Abstract:The process of simulating the conversion of arsenic from wastewater to scorodite in the As(V)-Fe(II) system was studied. The effects of excess coefficient of hydrogen peroxide, oxidation time, oxidation temperature on the oxidation rate in the oxidation of As(III) to As(V) and the oxidation mode of Fe(II), initial pH, molar ratio of Fe/As on arsenic removal effect in the experiment of arsenic precipitation by scorodite were investigated. The results showed that the oxidation rate of As(III) could be improved by increasing the excess coefficient of hydrogen peroxide, oxidation time and oxidation temperature. Accelerating the oxidation of Fe(II) was beneficial to the growth of scorodite crystals, and could improve the rate of arsenic deposition and the quality of scorodite in arsenic precipitation experiments. Appropriately increasing the initial pH and Fe/As molar ratio was conducive to increasing the arsenic deposition rate. Although the crystal quality of the scorodite was reduced, the toxicity was still low. Under the optimal conditions of excess coefficient of hydrogen peroxide of 1.5, oxidation time of 1 h, oxidation temperature of 45 ℃, addition of 0.3% H2O2 solution at a rate of 60 mL/h, initial pH of 2.0, and Fe/As molar ratio of 1.5, the average trivalent arsenic oxidation rate could reach 97.67%, the average arsenic deposition rate could reach 95.57%, the stability of scorodite was high and the average leaching toxicity was 1.00 mg/L.