Biosorption and desorption of chromiumand lead on shoots biomass of Schoenoplectus californicuswere investigated by performing\r\nbatch sorption tests in different conditions of pH, biosorbent dose, and initial concentration in simple and binary solutions.\r\nLangmuir, Freundlich, Temkin, and Dubinin-Radushkevich isotherm models were employed to describe sorption equilibrium.\r\nFilters and biomass were characterized before and after treatments by environmental scanning electron microscopy and X-ray\r\nenergy-dispersive spectrometry.The optimal conditions for biosorption were found to be pH 5 for both metals. The contact time\r\nto reach pseudoequilibrium changed as a function of pH and the metal studied.The highest optimisation of biosorbent dose was\r\n5 g L-1 at pH7 and 15 g L-1 at pH 5 for both metals. The most effective extracting agents for lead and chromium proved to be HNO3\r\nand NaOH, respectively. The recovery of lead was greater than of chromium because the Cr(III) sorption mechanisms involve a\r\nstronger binding energy than the mechanisms for Pb(II), such as in intern sphere complexes. Both metals accounted for a high %\r\nremoval (>90%) under the best sorption conditions. The use of Schoenoplectus californicus proved to be an efficient and economical\r\nalternative for the treatment of effluents contaminated with lead and chromium.
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