Salt-Resistive Photothermal Materials and Microstructures for Interfacial Solar Desalination

Xiaoqiang Yu,Xin Liu,Ning Xu,Lin Zhou,Qian Zhang

doi:10.3389/fenrg.2021.721407

Abstract

Solar interfacial evaporation, featured by high energy transfer efficiency, low cost, and environmental compatibility, has been widely regarded as a promising technology for solar desalination. However, the interplay between energy transfer and water transport in the same channels suggests that the tradeoff between high efficiency and long-term stability inherently exists in conventional photothermal nanomaterials. We summarize state-of-the-art research on various anti-salt clogging photothermal microstructures as long-term stable interfacial solar evaporators for solar desalination. The review starts with an overview of the current status and the fundamental limit of photothermal materials for solar desalination. Four representative strategies are analyzed in detail with the most recent experimental demonstrations, including fluid convection enhancement, surface wettability engineering, energy-mass-path decoupling, and surface chemistry engineering. Finally, this article focuses on the challenges in anti-salt clogging solar interfacial evaporators and potential point-of-use applications in the future.

Highlights

The shortage of freshwater resources has become one of the most severe global challenges nowadays (Shannon et al, 2008; Elimelech and Phillip, 2011; Cetrulo et al, 2019)
It illustrates that the reported anti-clogging mechanisms for solar interfacial systems can be categorized into four major groups: 1) fluid convection can dilute the formed high concentration brine in the absorbers during desalination; 2) Hydrophobic designs can prohibit the contact of salt ions with the solar absorber; 3) Thermal engineering by re-radiating infrared photons can entirely avoid fouling via the physical separation from the brine; 4) Donnan that
MXene, which has a theoretical light-to-heat conversion capability of 100 percent, can convert light to heat in combination with the Janus structure and protect the photothermal layer from direct bulk water interaction with the hydrophobic upper layer, thereby reducing heat loss and effectively inhibiting the crystallization of salt owing to its fast dissolution with continuous pumping water

Summary

Introduction

The shortage of freshwater resources has become one of the most severe global challenges nowadays (Shannon et al, 2008; Elimelech and Phillip, 2011; Cetrulo et al, 2019). The imperfections of the above methods are that the threat of salt accumulation on the absorber surface to light absorption and permeability can interrupt the generation of stable and high-efficiency steam in long-term desalination and highly concentrated brine.

Results

Conclusion