Near-infrared light to heat conversion in peroxydisulfate activation with MoS2: A new photo-activation process for water treatment

The advantage of light-to-heat conversion can be employed as an optical alternative for environmental remediation. As a proof of concept, for the first time we introduce the light-to-heat conversion application in peroxydisulfate (PDS) activation by molybdenum disulphide (MoS2) under near infrared (NIR) light irradiation. Theoretical kinetics analysis suggests that the reaction rates of PDS activation is increased up to 9.2 times when increasing from room temperature to 50 °C. MoS2 has the capability to quickly convert NIR light to heat energy (~45°C), thereby being able to activate PDS to generate hydroxyl and sulfate radicals. The observed reaction rate of carbamazepine degradation by NIR/MoS2/PDS process is 6.5 times of that in MoS2/PDS and even 2.6 times higher than the sum of those in NIR/MoS2, MoS2/PDS and NIR/PDS processes. Combining with theoretical calculation and oxidation species analysis, a new photo-activation PDS mechanism is proposed, in which MoS2 absorbs the energy of light to generate heat energy for overcoming the energy barrier of PDS activation. By loading MoS2 on carbon cloths, a flexible photothermal membrane is designed for practical application of sunlight-to-heat conversion to activate PDS with high efficiency, stability, and recycling. The present results demonstrate the potential of applying light-to-heat conversion in Fenton-like processes in pollution control, which opens new avenues towards utilization of inexhaustible solar energy and novel approaches for environmental remediation.