Efficient removal of As(III) via simultaneous oxidation and adsorption by magnetic sulfur-doped Fe-Cu-Y trimetal oxide nanoparticles

Abstract

A novel magnetic sulfur-doped Fe–Cu–Y trimetal oxide (MST) nanomaterial was successfully synthesized by a chemical coprecipitation method to remove As(III) via simultaneous oxidation and adsorption and then characterized by BET, VSM, FESEM, XPS, and FTIR techniques. The effect of solution initial pH on the adsorption of As(III), and the adsorption kinetics and isotherm were investigated in detail. The results indicated that the MST nanoparticles exhibited an excellent performance for As(III) removal in a pH range of 7–10 and were easily separated from aqueous solution with a magnet. The maximum removal capability for As(III) reached 202.0 mg/g at pH 7.0. The adsorption of As(III) was well fitted by the pseudo-second-order kinetic model and Langmuir isotherm model, respectively. The investigation of mechanism revealed that As(III) could be oxidized to As(V) by O2− and OH free radicals, generated via the dissolved O2 obtaining an electron from Cu(I) on the surface of the adsorbent and Fenton/Fenton-like reaction, respectively. Meanwhile, the produced As(V) was adsorbed onto the surface of the nanoparticles through the electrostatic attraction or diffusion. The adsorbed As(V) further interacted with –OH groups via ion exchange or with Y(III) on the surface of the adsorbent to form a precipitate. Therefore, the MST nanoparticles are promising for the removal of arsenic from water.