Removal of hexavalent chromium from contaminated water by adsorption using mango leaves (Mangifera indica)

摘要

The objective of this study is to assess the uptake of hexavalent chromium Cr(Ⅵ) from aqueous solutions onto mango leave dust. Batch adsorption procedure is utilized to test the ability of leave dust as an adsorbent for Cr(Ⅵ) (reduction coupled adsorption). The contribution of various parameters on sorption, such as contact time, sorbate concentration, pH of the medium, and temperature, was estimated, and maximum uptake of Cr(Ⅵ) from contaminated water was 250.23 mg g~(-1) at pH 2.0 and temperature 40℃. Cr(Ⅵ) uptake from contaminated water followed the pseudo-first-order rate expression. △G~0, △H~0, and △S~0 have also been evaluated, and it has been concluded that the sorption was feasible, spontaneous, and endothermic in nature. The process follows well Langmuir isotherm. The nature of the possible adsorbent and metal ion interactions was examined by the Fourier transform infra-red (FTIR) technique. FTIR spectroscopy revealed the involvement of -OH, C=O, C-O groups on the cell surfaces in chromium binding. This study indicated that mango leaves can be used as an effective and environmentally friendly biosorbent for the treatment of Cr (Ⅵ) containing aqueous solutions.