Surfactant effects on water recovery from produced water via direct-contact membrane distillation

Separation of saline oily wastewater by membrane distillation

“…The global expansion of maritime transport and various technologies (e.g., oil and shale gas production) generate a huge amount of saline wastewaters, which resulted in environmental degradation due to direct discharge of saline wastewater into the environment. The membrane processes can be used most effectively for the treatment of such wastewaters, but one of the major constrains is the durability of membranes, particularly during the separation of brines containing various surface-active contaminants (e.g., oils and surfactants) (Chew et al 2017;Lu et al 2018;Rezaeia et al 2017;Rezaeia et al 2018, Tanudjaja andChew 2018).…”

“…Moreover, the high salt concentration increases the scaling intensity of membranes, which additionally restricts the MD utilization for oily wastewater treatment (Duong et al 2015;Gryta 2017;McGaughey et al 2017). However, this process can be very attractive in the case the wastewater treatment by conventional methods is difficult or very expensive, especially for oily wastewaters such as bilge water (ships) or wastewater generated in the process of hydraulic fracturing (natural gas extraction) (Chew et al 2017;Gryta et al 2001;Lu et al 2018;Tavakkoli et al 2017).…”

“…The porous non-wetted hydrophobic membranes are used in the membrane distillation (Gryta 2017;Wang and Chung 2015;Winter et al 2017). However, the hydrophobic membranes are intrinsically prone to fouling by hydrophobic contaminants due to the strong hydrophobic-hydrophobic interaction (Chew et al 2017;Lin et al 2014;Rácz et al 2015;Rezaeia et al 2017). Therefore, the conventional hydrophobic membranes (made of PP, PTFE and PVDF) are usually applied for desalination of water when the hydrophobic contaminants concentration is relatively low (Gryta 2017;Guillén-Burrieza et al 2011;Winter et al 2017).…”

Performance enhancement of the membrane distillation process via membrane surface modification for surfactant-containing feed water

“…Adsorption of these substances on the membrane surface can lower the pore liquid entry pressure (LEP) or cause pore blockage, which compromises on the recovery rate and distillate quality [33].…”

“…The stark contrast in the performances of the pristine PVDF and PVDF-P membranes was believed to be due to their different surface hierarchical structures and opposing wetting properties. As discussed in Chapter 4 [33], Span ® 20 is a relatively hydrophobic surfactant with a low HLB value of 8.6. As such, the Span ® 20 unimers have the tendency to adsorb onto hydrophobic surfaces to form a monolayer via hydrophobic interactions [151].…”