Carboxymethylcellulose-quaternary graphene oxide nanocomposite polymer hydrogel as a biodegradable draw agent for osmotic water treatment process

Forward osmosis (FO) as a membrane-based water treatment process, utilizes the natural osmotic pressure gradient as driving force, originates from two solutions with different concentrations separated by a semipermeable membrane. Eligible FO draw agents of low cost, high water flux, easy recovery, and low reverse draw solute flux play a key role in the FO process. Some recently developed polymer hydrogels showed attractive features as draw agents in the FO process. In this study, a biocompatible and biodegradable polymer hydrogel was synthesized via free radical polymerization of the carboxymethylcellulose and acrylic acid as biocompatible monomers and subsequently used as an FO draw agent. In addition, to enhance the FO performance of polymer hydrogel, quaternary graphene oxide (QGO) as nanomodifier was synthesized and incorporated within the hydrogel matrix. The successful incorporation of QGO and its effect on FO performance of the hydrogel was systematically investigated. The obtained results showed that the QGO modified hydrogels have higher swelling ratio than the pure polymer hydrogel due to their more polar functional groups and more porous structures. The QGO hydrogel also has significantly higher water flux than the pure polymer hydrogel.