Carbon foam directly synthesized from industrial lignin powder as featured material for high efficiency solar evaporation

Interfacial solar evaporation has emerged as a promising method for clean water production. Among the various types of evaporators, biomass-based carbon evaporators have garnered significant attention due to their renewability and low cost. However, biomass-based carbon materials still face certain challenges, including limitations in terms of their morphology, size adjustability, light absorption capability, and mechanical strength. To overcome these issues, a novel carbon foam evaporator has been developed and extensively optimized. The carbon foam can be directly synthesized from industrial lignin powder without the need for any additives, using a simple and environmentally friendly methodology that involves foaming, carbonization, and activation processes. The evaporator demonstrates remarkable attributes, encompassing swift water transport capacity, broad-spectrum sunlight absorption, expeditious photo-thermal conversion capability, low density (0.281 g cm−3), low thermal conductivity (0.0473 W m−1 K−1), and a profusion of micro-pores (1430.49 m2/g of SBET). The developed lignin-based solar evaporator achieves a high water evaporation rate of 2.11 kg m−2h−1, coupled with an impressive evaporation efficiency of 93.37 % under 1 sun. Furthermore, the evaporator demonstrates exceptional resistance to salt accumulation and exhibits efficient recycling capabilities. Notably, the evaporator's flexible and plastic nature enhances its versatility and holds great promise for its application in the field of solar-powered seawater desalination.