Modification of ultrafiltration membranes via interpenetrating polymer networks for removal of boron from aqueous solution

Interpenetrating polymer networks (IPNs) are polymeric structures formed when two distinct multi-functional polymers become entangled at the molecular level. Thus, an IPN permits the combination of chemical and physical properties of individual polymers in the same material. The objective of this work was to develop new ultrafiltration membranes with the capacity of boron retention via IPNs. Cellulose ultrafiltration membranes were used as substrate resin (or primary network) for in situ polymerization of a boron selective monomer based on N-methyl-d-glucamine. Structural properties, percent of secondary network, change of hydrophilicity, permeability and boron retention properties were studied. Results suggest that surface porosity is not affected by the formation of IPN. In addition, pore radius was decreased at 40.9% whereas the pore number was increased at 202.1% and values of boron retention were 20.5%, 17.8% and 14.8% for pHs 5.0, 7.0, and 9.0, respectively. It was concluded that new ultrafiltration membranes could be produced by in situ polymerization of vinyl monomer in order to improve their retention, surface, and permeability properties.