Solar Absorbing Membranes for Water Desalination

Abstract

Over the past couple of decades, world has been shift from thermal desalination processes to membrane desalination technologies. Membrane technologies offer a variety of advantages[1]. Several researchers study the effects of adding nanoparticles to enhance membrane performance. However, there are some research gaps: specifically, no study has ever been carried out to examine the impact of incorporating activated carbon (AC) and carbon nanotubes (CNT) on membranes and test membrane performance in solar air-gap membrane distillation (AGMD). Typically, solar energy is integrated into desalination plants; this process is initiated by connecting a solar farm (electrical or thermal energy) to power a desalination plant[2]. However, this approach is restricted to the efficiency limit of various components, i.e., photovoltaic (PV), pumps, heat exchangers, etc. This study investigates multifunctional in-house fabricated membranes that are both directly solar-absorbing and fresh-water-transport-enabling materials, incurring a relatively low cost and using readily available (AC) and (CNT). This paper shows that the utilization of even small amounts (5 to 9%) of AC and (25 to 75%) of CNT can significantly boost the flux of AGMD, directly driven by solar energy. Our approach had four advantages: (1) solar membrane distillation (MD) was not assisted with external heating but was instead only driven by direct solar power, (2) scalable AC modified polyvinylidene fluoride (PVDF) membranes were fabricated via phase inversion, (3) scalable CNT modified PVDF membranes were fabricated via tape casting, 4) and efficiencies and energy demands were relatively competitive. This research will focus on AC and CNT nanoparticles and fabricated membranes with various concentrations, which will be tested in solar AGMD. In this work, experimental work has been applied for the first time to investigate the effects of a carbon-based nanomaterial in membrane performance flux, salt rejection, energy demand, and thermal efficiency.

Date of Award	Dec 2020
Original language	American English