Sorangium Cellulosum Nust06 Fiber Heap Capsule Bacteria Extracellular Polysaccharide Adsorption Characteristics Of Heavy Metal Ions

A novel exopolysaccharide was produced by Myxobacterium Sorangium cellulosum NUST06. Coarse EPS exhibited the optimal performance on lead and copper ions by study. The adsorptive capacity of EPS on lead ions was excel to that on copper ions, 123.3mg/g and 54.73mg/g dry weight individually. The Langmuir isotherm was more suitable for describing the biosorption of Pb2+ and Cu2+ by EPS than the Freundlich adsorption model, although they both had high coefficients. The adsorptive reaction was completed in ten minutes and was a fast and steady course. The kinetic data could be modeled by the pseduo-second order equation. For both metal ions, uptake increased with medium pH, being maximal at 3.96 and 4.51 respectively. In the same system, the pH increased gradually in lead ions solution while declined in copper ions solution. High or low temperature was not beneficial to the biosorption of lead ions but high temperature was good for copper ions. The light metal ions at low initial concentrations promoted the removal of lead ions, nevertheless, competition for binding sites on EPS was observed at high initial light metal ion concentrations. The removal of lead ions was independent of Cu2+ and Ni2+ at low initial concentration, but Cu2+ and Ni2+ at high initial concentration enhanced the removal. Opposition to lead ions, the metal ions such as Na+, If, Mg2+, Ca2+, Cu2+ and Ni2+ were competitive with copper ions severely. The breakthrough point of lead and copper ions both occurred at the volume of 490mL, and fix-bed was saturated completely at 640 and 610mL respectively. The biosorbed lead ions were effectively eluted by 0. 5M HCL solution. Breakthrough curve was not in good agreement with Thomas model. Lead and copper ions reacted with -COOH and -OH on EPS primarily by IR testify. The peculiar mechanism of lead biosorbed by EPS was regarded as hydrophobically elementarily.