Adsorption capacities of poorly crystalline Fe minerals for antimonate and arsenate removal from water: Adsorption properties and effects of environmental and chemical conditions

Antimonate (Sb(V)) and arsenate (As(V)) pollution frequently occur in aqueous environment and can be absorbed by poorly crystalline Fe minerals (i.e., ferrihydrite). In this study, the adsorption capacity and rate of Sb(V) and As(V) from water with fresh ferrihydrite were compared by establishing adsorption isotherms and kinetics, and the effects of ferrihydrite dosage, solution pH and humic substances on Sb(V) and As(V) adsorption were also investigated. The adsorption isotherms results showed that the equilibrium and maximum adsorption capacities of Sb(V) on ferrihydrite were approximately equal to those of As(V) under different temperatures. The results of adsorption kinetics showed that the adsorption rate of Sb(V) derived from the pseudo-second-order equation was much lower than that of As(V). In addition, the adsorption capacity and rate of Sb(V) and As(V) were greatly affected by various ferrihydrite dosage and solution pHs. The presence of humic acid and fulvic acid (FA) significantly affected the adsorption process of Sb(V) due to competition adsorption, whereas the adsorption properties of As(V) were little affected by FA under this experimental conditions. Copyright © 2018 Springer-Verlag GmbH Germany, part of Springer Nature.