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 H₂O₂ utilizing nano-TiO₂ 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 H₂O₂. The H₂O₂ added to the water samples could increase the formation rate of strong oxidant hydroxyl radicals (·OH), but excess H₂O₂ will consume ·OH and reduce the conversation rate. The optimum concentration of H₂O₂ obtained in this work was 740mg/L. At the condition of 60min and 740 mg/L of H₂O₂, the conversion rate of sodium glycerophosphate reached about 90%, and the maximum value of rate constant k was 0.0306 min^-1. Compared with the traditional thermal oxidation method for TP digestion, this UV/H₂O₂ photocatalysis digestion method enables the digestion process work at normal pressure. Compared with the individual UV photocatalysis process, UV/H₂O₂ digestion method decreases the digestion time from two hours to about an hour.