CASCA DE FEIJÃO GUANDU COMO BIOADSORVENTE DO AMARELO DE TARTRAZINA

Abstract

Synthetic dyes are part of many industrial effluents that contaminate natural waters. Tartrazine Yellow (TAR) is a dye from the azo group compounds, widely used in food industries. Therefore, when discarded as effluent by the industry, it may cause damage to the environment. Among various techniques to remove dyes from water bodies, adsorption stands out. Bioadsorbents are an alternative to reduce the adsorption cost technique. Thus, aim of this work was to investigate the use of the Pigeon Pea (PP) husk, in natura form, with basic treatment and with acid treatment, for the TAR removal. characterize the bioadsorbent, determined from the point of zero charge (pHPCZ), analyzed the bioadsorbent dosage, kinetics and adsorption isotherms. The FTIR showed the presence of cellulose, hemicellulose and lignin molecules, which are chemical species that contribute to the dyes adsorption. The pHPCZ determination was 3.68 for the bioadsorbent in natura , 3.35 treated with acid and 5.53 treated with basic. Dosage analysis showed that equilibrium was reached from 0.02 g of PP husk mass and adsorption (q) of 1.2 mg g-1 in FG with acid treatment and approximately 0.95 mg g-1 treated with basic and in natura . The pseudo second order kinetics was best fit and the amount of equilibrium adsorption (qe) was higher in the FG treated with acid, obtaining 1.49 mg g-1. The adsorption process in the in natura and treated with basic was faster, being 0.04204 and 0.04395 g mg-1 min-1, treated with acid and basic, respectively. The analysis of the adsorption isotherms showed that the Langmuir isotherm model was best fit. The PP husk, with acid treatment, showed the highest adsorption capacity, 2.63 mg g-1. For PP husk in natura and treated with basic was found 1.53 and 0.638 mg g-1, respectively.