Wetting Resistance of Commercial Membrane Distillation Membranes in Waste Streams Containing Surfactants and Oil

Abstract

Water management is becoming increasingly challenging and several technologies, including membrane distillation (MD) are emerging. This technology is less affected by salinity compared to reverse osmosis and is able to treat brines up to saturation. The focus of MD research recently shifted from seawater desalination to industrial applications out of the scope of reverse osmosis. In many of these applications, surfactants or oil traces are present in the feed stream, lowering the surface tension and increasing the risk for membrane wetting. In this study, the technological boundaries of MD in the presence of surfactants are investigated using surface tension, contact angle and liquid entry pressure measurements together with lab-scale MD experiments to predict the wetting resistance of different membranes. Synthetic NaCl solutions mixed with sodium dodecyl sulfate (SDS) were used as feed solution. The limiting surfactant concentration was found to be dependent on the surface chemistry of the membrane, and increased with increasing hydrophobicity and oleophobicity. Additionally, a hexadecane/SDS emulsion was prepared with a composition simulating produced water, a waste stream in the oil and gas sector. When hexadecane is present in the emulsion, oleophobic membranes are able to resist wetting, whereas polytetrafluoretheen (PTFE) is gradually wetted by the feed liquid.

Effects of volatile organic compounds on water recovery from produced water via vacuum membrane distillation

“…Especially, when the VOCs are alcohol or having surfactant properties, membrane wetting will occur and lead to further deterioration of the permeate quality as the feed water can pass through the membrane directly via the wetted pores [11][12][13]. Recently, some researchers studied the effect of the surfactant and oil existed in the produced water on the water recovery via MD and found that they had strong negative impact on the permeation flux and permeate quality [12,14]. However, none of researches have investigated the effect of VOCs in the produced water on the MD performance, which may share similar effects as the surfactant and oil.…”

Rapid formation of polyimide nanofiber membranes via hot-press treatment and their performance as Li-ion battery separators

“…The PI membranes showed a higher electrolyte uptake capability than that of the commercial PE membrane (with a water contact angle over 95 ), which may be due to their higher porosity and hydrophilicity. 36,37 The hotpress-induced PI membrane showed a higher electrolyte uptake efficiency than that of the thermally-treated PI membrane because of the higher porosity, along with the dense, uniform arrangement of the nanobers. The thermal behaviors of the commercial PE, neat PAA, and PI membranes were monitored by TGA under the N 2 environment (Fig.…”

Simultaneous Concentration of Dissolved Solids and Recovery of Clean Water from Acid Mine Drainage Employing Membrane Distillation

“…These hydrophobic membranes are characterized by the water contact angles and liquid entry pressures (LEP). The contact angles for PP 0.45 micron (Franken et al 1987) and PTFE membranes are greater than 100ᵒ (Eykens et al 2017) corresponding to hydrophobic surfaces. The operating pressure differences of the MD system were kept well below the LEP values in our MD tests.…”