Avaliação da capacidade de adsorção do capim elefante na remoção de cromo em leito fixo

Abstract

Industrial waste containing heavy metals released into water bodies represents a large risk to human health. Adsorption appears as a form of treatment of these effluents, being an alternative adsorbents widely studied as a way to make this process cheaper. The objective of this work was to evaluate the adsorption capacity of elephant grass, modified physical (steam explosion) and chemically (surfactant impregnation), in the removal of chromium present in aqueous solution. For this, a batch study was carried out, with the adsorbent grass elephant subjected to steam explosion and impregnated with surfactants (CExIT) for evaluation of the adsorption kinetics and a study in a fixed bed column using, with different adsorbents, washed elephant grass (CL), elephant grass impregnated with surfactant (CIT) and the adsorbent CExIT. For the batch experiments, the adsorption percentage was 83.3% and for the fixed bed column, 71%. The kinetics and isotherms that best adapted to the experimental points were the type pseudo-second order and the Freudlich model, respectively. In terms of the ability to adsorption equilibrium for the CExIT adsorbent in the batch process was 3.75 mg/g and in fixed bed 85.2 mg/g adsorbent. For this adsorbent (mads = 6g and bed height = 10 cm), the bed equilibration or saturation time was 80 min and rupture time equal to 12 min.