Photodegradation of N-Methyldiethanolamine over ZnO/SnO2 coupled photocatalysts

Abstract

A photocatalyst semiconductor can be used to remove organic pollutants from wastewater in the presence of UV light. In this research, coupled ZnO/SnO2 semiconductors with 1:1 and 2:1 ratios were prepared using the co-precipitation method. The prepared coupled ZnO/SnO2 photocatalyst was tested towards the photodegradation of simulated N-Methyldiethanolamine (MDEA) under UV-irradiation (λ = 365 nm, 100 V, 6 W). The ZnO/SnO2 was characterized using UV diffused reflectance spectroscopy and X-ray diffraction. The band gap energy for ZnO/SnO2 (ZS) catalyst calcined at 200 C, 400 C, 600 C and 900 C were 3.22, 3.13, 3.12 and 3.07 eV, respectively, while for Z2 S were 3.71, 3.28, 3.16, and 3.14 eV, respectively. XRD results indicated that ZS and Z2 S catalysts possessed mixed phases of ZnO, SnO2 and Zn2 SnO4 at a calcinations temperature above 600 C. The ZnO/SnO2 (2:1) catalyst, which was calcined at 600 C for 9 hours, gave the optimum percentage photodegradation of MDEA with 39.18%. The percentage degradation of MDEA was measured using ion chromatography with retention time at the measured peak of 4-5 minutes. The optimum system was applied on the photodegradation of MDEA in petroleum wastewater. The percentage degradation of MDEA in petroleum wastewater was 23.38%.