Membranas de matriz mista polisulfona/grafeno para remoção de contaminante emergente

Abstract

The methods applied in conventional water and wastewater treatment plants are not able to reduce and/or eliminate most of the emerging pollutants. Thus complementary processes are required for removal. The separation processes by membranes (PSM) need to be investigated, given the increasing evolution in the area of materials, such as the use of mixed matrix membranes (MMM) with unique properties. The aim of this PhD thesis was to synthesize MMM, aiming at the applicability in the removal of fluoxetine from water. The methodology consisted in the synthesis of the membranes by the phase inversion method, using polysulfone (PSU 15% and 20% by weight) as the base polymer, methylpyrrolidone (NMP 80% and 85% by weight) as solvent and distilled water as non-solvent, as well as, graphene oxide (GO) or reduced graphene oxide (rGO), were added as filler (0.5%, 1.0% and 1.5% by weight of PSU). The membranes were characterized for thermal, mechanical and transport properties, considering main parameters and standard molecules (salts and lactose) for their classification against the PSM typology and mechanisms. Drug quantification was performed by high performance liquid chromatography coupled to a mass spectrometer (UPLC-MS/MS). The results from the fabricated membranes showed that approximately 50% and 95% rejection of saline (NaCl and MgSO4) and lactose was achieved, respectively. Furthermore, the synthesized PSU20/rGO_1.0% and PSU20/GO_1.0% membranes achieved hydraulic permeability values of 25 and 48 L/h.m².bar respectively, a three-times increase over the pure polysulfone membrane, achieving high permeate fluxes. The fabricated membranes were classified as nanofiltration membranes The results showed removal between 50 and 80% of fluoxetine 20mg/L and approximately 60% for 1 mg/L, indicating physical removal. The rGO-loaded membranes, overall, showed higher removal rate of FLU compared to GO and comparable to commercial membranes. The results indicate that the mixed matrix membranes produced present potential for application in treatment of water contaminated with the psychopharmaceutical, according to the operational conditions submitted.