Highly Efficient, Antibacterial, and Salt-Resistant Strategy Based on Carbon Black/Chitosan-Decorated Phase-Change Microcapsules for Solar-Powered Seawater Desalination

Si Chen; Zhiheng Zheng; Huan Liu; Xiaodong Wang

doi:10.1021/acsami.2c21298

Highly Efficient, Antibacterial, and Salt-Resistant Strategy Based on Carbon Black/Chitosan-Decorated Phase-Change Microcapsules for Solar-Powered Seawater Desalination

ACS Appl Mater Interfaces. 2023 Apr 5;15(13):16640-16653. doi: 10.1021/acsami.2c21298. Epub 2023 Mar 23.

Authors

Si Chen¹, Zhiheng Zheng¹, Huan Liu¹, Xiaodong Wang¹

Affiliation

¹ State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China.

PMID: 36951291
DOI: 10.1021/acsami.2c21298

Abstract

Solar-powered interfacial evaporation has been recognized to be a promising and sustainable technology for seawater desalination, in view of the challenge of freshwater scarcity and fossil energy storage. Nevertheless, current cutting-edge interfacial evaporation systems mostly ignore the issues of intermittent solar irradiation and bacterial contamination. We have hereby developed a novel type of an interfacial evaporator equipped with carbon black (CB)/chitosan (CS)-decorated phase-change microcapsules as a multifunctional photothermal material for solar-powered seawater desalination, based on a highly efficient, antibacterial, and salt-resistant multipurpose strategy. In the developed microcapsules, an n-docosane phase-change material (PCM) core was engulfed in a TiO₂ shell, followed by surface decorating a CB/CS nanocomposite layer. A high thermal energy-storage capacity of more than 140 J g^-1 was achieved, thanks to tight sealing of n-docosane as a PCM core in the perfect core-shell structured microcapsules. Moreover, a rational combination of CS and CB nanoparticles not only contributes an extremely high solar absorption efficiency of 95.04% and good wettability to the as-synthesized microcapsules, but also imparts outstanding antibacterial and salt-resistant abilities to them. These innovative designs enable the developed evaporator to gain a high evaporation rate of 2.58 kg m^-2 h^-1, along with an evaporation efficiency higher than 90% for consecutive and stable evaporation of seawater under intermittent solar illumination. Compared to conventional evaporators without a PCM, there is an increase by 1.03 kg m^-2 in the total water production of the develop evaporator under natural solar illumination for 8 h on a semicloudy day. The resultant evaporated water presents good vegetation compatibility to meet the requirement of crop growth for agricultural cultivation. This work provides a new pathway for designing and developing the high-performance interfacial evaporators with prominent antibacterial and salt-resistant abilities to produce purified water through solar-powered sustainable seawater desalination.

Keywords: antibacterial performance; chitosan/carbon black nanocomposite; interfacial evaporation; phase-change materials; salt resistance; solar-powered seawater desalination.