Remoção de glifosato em meio aquoso usando carvão ativado proveniente de resíduos da casca da Acácia Negra ( Acásia mearnsii De Wild)

Abstract

The presence of pesticide residues in surface and groundwater is a growing problem, especially in agricultural areas where the intensive use of herbicides, such as glyphosate, poses an environmental and public health risk. Glyphosate, widely used in organic weed control, is persistent and can contaminate water sources, requiring efficient and affordable treatment methods for its removal. Among the most promising approaches is adsorption, which can be applied using low-cost and highly available materials. In this context, the aim of this study was to explore the use of black wattle bark (Acacia mearnsii De Wild) as a precursor material for the production of activated carbon to be used in the adsorption of glyphosate in aqueous media. Adsorption tests were carried out to evaluate the capacity of the activated trigger to remove glyphosate from aqueous solutions. Preliminary tests were performed, including a study of the zero charge point of activated carbon, a 2³ factorial experimental design, and determination of the adsorption kinetics and isotherms. The results showed that the zero charge point (pHpcz) was programmed at 6, with maximum glyphosate removal occurring at pH 3.5 and a concentration of 20 ppm. The dosage of 1.5 g/L of activated trigger showed the highest removal efficiency, with a removal range between 41% and 62%. The maximum adsorption capacity during the test was recorded at 0.5 g/L, reaching a value of 11.96 mg/g. The Intraparticle Diffusion kinetic model presented the best fit, indicating that the structure and porosity of the adsorbent influence the process. The Langmuir model best fitted the isotherm data, reaching a maximum adsorption capacity of 152.98 mg/g. Thus, the results indicated that the activated mechanism derived from the black wattle cascade presents a promising performance in the removal of glyphosate in aqueous media