A robust and renewable solar steam generator for high concentration dye wastewater purification

Abstract

As an eco-friendly and sustainable technology, the solar-driven interfacial evaporation for water purification garners widespread attention. In the field of dye wastewater purification, some solar steam generators with catalytic degradation have been developed. However, they can only deal with ultra-low concentration dye wastewater because of their poor degradability, which would lead to the decrease of the evaporation rate caused by dye blockage when treating high concentration dye wastewater. Meanwhile, the complex external environment puts forward a higher requirement to device robustness. Therefore, fabricating a robust and renewable solar steam generator for high concentration dye wastewater purification is still a challenge. Here, an Au/ceramic solar steam generator with renewability and robustness was fabricated for dye wastewater purification. This generator can achieve an evaporation rate of 5.52 kg m⁻² h⁻¹ by rational T-shaped thermal management and timely vapor diffusion with breeze. It can efficiently purify various kinds of wastewater with a wide range of dye concentrations. Furthermore, this generator exhibits good pH stability, thermostability and robust mechanical properties, which are beneficial to meet complex situations in practical applications. Meanwhile, the blocked generators after long-term purification of high concentration wastewater can be regenerated by calcination, solving the decrease of the evaporation rate caused by organic accumulation. This work shows great potential for organic wastewater purification in further practical applications.