Removal of Cu2+ from aqueous solution using proton exchange membrane by Donnan dialysis process

In the context of increasing heavy metal pollution (e.g., Cu2+, Cd2+, Pb2+ and Zn2+) in Liao River Basin of China in recent years due to metallurgical refinery, this study investigated the removal of Cu2+ from aqueous solution by Donnan dialysis process. Na+ was selected as the counterion, while GEFC-107 proton exchange membrane (GEFC Co., China) was used as the ion exchange membrane. Transport of Cu2+ from feed phase to receiver phase was enhanced by increasing NaR+CuF2+\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{{\text{Na}}_{\text{R}}^{ + } } \mathord{\left/ {\vphantom {{{\text{Na}}_{\text{R}}^{ + } } {{\text{Cu}}_{\text{F}}^{{ 2 { + }}} }}} \right. \kern-0pt} {{\text{Cu}}_{\text{F}}^{{ 2 { + }}} }}$$\end{document} ratio (subscripts R and F denote as receiver and feed phases, respectively). For the initial Cu2+ concentration of 200 mg L−1 and NaR+CuF2+\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{{\text{Na}}_{\text{R}}^{ + } } \mathord{\left/ {\vphantom {{{\text{Na}}_{\text{R}}^{ + } } {{\text{Cu}}_{\text{F}}^{{ 2 { + }}} }}} \right. \kern-0pt} {{\text{Cu}}_{\text{F}}^{{ 2 { + }}} }}$$\end{document} ratio of 20:1, a removal efficiency of 95.31 % was achieved for 190 min dialysis. The adsorption percentage by the proton exchange membrane increased from 12.12 to 85.15 % when the initial Cu2+ concentration decreased from 200 to 20 mg L−1. The kinetics data for Cu2+ removal was best interpreted by the first-order model. The removal efficiency decreased from 89.09 to 72.43 % when the proton exchange membrane was reutilized three times without membrane washing using acid. Higher initial pH of receiver phase or lower initial pH of feed phase facilitated the Cu2+ transport from feed to receiver phase. The feasibility of Donnan dialysis collaborated with precipitation to remove Cu2+ was found to be not suitable for Cu2+ removal with high concentration, i.e., initial concentration 200 mg L−1, since only a removal efficiency of Cu2+ of 54.08 % was achieved.