The effect of immobilization of Scenedesmus sp. ISC 109 on potential of reduction of Chromium

Recently, biological methods are used for remediation of various pollutants especially heavy metals. Algae are organisms which can accumulate and transform these pollutants with different mechanisms. In this regard immobilization of these microorganisms is a technique that is used for different purpose. So after primary screening of microalgae (Spirulina, Tetraselmis, Chlorella, Scenedesmus, Microchaete and Calothrix), selected microalgae treated with chrome in a domain of environmental factors [pHs (2-5), concentration (10-150 mg/L) and time (20-200 min)] and absorption of chrome was determined with atomic absorption. The condition of maximum absorption was selected for evaluation of the effect of immobilization on it. Also physiological responses of selected microalga in these treatments were determined. The results indicated that maximum of absorption was 16% in 110 minutes by free green alga Scenedesmus. The alga Scenedesmus cannot accumulate chrome by itself and absorbed chrome returned to medium. Also the potential of alga reduced with increasing concentration and the maximum rate of absorption was seen in lower concentrations. Higher Absorption was seen in higher pHs (pH 5). Also immobilization had positive effect on absorption of chrome and can use in other purposes.