Three-dimensional water evaporator based on carbonized silkworm cocoon for highly effective solar-driven water evaporation and wastewater purification

Natural silkworm cocoon is selected and carbonized at different temperatures as an excellent light-to-heat conversion material for highly effective solar-driven water evaporation. The carbonized silkworm cocoon exhibits a unique porous structure and has full-spectrum absorption characteristics at 200–2500 nm. Super-absorbent polymers (SAPs) with super water absorption capacity are filled in the silkworm cocoon as the “water pump” for water transportation. Under one-sun irradiation, the water evaporator (denoted as CSC (275 °C) + SAP) has better water evaporation performance (1.79 kg m−2 h−1) and higher light-to-heat conversion efficiency (η = 112.5%) than the other groups. The main reason is the high optical absorption of the carbonized cocoon and the assistance of SAPs, which are conducive to light-to-heat conversion and water transportation. Our work highlights the great potential of the as-prepared evaporator for realizing a highly effective solar energy-driven water evaporation and wastewater purification.