Plasmonic TiN and ZrN Composite Membranes for Solar-Driven Membrane Distillation

  • Meera Al Mehrzi

Student thesis: Master's Thesis

Abstract

The Arabian Peninsula is one of the world's driest regions lacking sufficient water sources. Although fresh water is currently mainly supplied through desalination processes, desalination is still considered very energy-intensive and is currently predominantly being powered by nonrenewable energy sources. The continuous dependence on these sources is causing them to diminish. It is, therefore, necessary that other, more sustainable methods and technologies be introduced for water purification. Employing renewable-energy-powered desalination technologies could significantly reduce the burden on the environment. Solar-powered desalination is one area of great potential since solar energy is abundant and very compatible. Solar-driven membrane distillation utilizes solar energy to drive membrane desalination processes without compromising water quality. To meet the growing freshwater demand, in this study, cost-effective plasmonic-based composite membranes as an alternative to metal-based plasmonic structures are proposed. Efficient light-to-heat conversion using plasmonic nanoparticles in polymeric membranes is beneficial for improving the efficiency of solar membrane distillation for seawater desalination. The as-fabricated zirconium nitride polymer (ZrN/PVDF) composite membranes exhibited outstanding thermal and surface properties while being very homogenous, robust, and stable. These thermal and surface characteristics render these membranes as ideal candidates for a novel photothermal Air Gap Membrane Distillation (AGMD) technology. This AGMD process has been prototyped, making it solely driven by solar energy; desalinating saline feed via a thermal separation process. The membrane is at the heart of this technology, and testing these ZrN/PVDF composite membranes revealed excellent membrane performance results. Over a long experiment of 6 hours, the ZrN/PVDF membrane maintained a very stable flux with an average of 0.4 L/m2h, with an excellent NaCl rejection of 99.6%. These results suggest that embedding ZrN nanoparticles into the membrane structure can enhance the membrane's performance in AGMD without compromising the quality of the permeate.
Date of AwardMay 2022
Original languageAmerican English

Keywords

  • Air Gap Membrane Distillation
  • Plasmonic
  • Zirconium Nitride
  • Solar
  • Photothermal.

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