A conical array water evaporator with anti-biofouling, salt-rejecting and anti-polyelectrolyte effect for efficient solar energy-driven seawater desalination

Abstract

Solar energy-driven water evaporation technology is a sustainable access to obtain clean water from natural seawater to tackle severe freshwater shortage worldwide. Several challenges including salt accumulation and biological contamination still exist, which cause insufficient water supply, low light absorption efficiency and thus reduced water evaporation rate. Herein, a high-performance conical array water evaporator with anti-biofouling, low water evaporation enthalpy, salt-rejecting and anti-polyelectrolyte effect has been developed for efficient solar energy-driven stable seawater desalination. The as-prepared conical array solar water evaporator is composed of phothothermal MXene/bismuth sulfide, thermally insulating ultralong hydroxyapatite nanowires, and hydrophilic polyvinyl alcohol and polymerized N-(3-sulfopropyl)-N-methacryloxyethyl-N,N-dimethylammonium betaine, which combine merits of high light absorption and energy efficiency, efficient photothermal conversion, low evaporation enthalpy, rapid water transportation, and superior water evaporation performance. The conical array solar water evaporator demonstrates a high water evaporation rate of 2.54 kg m⁻² h⁻¹ and superior energy efficiency of 106.78 % under one sun illumination (1 kW m⁻²). Moreover, the conical array solar water evaporator exhibits good resistance to both biofouling and bacterial adhesion. This research provides a new strategy for designing solar water evaporators with multiple functions and advances their applications in seawater desalination and wastewater treatment.