Salt Mitigation Strategies of Solar‐Driven Interfacial Desalination

Abstract

Solar‐driven interfacial desalination (SDID), which is based on localized heating and interfacial evaporation, provides an opportunity for developing environmentally friendly and cost‐effective seawater thermal desalination. However, localized heating and rapidly generated interfacial steam may cause salt to accumulate on the evaporator's surface and block the channel of steam evaporation. Salt accumulation inevitably reduces the light absorption and service period of the solar absorber, resulting in a significant decrease in evaporation efficiency over time. Salt accumulation makes it difficult to produce SDID devices with high energy efficiency and long‐term stability for large‐scale use in remote poverty‐stricken areas. Therefore, the exploration of novel and effective strategies for addressing salt accumulation through both material design and structural engineering has attracted more attention in recent years. This review presents an overview of the state‐of‐the‐art advancements in salt‐resistant photothermal evaporation and discusses the critical issues for achieving salt mitigation SDID, focusing on the classification of salt mitigation strategies based on photothermal evaporation configurations, the basic mechanism of salt mitigation, and the architectural design of photothermal materials. Finally, the important challenges and prospects of SDID are discussed to providing a meaningful roadmap to efficient salt mitigation SDID.

Dual‐Zone Photothermal Evaporator for Antisalt Accumulation and Highly Efficient Solar Steam Generation

“…Although the evaporation rate has been significantly improved, there are still critical issues that hinder the real‐world application of solar evaporation technology. [ 51–54 ] For example, salt accumulation on photothermal material surfaces, which blocks the incident light and consequently declines the evaporation rate, remained as one of the major problems that limit the long‐term solar evaporation. [ 55 ] In addition, the formed salt crystals may lead to pronounced slump of water transportation, thus limiting the lifetime and performance of photothermal evaporators.…”

Poly(ether‐block‐amide) membrane with deformability and adjustable surface hydrophilicity for water purification

“…[ 1–4 ] Nevertheless, the consumption of water resources has become increasingly severe with the progress of society; in the meantime, the solid waste generated in production and life causes water pollution resulting in the decrease of freshwater resources that can be directly consumed by humans, which will affect people's drinking water safety. [ 5–8 ] Increasing available clean freshwater has a significant impact on ensuring the sustainable development of society. [ 9,10 ] Compared with flowing freshwater resources, solid freshwater resources, i.e., ice, account for more than 70% of the world's total freshwater resources, but most of them contain dust and other solid pollutants, making the melted ice not directly usable.…”

Solar Selective Absorber for Emerging Sustainable Applications

“…Salt accumulation is a serious impediment to produce large-scale, long-term stable and efficient solar-driven desalination devices for application in underdeveloped areas. [70][71][72] As a result, a variety of salt rejection strategies have been proposed, but the conventional approach is still limited to the mode that the water and SSA absorber are contacting. [73][74][75][76] Recently, a novel and simple noncontact salt rejection strategy was developed by employing SSA and black body emitters.…”