Biomass-derived porous carbon for excellent low intensity solar steam generation and seawater desalination

Abstract

In recent times, solar-driven desalination has emerged as a sustainable solution for the impending water crisis. Herein, we report a novel solar-driven steam generator manufactured from porous carbon derived from sweet lime peels (a food waste) and polyvinyl alcohol sponge for efficient steam generation and its application in solar seawater desalination. The solar steam generator fabricated with a unidirectional pathway design satisfactorily absorbed incoming solar illumination, provided localized heat at the air-water interface and produced steam at a rate of 1.386 kg m−2 h−1, exhibiting an excellent photothermal efficiency of 90.88% under 1 sun (1000 W m−2) illumination. Furthermore, the steam generator proved capable of maintaining its performance in lower solar intensities (<1 sun), making it an excellent device for seawater desalination. Bearing in mind the aforementioned virtues, the steam generator was incorporated into a facile laboratory solar still for passive solar desalination. The modified solar still could generate clean water even at low simulated solar intensities with a near-100% salt removal efficiency. Moreover, the excellent performance of the solar still was retained in long-term and real-life experimentation and resulted in sustained clean water generation. The merits of the solar still, such as facile fabrication technique, low cost, scalability, and excellent desalination performance should inspire further research in solar steam generator-based solar stills for solar seawater desalination.