Highly efficient and environmentally benign As(III) pre-oxidation in water by using a solid redox polymer. (May 2017)

• Record Type: Journal Article
• Authors: Li, Hongchao; Zhang, Xiaolin; Wu, Mengfei; Zhang, Weiming; Lv, Lu; Pan, Bingcai
• Is Part Of: Chemosphere. Volume 175(2017)
• Page Start: 300
• Page End: 306
• Publication Date: 2017-05
• Subjects: As(III) -- Heterogeneous oxidation -- Active chlorine -- DBPs -- Regeneration; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2017.02.076
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: As(III) preoxidation to As(V) is usually a requisite step for its efficient removal from water. Traditional oxidants reacting with As(III) homogenously in water suffer from the excessive dosage as well as the possible formation of disinfection byproducts. Herein, we developed a heterogeneous oxidant, i.e., a solid redox polymer (DOX), by covalently binding chlorine to a commercially available cation-exchange resin, D001. As(III) pre-oxidation by DOX is independent upon the solution pH (6–8) and ionic strength (0–0.1 M NaNO3 ). The presence of natural organic matters (NOMs) exhibits slightly adverse effect on the As(III) oxidation. More attractively, much less disinfection byproducts (DBPs, CHCl3 in this study) is formed during oxidation by DOX than by chlorine, possibly ascribed to the electrostatic repulsion between NOMs and DOX as well as the steric effect of the solid matrix. The exhausted DOX could be fully refreshed by the NaClO solution for cyclic use. The column oxidation experiment were performed by feeding the synthetic groundwater containing As(III), various minerals, and NOMs. It could result in As(III) decline from 200 × 10 −3 mg/L initially to <1 × 10 −3 mg/L with the working capacity of >33, 200 bed volume (BV) even at the volumetric flow rate of 50 BV/h (i.e., EBCT = 1.2 min, equivalent to the linear velocity of 2.2 m/h). In summary, DOX is a highly efficient and environmental friendly oxidant for As(III) pre-oxidation in water treatment. Graphical abstract: Highlights: A heterogeneous oxidant DOX was synthesized for As(III) pre-oxidation. As(III) oxidation was independent of pH and ionic strength. DOX oxidation generated much less DBPs than chlorine in the presence of NOMs. The exhausted DOX could be fully refreshed with NaClO for cyclic runs. Column operation demonstrated the great potential of DOX in real application.