Synthesis and investigation of a novel nanocomposite for improved solar radiation absorbance of MD membranes

Abstract

Membrane distillation (MD) has emerged as a promising technology for seawater desalination to provide drinking water. The most considerable advantage of MD is the capacity to utilize thermal energy to reduce the energy cost of the solar-driven MD seawater desalination systems. However, limited thermal efficiency is one of the key challenges that prevent the wide application of MD for seawater desalination. Due to low thermal efficiency, most solar-driven MD systems require large and complex arrays of solar thermal collectors, leading to the significantly high investment costs of the MD systems. MD membranes coated with solar radiation absorbing materials have been proposed for the solar-driven MD process to obviate the need for large arrays of solar thermal collectors. In this study, we synthesized a novel black spinel-carbon nanocomposite for MD membrane coating to improve the solar radiation absorbance of the membrane, thus enhancing thermal efficiency of the MD system. The preliminary experimental results demonstrated that the black spinel-carbon nanocomposite could absorb light at a wider wavelength range from visible to far-red; therefore, they exhibited increased solar radiation absorbance and hence heating efficiency compared with single materials.