Tailoring the molecular weight cut off values of polyacrylonitrile based hollow fibre ultrafiltration membranes with improved fouling resistance by chemical modification

• Published in: Journal of membrane science 2013-01, Vol.425-426 (1), p.251-261
• Main Authors: Parashuram, K., Maurya, S.K., Rana, H.H., Singh, P.S., Ray, P., Reddy, A.V.R.
• Format: Article
• Language: English
• Subjects: ambient temperature; aqueous solutions; artificial membranes; bovine serum albumin; BSA and PEO permeation; Chemical modification; contact angle; fouling; Fouling resistance; Hollow fibre ultrafiltration membranes; hydrochloric acid; hydrolysis; molecular weight; Poly(acrylonitrile-co-methacrylic acid); polyacrylonitrile; polyethylene glycol; scanning electron microscopy; sodium hydroxide; ultrafiltration; zeta potential
• ISSN: 0376-7388; 1873-3123
• DOI: 10.1016/j.memsci.2012.09.013

Chemical modification was employed for tuning the molecular weight cut off (MWCO) values of poly(acrylonitrile-co-methacrylic acid) hollow fibre ultrafiltration membranes by treating them with aqueous NaOH solutions of different concentration (0.25, 0.75, 1.25 and 1.75M) separately for 1, 3, 6 or 9h and then with 0.1M HCl solution for 2h at room temperature. This has resulted in the decrease of MWCO values of the fibres from the initial 92kDa to the range of 9–75kDa. The flux was decreased from 215 to 28–150L/m2h at 1.5kg/cm2. NaOHHCl treated fibres exhibited somewhat higher MWCO value and permeate flux than those of the fibres which were treated with NaOH only. Modified fibres exhibited lower fouling tendency for the ultrafiltration of aqueous solutions of polyethyleneoxide and bovine serum albumin, as indicated by their flux recovery ratio values of 91%–93%, when compared to the 53%–58% for virgin fibres. IR spectra of NaOH treated fibres showed a new peak at about 1580cm−1 due to the conversion of nitrile group to cyclic CN naphthyridine structure. HCl treatment was resulted in the disappearance of the peak at 1580cm−1 and appearance of a new peak around 1695cm−1 due to the amide carbonyl group that was generated by the hydrolysis of naphthyridine structure. The fibres were characterized by scanning electron microscopy, contact angles and zeta potential measurements. ► Tuning the MWCO values of PAN based hollow fibre ultrafiltration membranes. ► Treated the fibres (MWCO: 92kDa) with aqueous NaOH and NaOH–HCl solutions. ► Obtained fibres with MWCOs of 9–75kDa from 92kDa depending on treatment. ► Treatment with NaOH–HCl solutions resulted somewhat higher MWCO values. ► Modified fibres exhibited low fouling for permeation of PEO/BSA solutions.