Nanocompósitos de nanocelulose bacteriana e CoXFe3-XO4 para degradação do contaminante 2,4-d em água via ativação de persulfatos

Abstract

Water, a vital resource for life, has been increasingly contaminated by micropollutants such as the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D), whose persistence and toxicity drive the search for efficient removal methods. In this study, in situ synthesis of cobalt ferrite (CoxFe3-xO4) within bacterial nanocellulose (BNC) membranes was employed to enhance Advanced Oxidation Processes (AOP), generating sulfate radicals via peroxymonosulfate (PMS). The methodology included: (i) cultivation and purification of BNC using the Hestrin-Scharam method; (ii) incorporation of cobalt ferrite nanoparticles through controlled alkaline coprecipitation; (iii) characterization of the composites using SEM, XRD, TGA/DTG, and FTIR; (iv) degradation tests of 2,4-D (5 mg/L) under different pH conditions (4, ~5-6, and 8) and PMS concentrations (10× and 50×). The results demonstrated that the BNC/CoxFe3-xO4 composite favors 2,4-D degradation, achieving up to 67.2% removal within 30 minutes, although catalytic efficiency declined after the first usage cycle. Thermal characterization (TGA) indicated greater stability of the composite compared to pure BNC, while FTIR analyses confirmed the incorporation of the metal oxide. Adjustments in pH and PMS concentration did not significantly improve catalytic performance, suggesting other limiting factors, such as probable saturation of active sites or irreversible modifications in the nanoparticles. Regeneration attempts (acidic/alkaline baths and UV light) failed to restore the initial efficiency. This pioneering and promising work suggests the potential application of BNC as a support for catalysts in advanced oxidation processes for the treatment of emerging contaminants.