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

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Thin Film Composite Reverse Osmosis (TFC-RO) membranes are crucial for water desalination.
• Improving TFC-RO membrane performance, including flux, rejection, and fouling resistance, is an ongoing challenge.
• Existing manufacturing processes often limit performance enhancements.

Purpose of the Study:

• To investigate the efficacy of post-treatment surface modification using crosslinkers on TFC-RO membranes.
• To evaluate the impact of Poly (ethylene Glycol) diacrylate (PEGDA) and Ethylene glycol dimethacrylate (EGDMA) on membrane properties.
• To assess improvements in water flux, salt rejection, antifouling, and heavy metal ion removal.

Main Methods:

• Virgin TFC-RO membranes were treated with varying concentrations of PEGDA and EGDMA after sodium hypochlorite activation.
• Membrane characterization included contact angle analysis (wettability), Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) (surface morphology/roughness), and Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) (chemical structure).
• Performance evaluation involved measuring water flux, salt rejection, organic fouling, and heavy metal ion (Zinc, Chromium) removal.

Main Results:

• PEGDA and EGDMA treatments significantly improved membrane performance compared to virgin membranes.
• A 3500 mg/l PEGDA treatment increased permeate flux by 48.7% and salt rejection by 3.43%.
• A 2000 mg/l EGDMA treatment increased water flux by 46.13% and salt rejection by 3.08%.
• PEGDA-treated membranes exhibited significantly lower organic fouling.
• Modified membranes showed enhanced removal of Zinc and Chromium ions.

Conclusions:

• Post-treatment surface modification with PEGDA and EGDMA is a competent and scalable approach to enhance TFC-RO membrane performance.
• These modifications lead to higher water flux, improved salt rejection, reduced organic fouling, and increased selectivity for specific heavy metal ions.
• This method offers a viable strategy for developing advanced membranes without altering existing manufacturing processes.