Preparation of composite hydrogel with high mechanical strength and reusability for removal of Cu(II) and Pb(II) from water

Abstract

An adsorbent with good reusability, rapid adsorption kinetics, cost-effectiveness, and high adsorption capacity is desired in practical adsorption processes. A new strategy was proposed herein, combining the ball-milling biochar (MBC) and double network to synthesize a composite hydrogel. The ball-milling biochar /carboxymethylcellulose/polyacrylic acid (MBC/CMC/PAA) composite hydrogel was prepared using a one-step method. Both the carboxymethylcellulose (CMC) and polyacrylic acid (PAA) were used to form double networks, immobilized and crosslinked with MBC. The MBC/CMC/PAA possessed a higher allowable compression force of 133.52 N. The FTIR and XPS results confirmed that -COOH, -OH, and -NH- functional groups were the main adsorption sites. The proposed adsorbent maintained a stable removal efficiency of 100 % for Cu2+ and Pb2+ within five cycles of use. Thomas model better described the Cu2+ and Pb2+ in the individual dynamic adsorption process. In the alternate fixed-bed column experiments, the treatment volume of Cu2+-containing water reached 13.7 L and produced 300 mL eluent. This work not only developed a new strategy for preparing composite hydrogel but also verified that the MBC/CMC/PAA could have great applicability for removing Cu2+ and Pb2+ in real solutions.