Adsorptive properties of highly porous activated carbon from açaí (Euterpe oleracea) towards the toxic herbicide atrazine

Abstract

The great variety and possibilities of consumption of açaí pulp (Euterpe oleracea) have made its consumption increase considerably in recent years, mainly in Brazilian territory. The big problem is the generation of tons of waste that characterizes the fruit stone. This waste was converted into a highly porous activated carbon and employed to remove the herbicide atrazine. The characterization analyses confirmed that the applied methodology generated an adsorbent with good textural characteristics (specific surface area 920.56 m² g−1, pore volume 0.467 cm3 g−1; average pore diameter 1.13 nm). Furthermore, it was found that the adsorption of atrazine reached satisfactory results at natural pH and with an adsorbent mass of 0.54 g for each liter of solution. The Redlich-Peterson model presented the most satisfactory fit with the equilibrium data. This study found that the evolution of system temperature increased the concentration in the solid phase of 178 mg g−1 at 328 K. Regarding adsorption kinetics, the linear driving force model can represent the experimental data. Also, the predicted adsorption data of the model follows the experimental data. The application of the adsorbent in the removal of the herbicide mixture presented an efficiency of 81.45%. Therefore, using residual açaí fruit seeds as biomass for producing activated carbon employing zinc chloride as an agent activator is the possible application of the material. The material showed high efficiency and affinity with the target molecule.