Highly selective and antifouling reverse osmosis membrane by crosslinkers induced surface modification

ABSTRACT

Post treatment is a very competent and scalable approach to develop the higher water-flux and salt-rejection membrane since it does not require any change in existing manufacturing process. The virgin Thin Film Composite Reverse Osmosis (TFC-RO) membrane was exposed to various concentrations of Poly (ethylene Glycol) diacrylate (PEGDA) and Ethylene glycol dimethacrylate (EGDMA) after activation with sodium hypochlorite for 1 h. Crosslinkers modified membranes were characterized for degree of wettability by contact angle analyses, surface morphology and surface roughness study by Scanning electron micrographs and Atomic force micrographs, chemical structural modifications by Attenuated total reflectance Fourier transform Infrared spectroscopy. These treatments resulted in improved membrane performance. 3500 mg/l PEGDA-treated membrane permeate flux increased by 48.7% and salt-rejection by 3.43%. 2000 mg/l EGDMA treated membrane demonstrated 46.13% increase in water-flux and 3.08% increase in salt-rejection as compared with virgin membrane. Organic fouling study indicated that fouling in PEGDA-treated membrane was significantly lower than virgin membrane. Heavy metal ion removal performances for Zinc and Chromium were also higher for modified membranes. Thus, the surface modification by crosslinkers led to increase in selectivity for certain metal ions and better antifouling performance as compared to virgin membrane.

GRAPHICAL ABSTRACT

KEYWORDS:

• Reverse osmosis membrane
• surface modification
• PEGDA
• EGDMA
• cross linker

Acknowledgment

Also, Authors acknowledge to the central instrument facility of CSIR-CSMCRI (CSIR-CSMCRI PRIS number 79/2020) Bhavnagar namely, Dr Babulal for AFM images, Mr Jayesh Chaudhary for SEM images and Mr Vinod Agrawal for ATR FTIR spectra.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was funded by Department of Science and Technology India [grant no. DST/TSG/WM/2015/438].