Reduction of scaling in microwave induced membrane distillation on a carbon nanotube immobilized membrane

Abstract

Membrane distillation (MD) is an emerging technology that has much potential in desalination and treatment of saline waste.

Enhanced Performance of Carbon Nanotube Immobilized Membrane for the Treatment of High Salinity Produced Water via Direct Contact Membrane Distillation

“…The flux enhancement in CNIM was mainly due to the fact that the CNTs serves as effective sorbent sites for water vapor transport while repelling the liquid water. This was followed by activated diffusion on the smooth CNTs surfaces, which was in line with our previously reported data [30,34,40,51]. Further, the addition of HEDP on the feed side led to an enhanced MD performance for both membranes.…”

“…In the presence of different foulants, such as dispersed oil, organic acids, polycyclic aromatic hydrocarbons (PAHs), and phenols, the contact angle decreased slightly (Figure 4c,d). The liquid entry pressure (LEP) was measured using a method described before [40]. The LEP of the pure water solution was found to be 75 and 71 psig, which changed to 69 and 65 psig with the produced water solution for unmodified PTFE and CNIM, respectively.…”

“…With a high concentration of CaCO 3 and different cations at near saturation level, any membrane process including MD is expected to foul rapidly. Recently, we reported that CNIM shows relatively lower fouling as the CNTs act as nano-brushes that prevent the salt crystals from depositing on the surface [40]. The CNIM has shown high salt tolerance compared to pure polymeric membranes and has been used to treat water with TDS as high as 230,000 mg/L [41].…”

Scaling Reduction in Carbon Nanotube-Immobilized Membrane during Membrane Distillation

“…Figure 2 demonstrates the DCMD experiment setup in the laboratory. The details have been previously described [29]. The hot aqueous feed solutions were circulated on one side of the membrane in the DCMD cell.…”

“…Due to the use of porous hydrophobic membranes, the fouling in MD tends to be significantly less than in RO, but is still an important consideration for high-salinity water desalting. Several approaches for fouling reduction, such as the introduction of nanobubble, ultrasound, and microwave irradiation have been reported [26][27][28][29][30]. Of particular interest has been the deposition of inorganic salts such as calcium carbonate (CaCO 3 ), calcium sulfate (CaSO 4 ), and barium sulfate (BaSO 4 ), which are found in hard waters as well as industrial waste from power plants, hydraulic fracturing, and wastewaters from industries such as textiles and pulp and paper [31].…”