Synthesis of polyoxometalates (POM)/TiO2/Cu and removal of nitrate nitrogen in water by photocatalysis

Nitrate nitrogen is one of the vital issues needed to be addressed in the water purification process utilizing groundwater as a drinking water source. In this study, a sandwich-type polyoxometalate Na [alpha-SiW9O34] has been synthesized and SiW9/TiO2/Cu composite has been prepared by sol-gel method. Samples have been characterized by XRD, BET, FTIR, SEM, ED-Mapping, UVeVis, XPS. The catalytic reduction of nitrate was performed in the presence of SiW9/TiO2/Cu composite as photocatalyst. The effects of catalyst loading, initial nitrate concentration, sandwich-type polyoxometalate loading, dissolved O-2, and concentration of formic acid on nitrate removal have been investigated. The results showed that the prepared composite catalyst had better photocatalytic activity than the TiO2. 76.53% of nitrate removal with 82.09% of N-2 selectivity was obtained under the following conditions: catalyst dosage 0.8 g/L, initial nitrate concentration of 30 mg/L, SiW9/Cu loading percentage of 10%, 30 mmol/L of formic acid, in presence of N-2, and 6 h reaction time. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

A sandwich-type polyoxometalate Na [alpha-SiW9O34] was synthesized and SiW9/TiO2/Cu composite was prepared for the catalytic reduction of nitrate. The prepared composite catalyst showed better photocatalytic activity than TiO2, achieving 76.53% nitrate removal with 82.09% N-2 selectivity under specified conditions.