Combination of Microwave Discharge Electrodeless Lamp and a TiO < sub > 2 < /sub > /HZSM-5 Composite for the Photocatalytic Degradation of Dimethyl Sulphide

In this study, an integrated photocatalytic system consisting of a microwave discharge electrodeless lamp (MDEL) and TiO2/HZSM-5 was established to investigate the intensified degradation of dimethyl sulphide (DMS). The system targets optimisation of the reactive oxygen species (ROS) and photocatalytic degradation pathways without catalyst deactivation. TiO2/HZSM-5, containing highly dispersed TiO2 nanoparticles, was prepared through the sol-gel method. TiO2/HZSM-5 exhibits strong acidity and can adsorb DMS in multiple adsorption forms. Thus, the adsorption capacity of TiO2/HZSM-5 is 20 and 53 times higher than that of Aeroxide TiO2 (P25) in dry and highly humid air, respectively. UV-Vis analysis was performed to investigate the ROS in the gas phase. The results show that the concentrations of the ROS increased by 8% and 62.7% in dry and highly humid air, respectively. 1O2 and O (1D), as well as ·OH are the major ROS, accounting for 73.6% and 61.6% in dry and highly humid air, respectively. A total of 92.5% DMS was removed over 600 min in dry air. Microwaves have strong desorption effects on absorbed substances, promoting the degradation of DMS via ROS in the gas phase. Moreover, 1O2, O (1D), and ·OH can mineralise more DMS molecules into SO2 and SO3 through methanesulfonic acid. The highest mineralisation rate of 89.48% was obtained at 90% humidity over 600 min without catalyst deactivation. Therefore, this integrated system induced by microwave radiation can improve ROS p...
Source: Environmental Research - Category: Environmental Health Authors: Source Type: research