On the use of linearized pseudo-second-order kinetic equations for modeling adsorption systems

The adsorption of Cu2+, Zn2+, Cd2+ and Pb2+ ions from aqueous solution by Algerian raw diatomite was studied. The influences of different sorption parameters such as contact pH solution, contact time and initial metal ions concentration were studied to optimize the reaction conditions. The metals ions adsorption was strictly pH dependent. The maximum adsorption capacities towards Cu2+, Zn2+, Cd2+ and Pb2+ were 0.319, 0.311, 0.18 and 0.096 mmol g−1, respectively. The kinetic data were modelled using the pseudo-first-order and pseudo-second-order kinetic equations. Among the kinetic models studied, the pseudo-second-order equation was the best applicable model to describe the sorption process. Equilibrium isotherm data were analysed using the Langmuir and the Freundlich isotherms; the results showed that the adsorption equilibrium was well described by both model isotherms. The negative value of free energy change ΔG indicates feasible and spontaneous adsorption of four metal ions on raw diatomite. According to these results, the high exchange capacities of different metal ions at high and low concentration levels, and given the low cost of the investigated adsorbent in this work, Algerian diatomite was considered to be an excellent adsorbent.

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Removal of Basic Orange 2 dye and Ni2+ from aqueous solutions using alkaline-modified nanoclay

Water Science & Technology ◽

10.2166/wst.2021.121 ◽

2021 ◽

Author(s):

Armin Geroeeyan ◽

Ali Niazi ◽

Elaheh Konoz

Keyword(s):

Experimental Data ◽

High Efficiency ◽

Adsorption Process ◽

Kinetic Equations ◽

Dye Adsorption ◽

Second Order ◽

Isotherm Models ◽

Order Kinetic ◽

Diffusion Kinetic ◽

Pseudo Second Order

Abstract In the present research, the removal of Basic Orange 2 (BO2) dye using alkaline-modified clay nanoparticles was studied. To characterize the adsorbent, XRD, FTIR, FESEM, EDX, BET and BJH analyses were performed. The effect of the variables influencing the dye adsorption process such as adsorbent dose, contact time, pH, stirring rate, temperature, and initial dye concentration was investigated. Furthermore, the high efficiency of Ni2+ removal indicated that it is possible to remove both dye and metal cation under the same optimum conditions. The experimental data were analyzed by Langmuir and Freundlich isotherm models. Fitting the experimental data to Langmuir isotherm indicated that the monolayer adsorption of dye occurred at homogeneous sites. Experimental data were also analyzed with pseudo-first-order, pseudo-second-order, and intra-particle diffusion kinetic equations for kinetic modeling of the dye removal process. The adsorption results indicated that the process follows a pseudo-second-order kinetic model. The thermodynamic parameters of the dye adsorption process such as enthalpy, entropy, and Gibbs free energy changes were calculated and revealed that the adsorption process was spontaneous and endothermic in nature. The results presented the high potential of the modified nanoclay as a cost-effective adsorbent for the removal of BO2 dye and Ni2+ from aqueous medium.

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Adsorption and dyeing properties of acid dyes on fine denier silk fibers

Textile Research Journal ◽

10.1177/0040517519869389 ◽

2019 ◽

Vol 90 (3-4) ◽

pp. 433-441

Author(s):

Sheng Sun ◽

Yuansong Zhang ◽

Yushan Zou ◽

Fangyin Dai ◽

Shixiong Yi

Keyword(s):

Kinetic Equations ◽

Dye Adsorption ◽

Second Order ◽

Silk Fiber ◽

Order Kinetic ◽

Order Model ◽

Dyeing Property ◽

Silk Fibers ◽

Ph Values ◽

Pseudo Second Order

In this work, the surface morphology and diameter distribution of fine denier silk fiber were observed and measured. The adsorption property of acid orange 7 on the fine denier silk fiber was studied. The pseudo-first-order model and pseudo-second-order model adsorption kinetic models were employed to evaluate the experimental data. The effects of pH values and reaction temperature on the dyeing property were investigated. The results indicated that the fine denier silk fiber exhibited a uniform fiber diameter (9 µm), which is smaller than that of conventional silk fiber (16 µm). The adsorption process of the dye could be described using pseudo-second-order kinetic equations. A higher the amount of dye adsorption at equilibrium and faster adsorption rate was obtained for the fine denier silk fiber. The color strength of fine denier silk fibers was improved for the decreased pH values and increased temperature, which exhibited an excellent dyeing property.

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Adsorption of Chromium Ions on Activated Carbon Produced from Cow Bones

Iraqi Journal of Chemical and Petroleum Engineering ◽

10.31699/ijcpe.2019.2.4 ◽

2019 ◽

Vol 20 (2) ◽

pp. 23-32

Author(s):

Marah Waleed Khalid ◽

Sami D. Salman

Keyword(s):

Surface Area ◽

Kinetic Equations ◽

Freundlich Isotherm ◽

Second Order ◽

Raw Material ◽

Isotherm Models ◽

Order Kinetic ◽

Solution Ph ◽

Chromium Ions ◽

Pseudo Second Order

Due to the broad range uses of chromium for industrial purposes, besides its carcinogenic effect, an efficient, cost effective removal method should be obtained. In this study, cow bones as a cheap raw material were utilized to produce active carbon (CBAC) by physiochemical activation, which was characterized using: SEM to investigate surface morphology and BET to estimate the specific surface area. The best surface area of CBAC was 595.9 m2/gm which was prepared at 600 ᵒC activation temperature and impregnation ratio of 1:1.5. CBAC was used in aqueous chromium ions adsorption. The investigated factors and their ranges are: initial concentration (10-50 mg/L), adsorption time (30-300 min), temperature (20-50 ᵒC) and solution pH (2-11). Isotherm of adsorption and its kinetics were studied. The adsorption process was modeled statistically and was represented by an empirical model. Equilibrium data were fitted to the Langmuir and Freundlich isotherm models and the data best represented by Freundlich isotherm. Pseudo- first order and pseudo- second order kinetic equations were utilized to study adsorption kinetics, where chromium adsorption on CBAC fitted pseudo- second order fitted the data more adequately. The best removal efficiency was found to be 94.32%.

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Removal of cationic dye (basic red 18) from aqueous solution using natural turkish clay

Global NEST Journal ◽

10.30955/gnj.000944 ◽

2013 ◽

Vol 15 (4) ◽

pp. 529-541 ◽

Cited By ~ 12

Keyword(s):

Experimental Data ◽

Ionic Strength ◽

Initial Conditions ◽

Kinetic Equations ◽

Agitation Speed ◽

Second Order ◽

Order Kinetic ◽

Cationic Dye ◽

Adsorbent Dosage ◽

Pseudo Second Order

<p>In this study, the removal of a cationic dye, basic red 18, used in the textile industry with montmorillonite was investigated as a function of initial dye concentration, pH, agitation speed, adsorbent dosage, ionic strength, and temperature. Adsorption process was attained to the equilibrium within 30 minutes. The adsorption capacity of basic red 18 increased with increasing ionic strength, initial dye concentration, pH, agitation speed, and temperature, but decreased with increasing adsorbent dosage. The experimental data were analyzed by Langmuir, Freundlich, Temkin, Elovich and Dubinin-Radushkevich isotherms, and it was found that the isotherm data were reasonably correlated by Freundlich isotherm. Pseudo-first order, pseudo-second order, Elovich kinetic equations and intraparticle diffusion model were used to examine the experimental data of different initial conditions. It was found that the pseudo-second order kinetic equation described the data of dye adsorption onto montmorillonite very well. Furthermore, for the removal of basic red 18, a semi-empirical model was established. Thermodynamic analysis was carried out for basic red 18 onto montmorillonite. It was found that the adsorption processes were endothermic in nature. The values of Ea, ΔH*, ΔS* and ΔG* at 293 K for basic red 18 adsorption on clay were calculated as 27.635 kJ mol-1, 25.041kJ mol-1, -0.090 kJ mol-1 K-1 and 51.412 kJ mol-1, respectively. The results indicated that montmorillonite could be employed as an alternative to commercial adsorbents in wastewater treatment for the removal of color and dyes.</p>

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High Efficiency of Natural Safiot Clay to Remove Industrial Dyes from Aqueous Media: Kinetic, Isotherm Adsorption and Thermodynamic Studies

Biointerface Research in Applied Chemistry ◽

10.33263/briac115.1271712731 ◽

2021 ◽

Vol 11 (5) ◽

pp. 12717-12731

Keyword(s):

High Efficiency ◽

Aqueous Media ◽

Kinetic Equations ◽

Experimental Tests ◽

Batch Process ◽

Second Order ◽

Synthetic Wastewater ◽

Isotherm Models ◽

Order Kinetic ◽

Pseudo Second Order

This study's objective was to demonstrate the potential of Natural Safiot Clay (NSC) for removing cationic dyes MB and Safranin from synthetic wastewater. The operation parameters investigated included initial concentrations, adsorbent dose, initial pH, and temperature. Experimental tests were conducted in a batch process. The experimental isotherms data were analyzed using Langmuir, Freundlich, and Dubinin–Radushkevich isotherm models. The Langmuir model obtained the best fit with a maximum monolayer adsorption capacity of 68.49 mg/g for MB and 45.45 mg/g for safranin. Pseudo-first-order, pseudo-second-order kinetic equations, and intraparticle diffusion models were used to examine the experimental data at different initial concentrations. It was found that the pseudo-second-order kinetic model described the data of dyes adsorption on NSC adsorbent very well. Thermodynamic adsorption processes were found to be spontaneous, exothermic, and physical reactions. The natural safiot clay was characterized using the following technique: DRX, XRF, SEM, EDX, and FT-IR.

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One step acid activation of bentonite derived adsorbent for the effective remediation of the new generation of industrial pesticides

Scientific Reports ◽

10.1038/s41598-020-76723-w ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Siti Fairos Ab Shattar ◽

Nor Azazi Zakaria ◽

Keng Yuen Foo

Keyword(s):

Fourier Transforms ◽

Kinetic Equations ◽

Second Order ◽

Polluted Water ◽

Acid Activation ◽

Standard Entropy ◽

Order Kinetic ◽

Equilibrium Data ◽

Pseudo Second Order ◽

One Step

AbstractHerein, the facile one step acid activation of bentonite derived functionalized adsorbent (AB) for the effective remediation of both ionic and non-ionic secondary pesticides, ametryn and metolachlor has been attempted. The surface characteristics of AB were examined by the nitrogen adsorption–desorption analysis, scanning electron microscopy (SEM), and Fourier Transforms Infrared (FTIR) Spectroscopy. The adsorptive behavior was evaluated with respect to the effect of contact time, initial concentrations and solution pH. The equilibrium data were fitted to the Langmuir, Freundlich and Temkin isotherm models, while the adsorption kinetic was analyzed using the pseudo-first order and pseudo-second order kinetic equations. Thermodynamic parameters including the standard enthalpy change (ΔH°), standard entropy change (ΔS°), and Gibbs free energy change (ΔG°) were established. Thermodynamic analysis illustrated that the adsorption process was feasible and exothermic in nature, while the characterization findings verified the alteration of FTIR bands, and a high specific surface area of 464.92 m2/g, with a series of pores distributed over the surface. Equilibrium data was best confronted to the pseudo-second order kinetic model, while the adsorptive removal of ametryn and metolachlor onto AB was satisfactory described by the Langmuir isotherm model, with the monolayer adsorption capacities for ametryn and metolachlor of 2.032 and 0.208 mmole/g respectively. The findings outlined the potential of the newly develop AB for the on-site treatment of pesticide polluted water.

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Kinetic of Phenol Adsorption by Mesoporous MCM-41 Nanoparticles

International Journal of Innovative Technology and Exploring Engineering - Special Issue ◽

10.35940/ijitee.l1083.10812s19 ◽

2019 ◽

Vol 8 (12S) ◽

pp. 316-323 ◽

Cited By ~ 1

Keyword(s):

Kinetic Equations ◽

Sem Analysis ◽

Second Order ◽

Isotherm Models ◽

Potential Candidate ◽

Order Kinetic ◽

Intraparticle Diffusion Model ◽

Langmuir Isotherm Model ◽

Pseudo Second Order ◽

Mcm 41

In the present study application of MCM-41 for removal of phenol was investigated. MCM-41nano-adsorbent was synthesized and characterized by FTIR, XRD and SEM analysis. Adsorption isotherm experiment was performed in batch shake flask. The experimental data were analyzed using various isotherm models. Result revealsthat,Langmuir isotherm model fitted the data very well for the removal of phenol by the MCM-41 adsorbents. The calculated dimensionless separation factor, RL indicates that the adsorption of phenol onto MCM-41 was favorable. Pseudo-first order, pseudo-second order kinetic equations and intraparticle diffusion model were applied to analyze the adsorption kinetics of the MCM-41 at different initial phenol concentrations. It was found that the adsorption of phenol on to the MCM-41 follows the pseudo-second order kinetic. At an initial phenol concentration of 130 mgl-1, more than 99% phenol, 93% COD along with 96% of toxicity removal were achieved. Thus, the synthesized mesoporous MCM-41 proved to be a potential candidate for removal of phenol from industrial wastewater.

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