Reza Jazini Zadeh; Mohammad Sayadi; Mohammad Reza Rezaei
Abstract
The present study was performed on the adsorption of 2,4-Dichlorophenoxyacetic acid from aqueous solutions by amine-modified magnetic nanoparticles. The adsorbent was synthesized by the co-precipitation method. The adsorbent properties of Fe3O4@SiO2-NH2 were investigated using XRD, FTIR, TGA, VSM and ...
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The present study was performed on the adsorption of 2,4-Dichlorophenoxyacetic acid from aqueous solutions by amine-modified magnetic nanoparticles. The adsorbent was synthesized by the co-precipitation method. The adsorbent properties of Fe3O4@SiO2-NH2 were investigated using XRD, FTIR, TGA, VSM and TEM. Adsorbent efficacy was studied by investigating the effect of pH, initial concentration of pollutants, and adsorbent dose, and times. Finally, kinetics equations and isotherms models were used to describe the data. The results showed that the highest removal percentage was observed at pH 6 and the initial concentration 20 mg/l of 2,4-Dichlorophenoxyacetic acid. Adsorption capacity was increased by 65.3% bypassing the time from the beginning of the process to 60 min. The results from the study of isotherms and adsorption kinetics presented that the sorption procedure follows the pseudo-second-order kinetics and the Langmuir isotherm with R2> 99. The maximum adsorption capacity of Fe3O4@SiO2-NH2 is 116.3 mg/g. Besides, thermodynamic studies have shown that the adsorption process in the present study is endothermic and spontaneous. The experiments showed that Fe3O4@SiO2-NH2 synthesized nanoparticles could be an excellent method to remove 2,4- Dichlorophenoxyacetic acid contaminants from the aqueous solutions due to the high efficiency, simplicity, and lack of secondary contamination in the solution.
Seyedeh Maedeh Hashemi Orimi; Maryam Khavarpour; Sohrab Kazemi
Abstract
In the present study, adsorption behavior of mesoporous molecularly imprinted polymers for bisphenol A was investigated. Molecularly imprinted nanopolymers were synthesized by precipitation polymerization using bisphenol A as a template molecule. Two molecular ratios of templet: functional monomer: cross-linker ...
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In the present study, adsorption behavior of mesoporous molecularly imprinted polymers for bisphenol A was investigated. Molecularly imprinted nanopolymers were synthesized by precipitation polymerization using bisphenol A as a template molecule. Two molecular ratios of templet: functional monomer: cross-linker (1:6:30 (MIP-6) and 1:4:20 (MIP-4)) was considered for experiments. Ethylene Glycol Dimethacrylate (EGDMA) as a Crosslinker, metacrylic acid (MAA) as a functional monomer and 2, 2´-azobisisobutyronitrile (AIBN) as an initiator were used for the synthesis of polymers. In addition, Langmuir and Freundlich adsorption isotherms and pseudo-first-order and pseudo-second-order kinetic models were studied for adsorption mechanism. Results showed that porous polymers with average pore diameter of 13 to 17 nm and specific surface area of 326 to 439 (cm3/g) were obtained. The maximum adsorption capacity was 400.1 μmol/g for MIP-6. SEM analysis showed that the synthesized polymer particles were spherical. The highest adsorption efficiency of bisphenol A achieved by MIP-6 was 71%.
Reza Tayebee; vahid Mazruy
Abstract
The limited adsorption capacity of natural clays is a crucial and economic issue which confined their applications in industry as cheap adsorbents to remove toxic contaminants from wastewaters. Here, the adsorption capacity of a natural nano bentonite was enhanced by a simple acid and thermal activation ...
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The limited adsorption capacity of natural clays is a crucial and economic issue which confined their applications in industry as cheap adsorbents to remove toxic contaminants from wastewaters. Here, the adsorption capacity of a natural nano bentonite was enhanced by a simple acid and thermal activation and the manufactured nano-adsorbent was characterized by FESEM, BET, FT-IR, and XRD. Effects of pH, temperature, sorbent capacity, and the initial concentration of malachite green were examined. The isotherm behavior of the adsorption system was investigated by the Langmuir and Freundlich isotherm models. Also, the kinetic inspections demonstrated that the adsorption of malachite green matched with the pseudo-second-order kinetic and the obtained thermodynamic parameters H, S, and G showed that the adsorption of malachite green was a spontaneous and endothermic process. The results indicated that the acid-thermal activated nano bentonite, with an enhanced surface area of >220 m2/g, can be depleted as a powerful and low-cost adsorbent to expel malachite green from aqueous solutions.
Marjan Tanzifi; Marzieh Kolbadi nezhad; Kianoush Karimipour
Abstract
The present work seeks to investigate the ability of polypyrrole/titanium dioxide nanocomposite to adsorb cadmium ions from aqueous solution. The impact of various experimental conditions, including solution pH, adsorbent dosage, adsorption time and initial concentration on the uptake of cadmium were ...
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The present work seeks to investigate the ability of polypyrrole/titanium dioxide nanocomposite to adsorb cadmium ions from aqueous solution. The impact of various experimental conditions, including solution pH, adsorbent dosage, adsorption time and initial concentration on the uptake of cadmium were studied. The adsorption kinetic was studied with the first-order, second-order, pseudo-first-order, pseudo-second-order and Morris–Weber models. The results revealed that adsorption process is controlled by pseudo-second-order model which illustrated that the adsorption process of cadmium is chemisorption-controlled. The adsorption capacity obtained from this model is 20.49 mg/g which close to the experimental value. The study yielded the result that when the initial concentration of the solution changed from 20 mg/l to 120 mg/l, the adsorption capacity increased from 0.99 to 24.52 mg/g. Further, Langmuir, Freundlich and Temkin isotherm models were applied to investigate the adsorption isotherm. Based on the results of the adsorption isotherm, Freundlich isotherm proved to be the best fit with the experimental data. Also, the morphology, chemical structure and thermal stability of adsorbent were studied by using SEM, EDX, FTIR, and TGA.
Marjan Tanzifi; Mohsen Mansouri; Maryam Heidarzadeh; Kobra Gheibi
Abstract
In the present study, adsorptive properties of Polyaniline (PAn) were investigated for Amido Black 10B dye in aqueous solution. Different variables, including adsorption time, adsorbent dosage, solution pH and initial dye concentration were changed, and their effects on dye adsorption onto PAn nano-adsorbent ...
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In the present study, adsorptive properties of Polyaniline (PAn) were investigated for Amido Black 10B dye in aqueous solution. Different variables, including adsorption time, adsorbent dosage, solution pH and initial dye concentration were changed, and their effects on dye adsorption onto PAn nano-adsorbent were investigated. The study yielded the result that an increase in pH decreases the adsorption efficiency of nano-adsorbent. Also, Dye adsorption capacity increased with increase in the initial dye concentration. Optimum adsorption time and nano-adsorbent dosage were obtained 30 min and 0.1 gr, respectively. Kinetic studies illustrated that the Amido Black 10B dye adsorption process onto PAn nano-adsorbent followed the pseudo-second-order model, which indicates that the adsorption process is chemisorption-controlled. Also, adsorption equilibrium data were fitted to Freundlich isotherm. The maximum dye adsorption capacity, predicted by the Langmuir isotherm, was 142.85 mg/g. Moreover, Dubinin-Radushkevich isotherm showed that the adsorption of dye onto PAn nano-adsorbent is a chemisorption process.