An efficient approach in water desalination using high flux induced magnetic-field hydroxyl-functionalized MgFe2O4 /CA RO membranes with organic/inorganic fouling control capability

Abstract

Reverse osmosis (RO) membranes are crucial for water purification and desalination, facing challenges like balancing permeate flux and rejection, dealing with membrane fouling, and chlorine resistance. This study focuses on developing new membranes using cellulose acetate (CA) polymers and magnetic nanoparticles of magnesium ferrite (MgFe₂O₄) and hydroxyl-functionalized magnesium ferrite (OH–MgFe₂O₄) through a phase inversion method, with and without the presence of a magnetic field, to address the limitations of RO membranes. This study conducted a unique experiment where magnetic nanoparticles migrated to the membrane surface and underwent phase exchange in the coagulation bath under the influence of a 2.0 T magnetic field. As a result, the magnetic nanoparticles were arranged in a specific pattern and evenly spread across the membrane surface, enhancing the membrane's surface characteristics and hydrophilic properties. Furthermore, the flux of the synthesized membranes experienced an increase when exposed to the magnetic field, while maintaining a consistently high rejection rate. An evaluation was conducted on the membranes' resistance to organic fouling from bovine serum albumin (BSA), inorganic fouling from scaling, and the combined effects of BSA and scaling. Based on the findings, the membranes showed a notable enhancement in their anti-fouling properties, particularly when exposed to a magnetic field. An assessment was conducted on the resistance to chlorine for both the standard and improved membranes. Comparing the flux and rejection of the membranes before and after chlorine exposure revealed a minor variation, suggesting the membrane's ability to resist surface damage from chlorine. Hence, through the creation of innovative MgFe₂O₄/CA and OH–MgFe₂O₄/CA membranes, the identified constraints of RO membranes were effectively addressed. One of the synthesized RO membranes, OH–MgFe₂O₄/CA, demonstrated superior performance in permeate flux, rejection, anti-fouling, and chlorine resistance when compared to MgFe₂O₄/CA membranes. Furthermore, the stability of the synthesized membranes was assessed through tensile strength testing, which confirmed the preservation of the membrane structure.