Dataset Information

Facile Preparation of Magnetic Chitosan Coprecipitated by Ethanol/NH₃·H₂O for Highly Efficient Removal toward Cr(VI).

ABSTRACT: The adsorption ability of chitosan (CS) usually decreases with the introduction of magnetic particles, and thus magnetic CS has to be chemically modified further to improve its adsorption performance. Herein, a novel magnetic chitosan composite (Fe₃O₄-CS3) with porous structure and evenly distributed Fe₃O₄ was successfully prepared via the reduction of the solubility of CS by ethanol (physical reaction), and followed the coprecipitation of the mixture of FeCl₃/FeCl₂/CS by ethanol/NH₃·H₂O. Without any modification, its maximum adsorption capacity toward Cr(VI) ions can achieve 242.1 mg/g (?468.6 mg/g of CS). This significant progress could be ascribed to the very fast precipitate rate of CS due to the decrease in solubility induced by ethanol. Ethanol causes rigorous solidification of CS, so that there is not enough time to densify, resulting in a looser CS matrix with a larger pore size. After adsorption, this Fe₃O₄-CS3 could not only be easily separated but also be effectively regenerated by NaOH solution in a rather wider concentration range, showing great potential in the field of heavy metal wastewater treatment.

SUBMITTER: Cai W

PROVIDER: S-EPMC6641757 | biostudies-literature | 2018 May

REPOSITORIES: biostudies-literature

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Facile Preparation of Magnetic Chitosan Coprecipitated by Ethanol/NH3·H2O for Highly Efficient Removal toward Cr(VI).

Cai Weiquan W Cai Weiquan W Xue Wenhui W Jiang Yihong Y

ACS omega 20180528 5

The adsorption ability of chitosan (CS) usually decreases with the introduction of magnetic particles, and thus magnetic CS has to be chemically modified further to improve its adsorption performance. Herein, a novel magnetic chitosan composite (Fe3O4-CS3) with porous structure and evenly distributed Fe3O4 was successfully prepared via the reduction of the solubility of CS by ethanol (physical reaction), and followed the coprecipitation of the mixture ...[more]

PMID: 31458772

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Project description:Heavy metal ions in water refer to significant risks to the biological system due to their high toxicity. Therefore, the decontamination of water polluted by heavy metal ions attracts significant interest of researchers. Adsorption by nanomaterials has been a widely used technique for removing heavy metal ions from water. Chitosan was extracted from shrimp shellfish and mixed with laboratory-prepared AgNPs/GO in the ratio of 3 : 1. A series of tests evaluates the best condition of pH, amount of adsorbent, retention time, stirring speed, temp, and initial concentration. The research was conducted under various conditions. Langmuir, Freundlich, Tempkin, and Dubinin-Radushkevich isotherms were also tested. Also, the column adsorption experiment was carried out on industrial wastewater at different flow rates and column bed heights. The optimal values of the contact time, pH, and adsorbent dose of Cr(vi) were found to be 80 min, 4, and 0.1 g 100 mL-1, respectively, at room temperature (30 °C), agitation at 150 rpm, and initial concentration of 50 ppm. On the other hand, the optimal value of contact time, pH, and adsorbent dose of Fe(iii) were found to be 30 min, 6, and 0.02 g 100 mL-1, respectively, at room temp (30 °C) with a stirring speed of 250 rpm and an initial concentration of 40 ppm. For Cr(vi) and Fe(iii), equilibrium studies show that the data fit the Freundlich isotherm well (correlation coefficient, R 2 = 0.98) (III). A link between the pseudo-second order active model and data fitting the pseudo-first order active models were made. Within the intraparticle diffusion model, there are four stages that the mechanism must go through before it is at equilibrium. The adsorbent was tested in an industrial adsorbent column. This test proves that the nanocomposite's adsorption capacity can be restored by washing it with 0.1 M HCl, as shown by the periodicity test. After four cycles, the amount of Cr(vi) adsorbed on AgNPs/GO/chitosan was just 20%, which is insufficient for further adsorption experiments. Cr(vi) removal rates (%R) decreased slightly.

Dataset Information

Facile Preparation of Magnetic Chitosan Coprecipitated by Ethanol/NH₃·H₂O for Highly Efficient Removal toward Cr(VI).

Publications

Facile Preparation of Magnetic Chitosan Coprecipitated by Ethanol/NH<sub>3</sub>·H<sub>2</sub>O for Highly Efficient Removal toward Cr(VI).

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