A highly efficient antibacterial solar-thermal evaporator based on waste tea leaves for water evaporation and thermoelectric generation

Abstract

Utilizing solar-driven interfacial water evaporation technology for desalination is one of the effective approaches to alleviate freshwater scarcity. However, practical applications face challenges such as high production costs of solar-thermal materials and poor resistance to microbial contamination, which hinder long-term development. Herein, we developed a strategy for preparing a highly efficient antibacterial solar-thermal evaporator by using waste Maojian tea rich in sunlight-absorbing pigments and antibacterial ingredients. The antibacterial capability of this solar-thermal evaporator mitigates microbial contamination and corrosion issues, extends the service life of the evaporator, and improves the water quality of evaporated water. Under 1 kW m⁻² simulated solar radiation, the water evaporation rate reaches 1.36 kg m⁻² h⁻¹. In addition, a novel solar-steam and thermoelectric co-generation device was designed and prepared and can attain superior water purification and electricity generation performance. It also drives a small electric fan to operate under high light intensity. The results demonstrate that this strategy for constructing highly efficient antibacterial solar-thermal hydrogels from waste tea leaves provides an effective solution to address the limitations of solar-thermal materials in antibacterial performance. It represents a green, low-cost, and highly efficient sustainable desalination technology.