Lanthanum(III)-Coated Ceramics as a Promising Material in Point-of-Use Water Treatment for Arsenite and Arsenate Removal

Low-cost and efficient As(V) (arsenate) and As(III) (arsenite) sorbents for point-of-use (POU) water filtration are needed for areas suffering from high arsenic contamination in their drinking water sources. In this study, lanthanum (La)-coated ceramic materials were used to produce both granules and disk filters for the removal of As(V) and As(III). Results from filtration experiments showed that the La-coated granules and disk filters could effectively treat ∼11200 and ∼14500 pore volumes (PVs) of As(V) contaminated solutions, as well as ∼6400 and ∼3200 PVs of As(III) contaminated solutions to meet the drinking water standard (<0.010 mg/L), respectively. Batch experiments were further conducted to elucidate the sorption behaviors of As(V) and As(III), and the sorption capacities reached 24.8 and 10.9 mg/g for As(V) and As(III), respectively. Characterization of La-coated ceramic material before and after As sorption suggested that the removal of As(V) may be primarily attributed to the formation of surface LaAsO4 precipitates, while formation of inner-sphere complexes with La on the ceramic surface contributed to As(III) removal. La-coated ceramic material could be used as a promising low-cost and efficient arsenic removal medium for POU household water treatment.