(767b) Facile Grafting of Zwitterions Onto Membrane Surface to Enhance Antifouling Properties for Wastewater Reuse

Facile grafting of zwitterions onto
membrane surface to enhance antifouling properties

for wastewater reuse

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.