Remoção de metais pesados Ni2+, Zn2+, Cu2+ e Cd2+ de efluente sintético utilizando coco de Jerivá (Syagrusromanzoffiana) como adsorvente – reator batelada e coluna de leito fixo.

Abstract

The disposal of effluents containing heavy metals above that permitted by legislation in water resources is a worrying environmental problem due to the toxicity of these metals. Among the most commonly used and most harmful heavy metals are cadmium, chromium, zinc, copper and nickel. The present work studied the removal of these metals in batch reactor and fixed bed column, using as adsorbent the coconut of Jerivá (Syagrusromanzoffiana). The adsorbent was physico-chemically characterized, in addition to the BET, BJH and MEV tests. The adsorption isotherms were performed with 0.2 g of adsorbent, under agitation of 150 rpm, 23±1 ° C and under concentrations of 20 to 100 mg L-1. The experimental data were adjusted by two models of adsorption isotherms, and the Langmuir model was better fitted to the experimental data. The highest adsorption capacity in batch reactor was found for Cd2 +, followed by Cu2+, Zn2+ and Ni2+. The fixed bed column experiments were performed for each metal at a concentration of 25 mg L-1.7 cm bed height and a 10 mL min-1 flow rate. With the experimental data of the column it was possible to determine operational parameters such as: rupture and exhaustion volume, ZTM length, bed depth and column adsorption capacity. The Cu2+, Cd2+ and Zn2+ ions presented discrepancies between the adsorption capacity values in batch reactor and fixed bed column. For Cu2+ the maximum adsorption capacity in batch reactor was 16,02 mg g-1 and in fixed bed column was 3,21 mg g-1. For Cd2+ the maximum adsorption capacity in batch reactor was 16, 38 mg g-1 and fixed bed column was 1,90 mg g-1. For Zn2 + the maximum adsorption capacity was 7,71 in batch reactor and 4,5 mg g -1 in fixed bed column. Ni2 + presented similar results for both types of systems, being 5,5 and 5,34 mg g -1 for the batch reactor and fixed bed column respectively.