-transition occurs in Ar adsorption which is not showed in its isotherm. Adsorption energies distribution functins are calculated using a double Gaussian as distribution function. Nitrogen cross-sectional areas, under experimental conditions are estimated respect to those of the Ar.
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19

Alam, Md Masud, and Md Nazrul Islam. "Study on water sorption isotherm of summer onion." Bangladesh Journal of Agricultural Research 40, no. 1 (June 19, 2015): 35–51. http://dx.doi.org/10.3329/bjar.v40i1.23753.

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The water sorption characteristics of dehydrated onion and onion solutes composite by vacuum drying (VD) and air drying (AD) were developed at room temperature using vacuum desiccators containing saturated salt solutions at various relative humidity levels (11-93%). From moisture sorption isotherm data, the monolayer moisture content was estimated by Brunauer-Emmett-Teller (BET) and Guggenheim-Anderson-de Boer (GAB) equation using data up to a water activity of 0.52 and 0.93 respectively. Results showed that in case of non treated samples the monolayer moisture content values (Wo) of BET gave slightly higher values than GAB (9.7 vs 8.2) for VD, while GAB gave higher value than BET (11.0 vs 9.8) for AD. It is also seen that the treated and non treated onion slice and onion powder absorbed approximately the same amount of water at water activities below about 0.44 and above 0.44 the treated samples begin to absorb more water than the non treated samples. It was observed that 10-20% added of sugar gave no change in water sorption capacity while the amount of sorbed water increases with increasing amount added salt for mix onion product.Bangladesh J. Agril. Res. 40(1): 35-51, March 2015
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20

Maigalura, K. A., and J. Suleiman. "MOISTURE SORPTION ISOTHERM CHARACTERISTICS OF AWARA FOOD." FUDMA JOURNAL OF SCIENCES 4, no. 2 (July 13, 2020): 620–26. http://dx.doi.org/10.33003/fjs-2020-0402-247.

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Moisture sorption and storage stability of Awara were evaluated using gravimetric method. Guggenhein-Anderson-de boer (GAB) and Brunauer Emmett and Teller (BET) were used in evaluating sorption and desorption isotherm at temperature range of 30, 40 and 50oc in the range of water activity (0.1-0.9).Sigmoid moisture isotherm shapes were obtained at various temperatures. Lowest level EMC was obtained at highest temperature (500c).A non-linear regression analysis was used to fit both BET and GAB. GAB was found to generate higher coefficient of determination R2 (0.9986, 0.9959 and 0.9933) and lowest mean of relative percentage p% (0.231, 0.0061 and 0.0017) at temperature range (30, 40 and 500c) respectively. Safe % water and storage stability were all predicted from adsorption isotherm curve. 3.14, 3.19 and 3.10 were found to be the safe % water which corresponds to the 3.8aw for GAB adsorption graphs at 30, 40 and 500c temperatures respectively. This safe % water will be useful in packaging and determination of shelf- life of Awara.
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21

Alfiah, Mutiara Nur, Sri Hartini, and Margareta Novian Cahyanti. "MATHEMATICAL MODELS AND THERMODYNAMIC PROPERTIES OF MOISTURE SORPTION ISOTHERMS OF FERMENTED CASSAVA FLOUR BY RED YEAST RICE." ALCHEMY Jurnal Penelitian Kimia 13, no. 1 (April 8, 2017): 29. http://dx.doi.org/10.20961/alchemy.13.1.4326.29-40.

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<p>This research aims to determine moisture sorption isotherm curves, moisture sorption isotherm models and thermodynamic properties of fermented cassava flour by red yeast rice. The moisture sorption isotherm model used are Guggenheim Anderson deBoer (GAB), Brunauer Emmet Teller (BET) and Caurie. Meanwhile, the test of modelling accuray by Mean Relative Deviation (MRD) and Root Mean Square Error (RMSE). The thermodynamic properties, i.e., enthalpy and entropy were calculated by Clausius - Clapeyron equation. The result shows that the moisture sorption isotherm curve on fermented cassava flour in a sigmoid form (type II). The GAB model is the best model for moisture sorption isotherm of fermented cassava flour by red yeast rice. The MRD and RMSE values at 30˚C, 35˚C and 40˚C are 3.12%, 2.71%, 3.81%, and 1.01, 0.35, 0.42, respectively. The monolayer moisture content at 30˚C, 35˚C and 40˚C are 6.61%, 6.27% and 6.91%, based on GAB model. Meanwhile, when the BET model was used, the monolayer moisture content are 4.92%, 4.86% and 5.19%, while by Caurie model are 6.37%, 6.18% and 5.30%, at 30˚C, 35˚C and 40˚C, respectively. The enthalpy and entropy of water sorption process were decreased when moisture content increased.</p>
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Alfiah, Mutiara Nur, Sri Hartini, and Margareta Novian Cahyanti. "MATHEMATICAL MODELS AND THERMODYNAMIC PROPERTIES OF MOISTURE SORPTION ISOTHERMS OF FERMENTED CASSAVA FLOUR BY RED YEAST RICE." ALCHEMY Jurnal Penelitian Kimia 13, no. 1 (April 8, 2017): 29. http://dx.doi.org/10.20961/alchemy.v13i1.4326.

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<p>This research aims to determine moisture sorption isotherm curves, moisture sorption isotherm models and thermodynamic properties of fermented cassava flour by red yeast rice. The moisture sorption isotherm model used are Guggenheim Anderson deBoer (GAB), Brunauer Emmet Teller (BET) and Caurie. Meanwhile, the test of modelling accuray by Mean Relative Deviation (MRD) and Root Mean Square Error (RMSE). The thermodynamic properties, i.e., enthalpy and entropy were calculated by Clausius - Clapeyron equation. The result shows that the moisture sorption isotherm curve on fermented cassava flour in a sigmoid form (type II). The GAB model is the best model for moisture sorption isotherm of fermented cassava flour by red yeast rice. The MRD and RMSE values at 30˚C, 35˚C and 40˚C are 3.12%, 2.71%, 3.81%, and 1.01, 0.35, 0.42, respectively. The monolayer moisture content at 30˚C, 35˚C and 40˚C are 6.61%, 6.27% and 6.91%, based on GAB model. Meanwhile, when the BET model was used, the monolayer moisture content are 4.92%, 4.86% and 5.19%, while by Caurie model are 6.37%, 6.18% and 5.30%, at 30˚C, 35˚C and 40˚C, respectively. The enthalpy and entropy of water sorption process were decreased when moisture content increased.</p>
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23

Rukmawati, Yulinda Eka Ayu, Sri Hartini, and Margaretha Novian Cahyanti. "Isoterm Sorpsi Air pada Tepung Ubi Jalar Terfermentasi dengan Angkak." Jurnal Kimia VALENSI 3, no. 1 (May 31, 2017): 71–78. http://dx.doi.org/10.15408/jkv.v3i1.4814.

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The research was aimed to obtain moisture sorption curve , moisture sorption isotherm models and obtain determine the water content monoleyer of fermented sweet potato flour with red yeast rice.The moisture sorption isotherm model used are GAB (Guggenheim Anderson deBoer), BET (Brunauer Emmet Teller) and Caurie.Meanwhile, the test of modelling accuray by MRD (Mean Relative Deviation). The results showed that the water sorption isotherm curve of sweet potato flour fermented with red yeast rice Sigmoid shaped the approach of type II. The precise mathematical models are models of GAB (Guggenheim Anderson deBoer) with a value of MRD at a temperature of 30 °C, 35 °C, 40 °C respectively at 4.41%, to 2.50%, 3.37%. Moisture content of the monolayer at temperature of 30 °C, 35 °C and 40 °C in GAB model was 7.34%, 6.57%, 16.09%, BET model was 2.09%, 1.05%, 4.26%, and Caurie model was 1.41%, 1.36%, 1.42%.DOI: http://dx.doi.org/10.15408/jkv.v0i0.4814
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24

Ahmed, Md Wadud, Mohammad Gulzarul Aziz, and Md Nazrul Islam. "Modeling of Moisture Adsorption Isotherm of Selected Commercial flours of Bangladesh." Agriculturists 16, no. 02 (December 22, 2018): 35–42. http://dx.doi.org/10.3329/agric.v16i02.40341.

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The moisture adsorption behavior is a fundamental knowledge in the processing and storage of food materials. In this paper, the experimental adsorption behavior of wheat, rice and corn flours were compared with five widely recommended adsorption models (BET, GAB, Oswin, Smith and Halsey) in the literature. From the sorption data, monolayer moisture content of wheat, rice and corn flours were estimated as per BET and GAB models. For all flours, GAB model gave higher monolayer moisture content compare to the BET model. Linear regression analysis was done to determine the model constants where all models were compared using regression coefficient and standard error of the estimate. It was observed that there is no single model that could describe accurately the sorption isotherm over the whole range of water activity (aw) and for all types of flours. BET model was found as the best model for the prediction of equilibrium moisture content (EMC) of the most stable region (i.e. EMC corresponding to aw range below 0.52) but it was not suitable at aw above 0.52. The GAB model was found to be the most suitable to predict the EMC for wide range of water activity (0.11 to 0.93). The Agriculturists 2018; 16(2) 35-42
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Msaad, Asmaa, Mounir Belbahloul, and Abdeljalil Zouhri. "Adsorption of an anionic dye on a novel low-cost mesoporous adsorbent: kinetic, thermodynamic and isotherm studies." E3S Web of Conferences 37 (2018): 02002. http://dx.doi.org/10.1051/e3sconf/20183702002.

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Our activated carbon was prepared successfully using phosphoric acid as an activated agent. The activated carbon was characterized by Scanning Electron Micrograph (SEM), Brunauer-Emmett- Teller (BET), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). The aim of our study is to evaluate the adsorption capacity of Methyl Orange (MO) on Ziziphus lotus activated carbon. Adsorption isotherms were studied according to Langmuir and Freundlich Model, and adsorption kinetics according to pseudo-first and second-order. Results show that the maximum adsorption was reached in the first 10min at ambient temperature with a yield of 96.31%. The Langmuir isotherm shows a correlation coefficient of 99.4 % higher than Freundlich model and the adsorption kinetic model follow a pseudo-second-order with a maximum adsorption capacity of 769.23 mg/g. FTIR and X-Ray spectroscopy indicate that our activated carbon has an amorphous structure with the presence of functional groups, where BET analysis revealed a high surface area of 553 mg/g, which facilitate the adsorption process
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26

HUMPOLA, PABLO D., HECTOR S. ODETTI, ETHEL S. E. FLORES, and JOSE LUIS VICENTE. "DESCRIPTION OF DIFFERENT SOLID ADSORBENT SURFACES ADSORPTION MECHANISMS BASED ON A SEQUENTIAL DECOMPOSITION OF ISOTHERMS." Surface Review and Letters 20, no. 02 (April 2013): 1350022. http://dx.doi.org/10.1142/s0218625x13500224.

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In order to analyze the adsorption capacities of different solid substrates, we present a multi-step method to separately study the isotherm at different pressure ranges (steps). The method is based on simple gas isotherm measurements (nitrogen, methane, carbon dioxide, argon, and oxygen) and is tested to describe the adsorption process and characterize a graphitized surface (GCB) and two different granular activated carbons (GAC). The GCB isotherms are described as a sum of Fowler-Guggenheim-Langmuir shifted curves; isotherm behaviors are quite similar at different temperatures, but change below a certain threshold. In GAC the first steps show the same adsorption characteristics at low pressures (Dubinin's description), but this behavior changes at higher pressure regimes, which allows one to elucidate how heterogeneous the surfaces are or how strong the interactions between adsorbed molecules are for this marginal adsorption to occur. We tested different approaches (from BET multilayer to Aranovich) and found quite different features. We finally conclude that if the description of the adsorption on complex substrates, such as those presented here, is carried using only one model, e. g. Dubinin in case of GACs, the resulting characteristics of the adsorbent would be very biased.
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Zhu, Hong Zhi, and Zhen Hua Xue. "Microstructure Analysis of Xanthoceras Sorbifolia Shell Activated Carbon." Advanced Materials Research 941-944 (June 2014): 1051–55. http://dx.doi.org/10.4028/www.scientific.net/amr.941-944.1051.

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The Xanthoceras sorbifolia shell activated carbon which was prepared by using zinc chloride as activating agent has a strong adsorption performance of cationic adsorbate (methylene blue) 845.275mg/g and anionic adsorbate (iodine) 1584.96mg/g. Specific surface area study showed that: the adsorption isotherms of activated carbonsamples are type I isotherm adsorption, BET specific surface area was 1455.233m2/g. Displayed by pore specific surface analyzer's measurement results that the pore radius ratio of activated carbon in the range of 3.2-3.4Å is the largest. This proves that these holes are mainly micropores. Meanwhile, the conclusions obtained by the SEM further proof.
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28

Zolriasatein, Ali A. "Sorption Isotherms and Thermodynamics of Direct Dye onto the Nano Poly(amidoamine) Dendrimer Treated Jute Yarn." Nanoscience & Nanotechnology-Asia 10, no. 5 (November 11, 2020): 673–81. http://dx.doi.org/10.2174/2210681209666190412141442.

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Background: In this study, the poly(amidoamine) (PAMAM) G-2 dendrimer was applied to the jute yarn. Methods: Untreated and dendrimer treated jute yarns were then dyed with Direct Yellow 24. Thermodynamic parameters of dyed samples, free energy (ΔG°), the enthalpy (ΔH°), and the entropy (ΔS°) were also evaluated. Results: Dendrimer treated jute yarn showed higher dye sorption compare to untreated jute yarn. The values of ΔH° and ΔG° indicated that the sorption process was exothermic and spontaneous at low temperature. Conclusion: Freundlich isotherm was found to be the optimum isotherm for untreated and BET isotherm defined for dendrimer treated jute yarn.
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29

Harja, Maria, Gabriela Buema, Nicoleta Lupu, Horia Chiriac, Dumitru Daniel Herea, and Gabriela Ciobanu. "Fly Ash Coated with Magnetic Materials: Improved Adsorbent for Cu (II) Removal from Wastewater." Materials 14, no. 1 (December 25, 2020): 63. http://dx.doi.org/10.3390/ma14010063.

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Fly ash/magnetite material was used for the adsorption of copper ions from synthetic wastewater. The obtained material was characterized by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET) surface area, and vibrating sample magnetometer (VSM). Batch adsorption experiments were employed in order to investigate the effects of adsorbent dose, initial Cu (II) concentration and contact time over adsorption efficiency. The experimental isotherms were modeled using Langmuir (four types of its linearization), Freundlich, Temkin, and Harkins–Jura isotherm models. The fits of the results are estimated according to the Langmuir isotherm, with a maximum adsorption capacity of 17.39 mg/g. The pseudo-second-order model was able to describe kinetic results. The data obtained throughout the study prove that this novel material represents a potential low-cost adsorbent for copper adsorption with improved adsorption capacity and magnetic separation capability compared with raw fly ash.
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30

Mitchison, T. J. "Beyond Langmuir: surface-bound macromolecule condensates." Molecular Biology of the Cell 31, no. 23 (November 1, 2020): 2502–8. http://dx.doi.org/10.1091/mbc.e20-06-0393.

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Macromolecule condensates, phase separation, and membraneless compartments have become an important area of cell biology research where new biophysical concepts are emerging. This article discusses the possibility that condensates assemble on multivalent surfaces such as DNA, microtubules, or lipid bilayers by multilayer adsorption. Langmuir isotherm theory conceptualized saturable surface binding and deeply influenced physical biochemistry. Brunauer-Emmett-Teller (BET) theory extended Langmuir’s ideas to multilayer adsorption. A BET-inspired biochemical model predicts that surface-binding proteins with a tendency to self-associate will form multilayered condensates on binding surfaces. These “bound condensates” are expected to assemble well below the saturation concentration for liquid–liquid phase separation, so they can compete subunits away from phase-separated droplets and are thermodynamically pinned to the binding surface. Tau binding to microtubules is an interesting test case. The nonsaturable binding isotherm is reminiscent of BET predictions, but assembly of Tau-rich domains at low concentrations requires a different model. Surface-bound condensates may find multiple biological uses, particularly in situations where it is important that condensate assembly is spatially constrained, such as gene regulation.
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31

Kovalenko, V., A. Borysova, I. Pliuta, and R. Likhnovsky. "ADSORPTION AS A BASIS OF PROTECTIVE ACTION OF FILTERS-ADSORBER." Науковий вісник: Цивільний захист та пожежна безпека 1, no. 2 (December 30, 2018): 59–63. http://dx.doi.org/10.33269/nvcz.2018.2.59-63.

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This article analyzes the regulatory documents on determination of protective action time of gas filters and FILTERS-ADSORBER, which are designed for individual and collective protection. The current absence of a current regulatory document in Ukraine is indicated according to which protective action time of filters is determined, adds relevance in the implementation of the method of determining this filter characteristic. The theoretical aspects of effect of absorbing capacity of filters are highlighted, the fundamental principles of adsorption are linked with the time of protective action time of filters against hazardous chemicals. The process of adsorption on the surface and formation of sorption layers in case of polymolecular adsorption is schematically shown, as described by the BET theory. It is indicated that protective action time on the direct depends on particular case of adsorption - chemisorption. The types of adsorption isotherms are considered, they are characterized and the Langmuir and BET equations are given. The protective action of filter as a phenomena of chemisorption on the surface of sorbent is described by the Langmuir isotherm, in particular, parts I and II. When determining protective action time the monomolecular adsorption of hazardous chemical substance occurs with formation of a chemical bond with the surface. The chemical bond is formed from the impregnated catalyst due to the redistribution of electrons. Solutions of metal salts are used as a catalyst, and the metal ion itself acts as an active center during the process of chemisorption. The role of adsorption kinetics in the implementation of sanitary cleaning of gas from the pollutant in the practical plane is considered. The possibility of calculating the amount of a chemical that a sorbent can absorb is shown by constructing an adsorption isotherm of a standard substance and a pollutant adsorption working line. Adsorption isotherm was captured for adsorbent from FG-130 FPK 95 filter on KELVIN 1042 sorptometr.
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32

Mohamed, AA, MS Alamri, S. Hussain, MA Ibraheem, and Akram A. Abdo Qasem. "Moisture sorption isotherm of cross-linked wheat gluten and epoxydized oil using GAB and BET." Polymers and Polymer Composites 27, no. 9 (June 3, 2019): 536–45. http://dx.doi.org/10.1177/0967391119853186.

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The moisture sorption isotherm of wheat gluten/epoxydized sesame or sunflower oil resin was determined at 25, 40, and 55°C. The resin was prepared by cross-linking epoxydized oil and wheat gluten using 1, 2, and 3% zinc chloride as the catalyst. The experiment was carried out over 0.1–0.9 water activity ( a w) range using gravimetric sorption analyzer (Q 2000, TA Instruments, New Castle, PA, USA). The resin isotherms were found to be type III shape where the equilibrium moisture content (EMC) was higher at lower temperatures. The EMC of gluten epoxy resin was dependent on the degree of cross-linking because more cross-linking decreased EMC. The Guggenheim Anderson-de Boer (GAB) parameters support the theory of the free volume as it relates to monolayer absorption. This could be attributed to the decrease in the number of water binding sites due to the development of dense areas during cross-linking and increase in the free volume. The GAB and Brunauer–Emmett–Teller were found to be suitable for predicting the water sorption isotherm for gluten protein resin because it provided low root mean square error. The heat of sorption based on the Clausius–Clapeyron equation (qst) increased with decrease in moisture content.
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33

Eslami, Akbar, Zahra Goodarzvand Chegini, Maryam Khashij, Mohammad Mehralian, and Marjan Hashemi. "Removal of acetaminophen (ACT) from aqueous solution by using nanosilica adsorbent: experimental study, kinetic and isotherm modeling." Pigment & Resin Technology 49, no. 1 (January 6, 2020): 55–62. http://dx.doi.org/10.1108/prt-06-2019-0057.

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Purpose A nanosilica adsorbent was prepared and characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and BET. Design/methodology/approach The optimum conditions for the highest adsorption performance were determined by kinetic modeling. The adsorbent was used for the adsorption of acetaminophen (ACT), and the parameters affecting the adsorption were discussed like pH, initial concentration, contact time and adsorbent dosage. The adsorbent have been characterized by SEM, XRD and BET analysis. The kinetic models including pseudo-first-order and pseudo-second-order with Langmuir and Freundlich isotherm models were applied to investigate the kinetic and isotherms parameters. Findings The adsorption of ACT increased to around 95% with the increase of nanosilica concentration to 30 g/L. Moreover, the adsorption process of ACT follows the pseudo-second-order kinetics and the Langmuir isotherm with the maximum adsorption capacity of 609 mg/g. Practical implications This study provided a simple and effective way to prepare of nanoadsorbents. This way was conductive to protect environmental and subsequent application for removal of emerging pollutants from aqueous solutions. Originality/value The novelty of the study is synthesizing the morphological and structural properties of nanosilica-based adsorbent (specific surface area, pore volume and size, shape and capability) and improving its removal rate through optimizing the synthesis method; and studying the capability of synthesis of nanosilica-based adsorbent for removal of ACT as a main emerging pharmaceutical water contaminant.
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34

Balasubramani, Ushadevi, Sangeetha Subramaniam, Liviu Mitu, and Vairam Sundararajan. "Batch and column studies on methylene blue using activated carbon/Al2O3 nano-composite and its impregnated calcium alginate beads." JOURNAL OF ADVANCES IN CHEMISTRY 12, no. 12 (December 20, 2016): 5599–612. http://dx.doi.org/10.24297/jac.v12i12.3890.

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Activated carbon/Al2O3 nano-composite (ANC) was synthesized by simple pyrolysis after incorporating the aluminium acetate precursor in activated carbon (AC) matrix. The as-synthesized composite was characterized by FT-IR, XRD, BET isotherm, SEM, EDX, and TEM. The size of Al2O3 nanoparticles in carbon matrix was found to be in the range of 10-35 nm. Adsorption characteristics of nano-composite was evaluated using methylene blue dye (MB) by batch and column studies. In batch process, the effect of concentration, temperature and pH were investigated. Batch adsorption study was interpreted with Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (D-R) isotherms. Results showed that adsorption follows Freudlich isotherm model with an adsorption capacity of 116 mg/g at pH 7 at 30 °C and it increases with increase in pH. Kinetic data indicated that the adsorption of dye follows pseudo-second order kinetics model. The negative value of ΔG indicates the spontaneous nature of the adsorption process. For column study the nano-composite was fabricated into Calcium alginate beads (CAB). The performance of CAB was studied with different influent concentrations of MB, pH and bed depth and the results have been interpreted using Thomas and BDST models. The column shows an adsorption capacity of 285.57 mg/g of CAB at pH 7 with bed height of 10 cm and best fitted to BDST model. These outcomes indicate the capability of carbon/Al2O3 nano-composite for dye removal.
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35

Teimouri, Abbas, Shima Ghanavati Nasab, Saeed Habibollahi, Mahmoud Fazel-Najafabadi, and Alireza Najafi Chermahini. "Synthesis and characterization of a chitosan/montmorillonite/ZrO2 nanocomposite and its application as an adsorbent for removal of fluoride." RSC Advances 5, no. 9 (2015): 6771–81. http://dx.doi.org/10.1039/c4ra13139h.

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Removal of fluoride by CTS/MMT/ZrO2 nanocomposite as adsorbent was investigated. Adsorbent was characterized by BET, FTIR, SEM and XRD. Effect of molar ratio, pH, temperature on adsorbent capacity and model of kinetics and isotherm was investigated.
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36

Zhang, Cai Xia, Yu Feng Jiang, Min Zhou, Xue Fei Hu, and Uwamungu J. Yves. "Adsorption Equilibrium and Thermodynamics Behavior of Sodium Pentachlorophenol to Biomass-Derived Biochars at Two Pyrolytic Temperatures." Advanced Materials Research 955-959 (June 2014): 2243–47. http://dx.doi.org/10.4028/www.scientific.net/amr.955-959.2243.

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Wheat straws were pyrolyzed at two temperatures (200 and 400°C). For two biochar, the Scanning electron microscope (SEM) and the BET surface area were analyzed. The thermodynamics of sodium pentachlorophenate adsorption on biochar were examined. Adsorption isotherm of sodium pentachlorophenate on biochar was determined and correlated with two well-known isotherm equations (Langmuir and Freundlich adsorption isotherm equation). The equilibrium data for sodium pentachlorophenate adsorption were fitted well with the Freundlich adsorption model. The thermodynamic parameters of Gibbs free energy (△Gθ), enthalpy (△Hθ), and entropy (△Sθ) were also calculated, and the positive value of △Hθsuggests the endothermic nature of the adsorption, whereas the negative values of △Gθtend (s) to prove the spontaneous nature of the adsorption process.
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37

Chentouf, Sadek, Smail Kacha, Réda Marouf, Fouad Mekhalef Benhafsa, Abdelkader Leboukh, and Ahmed Yahiaoui. "Synthesis, Characterization and Application of a Diatomite-Based Composite for the Adsorption of Anionic Dyes in Aqueous Solutions." Chemistry & Chemical Technology 15, no. 3 (August 15, 2021): 377–88. http://dx.doi.org/10.23939/chcht15.03.377.

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Synthesis, characterization and application of the polyaniline-diatomite (PAD) composite in the adsorption of Reactive Red 120 (RR 120) and Acid Blue (AB) dyes were carried out. The composite was prepared by the in situ polymerization of aniline. Mass of purified diatomite was mixed with a solution containing aniline dissolved in 2M hydrochloric acid at room temperature. The solid obtained was characterized using the SEM, XRD and FTIR analyses. The kinetic adsorption of dyes was described using the pseudo-second order kinetic model. The adsorption isotherm of the RR 120 dye can be fitted by the Freundlich adsorption isotherm model. However, the adsorption isotherm of the AB dye can be better fitted by the BET model.
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38

Ghadiri, S., R. Nabizadeh, A. Mahvi, S. Nasseri, A. Mesdaghinia, and S. Talebi. "Potential of granulated modified nanozeolites Y for MTBE removal from aqueous solutions: Kinetic and isotherm studies." Polish Journal of Chemical Technology 14, no. 2 (January 1, 2012): 1–8. http://dx.doi.org/10.2478/v10026-012-0063-8.

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Potential of granulated modified nanozeolites Y for MTBE removal from aqueous solutions: Kinetic and isotherm studies Adsorption of methyl tert-butyl ether (MTBE) from aqueous solutions by granulated modified nanozeolites Y was investigated. Nanozeolite Y powders were converted into granulated zeolites and subsequently modified with two cationic surfactants (20 mmol/dm3), to be used as adsorbent. Granulated nanozeolites were characterized by BET surface area analysis, elemental analysis and X-ray diffractometer. -Hexade-cyltrimethylammonium (HDTMA-Cl) modified granulated zeolite had more effective performance than N-cetylpyridinium bromide (CPB) modified granulated zeolite. The most conventional adsorption isotherms and kinetic models were applied to describe MTBE adsorption and reaction dynamic, respectively. The equilibrium sorption data fitted the Langmuir 2 isotherm model and the kinetic study was followed the pseudo-second-order model. The maximum adsorption capacities for HDTMA-Cl modified zeolite and CPB modified granulated zeolite were 333.33 and 142.8 mg/g, respectively as calculated by the Langmuir model. This study demonstrated that the removal of mtbe by granulated modified nanozeolites Y is a promising technique.
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39

Hong, Yong Pyo, and Keon Sang Ryoo. "Adsorption Of No3--N And Po43--P in Aqueous Solution Using Granular Activated Charcoal (Gac)." JOURNAL OF ADVANCES IN CHEMISTRY 15, no. 2 (December 3, 2018): 6296–305. http://dx.doi.org/10.24297/jac.v15i2.7881.

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In this study, adsorption of NO3- -N and PO43--P on granular activated charcoal (GAC) was investigated depending on pH, agitation time, GAC dosage, adsorption capacity and adsorption isotherms by employing batch adsorption type. The GAC was characterized by thermogravimetric analysis (TG-DTA), scanning electron micrograph coupled with energy-dispersive X-ray spectroscopy (SEM-EDX) and BET surface area analyzer. The GAC exhibited nearly similar adsorption equilibrium time. Both NO3--N and PO43—P appeared to approach equilibrium after approximately 4 h of agitation time. In the adsorption equilibrium, the removal efficiencies of NO3- -N and PO43--P were found to be 14.6-66.0 % and 52.4-99.0 %, respectively. The adsorption data for NO3--N and PO43--P was correlated to Freundlich and Langmuir isotherm model and the equilibrium data was fitted well to the Langmuir isotherm model due to their higher correlation coefficient (R2) value. The Langmuir adsorption capacity was 1.54 and 2.56 mg g-1 for NO3--N and PO43--P, respectively, which suggests that the GAC is a good adsorbent for removal of NO3--N and PO43—P from water.
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40

Mansour, R. A., Abeer El Shahawy, A. Attia, and Mokhtar S. Beheary. "Brilliant Green Dye Biosorption Using Activated Carbon Derived from Guava Tree Wood." International Journal of Chemical Engineering 2020 (July 20, 2020): 1–12. http://dx.doi.org/10.1155/2020/8053828.

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The removal of brilliant green (BG) dye from an aqueous solution using activated carbon (AC) derived from guava tree wood is conducted in batch conditions. The influence of different factors such as contact time, pH, adsorbent dosage, initial dye concentration, and temperature on the adsorption of BG onto AC was investigated. FTIR, BET, and SEM analyses were performed to determine the characteristics of the material. The isotherm results were analyzed using the Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich isotherms. Linear regression was used to fit the experimental data. It was found that the equilibrium data are best represented by the Freundlich isotherm, and the adsorption capacity (qe) was 90 mg dye/g AC. The values of the free energy (∆G), enthalpy (∆H), and entropy (∆S) were −86.188 kJ/mol, 43.025 kJ/mol, and 128 J/mol.K, respectively, at pH 7 for the BG dye. The kinetics of BG dye adsorption were analyzed using pseudo-first-order and pseudo-second-order models, and it was found that the pseudo-second-order model was suitable for the behavior of the BG dye at R2 = 0.999.
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41

Pourzamani, Hamidreza, Bijan Bina, Mohammad Mehdi Amin, and Alimorad Rashidi. "Monoaromatic Pollutant Removal by Carbon Nanotubes from Aqueous Solution." Advanced Materials Research 488-489 (March 2012): 934–39. http://dx.doi.org/10.4028/www.scientific.net/amr.488-489.934.

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The removal of monoaromatic (benzene (B) and toluene (T)) from aqueous solution by multi walled, single walled, and hybrid carbon nanotubes (MWCNTs, SWCNTs, and HCNTs) was evaluated for a nanomaterial dose of 1 g/l, concentration of 10-100 mg/l, and pH 7. The equilibrium amount removed by SWCNTs (B: 9.98 mg/g and T: 9.96 mg/g) was higher than for MWCNTs and HCNTs. Toluene has a higher adsorption tendency on CNTs than benzene, which is related to the increasing water solubility and the decreasing molecular weight of the compounds. The SWCNTs performed better for B and T sorption than the MWCNTs and HCNTs. Isotherms study based on isofit program, indicate that the Generalized Langmuir-Freundlich (GLF) isotherm expression provides the best fit for benzene sorption and Brunauer-Emmett-Teller (BET) isotherm is the best fit for toluene adsorption by SWCNT. SWCNTs are efficient B and T adsorbents and possess good potential applications to water and wastewater treatment and maintain water of high quality that could be used for cleaning up environmental pollution.
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42

Siripatrawan, U., and P. Jantawat. "Determination of Moisture Sorption Isotherms of Jasmine Rice Crackers Using BET and GAB Models." Food Science and Technology International 12, no. 6 (December 2006): 459–65. http://dx.doi.org/10.1177/1082013206072622.

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Moisture sorption isotherms of Thai Jasmine rice crackers were determined at 30, 45 and 60°C over a water activity range of 0.10 to 0.95 using a static gravimetric technique. Moisture sorption isotherms of rice crackers exhibited the sigmoid (Type II) shape. The moisture content of rice crackers decreased as temperature increased at a given water activity of the storage environment. The Brunauer, Emmett and Teller (BET) and Guggenheim-Anderson-de Boer (GAB) models were applied to fit the experimental data. The isosteric heat of sorption at different moisture levels was also determined using the Clausius–Clapeyron thermodynamic equation. A nonlinear regression analysis method was determined to evaluate the parameters of sorption equations. The criteria used to evaluate the goodness of fit of each model were the mean relative percentage deviation modulus (E) and the percentage root mean square error (RMSE). The more extended range of application of the GAB equation over the BET equation was evident. The GAB model gave the best fit to the experimental sorption data for a wide range of water activity (0.10–0.95) while the BET model gave the best fit for a water activity range of less than 0.60. The GAB model is considered suitable to predict the moisture sorption isotherm of rice crackers since it gave low E and RMSE values. The heat of sorption values of rice crackers were found to be large at low moisture content and decreased with an increase in food moisture content.
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43

Hu, Wenhai, Song Cheng, Hongying Xia, Libo Zhang, Xin Jiang, Qi Zhang, and Quan Chen. "Waste phenolic resin derived activated carbon by microwave-assisted KOH activation and application to dye wastewater treatment." Green Processing and Synthesis 8, no. 1 (January 28, 2019): 408–15. http://dx.doi.org/10.1515/gps-2019-0008.

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Abstract The waste phenolic resin was utilized as the raw material to prepare activated carbon (AC) used KOH as the activating agent via microwave heating. The phenolic resin was carbonized at 500°C and then performed with a KOH/Char ratio of 4 and microwave power of 700 W for a duration of 15 min. The physic-chemical characteristics of the AC were characterized by N2 adsorption instrument, FTIR, SEM and TEM. The BET surface area and pore volume of AC were found to be 4269 m2/g and 2.396 ml/g, respectively. The activation process to generate such a phenomenally high surface area of the AC has little reported in open literatures and could pave way for preparation adsorbents that are far superior to the currently marketed adsorbents. The methylene blue (MB) was used as the model to assess its suitability to dye wastewater treatment. Towards this, the MB adsorption isotherms were conducted at three different temperatures and tested with different adsorption isotherm models. The adsorption isotherms could be modeled using Langmuir isotherm. While the kinetics could be used the pseudo-second order kinetics to describe. Thermodynamic results demonstrated that the adsorption process was a spontaneous, as well as an endothermic.
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44

Zhao, Zhun, Zhenhua Li, Penglei Cui, Shengli Li, and Lingqian Kong. "Adsorption of Basic Brown and Chrysophenine from Water Solution by Magnesium Silicate Gel." Journal of Chemistry 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/374190.

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Noncrystalline, high surface area magnesium silicate gel was successfully prepared by hydrothermal method. Such product was characterized by BET and XRD to determine surface area 576.4 m2·g−1, average pore width 2.76 nm, and amorphous surface. The adsorption behaviors of Basic Brown and Chrysophenine on magnesium silicate gel were investigated through changing initial concentration, adsorbent dosage, solution pH, contact time, and temperature. The experimental data was analyzed by the adsorption isotherms and kinetics. The results showed the adsorption progress was fast for Basic Brown, and the adsorption equilibrium was finished in 2 h, while the adsorption equilibrium of Chrysophenine was finished in 7 h. Freundlich isotherm model and second-order kinetic models described the adsorption process very well.
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45

Ebili, Peter Emmanuel, Manase Auta, Kehinde Shola Obayomi, Joseph Onyebuchi Okafor, Muibat Diekola Yahya, and Aisha Abubakar Faruq. "Comparative analysis of linear and nonlinear equilibrium models for the removal of metronidazole by tea waste activated carbon." Water Science and Technology 82, no. 7 (September 7, 2020): 1484–94. http://dx.doi.org/10.2166/wst.2020.428.

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Abstract Tea waste was carbonized at 400 °C for 45 min and modified with potassium hydroxide (KOH), to enhance the active sites for the adsorption of antibiotics. The developed tea waste activated carbon (TWAC) was used as a novel eco-friendly and cost-effective adsorbent for metronidazole (MZN) removal from aqueous solution. The textural and surface properties of the adsorbent were determined using Brunauer-Emmett-Teller (BET) and FT-Raman analysis. The BET surface was found to have increased from 24.670 to 349.585 after carbonization and KOH modification. The batch experimental parameters were optimized and equilibrium time was found to be 75 min. Linear and non-linear models were carried out on the adsorption isotherm and kinetics to determine the best fit for the adsorption data. The adsorption equilibrium data were well fitted by the Freundlich isotherm and pseudo-second order models, with higher regression correlation (R2) and smaller chi-square (χ2), as predicted by the non-linear model. The thermodynamic results revealed the adsorption of MZN as spontaneous, physical, and consistently exothermic in character. The activation energy value of 7.610 kJ/mol further revealed that the adsorption process is dominated majorly by physical adsorption. The removal of MZN onto TWAC was best described by the non-linear adsorption isotherm and kinetics model.
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46

Sananmuang, Ratana, Wipharat Chuachuad Chaiyasith, and Kalayaporn Paroon. "Adsorption of Reactive Dye (RB 222) in Solution onto Chitosan-Rice Husk Ash Composite Beads Cross-Linked with Glutaraldehyde." Key Engineering Materials 751 (August 2017): 719–25. http://dx.doi.org/10.4028/www.scientific.net/kem.751.719.

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The adsorption of reactive dye (RB 222) onto cross-linked chitosan-rice husk ash composite beads was investigated. BET, SEM and FTIR methodologies were used to characterize the properties of the composite beads. The results indicated that the BET surface area values of cross-linked chitosan-rice husk ash composite beads were 4 .740 m2 /g . The effects of various parameters on the adsorption behavior of composite beads including pH (2-12), temperature (20°C, 30°C and 40°C), and initial concentration (10-850 mg/L) were studied. The dye concentrations after adsorption process were measured using a UV/VIS Spectrophotometer at 611 nm. For the effect of pH on reactive dye (RB 222) removal, the highest value of dye removal was obtained at pH 2. The isotherm study was fitted by Freundlich Isotherm. Moreover, thermodynamics of adsorption was also found that the △Go had negative values. It indicates the feasibility of adsorption process at temperature below 40°C.
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47

Adeleke, Abdul Rahman O., Ab Aziz Abdul Latiff, Zawawi Daud, Baharudin Ridzuan, and Nur Falilah Mat Daud. "Remediation of Raw Wastewater of Palm Oil Mill Using Activated Cow Bone Powder through Batch Adsorption ." Key Engineering Materials 705 (August 2016): 380–84. http://dx.doi.org/10.4028/www.scientific.net/kem.705.380.

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The most critical parameter of palm oil mill effluent (POME) is chemical oxygen demand (COD mg/L). The adsorption of COD mg/L from raw POME using activated cow bone powder has been investigated. The raw POME contains 4.786 g/L of COD, which has to be treated effectively before discharge. Batch experiments were conducted at fixed condition of pH, contact time and speed at different weight dosages for different particle sizes of 75, 150 and 300μm. The result obtained showed a similar adsorption pattern for the particle sizes, the optimum removal was obtained at 150 μm at 0.025g/L with 71% removal efficiency, there was no further significant diference after the adsorption at this stage. The BET adsorption model was adopted to describe the experimental isotherm and isotherm constants for the optimum particle size. The equilibrium data fitted well to the BET model. The hydrophobic behaviour of the CBP proved by the WDPT analysis influenced the removal of COD mg/L on CBP.
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48

Hu, Chunlian, Wei Zhang, Yuantao Chen, Na Ye, DaWa YangJi, Haizhe Jia, Yanting Shen, and Minna Song. "Adsorption of Co(II) from aqueous solution using municipal sludge biochar modified by HNO3." Water Science and Technology 84, no. 1 (May 24, 2021): 251–61. http://dx.doi.org/10.2166/wst.2021.199.

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Abstract Here adsorption studies were proposed on a carboxylated sludge biochar (CSB) material modified by HNO3 to assess its capacity in the removal of cobalt from aqueous solution. The as-prepared sludge biochar material was characterized by Brunauer-Emmett-Teller (BET) analysis, Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), energy-dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The isotherm process could be well described by the Langmuir isotherm model. The adsorption kinetics indicated that cobalt adsorption followed a pseudo-second-order kinetics model. The mechanism between Co(II) and biochar involved electrostatic interaction, ion exchange, surface complexation and physical function. The adsorption capacity on CSB was as high as 72.27 mg·g−1, surpassing original sludge biochar (SB) as CSB had abundant oxygen-containing functional groups and many hydroxyls, plus the BET surface areas increased when SB was modified by HNO3, which stimulated adsorption effect. Therefore, this work shows that CSB could be used as an efficient adsorbent to remove Co(II) in wastewater.
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49

Esmaeili Bidhendi, Mehdi, Zahra Poursorkh, Hassan Sereshti, Hamid Rashidi Nodeh, Shahabaldin Rezania, and Muhammad Afzal Kamboh. "Nano-Size Biomass Derived from Pomegranate Peel for Enhanced Removal of Cefixime Antibiotic from Aqueous Media: Kinetic, Equilibrium and Thermodynamic Study." International Journal of Environmental Research and Public Health 17, no. 12 (June 13, 2020): 4223. http://dx.doi.org/10.3390/ijerph17124223.

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Nano-sized activated carbon was prepared from pomegranate peel (PG-AC) via NaOH chemical activation and was fully characterized using BET, FT-IR, FE-SEM, EDX, and XRD. The newly synthesized PG-AC was used for cefixime removal from the aqueous phase. The effective parameters on the adsorption process, including solution pH (2–11), salt effect (0–10%), adsorbent dosage (5–50 mg), contact time (5–300 min), and temperature (25–55 °C) were examined. The experimental adsorption equilibrium was in close agreement with the type IV isotherm model set by the International Union of Pure and Applied Chemistry (IUPAC). The adsorption process was evaluated with isotherm, kinetic, and thermodynamic models and it is were well fitted to the Freundlich isotherm (R2 = 0.992) and pseudo-second-order model (R2 = 0.999). The Langmuir isotherm provided a maximum adsorption capacity of 181.81 mg g−1 for cefixime uptake onto PG-AC after 60 min at pH 4. Hence, the isotherm, kinetic and thermodynamic models were indicated for the multilayer sorption followed by the exothermic physical adsorption mechanism.
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50

Binh, Quach An, and Puangrat Kajitvichyanukul. "Adsorption mechanism of dichlorvos onto coconut fibre biochar: the significant dependence of H-bonding and the pore-filling mechanism." Water Science and Technology 79, no. 5 (December 28, 2018): 866–76. http://dx.doi.org/10.2166/wst.2018.529.

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Abstract The adsorption mechanism of dichlorvos onto coconut fibre biochar (CFB) was investigated by the batch adsorption technique. Coconut fibre waste material was synthesised at 600 °C for 4 h under oxygen-limited conditions. The biochar was modified by HCl acid to enhance the specific surface area and porosity. The characteristics of the biochar were analysed by scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) specific surface area, and Fourier transform-infrared (FT-IR). The results showed that the BET specific surface area of biochar was 402.4 m2/g. Experimental data presented a good fit to Langmuir isotherm and the pseudo-second-order model. Langmuir isotherm illustrated that monolayer adsorption of dichlorvos occurred on the surface of CFB, with a maximum adsorption capacity of 90.9 mg/g. The diffusion model confirmed that the liquid film diffusion was the rate-limiting step, and the major diffusion mechanism of dichlorvos onto biochar. The BET result after dichlorvos adsorption demonstrated that pore-filling occurred and occupied 58.27%. The pore-filling and chemical interactions, performed important roles in the adsorption of dichlorvos onto CFB. Chemical adsorption is comprised of two interactions, which are hydrophobic and H-bonding, but the prime is H-bonding. CFB is a very potential material for the removal of dichlorvos and environmental pollutants.
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