Fast electrochemical reduction behavior and kinetics of nanoflower-like MoS2-modified titanium plate cathode to oxidized mercury

Abstract

Although mercury is a highly toxic environmental pollutant, it is also an important industrial resource. An attempt was made to use electrochemical method to reduce and collect mercury oxide in wastewater for resource utilization of mercury. In this study, nanoflower-like MoS2 powder and MoS2@Ti electrode were successfully prepared by one-step hydrothermal method. The successful preparation of MoS2@Ti electrodes and their better HER activity than Ti electrodes were confirmed using SEM, EDS and XRD characterisation methods, as well as exploring the reaction mechanism of the electroreduction system in conjunction with other characterisation methods. In the electrochemical system with MoS2@Ti electrode as cathode and IrO2/Ti as anode, the removal efficiency of Hg2+ can reach 92 % under optimal conditions. At the same time, the effects of reaction time, current, initial concentration of Hg2+, stirring rate and voltage on the reduction system were investigated. Compared with pure Ti plate system, the reaction time is shortened by 14 h while the reduction efficiency of Hg2+ is guaranteed, and the energy consumption is reduced. Moreover, by fitting the system kinetics, the reaction system conforms to the secondary kinetics.