Photocatalytic digestion of total phosphorus in the presence of H2O2 utilizing nano-TiO2 photocatalyst
In this work, an ultra-violet (UV) photocatalysis method in the presence of H<sub>2</sub>O<sub>2</sub> utilizing nano-TiO<sub>2</sub> photocatalyst is presented for the digestion of total phosphorus (TP) in water. The UV digestion of 4 mg/L of sodium glycerophosphate solutions (by weight of P) were conducted at different digestion time and concentrations of H<sub>2</sub>O<sub>2</sub>. The H<sub>2</sub>O<sub>2</sub> added to the water samples could increase the formation rate of strong oxidant hydroxyl radicals (·OH), but excess H<sub>2</sub>O<sub>2</sub> will consume ·OH and reduce the conversation rate. The optimum concentration of H<sub>2</sub>O<sub>2</sub> obtained in this work was 740mg/L. At the condition of 60min and 740 mg/L of H<sub>2</sub>O<sub>2</sub>, the conversion rate of sodium glycerophosphate reached about 90%, and the maximum value of rate constant k was 0.0306 min<sup>-1</sup>. Compared with the traditional thermal oxidation method for TP digestion, this UV/H<sub>2</sub>O<sub>2</sub> photocatalysis digestion method enables the digestion process work at normal pressure. Compared with the individual UV photocatalysis process, UV/H<sub>2</sub>O<sub>2</sub> digestion method decreases the digestion time from two hours to about an hour.