Journal articles: 'Temkin isotherm'

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El-Aswad, Ahmed F., Mohamed R. Fouad, Mohamed E. I. Badawy, and Maher I. Aly. "Modeling study of adsorption isotherms of chlorantraniliprole and dinotefuran on soil." Current Chemistry Letters 13, no. 3 (2024): 503–14. http://dx.doi.org/10.5267/j.ccl.2024.2.008.

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Knowledge of pesticide adsorption characteristics is essential to predict their behavior in soil. The adsorption equilibrium isotherms of two insecticides chlorantraniliprole (CAP) and dinotefuran (DNF) on two common Egyptian soil types, clay loam and sandy loam were studied and modeled. To predict the adsorption isotherms and to determine the adsorption parameters, ten isotherm models: Langmuir (five linear forms), Freundlich, Temkin, Dubinin-Radushkevich, Elovick, Fowler-Guggenheim, Kiselev, Jovanoic, Harkins-Jura, and Halsey were applied on experimental data. The results revealed that the adsorption isotherm models fitted the data in the order of Halsey > Freundlich > Jovanoic > Langmuir isotherme. The models of Harkins-Jura, Elovich, Temkin, and Fowler-Guggenheim are not applicable to predict the adsorption isotherms of the tested insecticides. In order to determine the best-fit isotherm, the correlation coefficient (R2), comparing the experimental (exp) and calculated (cal) adsorption data, and a normalized standard deviation (Δg%) were used to evaluate the data. Therefore, the isotherm models Halsey and Freundlich could be used to predict the adsorption characteristics of CAP and DNF in the common Egyptian soil types, clay loam and sandy loam. Consequently, the mathematical models Halsey, Freundlich, and Jovanoic can describe the fate of CAP and DNF and can be used to control Egyptian soil contamination.

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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 (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 &gt; Temkin &gt; 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 &gt; 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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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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Alcides, M. M. Michellod, N. Pila Andrea, I. Profeta Mariela, et al. "Models Sorption of Cyhalofop-Butyl, on Mesopotamic Agricultural Soils." Chemistry Research Journal 5, no. 4 (2020): 54–61. https://doi.org/10.5281/zenodo.12595863.

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Abstract The adsorption equilibrium of butyl (2R)-2-[4-(4-cyano-2-fluorophenoxy) phenoxy]propanoate (CB) was studied in rice-growing soil. The equilibrium sorption data were fitted into Langmuir, Temkin and Dubinin–Radushkevich (DRK) isotherms. Of the four adsorption isotherm, the R2 value of Dubinin–Radushkevich isotherm model was the highest. The maximum monolayer coverage (qm) from Langmuir isotherm model was determined to be 0.079 mg g-1, the separation factor indicating a favorable sorption experiment is 0.38. The heat of sorption process was estimated from Temkin Isotherm model to be 0.0004 J mol-1 and the mean free energy was estimated from DRK isotherm model to be 7.0 KJ mol-1 which vividly proved that the adsorption experiment followed a physical process.

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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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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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Javed, Ifrah, Muhammad Asif Hanif, Umer Rashid, Farwa Nadeem, Fahad A. Alharthi, and Elham Ahmed Kazerooni. "Enhancing Functionalities in Nanocomposites for Effective Dye Removal from Wastewater: Isothermal, Kinetic and Thermodynamic Aspects." Water 14, no. 17 (2022): 2600. http://dx.doi.org/10.3390/w14172600.

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The adsorption process combined with electrocoagulation is a highly effective technique for dye removal. Calcinized and non-calcinized composites based on bentonite and sodium zeolite were prepared for adsorptive removal of Foron EBL blue, Terasil brown 2RFL, Torque blue PG, and Orange P3R dyes. Factors affecting the adsorption process, such as contact time, initial dye concentration, and temperature, were also explored in this study. Equilibrium data of natural clay composites was explained by Freundlich, Langmuir, Dubinin Radushkevich isotherm, Harkin Jura, and Temkin isothermal models. Harkin Jura isotherm model best fitted on the adsorption mechanism compared to Langmuir and Temkin isotherm model. Morphology of clay-based adsorbents and functional group arrangement were investigated by scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR). The calcinized nano-composite material exhibited better adsorption capacity than non-calcinized nano-composite and could be employed as a low-cost alternative for dye removal.

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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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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 (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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Rashi, Gupta, and Rawal Nekram. "Removal of chromium(VI) in wastewater by adsorption on iron oxide nanoparticles." Journal of Indian Chemical Society Vol. 95, Mar 2018 (2018): 243–46. https://doi.org/10.5281/zenodo.5641981.

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Civil Engineering Department, Motilal Nehru National Institute of Technology, Allahabad-211 004, Uttar Pradesh, India E-mail : rashigpt97@gmail.com, nek_friend@rediffmail.com Manuscript received 15 November 2017, revised 26 February 2018, accepted 07 March 2018 The nanoparticles are used in various applications because of their narrow size distribution, huge surface area, better compatibility and great adsorption efficiency to various heavy metal ions. In this paper, iron oxide nanoparticles were prepared from low-grade iron ore by coating with ferric chloride. This iron oxide nanoparticles adsorbent was used for the removal of chromium(VI) from aqueous solution in the batch reactor with different conditions such as pH, contact time and heavy metal ion concentration. The adsorption of 37 nm size iron oxide nanoparticles adsorbent was achieved 87% greater adsorption capacity of 10 mg/L solution at 3 pH with the contact time of 5 min. The Langmuir, Freundlich and Temkin adsorption isotherm was used to explain the isotherms and isotherm constants. The experimental data were best fitted by Temkin isotherm with 0.99 consistency.

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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 (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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Adejo, S. O., M. M. Ekwenchi, J. A. Gbertyo, T. Menengea, and J. O. Ogbodo. "Determination of Adsorption Isotherm model best fit for methanol leaf extract of Securinega virosa as corrosion inhibitor for corrosion of mild steel in HCl." JOURNAL OF ADVANCES IN CHEMISTRY 10, no. 5 (2014): 2737–42. http://dx.doi.org/10.24297/jac.v10i5.891.

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The adsorption isotherm model best fit of the methanol leaf extract of Securinega virosa as corrosion inhibitor for the corrosion of mild steel in 2 M HCl medium was determined with the assistance of the Adejo-Ekwenchi adsorption isotherm. The corrosion inhibition study was carried out using the weight loss method at the temperature range of 301 K to 313 K. The inhibition efficiency, %IE, of the extract was found to increase with increase in both concentration and temperature. On the account of, R2 this adsorption process well fitted into Langmuir, Freundlich, Temkin isotherm, Flory-Huggins and Adejo-Ekwenchi models. However, through the parameter b of the Adejo-Ekwenchi isotherm, which clearly shows the adsorption process to be chemisorption, the best isotherm fit for the extract has been resolved to be the Langmuir isotherm and Temkin isotherm models.

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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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Johnson, Robert D., and Frances H. Arnold. "The temkin isotherm describes heterogeneous protein adsorption." Biochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology 1247, no. 2 (1995): 293–97. http://dx.doi.org/10.1016/0167-4838(95)00006-g.

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Kanwal, Farah, Muhammad Imran, Liviu Mitu, Zeeshan Rashid, Huma Razzaq, and Qurat-Ul-Ain. "Removal of Chromium(III) Using Synthetic Polymers, Copolymers and their Sulfonated Derivatives as Adsorbents." E-Journal of Chemistry 9, no. 2 (2012): 621–30. http://dx.doi.org/10.1155/2012/857579.

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This study is concerned with the development of some synthetic polymers, copolymers and their sulfonated derivatives as adsorbents. The effectiveness of these adsorbents in removing Cr(III) from aqueous solution was evaluated by batch technique. The influence of different experimental parameters on removal process such as solution pH, contact time, adsorbent dose, Cr(III) concentration and temperature were evaluated. Adsorption equilibrium was achieved in 20 to 30 min. at pH > 5. The Langmuir, Freundlich and Temkin adsorption isotherms were used to elucidate the observed sorption phenomena. The maximum Cr(III)37.8 mg/gram of PS(polystyrene) and 37.2 mg/g of SAN (styrene/acrylonitrile copolymer) was removed as evaluated from Langmuir isotherm while the heat of sorption was in the range 0.21–7.65 kJ/mol as evaluated from Temkin isotherm. It can be concluded that PS developed in this study exhibited considerable adsorption potential for application in removal of Cr(III) from aqueous media as compared to its copolymers and other derivatives used in this study.

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Anwar Mohamad Said, Khairul, Nor Zakirah Ismail, Ramizah Liyana Jama'in, et al. "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 (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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Phung, Thi Lan, Thi Kim Giang Nguyen, Phuong Hien Ho, and Thanh Nga Pham. "Study on the equilibrium and kinetics of nickel (II) adsorption on cellulose from peanut shell modified with chitosan." Ministry of Science and Technology, Vietnam 66, no. 1 (2024): 24–33. http://dx.doi.org/10.31276/vjste.66(1).24-33.

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In this study, cellulose was produced by activating peanut shells with 5% NaOH as an alkaline agent and bleaching with 5 wt.% H2O2. Before being modified with chitosan, the cellulose was slightly oxidized with ammonium persulfate to introduce carboxyl groups. The equilibrium and kinetics of nickel adsorption on the as-prepared material were investigated. Langmuir, Freundlich, and Temkin isotherm models were used to describe the equilibrium isotherms. The Langmuir and Temkin adsorption isotherms were better fits to the equilibrium data than the Freundlich equation. The Langmuir monolayer adsorption capacity of nickel ions on cellulose from peanut shells modified with chitosan was found to be 25.70 mg/g. The Temkin adsorption constant was calculated as 0.45 kJ/mol. Therefore, the interaction between nickel ions and the surface of the as-prepared material are assumed to be weak. Kinetic data were evaluated by pseudo-first-order and pseudo-second-order models, and rate constants were determined. Simulations demonstrated that the pseudo-second-order equation could adequately describe the adsorption of nickel ions.

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El-Khatib, Ahmed M., N. S. Yousef, Z. F. Ghatass, Mohamed S. Badawi, M. M. Mohamed, and Mostafa Elkhatib. "Synthesized Silver Carbon Nanotubes and Zinc Oxide Nanoparticles and their Ability to Remove Methylene Blue Dye." Journal of Nano Research 56 (February 2019): 1–16. http://dx.doi.org/10.4028/www.scientific.net/jnanor.56.1.

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A promising rotating arc discharge method has been developed for producing high purity silver carbon nanotube and zinc oxide nanoparticles, to study their capacities for methylene blue (MB) dye removal under different conditions such as contact time, initial methylene blue dye ion concentration, solution pH, and adsorbent dose. The equilibrium isotherm data were analyzed using Langmuir, Freundlich, Temkin isotherms. Correlation coefficients indicated the following order to fit isotherms for silver carbon nanotube: Freundlich > Langmuir > Temkin. On the other hand, for zinc oxide nanoparticles, the following adjustment founded to fit isotherms was: Langmuir > Temkin> Freundlich. Furthermore, separation factors and distribution coefficients of Methylene blue (MB) dye were calculated. Adsorption kinetic data were analyzed using pseudo-first and second -orders and Elovich model. Film and intraparticle Diffusion model were used to investigate Adsorption mechanism. Kinetic studies showed that the adsorption of methylene blue onto silver carbon nanotubes followed Elovich kinetic model, and the rate of adsorption is controlled by the liquid film diffusion model. Adsorption of methylene blue on zinc oxide nanoparticles followed the pseudo-second-order kinetic model, and the rate of adsorption is controlled by the intraparticle diffusion model.

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AMOKO, Justinah, Babatunde OJO, Ayotunde BABATOLU, Abidemi DEMEHIN, and Isaiah Oke. "Linear and Non-Linear of 2-Parameters Adsorption Equilibrium Isotherm Models of Synthetic Arsenic Wastewaters." Fundamental and Applied Agriculture 8, no. 4 (2023): 684. http://dx.doi.org/10.5455/faa.143385.

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Contamination of groundwater and surface water with arsenic (Asic) has become emerging health and environmental problem around the world. This problem has received significant attention amongst scientists for the development of new adsorbents to remediate Asic -contaminated water. The ability of the immobilized powdered eggshell (Poes), as adsorbent, to remove Asic was studied under batch conditions. Equilibrium data were analysed using non-linear and linearized two-parameter adsorption isotherms models (Langmuir, Freundlich, Elovich, Flory–Huggins, Temkin, Frenkel- Hasley- Hill; Langmuir- Vageler, Hill-de Boer, Kiselev, Fowler- Guggenheim, Dubinin –Radushkevich, Jovanovic, Harkins–Jura and Halsey). The performance of adsorption equilibrium isotherm models was evaluated statistically using the following analysis of variance (ANOVA), model of' selection criterion (MSC), Coefficient of Determination (CD), Correlation coefficient (R) and Akaike Information Criterion (AIC). The study revealed that for non-linear equilibrium isotherm models, Freundlich (0.986 and 3.906) > Fowler—Guggenheim (0.996 and 5.176) and Hasley (0.986 and 3.906) performed well in predicting experimental data-based on the magnitudes of R and MSC. The linearized adsorption equilibrium isotherm models, Dubinin – Radushkevich (0.993 and 4.621) <Temkin (0.994 and 4.701) < Kiselev (0.9999 and 8.856). These three models are the best isotherm models for Asic adsorption onto Poes. It was concluded that Poes particles contain numerous materials that aid Asic adsorption. Based on the performance indicators and to ensure reliable results of adsorption equilibrium data analysis through the adsorption isotherm models, it is necessary that these data sets should be evaluated by both non-linear and linear regression analyses.

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Charnkeitkong, Panida, and Siriporn Sripiboon. "Potassium Hydroxide Activation as an Adsorbent for Equilibrium Isotherms of Hexavalent Chromium Adsorptions onto Garcinia mangosteen Shell." Materials Science Forum 1086 (April 27, 2023): 107–14. http://dx.doi.org/10.4028/p-ta8d2y.

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The equilibrium isotherms of hexavalent chromium adsorption from water on potassium hydroxide (KOH) activated for mangosteen shell as an adsorbent by carbonization at 400 °C for 2 hours has been researched. The effective specific surface area of a biochar adsorbent is 164 m2/g, and its hexavalent chromium adsorption capacity can be encountered to be replied to on the pH 2.0 with initial feed concentration and temperature. The equilibrium adsorption isotherm models based on the Freundlich, Langmuir, Temkin, Hurkins-Jura, Halsay, Dubinin-Radushkevich, and Jovanovic models have been accompanied to compare the sorbate-sorbent system. The Freundlich isotherm model indicated a good fit with the experimental data for the system studied.

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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 (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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Yaqoob, Dr Ghassan Burhan. "Adsorption of Some Heavy Elements on Surface of Activated Carbonized Cellulose from Aqueous Solution." Journal of Petroleum Research and Studies 12, no. 2 (2022): 110–22. http://dx.doi.org/10.52716/jprs.v12i2.661.

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In this study the activated carbonized cellulose in (350 ºC) by citric acid have been used to remove some heavy metals (Hg Cd, Cu, Pb) from its aqueous solution at room temperature. The adsorbed metals data applied on three adsorption isotherm models, Freundlich, Langmuir and Temkin isotherms. The adsorption results were very good fitted with isotherm models by the (R2) meaningful value. The removal metals adsorbed on surface of adsorbent from high to the less remove arranged according to its ability depending on the nature and size of metals. The free energy (ΔG) and constants of the adsorption process (Ɵ, n, kf, kT, b, bT) for copper, lead and cadmium were measured from isotherm curves, infra-red spectrums of the activated carbonized cellulose and cellulose itself were measured by FTIR spectrophotometer.

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Sarker, Tithi, Jannatun Nayeema, Joy Sarker, Mst Jannatul Ferdous, Mst Bushra Fatema, and Md Sadiqul Amin. "Phosphate Sorption Characteristics in Some Soils of Ganges Tidal Floodplains." Asian Journal of Soil Science and Plant Nutrition 10, no. 4 (2024): 288–300. http://dx.doi.org/10.9734/ajsspn/2024/v10i4404.

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A laboratory experiment was carried out with four representative soil series named Bajoa, Dumuria, Jhalakati, and Ghior which are collected from the Ganges tidal floodplain in Bangladesh where the main cropping pattern is rice-vegetables to determine the phosphorus adsorption. The selected physical and chemical properties of the soils were estimated in triplicate using standard methods. The highest phosphate sorption was found in Jhalakati soil using the Freundlich adsorption isotherm, in Bajoa soil using the Langmuir adsorption isotherm, and in Dumuria soil using the Temkin adsorption isotherm. The experiment revealed that the Langmuir equation provided the best fit for phosphorus adsorption data across the soils compared to the Freundlich and Temkin models. The good fit of the Langmuir model suggests that the phosphorus sorption affinity of the soils remained constant as surface saturation increased.

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Abdullah, Salah M., Aseel F. Alwan, Atheer M. Majeed, and Enageh T. A. Abdalgader. "Linear and Non-linear Regression Methods to Study the Adsorption of Cr(VI) from an Aqueous Solution Using Pomegranate Peel." Al-Mustansiriyah Journal of Science 34, no. 4 (2023): 58–65. http://dx.doi.org/10.23851/mjs.v34i4.1340.

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In this study, the previous data of the adsorption of Chromium (VI) ions on the pomegranate peels (MPGP) as adsorbents were used. linear and non-linear equations for Langmuir, Freundlich, Dubinin-Radushkevich, Tempkin, Redlich-Peterson, Sips, and Toth adsorption isotherm models were applied. The five error functions ERRSQ, HYBRD, MPSD, ARE, and EABS were analyzed for non-linear isotherm equations and in each case a set of isotherm parameters were determined. The algorithms for the simulation of linear and non-linear isotherm models using error functions were achieved with the aid of Microsoft Excel solver Add-Ins for minimizing the respective error function across the concentration range studied. Linear and non-linear methods show comparable data for two-parameter models, also high R2 values were obtained for Langmuir, Freundlich, and Temkin models while the Dubinin-Radushkevich model reveals low R2 values, on the contrary, three-parameter models show different data between linear and non-linear methods with high R2 value for all. Which indicates that the error does not obey the Gaussian distribution.

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Akbar, Ishaa, Muhammad Asif Hanif, Umer Rashid, Ijaz Ahmad Bhatti, Rais Ahmad Khan, and Elham Ahmed Kazerooni. "Green Nanocomposite for the Adsorption of Toxic Dyes Removal from Colored Waters." Coatings 12, no. 12 (2022): 1955. http://dx.doi.org/10.3390/coatings12121955.

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The discharge of dyes from textile industries led to a broad range of toxicological and environmental effects, posing severe health issues for humans and animals worldwide. These dyes are highly stable and, if not adequately treated, remain in the environment for extended periods. Adsorption, the most efficient and cost-effective method, offers unique advantages for using natural adsorbents, such as marble waste composites, for dye removal. The easy availability of marble waste, its low cost, its eco-friendly nature, its ease of operation, its simplicity of design, its flexibility, and its great affinity for dyes make it a suitable option for dye removal. Golden marble waste nanocomposites are prepared for dye removal. The results from the studies suggested that treated golden marble composite materials exhibit better adsorption efficiency (224.8, 299.5, and 369.2 mg/g) for adsorptive removal of dyes than untreated golden marble composite materials (114.4 mg/g). This research also used isothermic and kinetic models to evaluate the effects of numerous parameters, for example, the initial dye concentration, pH, time, temperature, and adsorbent dose. The highest removal of 369.9 mg/g was achieved during the present study for blue dye at an optimized pH of 7 and a temperature of 30 °C. It was observed that golden marble waste composites gave better R2 (0.99) values for second-order kinetics in the kinetic model. Results obtained from comparing Langmuir, Freundlich, Temkin, Dubinin, and Herkin Jura isotherms showed that the R2 values of the Langmuir isotherm for Foron red (0.97), the Temkin isotherm for Foron blue (0.98), and the Freundlich isotherm for Foron black dye (0.97) fit on adsorption for both treated and untreated composites. Characterization techniques, such as scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR), are also discussed for the structural determination of golden marble waste composites.

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Dinh, Van Phuc, Ngoc Chung Le, Thi Phuong Tu Nguyen, Thi Dong Thuong Hoang, Van Dong Nguyen, and Ngoc Tuan Nguyen. "Zinc Adsorption Property of Gamma-MnO₂ Nanostructure: Equilibrium and Kinetic Studies." Key Engineering Materials 708 (September 2016): 3–8. http://dx.doi.org/10.4028/www.scientific.net/kem.708.3.

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In this work, gamma–MnO2 nanostructure was used as a sorbent to remove Zn (II) ion from aqueous solution. The influence of pH, sorption time and Zn (II) ion initial concentration were examined. The results showed that equilibrium adsorption was obtained after 60 minutes with 240 rpm of shaking speed at pH = 4.0. The experimental data were analyzed using five non-linear isotherm models: Langmuir, Freundlich, Sips, Tempkin and Dubinin – Radushkevich. The adsorption capacity (qm) from the Langmuir isotherm model for Zn (II) is founded as 55.23 mg/g. The heat of sorption process and the mean free energy were estimated from Temkin and Dubinin – Redushkevich isotherm models to be less than 8 kj/mol which vividly proved that the adsorption experiment followed a physical process. Kinetic studies have shown that although the adsorption data partially followed pseudo-first-order and pseudo-second-order equation for different time, it was well expressed by pseudo-second-order model.

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Kemi, Damilola Ogundipe, and Babarinde Adesola. "Comparative study on batch equilibrium biosorption of Cd(II), Pb(II) and Zn(II) using plantain (Musa paradisiaca) flower: kinetics, isotherm, and thermodynamics." Chemistry International 3, no. 2 (2017): 135–49. https://doi.org/10.5281/zenodo.1473092.

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The potential of plantain (Musa paradisiaca) flower to remove Cd(II), Pb(II) and Zn(II) from aqueous solutions has been investigated under different process parameters like pH, contact time, biomass dose and initial metal ion concentration. The optimum pH for the biosorption of each of the metal ions is pH 6. The kinetic data obtained were subjected to four kinetic models, among which the pseudo-second order kinetic model was found to be the best model that describes the biosorption of each of the metal ions. The equilibrium sorption data were fitted into Langmuir, Freundlich, Temkin and D-R isotherms. In each case, the Freundlich isotherm model gave the best fit giving the sorption intensity (n) values of 1.17, 0.91 and 0.90 which indicate favourable sorption of Cd(II), Pb(II) and Zn(II), respectively. The heat of the sorption process was estimated from Temkin Isotherm model and the mean free energy was estimated from D-R isotherm model to be 312.81Jmol-1, 223.61Jmol-1 and 316.55Jmol-1 for Cd(II), Pb(II) and Zn(II), respectively. Thermodynamically, the biosorption of each of the metal ions is endothermic and the order of spontaneity of the biosorption process being Cd(II) > Zn(II) > Pb(II). Similarly, positive change in entropy was observed for each, the order of disorderliness is Cd(II) > Zn(II) = Pb(II).

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Ayad Alshammari, Najah, Ehteram A. Noor, and Jamilah Mohammad Alahmari. "Adsorption Behavior of some N-alkyl Pyridinium Salts from Aqueous Solution on Amberlite-IR 120 H+ resin." Oriental Journal of Chemistry 34, no. 3 (2018): 1283–96. http://dx.doi.org/10.13005/ojc/340312.

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The effect of Amberlite-IR 120 H+ resin to remove some organic compounds (N-alkyl pyridinium salts) from aqueous solutions at certain conditions was investigated. The effect of resin dosage, contact time, adsorbate concentration, ionic strength and solution temperature on the adsorption efficiency was examined. The experimental data collected generally proved that the adsorption efficiency decreased as the alkyl chain increased. The thermodynamic equilibrium parameters of the adsorption processes were evaluated and showed that the adsorption process is spontaneous, disordered and exothermic. Langmuir, Freundlich, Temkin and Dubinin–Radushkevich (D.R) isotherm models were applied based on the batch method. Freundlich, Temkin and D. R gave bilinear segments model based on the adsorbate initial concentrations except that for compound III where it gave straight of one segment for Temkin adsorption isotherm. Overall, Amberlite-IR 120 H+ resin is effective in removing some N-alkyl pyridinium salts from an aqueous solution.

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29

Fodeke, A. A., and O. J. Ayejuyone. "Adsorption of methylene blue on corncob charcoal: Thermodynamic studies." Ife Journal of Science 23, no. 1 (2021): 131–44. http://dx.doi.org/10.4314/ijs.v23i1.13.

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To obtain the thermodynamic properties of adsorption of methylene blue (MB) on corncob carbonaceous adsorbents - untreated (UCC) and acid treated (TCC) - their equilibrium adsorption was determined between 10 o– 40o C at different pH conditions. The adsorption isotherms were fitted to Freundlich, Langmuir and Temkin isotherm models. The point of zero charge of each of the adsorbents was also determined. The point of zero charge was 10.58 ±0.09 for TCC, and 7.55 ± 0.10 for UCC. Only Freundlich model could account for the observed thermodynamic properties of MB adsorption by the adsorbents, though Temkin and Langmuir models have higher correlation coefficients. MB adsorption by TCC was an entropically driven process which depends on pH;ΔSo at pH 10.5 < ΔSo at pH 8.0 <ΔSo at pH 12.0. The ΔHo of the endothermic process at pH 12 is > ΔHo at pH 8 > ΔHo at pH 10.5. The results suggest that MB adsorption by the adsorbents occur by physisorption and is optimum when the pH is around the point of zero charge. It is important to ensure that in addition to fitting and equilibrium adsoption data by an isotherm model, the fit of the relevant equilibrium parameter should also be good and give thermodynamic quantities that could satisfactorily account for the observed adsorption properties of the system. Deciding the suitability of an isotherm model for fitting adsorption equilibrium experiment based on compared error function of the fitted curves or lines through single temperature isotherm could lead to erroneous conclusion. Keywords: adsorption, adsorbent; methylene blue; enthalpy; entropy; Freundlich

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30

Kulkarni, Kavita, Rahul Kulkarni, Yogesh Chendake, Arghya Garg, and Pragati Srivastava. "Adsorptive Removal of Acetic Acid by Walnut Shell as Low-Cost Adsorbent." Asian Journal of Chemistry 34, no. 9 (2022): 2318–24. http://dx.doi.org/10.14233/ajchem.2022.23851.

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Walnut shell was used as an adsorbent for adsorption of acetic acid. Batch experiments were conducted for adsorption equilibrium studies and kinetics by using walnut shell. Optimization of parameters like temperature, rotation, adsorbent dose and contact time were studied. Amount of acetic acid adsorbed was analyzed by titration. Equilibrium condition was investigated. Adsorption kinetics were tested for different models and found best suitable for intraparticle diffusion model. The batch experimental data was fitted to Langmuir, Freundlich, Temkin, Sips and Redlich-Peterson isotherms. The best fitted isotherm was Langmuir isotherm. Regeneration was tried by heating the adsorbent in microwave at 200 ºC. Up to three cycles adsorbent gave good efficiency for adsorption of acetic acid.

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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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32

SD, Pardeshi. "Kinetic and Equilibrium Studies of Methylene Blue Adsorption on Alstonia Scholaris Plant Leaf Powder." Physical Science & Biophysics Journal 7, no. 1 (2023): 1–7. http://dx.doi.org/10.23880/psbj-16000249.

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In the current work the methylene blue removal using leaf powder of Alstonia Scholaris was investigated. Pseudo first order, second order and Elovic model ware applied, it has been observed that the adsorption follows second order kinetic model. The isotherm study was done by using Langmuir, Temkin and Freundlich isotherm, the Freundlich isotherm was best suited for present investigation. The maximum adsorption was observed at pH 7.5.

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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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Bodunde, V. T., F. A. Adekola, and N. Abdus-Salam. "Investigation of Sorption of Chromate Ion On A Synthetic Hematite." Journal of North Carolina Academy of Science 129, no. 1 (2013): 24–33. http://dx.doi.org/10.7572/2167-5880-129.1.24.

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Abstract A Hematite sample was synthesized using precipitation method and it was characterized using a combination of analytical techniques such as infrared spectroscopy, X-ray diffractometry and atomic absorption spectrometry. The hematite was then studied for its potential to remove chromate ion from aqueous solution. The maximum adsorption capacity was found to be 1.91 mg/g. The influence of contact time, ionic strength and pH on the sorption capacity was also investigated. Maximum adsorption was observed in the range pH 4.0 and pH 6.0 at an optimum time of 3 hours 20 mins. The experimental results were finally analyzed using Langmuir, Freundlich and Temkin isotherms. The Temkin isotherm was found to have the most satisfactory fitting for the sorption data. The sorption kinetics was studied for the pseudo-first order and pseudo-second order models.

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35

Wu, Xiu Jie, Ju Xiu Tong, Chao Qun Tan, Bill X. Hu, and Jin Zhong Yang. "Study on the Adsorptive Solute Cr(VI) Loss from Soil to Surface Runoff with Temkin Adsorption." Applied Mechanics and Materials 641-642 (September 2014): 209–16. http://dx.doi.org/10.4028/www.scientific.net/amm.641-642.209.

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Based on the water balance and solute mass conservation, a simple two-layer incomplete mixing model by Tong et al. (2009) is used to study adsorptive solute of Cr (VI) loss from soil into surface runoff with nonlinear Temkin adsorption. Laboratory experimental data are used to verify the model with nonlinear Temkin isotherm adsorption equation. Study results suggest that model simulations with Temkin isotherm equation agree well with the observed data, which means that the model is valid. The sensitivity of the model parameters were analyzed, which shows that the mixing parameters γ and α are more sensitive to the soil solute of Cr (VI) loss to surface runoff while the parameter B1 and A1 of adsorption equation is less sensitive. The solute of Cr (VI) loss to surface runoff is decreasing with increasing θ0, while soil bulk density is vice verse. The study results will provide references to prevent soil solute of Cr (VI) pollution to surface water system.

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Salahudeen, N., and M. Abubakar. "Isotherm Study of Crystal Violet on Activated Carbon Synthesized from Millet Stover." Journal of Engineering Sciences 9, no. 2 (2022): F1—F5. http://dx.doi.org/10.21272/jes.2022.9(2).f1.

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Continuous release of synthetic dyes from industrial effluent into surface water poses a huge environmental threat and health hazard to humans and aquatic life. The need to right the wrong occasioned by the inimical industrial practice of uncontrolled release of carcinogenic dyes into the surface water calls for research into effective treatment technologies for the treatment of dye-contaminated industrial effluent. The isotherm of Crystal Violet (CV) solution on activated carbon (AC) synthesized from millet stover was investigated and presented herein. Samples of AC were synthesized from millet stover at 120⁰C using phosphoric acid as the activating agent. Employing varying mix ratios of stover-to-phosphoric acid (1:0, 1:1, 1:2, 1:3, and 1:4), respective samples of AC were synthesized. The batch adsorption process of the various samples of the AC in 15 mg/l initial concentration of an aqueous solution of CV was carried out at varying times. The CV’s change in the sorbate’s concentration was monitored using a UV spectrophotometer. The optimum adsorption time was 240 min. The optimally synthesized activated carbon was the 1:2 sample having an equilibrium sorbent concentration of 0.74 mg/L and sorbate uptake of 95.1%. Langmuir, Freundlich and Temkin isotherm models were employed for the isotherm analysis. The values of the Langmuir, Freundlich and Temkin models were 0.99, 0.90, and 0.94, respectively. The isotherm constants for the Langmuir, Freundlich and Temkin models were –1.52 l/mg, –4.08, and 0.005 l/min, respectively. The Langmuir isotherm model best fitted the adsorption mechanism with a maximum equilibrium adsorption capacity of 14.0 mg/g.

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Choi, Jung-Weon, and Sang-June Choi. "Polyacrylamide Functionalized Graphene Oxide/Alginate Beads for Removing Ciprofloxacin Antibiotics." Toxics 10, no. 2 (2022): 77. http://dx.doi.org/10.3390/toxics10020077.

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Ciprofloxacin (CPX), a widely used antibiotic, was removed by synthesizing graphene oxide/calcium alginate–polyacrylamide (GO/Ca-Alg2–PAM) beads, a three-dimensional double-network complex. The synthesis of GO/Ca-Alg2–PAM beads was performed by crosslinking and cation exchange mechanisms with graphene oxide (GO), sodium alginate (Na-Alg), and polyacrylamide (PAM). The properties of GO/Ca-Alg2–PAM beads were confirmed using field emission scanning electron microscopy, Fourier transform infrared spectroscopy, and a thermogravimetric analysis. Furthermore, isothermal adsorption experiments were performed and fitted using three isothermal adsorption models (Langmuir, Freundlich, and Temkin). The adsorption isotherm experimental data fit well with the Langmuir isotherm model with a qm value of 6.846 mg/g. In addition, the spontaneous reaction of the CPX adsorption using GO/Ca-Alg2–PAM was confirmed by temperature-dependent experiments.

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Jung, Y., Jei Won Yeon, and Yeong Keong Ha. "Preparation and Cu(II) Complexation Characteristics of Carboxymethylated Polyethyleneimine (CM-PEI) / Microporous Activated Carbon Composite." Solid State Phenomena 119 (January 2007): 303–6. http://dx.doi.org/10.4028/www.scientific.net/ssp.119.303.

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We present the preparation and Cu(II) adsorption characteristics of a new and innovative composite which was composed of a carboxymethylated polyethyleneimine (CM-PEI) and an activated carbon with a nanopore less than 2 nm in diameter. In this study, we examined the adsorption phenomena of Cu(II) on the CM-PEI/F400 composite and evaluated the adsorption data using three kinds of isotherm models (Langmuir, Freundlich, and Temkin isotherms). It was found that the adsorption of Cu(II) on the CM-PEI/F400 composite obeys the Langmuir isotherm model. Furthermore, The Cu element mapping results showed that Cu was well distributed throughout all the surface of the composite particle, suggesting that the surface of the F400 particle was uniformly covered with CM-PEI.

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Chu, Khim Hoong. "Revisiting the Temkin Isotherm: Dimensional Inconsistency and Approximate Forms." Industrial & Engineering Chemistry Research 60, no. 35 (2021): 13140–47. http://dx.doi.org/10.1021/acs.iecr.1c01788.

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Shi, Wei Mei, Ye Chun Ding, and Long Huo Wu. "The Adsorption Properties of Ciprofloxacin by KMnO₄Modified 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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Lee, Jong Jib, and Jong Ki Jeon. "Isotherm, Kinetic and Thermodynamic Studies on Adsorption of Bromocresol Purple, Acid Red 66 and Acid Blue 40 Using Activated Carbon." Journal of Nanoscience and Nanotechnology 21, no. 7 (2021): 4104–9. http://dx.doi.org/10.1166/jnn.2021.19176.

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This study was conducted with a batch reaction to equilibrium isotherm, kinetic and thermodynamic parameters on adsorption of bromocresol purple (BCP), acid red 66 (AR 66) and acid blue 40 (AB 40) from aqueous solution by using activated carbon with nanopores. Freundlich and Temkin isotherm models were used to evaluate the suitability of isotherm for adsorption equilibrium data. The adsorption equilibrium was best fitted by Temkin model. The Freundlich separation factor values indicated that adsorption on the nanoporous activated carbon could effectively treat three dyes. The kinetic analysis of the adsorption process confirmed that it was more consistent with the pseudo second order model. The intraparticle diffusion was rate limiting step. The adsorption process of three dyes were endothermic because they were positive enthalpy values. The free energy values of three dyes decreased with increasing temperature, so that the spontaneity becomes higher with temperature increase. The activation energy value of three dyes were confirmed the physical adsorption.

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Lahuri, Azizul Hakim, Mohd Ambar Yarmo, Maratun Najiha Abu Tahari, et al. "Comparative Adsorption Isotherm for Beryllium Oxide/Iron (III) Oxide Toward CO₂ Adsorption and Desorption Studies." Materials Science Forum 1010 (September 2020): 361–66. http://dx.doi.org/10.4028/www.scientific.net/msf.1010.361.

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Surface modification of Fe2O3 by adding BeO was synthesized and calcined at different temperatures of 200-600 °C. The adsorbents were characterized by using XRD, N2 adsorption-desorption isotherm prior to performing CO2 adsorption and desorption studies. The CO2 adsorption data were analyzed using adsorption isotherm models such as Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich. BeO/Fe2O3-300 that calcined at 300 °C showed the most efficient adsorbent with physisorption and chemisorption were measured at 5.85 and 45.88 mg/g respectively. The CO2 adsorption notably best fitted with Freundlich isotherm with R2 = 0.9897 and calculated adsorption capacity closest to experimental data. This implies the CO2 adsorption process was governed by multilayer adsorption on the heterogeneous surface of the adsorbent. The mean free energy of adsorption (E=3.536 kJ/mol) from Dubinin-Radushkevich and heat of adsorption (bT=3.219 kJ/mol) from the Temkin model support that the adsorption process is physical phenomena.

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Olufemi, Babatope Abimbola, and Anne Nlerum. "Parametric Statistical Significance of Iron (II) Ions Adsorption by Coconut Shell in Aqueous Solutions." NUST Journal of Engineering Sciences 11, no. 1 (2019): 17–25. http://dx.doi.org/10.24949/njes.v11i1.285.

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The parametric statistical adsorption of chemically unmodified coconut shell powder (CSP) to adsorb iron (II) ions from aqueous solutions was examined in this work. It was observed that the adsorption capacity increased with increasing adsorbent dose, reducing adsorbate dose, increasing contact time, decreasing temperature and reducing particle size. As observed about one gram of the adsorbent was sufficient enough to remove 98 % iron (II) ions. A total contact time of about 40 minutes was sufficient for almost complete adsorption of the ions, while a pH of about 6.0 exhibited the maximum adsorption capacity. The sorption data were fitted into Langmuir, Freundlich, Temkin and the Dubinin-Radushkevich isotherms, fitted most with the Freundlich Isotherm model. The energy values obtained from the Temkin and Dubinin-Radushkevich isotherm model indicated high chemisorption phenomenon with the adsorbents. Investigation of some kinetic models confirmed that the adsorption of iron (II) ions using CSP was a pseudo-second order kinetic process, which further corroborates that chemisorption dominates the adsorption. Fourier Transform Analysis (FTIR) further established and justified the outcome of the study. The adsorption was parametrically justified statistically with Analysis of Variance (ANOVA) and Bonferroni-Holm Posthoc significance test. Conclusively, coconut shell proved strongly to be an effective and suitable adsorbent for removing iron (II) ions from aqueous solutions.

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Onwordi, Chionyedua T., Cosmas C. Uche, Alechine E. Ameh, and Leslie F. Petrik. "Comparative study of the adsorption capacity of lead (II) ions onto bean husk and fish scale from aqueous solution." Journal of Water Reuse and Desalination 9, no. 3 (2019): 249–62. http://dx.doi.org/10.2166/wrd.2019.061.

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Abstract The present study compared the adsorption capacity of Pb (II) ions from aqueous solution onto biopolymer materials (BPMs): (bean husk (BH) and fish scale (FS)). Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques were used to characterize the BPMs. The optimal conditions of the variables: pH, adsorbent dosage, initial metal concentration, contact time and temperature were ascertained. Experimental data were applied to the Langmuir, Freundlich and Temkin sorption isotherms using the linear equations form. The optimal removal of Pb (II) ions with BH and FS was obtained at pH 7.0 and 6.0, and 0.2 g adsorbent dosage each, respectively. The removal of Pb (II) ions fitted the pseudo-second order kinetic model well for the materials. Equilibrium Langmuir isotherm, which indicated a heterogeneous process, gave a better conformity than the other models used for BH while the Temkin isotherm gave better conformity for FS. The FS reached equilibrium faster (at about 30 min) compared to BH (at about 60 min); however, the processes are both spontaneous and endothermic. The BPMs gave about 90% removal of Pb (II) ions at the optimum dosage when used for textile wastewater. The BPMs, therefore, can be used as effective, low-cost and environmentally friendly adsorbents.

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Mahajan, Tanuj, Susanta Paikaray, and Pooja Mahajan. "Applicability of the equilibrium adsorption isotherms and the statistical tools on to them: a case study for the adsorption of fluoride onto Mg-Fe-CO₃ LDH." Journal of Physics: Conference Series 2603, no. 1 (2023): 012056. http://dx.doi.org/10.1088/1742-6596/2603/1/012056.

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Abstract The demand for a low-cost, easy-to-use, low-maintenance system of adsorbents for detoxifying wastewater effluents is growing. A proper understanding of adsorption mechanisms, their controls, and adsorbate-adsorbent behavior is essential. Thus, the current study deals with the required understanding of linear equilibrium adsorption isotherm models. The adsorption data of different concentrations of fluoride onto Mg-Fe-CO3 LDH is fitted to isotherm models. The two-parameter models discussed are Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich, whereas the three-parameter model cited is Redlich-Peterson. To identify the best-fitting model(s) in an equilibrium isotherm study to quantitatively represent the relevant sorption system, various error functions and statistical tools, such as average relative error deviation (ARED), sum of square errors (ERRSQ or SSE), hybrid relative error function (HYBRID), Marquardt’s percent standard error deviation (MPSD), sum of absolute errors (EABS), sum of normalized errors (SNE), correlation coefficient of Pearson (r), coefficient of determination (r2), chi-square test (χ2), student’s T-test and F-test were applied. It is found that the Temkin model best fits the isotherm data, and the sorption process occurs over multiple layers as per the Freundlich isotherm and was found to be more promising than Langmuir’s monolayer sorption process. The exothermic physisorption course for the adsorbate-absorbent interactions is deduced from the isotherm parameters.

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Liu, Xiangyao, Baohui Wang, Guolin Jing, and Ya'nan Sun. "Adsorption behaviors of methylene blue on sunflower stem pith." Water Science and Technology 79, no. 8 (2019): 1458–66. http://dx.doi.org/10.2166/wst.2019.142.

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Abstract Adsorption behaviors of methylene blue (MB) from aqueous solution using sunflower stem pith (SSP) as adsorbent were investigated. The effects of adsorption conditions such as adsorption time, initial concentration of MB and dosage of SSP on the detoxification of MB were examined. The equilibrium adsorption data were analyzed using three well-known isotherms: Langmuir, Freundlich and Temkin. The results indicated that the Langmuir isotherm fitted well to the data as compared with another isotherm model. The maximum adsorption capacity calculated by the Langmuir isotherm model was 277 mg/g at 338 K. Kinetic analyses were conducted using pseudo first order, pseudo second order and the Elovich model. The regression results showed that the MB adsorption was described by the pseudo second order model. Different thermodynamic parameters such as Gibb's free energy (ΔGo), standard enthalpy change (ΔHo) and standard entropy change (ΔSo) were also evaluated. The results showed that the detoxification of MB using SSP as adsorbent was feasible, non-spontaneous and exothermic under experimental conditions.

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Chauhdary, Yusra, Muhammad Asif Hanif, Umer Rashid, et al. "Effective Removal of Reactive and Direct Dyes from Colored Wastewater Using Low-Cost Novel Bentonite Nanocomposites." Water 14, no. 22 (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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48

Khan, A. S. A. "Equilibrium and Thermodynamic Study of Cadmium Adsorption on Dalbergia Sissoo Sawdust." Nucleus 53, no. 1 (2017): 1–8. https://doi.org/10.71330/thenucleus.2016.231.

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In the present paper, the equilibrium and thermodynamic parameters of cadmium adsorption from aqueous solution on sodium hydroxide modified Dalbergia sissoo sawdust were evaluated on the basis of Langmuir, Temkin and Dubinin-Radushkevich isotherms. The adsorption of cadmium on sawdust was monolayer type, renewable and occurred by complexation mechanism. The analysis of thermodynamic data indicated that adsorption of cadmium on Dalbergia sissoo sawdust is spontaneous, exothermic and entropy driven. The linear form of Dubinin-Radushkevich isotherm was established which can be used for evaluation of saturated equilibrium concentration of adsorbate where all adsorption sites become fully occupied. The correlation between Langmuir and Temkin adsorption parameters was also explored which indicated that the magnitude of enthalpy of adsorption is equal to the heat of adsorption at half coverage. The results and interpretations based on present study may be used as a source for understanding the nature of adsorption phenomena.

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Issa, Ragiab A. M., Hana B. AlHanash, Mona M. Abdulsalam, Amar A. Tekalli, Laila K. Ben Hamed, and Suha A. Ben Omran. "Study on Natural Diatomite as an Adsorbent for Uranyl (VI) ions, Using Spectrophotometric Method." Journal of Pure & Applied Sciences 23, no. 1 (2024): 58–63. http://dx.doi.org/10.51984/jopas.v23i1.2910.

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This work is based on the investigation of uranyl (VI) ion adsorption onto natural diatomite using batch sorption method under different parameters such as pH, initial ion concentration, adsorbent amount and effect of sulfate ion as a foreign ion. 8-hydroxyquinoline is used as a chromogen forming a pale-yellow complex with ions in chloroform, the absorbance was measured spectrophotometrically at λmax 460 nm, obtaining a linear calibration curve with R2=0.998, LOD=3.03 mg/L and LOQ=9.21 mg/L. Prior to the implementation of the batch experiment, the morphology and composition of diatomite was confirmed using XRF (Bruker S8 Tiger), XRD (Bruker D5005), FTIR (Bruker Vector 22), and SEM (JEOL JSM-5610 LV) techniques. From spectrophotometric analysis, the results showed that the maximum uranyl ion adsorption distribution coefficient reached at the initial concentration of 50ppm, pH 4.5, contact time 5hrs and adsorption dosage of 2 g/L. There was no significant effect of sulfate ion on the adsorption affinity. Adsorption isotherm was studied by Langmuir which was favourable model fitting with R2=0.996 and maximum adsorption capacity of 16mg/g, and separation factor RL = 0.0122. Freundlich isotherm model also applied for the same data and give a very straight line with R2= 1.00 and maximum adsorption capacity of 200 mg/g. Temkin model was less fit and gave a negative isotherm curve with R2= 0.78, KT= 0.9405 L/g, bT= 24.724 J/mol. Langmuir and Freundlich isotherms gave exothermic adsorption while Temkin gave an endothermic one.

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Surisetty, Venkateswara Rao, Janusz Kozinski, and L. Rao Nageswara. "Biosorption of Lead Ions from Aqueous Solution UsingFicus benghalensisL." Journal of Engineering 2013 (2013): 1–8. http://dx.doi.org/10.1155/2013/167518.

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Ficus benghalensisL., a plant-based material leaf powder, is used as an adsorbent for the removal of lead ions from aqueous solution using the biosorption technique. The effects of process parameters such as contact time, adsorbent size and dosage, initial lead ion concentration, and pH of the aqueous solution on bio-sorption of lead byFicus benghalensisL. were studied using batch process. The Langmuir isotherm was more suitable for biosorption followed by Freundlich and Temkin isotherms with a maximum adsorption capacity of 28.63 mg/g of lead ion on the biomass ofFicus benghalensisL. leaves.

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Journal articles on the topic 'Temkin isotherm'

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