2,4-Dichlorophenol removal from water using an electrochemical method improved by a composite molecularly imprinted membrane/bipolar membrane

• Published in: Journal of hazardous materials Vol. 377; pp. 259 - 266
• Main Authors: Liu, Yaoxing, Yan, Zhang, Chen, Riyao, Yu, Yaping, Chen, Xiao, Zheng, Xi, Huang, Xuehong
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 05.09.2019
• Subjects: 2,4-Dichlorophenol; Bipolar membrane; Electrochemical reduction; Fenton oxidation; Molecularly imprinted membrane; Bipolar membrane; Molecularly imprinted membrane; Fenton oxidation; ERHD; TOC; XRD; MIM; CS; NIM; 2,4-Dichlorophenol; BPM/MIM@Pd/Ti; CMC; FE-SEM; COD; Electrochemical reduction; PVA; SEM; BPM
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2019.05.064

[Display omitted] •A molecularly imprinted/bipolar membrane enhanced 24DCP removal by a Pd/Ti electrode.•24DCP hydrodechlorination increased with current density and electrolyte concentration.•Complete 24DCP removal was achieved by Fenton treatment after hydrodechlorination.•The sequential treatment decreased COD and TOC more than Fenton's reagent alone.•24DCP was removed and degraded via adsorption, reduction by Hads, and Fenton oxidation. Low efficiency is often a problem in electrochemical reductive hydrodechlorination (ERHD) to remove chlorinated compounds such as 2,4-dichlorophenol (24DCP) from water. In this study, a composite molecularly imprinted membrane (MIM)/bipolar membrane (BPM) was introduced onto a palladium-coated titanium mesh electrode (BPM/MIM@Pd/Ti) to increase the concentration of 24DCP on the surface of electrode and ERHD efficiency. The efficiency of ERHD of 24DCP increased from 70 to 88% by introduction of the two membranes, from 71 to 89% by increasing current density from 5.0 to 30 mA/cm2, and from 80 to 94% by increasing the electrolyte concentration from 0.25 to 1.00 mol/L. Treatment with Fenton’s reagent after ERHD achieved 100% 24DCP removal, with chemical oxygen demand and total organic carbon reductions of 91 and 87%, respectively. Notably, these reductions were greater than obtained from the direct oxidation of the 24DCP solution by Fenton’s reagent alone (i.e., 98, 84, and 72%, respectively). No products were detected in solution by GC–MS after treatment with the proposed combination technology. The mechanism of 24DCP removal and degradation involved adsorption, electrochemical hydrodechlorination via Hads, and Fenton oxidation. Results show the process has high potential for removing 24DCP from aqueous solution.