Micro-3D Printing-enhanced Membrane Distillation for Direct Solar Desalination

  • Abdulrahman Kharbatli

Student thesis: Master's Thesis

Abstract

Limited freshwater availability in the world has encouraged research for innovative desalination technologies to produce drinking water. The UAE is one of the countries under extremely high risk of water scarcity. The abundant solar energy in the UAE provides great potential to be utilized in a sustainable desalination system. 3D printing is a powerful tool to fabricate components for improved distillation performance. The aim of this thesis research is to develop a direct solar driven membrane distillation (MD) unit integrated with 3D printed feed spacer. To further enhance the photothermal properties, the spacer was either coated with graphene oxide (GO) or coupled with titanium (Ti) mesh at the interface with a commercial membrane. The three study cases were compared with the performance of commercial spacer made of polypropylene (pp) in direct solar driven MD. The performance in each study case was tested in airgap membrane distillation (AGMD) setup to compare the influence of each spacer on the permeate flux production. The study was supported by characterization of the spacer for better understanding of the optical properties, heat loss emissivity, wettability, and GO coating stability. While the commercial spacer did not show a remarkable flux in the AGMD experiments, the 3D printed spacer showed the best performance in terms of permeate flux but with longer time to reach steady state. GO coating the spacer was found to decrease the AGMD performance due to low light transmission that minimized the sunlight absorption at the interface with the membrane. Hybrid Ti mesh/3D printed spacer reduced the stability time, but it did not show an improvement in the flux compared to the uncounted stand-alone 3D printed spacer due to difficulty in assembling the cell components. The study was concluded with calculations of photothermal efficiency and heat demand for industrial scale system.
Date of AwardMay 2022
Original languageAmerican English

Keywords

  • 3D printing; membrane distillation; temperature polarization; photothermal properties; wettability.

Cite this

'