Membrane distillation: recent technological developments and advancements in membrane materials

Abstract

Membrane distillation (MD) is a novel desalination technology that has potential to produce distilled quality water from high salinity brine streams. The driving force for MD is the vapor pressure difference across a hydrophobic membrane resulting in transfer of water vapor from hot to cold side. This vapor contacts a cold surface and condenses to produce distillate. This paper reviews recent and/or multi-year research programs that focused on MD pilot or field testing. The various investigations concluded that while MD can produce distilled water quality, the energy efficiency remains the key bottleneck for future deployment of MD. Membrane wetting and fouling also presents key challenges for desalination due to both the high salinity and the presence of organics in the feed water. The authors contacted several MD vendors requesting updates on their latest products and technology developments. MD vendors with innovative module designs, some of which promise a step change in performance, have recently emerged on the market. In addition to water desalination, MD has a wide range of industrial applications such as hydrogen sulfide removal, the treatment of wastewater from the pharmaceutical, metal finishing industries, direct sewer mining, oily wastewater, and water recovery from flue gas. This paper also reviews novel membrane chemistries with emphasis on membranes prepared by phase inversion and electrospinning techniques to which nanomaterials have been added. The primary objectives in adding various nanomaterials (e.g., carbon nanotubes, graphene, silicon dioxide, fluorinated compounds) are to increase hydrophobicity (to reduce wetting) and increase mass transfer rates (to increase flux and lower cost).

Advances in Membrane Distillation Module Configurations

“…Most improved and novel configurations seek to enhance thermal energy efficiency and vapor flux. New configurations stem from modification of AGMD and VMD, Some examples of modified MD configurations include material gap membrane distillation (MGMD) [71], vacuumed air gap membrane distillation (VAGMED), or subatmospheric AGMD [72,73] submerged membrane distillation (SMD) [74,75], conductive gap membrane distillation (CGMD), permeate gap or liquid gap membrane distillation (PGMD or LGMD) [76], flashed-feed-VMD [77], vacuum-enhanced DCMD [78] and vacuum multi-effect membrane distillation (V-MEMD) [79][80][81], (Hassan et al, 2020), [82]. Among the aforementioned MD configurations, V-MEMD and PGMD/LGMD have already been introduced into the market in the pilot scale module.…”

“…[122,123].Carnote cycle based on the Joule-Thomson effect to control the temperature. KMX technology is based on PTFE hollow fiber membranes with VMD configuration for Lithium recovery, acid mine drainage, and produced water treatment[82].Jia et al…”

Membrane Distillation: Recent Configurations, Membrane Surface Engineering, and Applications

“…This has pushed the research towards full-scale/pilot plant studies of MD and a limited number of publications are available for outdoor MD testing with the major focus on desalination. Several manufacturers [111,116] who have installed pilot plants include Fraunhofer ISE, Memsys, Mediras, SolarSpring from Germany, Keppel Seghers from Singapore, and Aquastill from the Netherlands. They are mainly located in Germany, the Netherlands, USA, Saudi Arabia, Singapore, and Qatar and they are contributing about 2% to the share of total desalination.…”

Flat sheet metakaolin ceramic membrane for water desalination via direct contact membrane distillation

“…Membrane-based water desalination technologies are more energy-efficient, economic, and sustainable than thermal-based water desalination technologies (Baten & Stummeyer 2013;Roy & Ragunath 2018;Zewdie et al 2021a). Among membrane-based water purification techniques, membrane distillation represents an emerging and promising approach for desalination and wastewater treatment application (Sanmartino et al 2016;Alkhudhiri & Hilal 2018;Ashoor et al 2018;Hussain et al 2021;Saavedra et al 2021;Tai et al 2021). Membrane distillation is a hybrid separation technique combining thermal-driven distillation and membrane separation processes (Belessiotis et al 2016;Ghaffour et al 2019).…”