The Interaction Between Isochrysis Galbana And Heavy Metal

To describe the characteristic of microalgae as the material for biosorbtion, a kind of marine microalgae, Isochrysis galbana, and Cd2+,Cu2+,Zn2+ and Cr6+ were chosen as the experimental material. The effects of the four heavy-metals of Cd2+,Cu2+,Zn2+ and Cr6+ on the growth of Isochrysis galbana and the concentration of some biological compounds in the cells were researhed. The effects of N and P on the growth of Isochrysis galbana under the different concentrations of the four heavy metal were also studied. And the adsorption characteristic, absorbtion kinetics and absorbtion isotherm of Isochrysis galbana on the four heavy-metals were discribed. The results were showed as follow.1. Under the lower concentration, the growth of the Isochrysis galbana would not be obstructed by the four heavy metals, especially when the concentration of Zn2+, Cd2+, Cu2+ and Cr6+ were lower than 4.0, 5.0, 3.0 and 10.0 mg/L. The biomass, chlorophyll-a and protein in the cells of Isochrysis galbana decreased with the increasing of the ion concentration, but, the content of polysaccharide in the cells increased with increasing ion concentration first, then decrease slowly.2. Under the concentration of Cu2+, Cd2+, Zn2+ and Cr6+ was 0.1mg/L, 0.005mg/L, 0.1mg/L and 1.0mg/L, the optimum concentrations of N and P in culture medium were determined by the method of uniform design, which were 12.69, 14.93, 15.94 and 12.26 mg/L for N, and 1.13, 1.21, 1.33 and 0.85 mg/L for P, respectinely.3. According to our data, the biosorption process of the cells of Isochrysis galbana for the four heavy metals could be divided the fast and the slow stages. The biosorption efficiency of the cells of Isochrysis galbana to the four heavy metals was Cu2+> Cr6+ >Zn2+ >Cd2+. Langmuir and Freundilich isotherm could be used to describe the sorption processes,the results showed that the Frenundlich model was in good agreement with the biosorption of Isochrysis galbana for Zn2+, Cd2+, Cr6+ and Cu2+, while the Langmuir isotherm model was only fitted for Cu2+.