Research on Coal Chemical Wastewater Treatment by Nano-TiO<sub>2</sub> Powder Photocatalytic Oxidation Process

Abstract

Abstract. With TiO2 as photocatalyst, hydrogen peroxide(H2O2) as oxidant, treated the coal chemical wastewater under the condition of 30W UV lamp irradiation. Discussed the effects of those factors—pH, dosage of TiO2 powder, dosage of FeCl3, dosage of H2O2 and illumination time etc. on Chemical Oxygen Demand(COD) removal rate of wastewater. The results have shown that: when taking the pH of raw water, TiO2 0.2g per 100ml wastewater, FeCl3 0.01g per 100ml wastewater, H2O2 1.2 ml per 100ml wastewater, 5h illumination time, quiet place 3h, acquired the best photocatalytic effect. After treated under the optimum technological conditions, the COD removal rate reached 70.09%; the removal rate of Biological Oxygen Demand(BOD5), ammonia nitrogen, cyanide and color reached respectively to 58.60%、39.99%, 72.41% and 90%. After repeated 10 times, all the active of TiO2 was almost lost. With the regeneration treatment by high-temperature cauterization, the regenerated catalyst was added into the raw wastewater. Then under the optimum technological conditions, after illuminated 7h, the COD removal rate of wastewater recovered to 49.47%.