Arsenic adsorption and removal by a new starch stabilized ferromanganese binary oxide in water.

A new starch stabilized ferromanganese binary oxide (starch-FMBO) with an Fe/Mn ratio of 1.00-2.00 and a synthetic pH of 2 was prepared using an organic polymer (starch) as the stabilizing dispersant. The maximum arsenic adsorption capacity of starch-FMBO was 161.29 mg/g. Adsorption optimization was also conducted, which revealed that starch-FMBO had a high adsorption capacity over a wide pH range (pH 3.0 to pH 11.0) and in the presence of some common anions (HCO3-, SO42-, Cl-, and NO3-). Arsenic removal by FMBO and starch-FMBO followed pseudo-second-order dynamics (R2 ≥ 0.99), indicating that the adsorption rate depended on the chemical adsorption process. Through the analysis of X-ray photoelectron spectroscopy (XPS), and Fourier-transform infrared spectroscopy (FTIR), it was shown that hydroxyl was continuously produced and complexated with As(III) and As(V) during the adsorption process. Thus, the reaction of iron oxide and manganese oxide with arsenic was inferred and explained. The developed starch-FMBO shows promise for its application in the treatment of arsenic-contaminated water.