Abstract:
The sorption and desorption of Cr (III) on Spirogyra candensala was studied using Flame Atomic Absorption Spectroscopy (FAAS). Spirogyra condensata was found to have relatively higher capacity of adsorption at pH 5. The sorption isotherm obeyed Freundlich equation suggesting involvement of a multiplicity of sorption sites. The biosorption capacity of Spirogyra condensata was higher at low cation concentration implying that the biosorbent was suitable for treatment of effluent with low Cr (III) concentration. The presence of other cations such as Mg(II), Ca(II), Cu(II), Fe(II) and Pb(II) in solution was found to reduce the sorption of Cr(III), suggesting a competition for sorption on Spirogyra condensara. The desorption of Cr(III) from Spirogyra condensata was studied and the results showed that both 0.5 M I-ICI and 0.5 M HZSO4 solutions were very effective in desorbing Cr(III) with up to over 80% recovery. The regenerated biomass showed undiminished sorption P6I‘fOl'I1'lfl1'1C6 suggesting the potential of re-use of Spirogyra condensata in waste—water treatment. Comparison study between Spirogyra condensata and Amberlite (cation exchanger) revealed that their sorption capacities for Cr (III) are comparable suggesting that the biosorbents (Spirogyra condensata) can be substituted for the cation exchanger (Amberlite). Infrared (IR) analysis of Spirogyra conderzsala revealed the presence of carboxylate and amine groups which may be acting as binding site. Amberlite XAD- 8 immobilized Spirogyra condensala showed improved yield on biosorption of chromium (III) from wastewaters. This study revealed that Spirogyra condensata is an efficient biomass for chromium (III) recovery from wastewaters at low concentration.
