Ref.: MpoErec29-002
Apresentador: João Gabriel Ribeiro
Autores (Instituição): Ribeiro, J.G.(Universidade Federal do ABC); Vieira, R.P.(Universidade Federal do ABC); Lemes, G.D.(Universidade Federal do ABC); Rosa, D.d.(Universidade Federal do ABC);
Resumo:
Potentially toxic elements (PTE) like Cd2+, Cu2+, Mn2+, Ni2+, Zn2+, and Cr6+ persist as contaminants in water, resisting complete removal by conventional treatment methods, posing health risks even at low concentrations. In response, adsorbent materials such as porous membranes have been developed targeting the removal of PTE from water.
PBAT stands out as a promising polymer for membrane development due to its characteristics of high flexibility and biodegradability. However, its chemical structure lacks efficient chemical groups for sorption, needing the incorporation of adsorbent fillers into the membrane structure, creating a composite. Among the materials suitable for this purpose is microfibrillated cellulose (MFC), which can be extracted from eucalyptus sawdust waste, which is generally discarded or burned. With its fibrillar structure and abundant hydroxyl groups on the surface, MFC serves dual roles as a mechanical reinforcement and an adsorbent in composite membranes, adding value to eucalyptus sawdust waste.
This study focuses on the development of adsorbent, biodegradable, and porous PBAT membranes. These membranes incorporate MFC extracted from eucalyptus sawdust waste at varying concentrations (0%, 1%, 3%, and 5% w/w). The investigation aims to assess how the inclusion of MFC influences the mechanical, thermal, and compositional properties, as well as the adsorption capacity of the membranes.
The MFC was prepared from alkaline and oxidative treatments of eucalyptus sawdust, removing lignin and hemicellulose present in the fiber, followed by a mechanical grinding treatment to obtain microfibers. The membranes were produced using the airbrushing technique, spraying a solution of PBAT and a cellulose dispersion onto an inert matrix (glass plate) using the non-solvent induced phase separation (NIPS) technique to separate the membrane from the glass plate.
The isolation of MFC was confirmed by FTIR spectra and by the thermal behavior observed in TGA and DTG thermograms. SEM imaging revealed the production of microfibers, displaying fibers with an average diameter of 944 nm. For the membranes, SEM images depicted a uniformly porous structure with interconnected pores. In the FTIR spectra of the membranes, cellulose signals were not observed due to the architecture of the membranes having been constructed with a layer of cellulose between two layers of PBAT, being inaccessible for FTIR-ATR analysis which performs a surface analysis. TGA and DTG thermograms affirmed the presence of cellulose within the membrane structure, and the sorption tests showed an increase in sorption with increasing MFC content in the membranes, reaching a maximum of 4 mg/g of total ions in the membrane containing 5% MFC w/w.
The membranes exhibited a permeable structure with interconnected pores and cellulose available for adsorption, making them a promising material for use in the treatment of water contaminated by PTE.