scholarly journals Modified Spruce Sawdust for Sorption of Hexavalent Chromium in Batch Systems and Fixed-Bed Columns

Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 5156
Author(s):  
Dororthea Politi ◽  
Dimitrios Sidiras
Keyword(s):  
Sulfuric Acid ◽  
Adsorption Capacity ◽  
Hexavalent Chromium ◽  
Diethylene Glycol ◽  
Fixed Bed ◽  
Second Order ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Order Kinetic Model ◽  
Pseudo Second Order

This study investigated the potential use of spruce sawdust that was pretreated with diethylene glycol and sulfuric acid for the removal of hexavalent chromium from wastewater. The sawdust pretreatment process was conducted at different temperatures and times. The adsorbent was characterized by quantitative saccharification, scanning electron microscopy, and Brunauer–Emmet–Teller surface area analysis. Adsorption capacity was studied for both batch and column processes. The experimental adsorption isotherms were simulated using seven isotherm models, including Freundlich and Langmuir models. By using the Langmuir isotherm model, the maximal Cr(VI) adsorption capacity of organosolv-pretreated spruce sawdust (qm) was 318.3 mg g−1. Furthermore, the kinetic data were fitted to Lagergren, pseudo-second-order, and intraparticle diffusion models, revealing that the adsorption of Cr(VI) onto spruce sawdust pretreated with diethylene glycol and sulfuric acid is best represented by the pseudo-second-order kinetic model. Three kinetic models, namely, the Bohart–Adams model, Thomas model, and modified dose–response (MDR) model, were used to fit the experimental data obtained from the column experiments and to resolve the characteristic parameters. The Thomas adsorption column capacity of the sawdust was increased from 2.44 to 31.1 mg g−1 upon pretreatment, thus, demonstrating that organosolv treatment enhances the adsorption capability of the material.

scholarly journals Kinetics and Isotherm Studies on Adsorption of Hexavalent Chromium Using Activated Carbon from Water Hyacinth

2021 ◽  
Vol 15 (1) ◽  
pp. 1-8
Author(s):  
Angelica Macalalad ◽  
◽  
Quennie Rose Ebete ◽  
Dominic Gutierrez ◽  
Madelaine Ramos ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Adsorption Capacity ◽  
Hexavalent Chromium ◽  
Water Hyacinth ◽  
Freundlich Isotherm ◽  
Second Order ◽  
Order Kinetic ◽  
Adsorbate Concentration ◽  
Order Kinetic Model ◽  
Pseudo Second Order

The present study is focused on the use of activated carbon derived from water hyacinth (WH-AC) as adsorbent for the removal of Cr(VI) from aqueous solution. The optimized WH-AC was found to be mesoporous and considered as granular. The surface area of 11.564 m2/g was found to have a good adsorption capacity. The adsorption data of the optimized WH-AC followed a pseudo-second order kinetics and the Freundlich isotherm model. Based on the correlation coefficient obtained from pseudo-second-order kinetic model, the R2 values were all above 0.99, which is closer to unity of one (1) indicating that it followed a chemisorption process. The adsorption capacity of WH-AC increased from 1.98 to 4.68 mg/g when adsorbate concentration increased from 20 to 50 mg/l. The overall study proved that the adsorption by activated carbon derived from water hyacinth can be an alternative and efficient technique in hexavalent chromium removal.

scholarly journals Comparative Study of Ni-Zn LHS and Mg-Al LDH Adsorbents of Navy Blue and Yellow F3G Dye

2018 ◽  
Vol 16 (1) ◽  
pp. 36 ◽  
Author(s):  
Idha Yulia Ikhsani ◽  
Sri Juari Santosa ◽  
Bambang Rusdiarso
Keyword(s):  
Adsorption Capacity ◽  
Freundlich Isotherm ◽  
Second Order ◽  
Isotherm Models ◽  
Disperse Dyes ◽  
Order Kinetic ◽  
Initial Ph ◽  
Isotherm Adsorption ◽  
Order Kinetic Model ◽  
Pseudo Second Order

Adsorption of disperse dyes from wastewater onto Ni-Zn LHS (layered hydroxide salts) and Mg-Al LDH (layered double hydroxides) has been compared in this study. Effects of initial pH solution, contact time and initial dye concentration were investigated. The ability of the adsorbent to be reused was also studied. The results showed that acidic condition was favorable for the adsorption of each dyes onto both adsorbent. The adsorption kinetics was studied using pseudo-first-order, pseudo-second-order and Santosa’s kinetics models. The experimental data fits well with the pseudo-second order kinetic model. The equilibrium adsorption data were analyzed using Langmuir and Freundlich isotherm models. The results showed that adsorption of navy blue onto both adsorbent followed Freundlich isotherm adsorption, while yellow F3G followed Langmuir isotherm adsorption. In the application for the adsorption the wastewater containing dyes, Ni-Zn LHS has a better adsorption capacity of 52.33 mg/g than that of Mg-Al LDH that 30.54 mg/g. Calcination of the adsorbent which has already been used increased the adsorption capacity of Mg-Al LDH to 84.75 mg/g, but decreased the adsorption capacity of the Ni-Zn LHS to 42.65 mg/g.

scholarly journals Removal of Rhodamine B from aqueous solution by ZnFe2O4 nanocomposite with magnetic separation performance

2017 ◽  
Vol 19 (4) ◽  
pp. 65-74 ◽  
Author(s):  
Wojciech Konicki ◽  
Daniel Siber ◽  
Urszula Narkiewicz
Keyword(s):  
Aqueous Solution ◽  
Kinetic Model ◽  
Adsorption Capacity ◽  
Rhodamine B ◽  
Second Order ◽  
Isotherm Models ◽  
Separation Performance ◽  
Order Kinetic ◽  
Order Kinetic Model ◽  
Pseudo Second Order

Abstract Magnetic ZnFe2O4 nanocomposite (ZnFe-NC) was used as an adsorbent for the removal of Rhodamine B (RB) from aqueous solution. The synthesized nanocomposite was characterized by XRD, SEM, HRTEM, BET and FTIR. The effects of various parameters such as initial RB concentration (5–25 mg L−1), pH (3.4–11.1) and temperature (20–60°C) were investigated. The adsorption capacity at equilibrium increased from 5.02 to 9.83 mg g−1, with the increase in the initial concentration of RB from 5 to 25 mg L−1 at pH 7.0 and at 20°C. The experimental results indicated that the maximum RB removal could be attained at a solution pH of 4.4 and the adsorption capacity obtained was 6.02 mg g−1. Kinetic adsorption data were analyzed using the pseudo-first-order kinetic model, the pseudo-second-order model and the intraparticle diffusion model. The adsorption kinetics well fitted using a pseudo-second-order kinetic model. The experimental isotherm data were analyzed using two isotherm models, namely, Langmuir and Freundlich. The results revealed that the adsorption behavior of the RB onto ZnFe-NC fitted well with the Langmuir isotherm model. In addition, various thermodynamic parameters, such as standard Gibbs free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°) have been calculated.

scholarly journals Isotherm and selectivity studies of Ni(II) removal using natural and acid-activated nanobentonites

2021 ◽  
Author(s):  
Zahra Ashouri Mehranjani ◽  
Majid Hayati-Ashtiani ◽  
Mehran Rezaei
Keyword(s):  
Experimental Data ◽  
Sulfuric Acid ◽  
Adsorption Capacity ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Adsorption Isotherm Models ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Selectivity Studies ◽  
Working Out

Abstract In this research, natural bentonite and its acid-activated forms were employed as adsorbents for the adsorption of Ni2+ ions from wastewater. Natural bentonite was activated with 2M sulfuric acid, 4.5 h and 95 °C (the beast acid-activated sample with the highest adsorption capacity) and the other 6M sulfuric acid, 7.5 h and 95 °C (the worst acid-activated sample with the lowest adsorption capacity). The adsorption of Ni2+ was studied through experiments including equilibrium contact time and selectivity. The equilibrium time of contact for bentonite was obtained at 180 min. The Ni2+ separation process along with Zn2+ selectivity studies was considered through adsorption experiments. The results showed that there was a maximum amount of Ni2+ adsorption in the absence of Zn2+ for all samples. The results showed the best fit is obtained with the pseudo-second-order kinetic model. Working out different bentonite types to determine the best kinetic models, we explored the Langmuir and Florry–Huggins models provided a good fit with experimental data for acid-activated bentonites and the best results from linear forms of the adsorption isotherm models for fitting the experimental data of natural bentonite are obtained Langmuir, Temkin and Freundlich models.

scholarly journals Enhancing Adsorption Capacity of Clay and Application in Dye Removal from Waste Water

2014 ◽  
Vol 39 ◽  
pp. 35-51 ◽  
Author(s):  
O.T. Ogunmodede ◽  
O.L. Adebayo ◽  
A.A. Ojo
Keyword(s):  
Waste Water ◽  
Adsorption Capacity ◽  
Surface Area ◽  
Kinetic Models ◽  
Second Order ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Small Surface ◽  
Intercalation Process ◽  
Pseudo Second Order

Natural clay has been considered as a potential absorbent for removing pollutants from water and waste water. Nonetheless, the effective application of clay for water treatment is limited due to small surface area and presence of net negative surface charge, leading to it low adsorption capacity. The absorption capacity was boosted via intercalation of CaO derived from snail shell (SS). The methylene blue sorption potential, PZC, and the surface area of unmodified clay sample were substantially enhanced by the intercalation process. The process of sorption of MB from solution was analyzed using five different isotherm models (Langmuir, Freundlich, Temkin, Harkins-Jura, and Halsey isotherm equations). The value of the Langmuir monolayer sorption capacity qm (mg/g) increased from 50.12 to 88.71, PZC values increased from 4.50 to 7.40, and the surface area (m2/g) value increased from 27 m2/g to 123 m2/g after the intercalation process. The experimental data were fitted into two kinetic models: Lagergren pseudo-first order and the chemisorptions pseudo-second order. It was observed that chemisorptions pseudo-second order kinetic model described the sorption process with high coefficients of determination (r2) better than pseudo first other kinetic models. The modification caused no change in the clay surficial microstructure but increased the lattice spacing of the clay framework.

scholarly journals Equilibrium and kinetics studies for the adsorption of Ni2+ and Fe3+ ions from aqueous solution by graphene oxide

2017 ◽  
Vol 19 (3) ◽  
pp. 120-129 ◽  
Author(s):  
Wojciech Konicki ◽  
Małgorzata Aleksandrzak ◽  
Ewa Mijowska
Keyword(s):  
Graphene Oxide ◽  
Kinetic Model ◽  
Metal Ion ◽  
Second Order ◽  
Ion Concentration ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Intraparticle Diffusion Model ◽  
Order Kinetic Model ◽  
Pseudo Second Order

Abstract In this study, the adsorption of Ni2+ and Fe3+ metal ions from aqueous solutions onto graphene oxide (GO) have been explored. The effects of various experimental factors such as pH of the solution, initial metal ion concentration and temperature were evaluated. The kinetic, equilibrium and thermodynamic studies were also investigated. The adsorption rate data were analyzed using the pseudo-first-order kinetic model, the pseudo-second-order kinetic model and the intraparticle diffusion model. Kinetic studies indicate that the adsorption of both ions follows the pseudo-second-order kinetics. The isotherms of adsorption data were analyzed by adsorption isotherm models such as Langmuir and Freundlich. Equilibrium data fitted well with the Langmuir model. The maximum adsorption capacities of Ni2+ and Fe3+ onto GO were 35.6 and 27.3 mg g−1, respectively. In addition, various thermodynamic parameters, such as enthalpy (ΔHO), entropy (ΔSO) and Gibbs free energy (ΔGO), were calculated.

scholarly journals Modelling and Optimizing the Removal of Methylene Blue by a Mixture of Titaniferous Sand and Attapulgite Using Complete Factorial Design

2021 ◽  
Vol 17 (40) ◽  
pp. 88
Author(s):  
Kalidou Ba ◽  
Alpha Ousmane Toure ◽  
El Hadji Moussa Diop ◽  
Falilou Mbacke Sambe ◽  
Codou Guéye Mar Diop
Keyword(s):  
Methylene Blue ◽  
Adsorption Capacity ◽  
Desirability Function ◽  
Second Order ◽  
Order Kinetic ◽  
Methylene Blue Adsorption ◽  
Charge Potential ◽  
Adsorbate Concentration ◽  
Order Kinetic Model ◽  
Pseudo Second Order

This paper focuses on the removal of methylene blue by adsorption using a mixture of titaniferous sand and attapulgite. The different adsorbents were characterized by X-ray fluorescence spectroscopy and their different parameters such as pH, zero charge potential, and specific surface area were determined. The experiments performed were optimized and modeled by a full 2-level and 4-factor design. The four factors are the ratio of titaniferous sand and attapulgite, the concentration of methylene blue, pH, and time. These vary from 4 to 19, 20 to 100 mg/L, 2 to 9, and 30 to 150 min respectively. The study of the effects of the different factors showed that the effect of methylene blue concentration and pH significantly influence the adsorption capacity and removal efficiency of the dye. The optimum parameters (adsorbent ratio, adsorbate concentration, pH and time) obtained for the adsorption capacity through the desirability function are: 19, 100mg/L, 9 and 150min. Those obtained for the yield are: 4, 100mg/L, 9, 150min. The pseudo second order adsorption kinetics gave an equilibrium adsorption capacity qe (calculated) = 7.6863 mg/g which is almost equal to that obtained experimentally qe (exp) = 7.3562 mg/g. This shows that the pseudo second order kinetic model is the adequate mathematical model to describe the methylene blue adsorption phenomenon on the mixture of titaniferous sand and attapulgite. The thermodynamic study showed that the methylene blue adsorption reaction is exothermic, non-spontaneous, and the degree of disorder of the particles at the adsorbing surface decreases.

Use of sesame stalk biomass for the removal of Ni(II) and Zn(II) from aqueous solutions

2012 ◽  
Vol 66 (2) ◽  
pp. 231-238 ◽  
Author(s):  
Çisem Kırbıyık ◽  
Murat Kılıç ◽  
Özge Çepelioğullar ◽  
Ayşe E. Pütün
Keyword(s):  
Aqueous Solutions ◽  
Metal Ions ◽  
Metal Ion ◽  
Low Cost ◽  
Second Order ◽  
Solution Temperature ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Order Kinetic Model ◽  
Pseudo Second Order

In this study an agricultural residue, sesame stalk, was evaluated for the removal of Ni(II) and Zn(II) metal ions from aqueous solutions. Biosorption studies were carried out at different pH, biosorbent dosage, initial metal ion concentrations, contact time, and solution temperature to determine the optimum conditions. The experimental data were modeled by Langmuir, Freundlich, Dubinin-Radushkevich (D-R) and Temkin isotherm models. Langmuir model resulted in the best fit of the biosorption data. The pseudo-first-order and pseudo-second-order kinetic models were used to describe the kinetic data and to evaluate rate constants. The best correlation was provided by the second-order kinetic model. The thermodynamic parameters such as ΔG°, ΔH° and ΔS° were calculated for predicting the nature of adsorption. The experimental results showed that sesame stalk can be used as an effective and low-cost biosorbent precursor for the removal of heavy metal ions from aqueous solutions.

scholarly journals Biosorption of Hexavalent Chromium from Aqueous Medium withOpuntiaBiomass

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
José A. Fernández-López ◽  
José M. Angosto ◽  
María D. Avilés
Keyword(s):  
Hexavalent Chromium ◽  
Low Cost ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Biosorption Capacity ◽  
Biosorption Process ◽  
Equilibrium Data ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Two Parameter

The biosorption of hexavalent chromium from aqueous solutions byOpuntiacladodes and ectodermis from cactus fruits was investigated. Both types of biomass are considered low-cost, natural, and ecofriendly biosorbents. Batch experiments were carried out to determine Cr(VI) biosorption capacity and the efficiency of the biosorption process under different pH, initial Cr(VI) concentration, and sorbent dosage. The biosorption of Cr(VI) byOpuntiabiomass was highly pH dependent, favoring higher metal uptake at low pH. The higher biosorption capacity was exhibited at pH 2. The optimal conditions were obtained at a sorbent dosage of 1 g L−1and initial metal concentration of 10 mg L−1. Biosorption kinetic data were properly fitted with the pseudo-second-order kinetic model. The rate constant, the initial biosorption rate, and the equilibrium biosorption capacity were determined. The experimental equilibrium data obtained were analyzed using two-parameter isotherm models (Langmuir, Freundlich, and Temkin). The Langmuir maximum monolayer biosorption capacity (qmax) was 18.5 mg g−1for cladodes and 16.4 mg g−1for ectodermis. The results suggest thatOpuntiabiomass could be considered a promising low-cost biosorbent for the ecofriendly removal of Cr(VI) from aqueous systems.

scholarly journals Synthesis of Specific ZnF Based Nanoparticles (ZnFe2O4): Antimicrobial Properties, Surface Characteristics, and Adsorption Activity for AB 29 Textile Dye

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Ferda Gönen ◽  
Gökhan Tekinerdoğan
Keyword(s):  
Kinetic Model ◽  
Kinetic Data ◽  
Second Order ◽  
Color Removal ◽  
Isotherm Models ◽  
Textile Dye ◽  
Order Kinetic ◽  
Adsorption Activity ◽  
Order Kinetic Model ◽  
Pseudo Second Order

In this investigation, the color removal from synthetic wastewaters containing Acid Blue 29 (AB 29) dye was investigated by ZnF-based nanomaterials (ZnFe2O4) synthesized by the coprecipitation method in a batch system. SEM, FT–IR, and XRD analysis were used for the characterization of the nanoparticles (before and after adsorption), and the analysis results were compared with each other. The parameters such as pH, temperature, dye concentration, and nanoparticle dosage affecting color removal were examined systematically, and favorable color removal conditions were determined by the classical approach. From the experimental results, the favorable conditions with high removal efficiency for the adsorption were determined: removal temperature 35°C and the removal pH 2.0. At these experimental conditions, the adsorbed dye amount per unit mass of adsorbent and the percentage dye removal were determined as 1489.79 mg·g−1 and 98.83%, respectively. In the other part of the research, three different isotherm models (Langmuir, Freundlich, and Temkin) were used to examine the adsorption equilibrium data. Langmuir and especially Freundlich linear isotherm models provided the highest R2 regression coefficients, successfully. The kinetic data was evaluated by pseudo-first-order and pseudo-second-order kinetic model approach. It was observed that pseudo-second-order kinetic model best represented AB 29-ZnF adsorption kinetic data. The determined thermodynamic parameters such as ΔH, ΔS, and ΔG were proved that the AB 29-ZnF adsorption system was an exothermic (ΔH < 0), spontaneous, thermodynamically favorable (ΔG < 0), and stabilized system without any structural changes in sorbate and sorbents (ΔS<0).

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