Enhanced membrane distillation of organic solvents from their aqueous mixtures using a carbon nanotube immobilized membrane

• Published in: Journal of membrane science 2018-12, Vol.568, p.134-140
• Main Authors: Gupta, Oindrila, Roy, Sagar, Mitra, Somenath
• Format: Article
• Language: English
• Subjects: Carbon nanotubes; Hydrophobic membrane; Mass transfer coefficient; Solvent recovery/removal; Sweep gas membrane distillation
• ISSN: 0376-7388; 1873-3123
• DOI: 10.1016/j.memsci.2018.10.002

In this paper, we report for the first time the application of carbon nanotube immobilized membrane (CNIM) for enhanced separation of organic solvents from their aqueous mixtures via sweep gas membrane distillation. The presence of carbon nanotubes (CNTs) on the hydrophobic membrane surface significantly altered the liquid–membrane interactions to promote isopropanol (IPA) transport in IPA-water mixture by inhibiting water penetration into the membrane pores. The preferential sorption of IPA on the CNIM was evident from the contact angle measurements. The isopropanol flux, selectivity and mass transfer coefficient obtained with CNIM were significantly higher than the corresponding unmodified PTFE membrane at different isopropanol concentrations and temperatures with enhancement in separation factor reaching as high as 350% at 70 °C. An increase in mass transfer coefficient of about 132% was also observed. Performance enhancement in CNIM was mainly attributed to the preferential sorption on the CNTs followed by rapid desorption from its surface. •Carbon nanotube immobilized membrane was used for membrane distillation of organics.•Higher flux and selectivity were observed in the presence of carbon nanotubes.•Preferential sorption of the organic on the CNIM was evident from contact angle data.•Higher vapor pressure, selective partitioning and fast desorption on CNIM led to the enhanced separation.