Intensifying the co-production of vapor and salts by a one-way brine-flowing structure driven by solar irradiation or waste heat

Abstract

Interfacial evaporation technology holds great promise in seawater desalination with zero liquid discharge. Here, a salt-extraction evaporator enabling high-productivity co-generation of vapor and salts is designed by combining a one-way brine-flowing evaporation structure with solar irradiation or waste heat. A highly scalable thermo-evaporative structure, prepared by growing polypyrrole (PPy) onto glass fiber (PPy-GF), is employed for investigations. Modeling tools are further developed to guide the rational geometric design of the evaporator based on PPy-GF. This merit also allows us to investigate the complex effects of salt concentration and ionic species on the evaporation-salt generation behaviors to achieve intensified site-specific co-production of vapor and salts. Specifically, this evaporator enables the concentrated seawater to evaporate at an average evaporation rate of 1.12 kg m−2 h−1 and simultaneously produces 4.21 g of salts in 24 h under 1 sun. In addition, the stable evaporation rate of 2.58 kg m−2 h−1 and a salt production amount of 12.92 g in the concentrated seawater are obtained under 60 °C in continuous 30 h. This study is believed to provide a novel avenue for stable and efficient seawater desalination with zero liquid discharge.