Síntese de hidrocarvão a partir da casca do fruto de bocaiuva e sua aplicação na remoção de diuron de água contaminada

Abstract

Chemical control using herbicides enhances the integrated management of weeds/spontaneous plants, in order to reduce production costs and increase productivity per area. Among the herbicides used, due to its efficiency in controlling weeds in large crops, is diuron. From an environmental point of view, diuron is highly persistent. In view of the fact that emerging contaminants are highly harmful, new efficient, sustainable and low-cost technologies for removing this contaminant from the environment are necessary. In this study, hydrocharcoal was synthesized from the bark of the bocaiuva fruit, characterized and applied in the removal of diuron from contaminated water through the adsorption process to verify its effectiveness. The influence of the initial pH of the solution was evaluated and it was observed that there was greater adsorption at pH 4. Hydrochar concentration in 4.0 g L-1 provided a removal of 67.8%, during the contact time it was observed that in the In the first 20 minutes there was a rapid uptake of the herbicide and it was gradually decelerated until t = 150 min. The temperature in the adsorption process was evaluated, and the best evaluated condition was at 30°C, at this temperature the maximum adsorption capacity was estimated at 10.06 mg g-1, and pH 4.0. The pseudo-second order kinetic model and the Langmuir isotherm model provided the best fits to the adsorption data. The activation energy calculated by the Dubinin-Radushkevich isotherm model was 7.805 kJ mol-1, indicating that a physical process is responsible for the adsorption of diuron on hydrochar. Thermodynamic parameters (ΔH < 0 and ΔG > 0) suggested that the adsorption process is exothermic and not spontaneous. The results obtained in this work indicated that the hydrocharcoal derived from the bark of the bocaiuva fruit can be an alternative adsorbent for the removal of the diuron herbicide from the water.