Cryptomelane Modified Biomass Wastes for Solar Interfacial Evaporation and Stabilization of Cadmium

Abstract

In this work, after carbonization of two biomass wastes, rice husk and coconut husk, they were modified by hydrothermally synthesized cryptomelane manganese and prepared into a solar interfacial evaporation system to explore their evaporation performance and stabilization performance of cadmium. The results demonstrate that the cryptomelane-modified biochar can obtain an evaporation rate of 1.247 kg m−2 h−1 and a photothermal conversion efficiency of 89.36% under one sun (1 kW m−2). In an outdoor experiment with an average solar power density of only 465.22W m−2, the evaporation capacity reached 4.7 kg m−2 and the evaporation rate reached 0.78 kg m−2 h−1 within 6 h. The cadmium adsorption capacity of biomass waste modified by manganese potassium ore increased by 50.94%, which could be well used for long-term stabilization and recycling of Cd. It could be verified that the cryptomelane-modified biochar material is a low-cost, scalable, and efficient material for interfacial evaporation and reduce wastewater pollution. The evaporation system designed in this work is a feasible way to obtain clean water and solve wastewater problems in the future.