Remoção de glifosato comercial em água contaminada via destilação solar

Abstract

Water scarcity is a problem that affects several areas of the world and can be associated with several factors, one of which is contamination. There are many ways to contaminate water, such as the release of effluents, fertilizers and pesticides. Pesticides are very present in water at high levels and the one that stands out most is glyphosate due to its high consumption, which can be found in surface and groundwater. Alternative methods for treating these contaminated waters have been developed, where solar distillation stands out for its potential. Therefore, combining these factors, this research brings the results of the use of a waterfall-type solar distiller to remove glyphosate and salts naturally present in groundwater. The experiments were carried out at the State University of Paraiba, Campina Grande campus, where a combination of brackish water collected from an artesian well with initial glyphosate concentrations of 5, 10 and 15 mg.L-1 were used. Meteorological parameters on the experiment days, temperature profiles, as well as thermal efficiency and calculations of heat transfer coefficients of the solar still were evaluated. With the application of the solar distillation process, removals of 97.23%, 98.41% and 98.82% of glyphosate were recorded, ending the experiments with concentrations of this herbicide below the maximum permissible values. For the other physical-chemical parameters, there were satisfactory decreases when obtaining values that fell within those established by Ordinance No. 888 of the Ministry of Health, reaching removals of up to 100% for sodium, potassium and hardness on all days of the experiment. and more than 90% for parameters such as turbidity, electrical conductivity, alkalinity, chlorides and total dissolved solids (TSD). The volume of distilled water also showed excellent results, recording volumes of 3205.13 mL.m-2.d-1, 2705.13 mL.m-2.d-1 and 1923.08 mL.m-2.d-1. The cost per liter of water was 0.08 R$.L-1.year-1, this value being below those already found in other studies. The research comes as one of the pioneers of using the solar distillation technique to remove glyphosate, showing good results. Considering all these factors, the use of this technique to remove contaminants from water appears to be a viable alternative to be implemented, demonstrating its potential for making contaminated water safe according to the parameters analyzed.