Incorporation of graphene nanoplatelets in the synthesis of polysulfone-based polymeric membranes

This study aimed to develop PSU membranes by adding different concentrations (zero, 0.5, 1.0, and 1.5 wt.%) of graphene nanoplatelets (GNP) during synthesis to evaluate the influence of GNP on membrane permeability, retention capacity, mechanical and chemical resistance, structure, and membrane chemistry. All produced membranes had a hydrophilic character, which reduced with the increase in GNP content (72.4° to 84.4°) and a decrease in thickness (200.8 µm to 109.3 µm). Adding GNP did not affect the membranes' mechanical properties and chemical resistance. GNP addition increased the compaction time (from 5.35 h to 35.62 h) and reduced membrane permeability (from 6.78 L∙m−2∙h−1∙bar−1 to 0.10 L∙m−2∙h−1∙bar−1) of pure water. The obtained membranes were classified as ultrafiltration membranes, with an egg albumin retention rate (45 kDa) above 80 %. A greater retention of egg albumin was observed with the highest amount of GNP (1.5 wt.%). Adding GNP stabilized the polymeric matrix (PSU) properties, including increased chemical and mechanical resistance, interaction between the polymer and the nanofiller, and hydrophobic characteristics with a smaller thickness. This study contributed to Brazilian research in membrane synthesis, promoting the investigation of outstanding materials in the field of nanotechnology, in particular, the use of GNP as an additive in the preparation of mixed matrix membranes for water treatment.