Electrical Impedance Tomography Monitoring of Salt Transportation in Cellulose Hydrogel for Solar-Driven Evaporative Desalination via Laser Defined Wettability

Abstract

The scarcity of clean water has become a growing problem worldwide. Solar-driven desalination based on evaporation has become a promising green technology for obtaining drinking water from saline water for the welfare of human society. However, the accumulation of salt precipitated from the saline at the evaporator surface remains a severe problem in improving evaporation efficiency. To overcome this problem, it is crucial to investigate the transportation mechanism of salt in the saline during the evaporation process. Herein, an in situ monitoring strategy with the electrical impedance tomography (EIT) method is proposed to characterize the salt transportation and accumulation process inside the nano-crystal cellulose (NCC)-MnO₂ nanoparticle solar evaporator. The coating of laser-induced graphene (LIG) with tunable water wettability shows that the hydrophobic structures can suppress salt accumulation during evaporation. The collected condensation water generated from the bacteria-polluted saline proves to be clean. It is hoped that this work can further inspire research on the salt-resistive evaporator design.