Antifouling Membranes By Surface Modification Using Hydrophilic Polymers

Antifouling Membranes by Surface Modification Using Hydrophilic Polymers

Nima Shahkaramipour, Chong Cheng, and Haiqing Lin*

¹Department of Chemical and Biological Engineering, University at Buffalo,

The State University of New York, Buffalo, NY 14260, USA

 

*Corresponding author.  Tel: +1-716-645-1856, Email: haiqingl@buffalo.edu

 

Abstract

Polymeric membranes for wastewater reuse are often fouled by suspended solids and dissolved organic matters, resulting in dramatic decrease in water flux. Fouling can be mitigated by enhancing hydrophilicity of membrane surface to avoid favorable interactions between the membranes and foulants. However, the modification of membrane surface is often complicate and difficult to integrate into industrial membrane production processes. Herein we demonstrate a facile one-step coating of superhydrophilic zwitterions on the surface of ultrafiltration (UF) and nanofiltration (NF) membranes by coating with dopamine and sulfobetaine methacrylate (SBMA). In the presence of oxygen, dopamine forms polydopamine (PDA) adhering onto the membrane surface and anchors SBMA via Michael addition to form a robust thin superhydrophilic layer, as confirmed by contact angle measurement, thickness measurements, and x-ray photoelectron spectroscopy (XPS). The effect of coating solution composition and coating time on the water flux through the membranes with time was thoroughly studied. The modified UF membranes demonstrate up to 80% higher water flux than the uncoated ones, when tested with water containing bovine serum albumin (BSA) as a model foulant in a crossflow system. This presentation will also discuss the effect of zwitterion chemistry on the antifouling properties of the modified membranes for the wastewater reuse. This facile approach of membrane modification is also adapted for post‑modification of a commercial nanofiltration membrane module, which demonstrates superior antifouling properties when tested with real wastewater at a wastewater treatment plant.