Adsorption behavior of As(III) onto a copper ferrite generated from printed circuit board industry

A copper ferrite generated from the sludge of printed circuit board (PCB) industry was investigated for its As(III) adsorption behavior. The adsorption of As(III) by this copper ferrite exhibited a L-shaped nonlinear isotherm and fitted well the Langmuir isotherm, implying limited binding sites and monolayer sorption occurred on the surface. The K-edge X-ray Absorption Near-Edge Structure (XANES) showed that the adsorbed As(III) could be oxidized to less toxic As(V) by copper ferrite. The maximum As adsorption capacity of the copper ferrite was 41.2mgg^-1 at pH 4.2 and decreased dramatically at higher pH (pH>9.2) due to enhanced electrostatic repulsion between As(III) and the adsorbent surface. Desorption of As(III) using four different acid solutions demonstrated that the desorption rate decreased in the order of H₃PO₄H₂SO₄>HCl>HNO₃. These results demonstrate that the synthesized copper ferrite is an effective adsorbent for removing As(III) in aqueous solution. The new data obtained reveals informative knowledge for designing an arsenic removal technology in treating contaminated groundwater.