Thermally Driven Energy Efficient Desalination Process: A Hybrid Membrane Distillation-Adsorption Desalination System for Concentrate Treatment

Description

Continual efforts by scientists and engineers to advance desalination technology, not only forlarger production of clean water but also for cost reduction and lessened environmental impact,have introduced new materials and process development in desalination, most notably, seawaterreverse osmosis (SWRO) technique. Over the last four decades, SWRO reduced energyconsumption from 12 kWh/m3to 3-4 kWh/m3with energy recovery and drastically reducedproduction costs, and thus greatly replaced conventional thermal desalination techniques that areheavily dependent on fossil fuel availability. However, while SWRO desalination is a viablemethod of procuring fresh water, the process of desalination remains energy intensive andgenerates large amount of concentrated brine by-product which presents a major environmentalchallenge to most plants and is costly to dispose or manage.As a potential next generation desalination technique that can address the intrinsic drawbacks ofSWRO, membrane distillation (MD) has been gaining recognition and studies on developing moresuitable membranes for MD have been growing. Yet, there still exists many gaps in the researchon MD and multiple challenges before the MD process can be fully applicable to the industry, suchas making the MD process more energy-efficient and cost-effective to a level where MD canreplace or at least be comparable to RO. The proposed project will build on the PI’s recent findingson developing carbon nanotube composite electrospun nanofibrous membranes (CNT-ENMs) tobridge the gap in existing MD research on improving membrane performance through a systematicstudy while investigating the viability of an innovative system that integrates MD with adsorptiondistillation (AD) as a possibility for MD’s industrial upscaling.The following tasks will be performed in this study: (1) Design and fabricate electrospunnanocomposite super-hydrophobic MD membranes by modifying the integral structure and surfaceof nanofibers; (2) Demonstrate a non-solvent membrane fabrication process for developing arobust, economical, and eco-friendly membrane; (3) Characterize the heat and mass transfer ofelectrospun nanofibers when treating concentrate to provide much-needed long term performancedata; and (4) Innovate MD system design to reduce specific energy consumption by coupling withAD.The implementation of this project will not only advance the fundamental understanding of thephysiochemical qualities of optimal membranes for MD but also open the door to a widerexploration of combining innovative and alternative technologies to propel the applicability andsuitability of MD for the desalination industry.