Folhas de Neem como biossorvente na remoção de cobre de águas contaminadas

Abstract

The present study aimed to evaluate the ability to remove copper present in contaminated solutions by the adsorption process using Neem leaves as an adsorbent. Neem leaves were washed in running water, then washed in distilled water, dried in an oven at 60 ºC and crushed. The synthetic solution used in the experiments was prepared with concentrations ranging from 0.1 to 1.0 meq. L-1 of Cu+2. The tests were carried out in a leacher with a constant stirring speed of 30 rpm at 25 °C for a period of 24 hours. Copper precipitation was evaluated with pH adjustment and zero charge point (PCZ) test to determine the optimal pH of 5.18. Subsequently, the test with variation of Neem masses was carried out in order to obtain the optimal mass, resulting in 10 g of adsorbent. The kinetic study was obtained at 25 °C, with pH of the solution, in the acceleration of 30 rpm and the isotherms were transferred at 25 °C with solutions of pH 5.18, in concentrations that varied from 0.1 to 0, 7 meq L-1. The results obtained indicated that the adsorption process occurred in monolayers and the maximum adsorption capacity under the conditions was up to 35.59 mg Cu+2 g -1 of Neem.