Chemical and toxicological assessment of arsenic sorption onto Fe-sericite composite powder and beads

Batch sorption and leaching of arsenic (1–30 mg L⁻¹) on Fe-sericite composite powder and beads were investigated in this study. Fe-sericite composite powder was made from natural sericite modified with iron, and alginate was used to transform the powder into beads. The maximum sorption capacities of the Fe-sericite composite powder (15.04 and 13.21 mg g⁻¹ for As(III) and As(V), respectively) were higher than those of the corresponding beads (9.02 and 7.11 mg g⁻¹ for As(III) and As(V), respectively) owing to the higher specific surface area of the powder. In addition, the leaching amounts of As(III) from Fe-sericite composite beads (≤ 15.03%) were higher than those of the corresponding powder (≤ 5.71%). However, acute toxicity of As(III)-sorbed Fe-sericite composite beads toward Daphnia magna was not significantly different from that of the corresponding powder (p > 0.05). Considering higher uptake of the powder particles by the daphnids, Fe-sericite composite beads seem to be a more appropriate and safer sorbent for arsenic removal in practical application. Based on Fe content, Fe-sericite composite beads had similar or higher maximum sorption capacities (71.19 and 56.11 mg g⁻¹ Fe for As(III) and As(V), respectively) than those of previously reported sorbents.