Construction of Superhydrophilic/Superhydrophobic Composite Photocatalysts for Efficient Gas-Liquid-Solid Three-Phase Photocatalytic Degradation of Methyl Mercaptan

Abstract

Photocatalytic oxidation technology holds considerable promise for effectively removing volatile organic compounds. However, conventional gas-solid photocatalytic technology faces significant limitations, including a low mineralization rate and incomplete degradation, leading to the accumulation of undesirable intermediate products. This study introduces an innovative gas-liquid-solid photocatalytic oxidation system that utilizes a superhydrophilic/superhydrophobic photocatalyst for the efficient removal of methyl mercaptan. By synthesizing superhydrophobic Cu-doped UiO-66 and combining with TiO2, the resulting OCUN/T photocatalysts was thoroughly chatacterized and tested under various conditions. The dynamic system consistently maintains a high removal rate (exceeding 99%) at flow rate of 50 ml/min and a substantial mineralization rate of methyl mercaptan over 10 hours operation. The removal efficiency of methyl mercaptan shows remarkable improvement under sunlight intensities exceeding 35×1000 lm. Furthermore, a detailed mechanism for its degradation through the gas-liquid-solid photocatalytic oxidation system is proposed, highlighting a novel and cost-effective approach for the VOCs removal.

Keywords: Gas-liquid-solid photocatalytic oxidation system, Metal-organic framework (MOFs), Superhydrophilic/superhydrophobic photocatalysis, Volatile organic compounds (VOCs)