HO modified peanut shell-derived biochar/alginate composite beads as a green adsorbent for removal of Cu(II) from aqueous solution.

In this study, a novel composite bead (MPB-ALG) was prepared by encapsulating HO modified peanut shell-derived biochar (MPB) into alginate matrix through a facile method. The structure and properties of prepared materials were characterized using FTIR, BET, SEM, and XPS. Batch adsorption experiments were performed to compare the Cu(II) adsorption performance of MPB, plain alginate beads (ALG), and MPB-ALG. The effect parameters of the components, solution pH, contact time, initial concentration, and coexisting ions were studied systematically. The results showed that the maximum adsorption capacity of the optimized MPB-ALG-1 (MPB/alginate = 1:1 w/w%) was 117.4 mg g at pH 5, which was much higher than that of MPB (37.4 mg g). The adsorption kinetics and isotherms data of Cu(II) on MPB-ALG-1 were well described by Elovich kinetic model and Freundlich adsorption isotherm. Compared with plain ALG beads, MPB-ALG-1 exhibited better reusability and anti-interference of coexisting ions. Finally, the adsorption mechanisms of Cu(II) on MPB-ALG-1 beads were revealed by FTIR and XPS analysis. The experimental results demonstrated that MPB-ALG-1 beads can be used as an environmentally friendly and efficient adsorbent for the removal of Cu(II) from wastewater.