Abstract
ABSTRACT Thin Film Composite Reverse Osmosis (TFC RO) membranes have undergone significant changes since inception; particularly the top polyamide layer has been tuned for optimal performance. The present paper demonstrates the novel approach to alter the polyamide membrane performance by subjecting it to ionic liquids. Ionic liquids 1-Butyl-3-Methylimidazolium Chloride [BMIM][Cl], 1-Methyl-3-Octylimidazolium Chloride [C8MIM][Cl] and 1-Butyl-3-Methylimidazolium Bromide [BMIM][Br] were used to alter the membrane performance. About a 6.5% increase in MgSO4 rejection and about an 87% increase in water-flux were noted when the membrane was subjected to 3000 mg/L [BMIM][Cl] after 2000 mg/L sodium hypochlorite each for 2 hours. Also, the decline in contact angle from 52.86o to 43.12o by this treatment demonstrated higher hydrophilicity. Atomic force microscope images showed a decline in surface roughness with the treatment. Scanning electron micrographs were taken to understand the changes in morphology of thin film composite reverse osmosis membranes with ionic liquid treatment. Attenuated total reflectance, infrared spectroscopy and nuclear magnetic resonance analysis were done to evaluate the changes in chemical structure and it was found that the treatment resulted in chemical structural modification of thin film composite reverse osmosis membranes with ionic liquid treatment.
Highlights
The process of reverse osmosis, which was first commercially developed in the mid-1960s, has undergone significant development since (Glater, 1998)
For 1-Methyl-3-Octylimidazolium Chloride [C8MIM] [Cl] treated membranes, the water-flux is identical or more as compared to [BMIM][Cl] treated membrane but magnesium sulfate rejection declined for all concentrations, as shown in Figures 3 and 4
For 1-Butyl-3-Methylimidazolium Bromide [BMIM][Br] treated membranes, magnesium sulfate rejection was lower as compared to 1-Butyl-3-Methylimidazolium Chloride [BMIM][Cl] treated membrane
Summary
The process of reverse osmosis, which was first commercially developed in the mid-1960s, has undergone significant development since (Glater, 1998). Concentration polarization is one of the major hindrances, which causes a reduction in salt rejection and flux in reverse osmosis thin film composite membranes (Tang et al, 2010). Thin film composite reverse osmosis membranes are either cellulose acetate or polyamide membrane. The latter is widely used because of its higher operating pH range, wider temperature range, higher stability to biological attack and ease of surface modification (Petersen et al, 1993; El-Saied et al, 2003; Younos et al., 2005; Wethern et al, 1995; Asano, 1998; Kulkarni et al, 1996)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
