High-performance photothermal conversion of sludge derived biochar and its potential for peroxydisulfate-based advanced oxidation processes

Exploring low-cost, high-efficiency photothermal materials has an important significance in solar thermal utilization. In this work, a sewage sludge-derived biochar (SDBC) as an efficient solar receiver is fabricated via a simple pyrolysis method and applied in peroxydisulfate (PDS) activation based on the fact that PDS can be thermally activated. Under the irradiation of concentrated solar light, the SDBC exhibits excellent broad-spectrum response and high photothermal conversion performance. The heat generated from light conversion provides sufficient activation energy for activating PDS. Meanwhile, PDS can also be directly activated by ultraviolet rays in the solar spectrum. Combining with oxidation species analysis, the underlying mechanism of photothermal-activation PDS is developed. As a proof of concept, an example of treating landfill leachate is taken. The present results demonstrate great potential for degrading landfill leachate in the actual water, which provides a new perspective on the utilization of solar energy for wastewater treatment.