NANOCOMPÓSITOS DE PVA RETICULADO / ÓXIDO DE GRAFENO PARA FABRICAÇÃO DE MEMBRANAS DESSALINIZADORAS

Abstract

The scarcity of drinking water is a growing concern; the limited availability of freshwater and increased demand due to population growth, urbanization and industrial activities have exacerbated this problem. This study investigates the use of graphite to synthesize low-cost graphene oxide (GO) and modify commercial membranes by polymeric crosslinking with Polyvinyl Alcohol (PVA)/Citric Acid (CA), aiming to improve its properties for retaining salts from brackish water. The samples were characterized by optical analysis and mechanical stability tests, X-ray diffractometry (XRD), and differential scanning calorimetry (DSC), to investigate changes in the physicochemical, thermal, and microstructural properties of the modified membranes. Characterization via DSC confirms the polymeric crosslinking in membranes modified with PVA in relation to pure polyamide (PA) membranes, and characterization by XRD indicates traces of crystallization due to the PVA-AC interaction. The filtration results obtained showed that polyamide membranes crosslinked with 0.75 mg of OG (PA0.75/RET) obtained better efficiency in the salt retention test (54.77±2.68%) and permeate flux (1.42±0.28 L/m². h. bar) using magnesium sulfate solution. This study confirms the importance of polymeric cross-linking in OG-modified membranes for mechanical stability and salt retention efficiency.