Remoção de glifosato a partir de soluções aquosas utilizando carvão ativado para fins de reúso

Abstract

One of the main problems in the practice of effluent reuse is the presence of micro-contaminants and their potential risks, especially because many of these compounds are not totally removed by conventional treatment processes. Particularly noteworthy among these contaminants are pesticides, especially glyphosate, which due to its increasing use, with both urban and rural applications, have been frequently reported in sewage treatment plants, in water and in various environmental compartments. In face of studies that raise the possibility of this pesticide being harmful to human health and taking as a starting point the importance of safe reuse of effluents as a measure of management and maintenance of water availability, studies are needed on efficient treatments in the removal of this contaminant as tertiary phase in sewage treatment plants. In this context, the present work aimed to subsidize the complementary treatment of effluents that allows better quality for the practice of reuse, minimizing the environmental and human exposure to harmful compounds. For this, the adsorption efficiency in pulverized activated carbon was evaluated for the removal of glyphosate from aqueous solutions. Adsorption tests were performed maintaining the initial glyphosate concentration at 79.5 mg / L and optimizing the adsorbent (0.1-4g), pH (4-7) and agitation (150-250 rpm) dosage to obtain the best glyphosate removal response from the Response Surface Methodology (RSM) and Rotational Central Compound Design (RCCD), with a contact time of 2 h (two hours) and a temperature of 30 ° C. The adsorbent used is manufactured from the endocarp of babassu coconut (Attalea ssp) and by the physical activation process with water vapor. From the results obtained it was observed that the adsorption process in activated carbon from the experimental optimization was efficient in the removal of high concentrations of glyphosate in water (59.7%), which makes possible the use of the technique in tertiary treatment of effluents generating better quality water for reuse in terms of concentration and exposure to this pesticide.