Influence of dissolved organic matter components on arsenate adsorption/desorption by TiO2.
The influences of different dissolved organic matter (DOM) components and ionic matters on As(V) adsorption/desorption behavior on the TiO2 surface were investigated. The results demonstrated that the characteristics and involving order of DOM significantly affected the As(V) adsorption/desorption behavior. The presence of DOM decreased the As(V) adsorption quantity. Fulvic acid (FA) exhibited the most negative effect, and followed by the order of alginate ≈ BSA > SDBS. The precomplexation DOM prevented more As(V) adsorption. While, the presence of DOM caused more As(V) release when the surrounding changed and FA exhibited the strongest effect. The results indicated that the site competition and electrostatic repulsion were the major mechanisms to resist As(V) adsorption. The presence of Fe3+ and Ca2+ increased As(V) adsorption by bridge effect, while PO43- and CO32- decreased As(V) adsorption owing to the competition.