15th International Conference on Environmental Chemistry and Engineering
ChongQing University, China
Title: Application of magnetic graphene-based composites in the area of water treatment adsorption
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Biography: Yongjuan Wang
With the significant increase in production and use of heavy metal (especially hexavalent chromium), it will be inevitably released into aquatic environments, which can result in accumulating throughout the food chain and having high toxicity to the living organisms. Therefore, developing a kind of low-cost adsorbent with high adsorption capacity of Cr(VI) from aqueous solution have attracted extensive attention. In this study, novel adsorbents, poly([2-(methacryloxy)ethyl]trimethylammonium chloride) modified magnetic chitosan particles (DMCPs), were synthesized under N2 atmosphere via free radical polymerization using [2-(methacryloxy)ethyl]trimethylammonium chloride (DMC) as grafting monomer and potassium persulfate (KPS) as initiator, and applied to adsorb Cr(VI) from aqueous solution. The effects of pH (2-11), Cr(VI) concentration (10-200 mg/L) contact time (0-420 min) on the adsorption performance were evaluated. The results showed that the adsorption capacity of DMCPs was much larger than that of magnetic chitosan particles (MCPs) in the examined pH range and decreased with Cl- concentration increasing, indicating that electrostatic interaction and ion exchange are the governing mechanisms of Cr(VI) adsorption by DMCPs. The Langmuir isotherm model and pseudo-second-order kinetic model fitted the experimental data well, which further demonstrated heterogeneous monolayer adsorption was formed in the adsorption process and the rate controlling step was chemisorption, respectively. The maximum adsorption capacity of DMCPs is 153.85 mg/g. Besides, the regeneration and reusability of DMCPs were also explored. Results showed that more than 80% adsorption capacities of DMCPs for Cr(VI) remained after five adsorption-desorption cycles, verifying that Cr(VI)-loaded DMCPs could be easily separated and efficiently regenerated. Therefore, DMCPs are promising candidates for Cr(VI) adsorption owing to their excellent performance in a wide pH range, easy separation and good reusability.