The oxidative and adsorptive effectiveness of hydrous manganese dioxide for arsenite removal

摘要

This study focuses on the effectiveness of hydrous manganese dioxides (delta MnO_2) removing arsenite (As(III)) from aqueous solution. Effects of such factors as permanganate oxidation, pH, humic acid and Ca~(2+) on As removal and possible mechanisms involved in have been investigated. Permanganate oxidation increases As removal to a certain extent; the higher pH results in the formation of more easily adsorbed As species, contributing to higher As removal; humic acid occupies adsorbing sites and decreases zeta potential of delta MnO_2, therefore inhibiting As removal; Ca~(2+) facilitates As adsoiption on delta MnO_2, mainly through increasing ￡ potential and decreasing repulsive forces between As and surface sites. Delta MnO_2 exhibits oxida-tive and adsorptive potential for As (III), and may be employed as adsorbents or filter coating for As removal in water treatment process.