Fiber Heap Capsule Preparation Of Heavy Metal Adsorption Of The Hydrophobic Polysaccharide Of The Bacteria

The preparation and heavy mentals adsorption of a hydrophobic expolysaccharide (EPS) from Sorangium cellulosumNUSY06 were investigated. The culture medium was composed of soluble starch 30g/L, KH₂PO₄ lg]L, CaCl₂ 0.1g/L, MgSO₄ 0.15g/L, FeCl₂ 0.01g/L, NaNO₃ 2.5g/L, pH 7.0-7.2. The batch fermentation was carried out on a rotary shaker at 28℃, 220r/min for 48h. Then the fermentation broth was denaturalization by NaOH, combined by CaCl₂, neutralized by acidic ethanol. The hydrophobie EPS was obtained with the yield of 65.0g/L±5.0.The hydrophobic EPS exhibited the optimal performance on lead and copper ions in the progression of adsorption. The adsorptive capacity of hydrophobic EPS on lead ions was excel to that on copper ions, 416.67mg/g and 384.61mg/g respectively. The Langmuir isotherm was more suitable for describing the adsorption of Pb²⁺ and Cu²⁺ by hydrophobic 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 pseudo-second order equation. For both metal ions, adsorption increased with medium pH, being maximal at 4.05 and 4.38 respectively. High or low temperature was not beneficial to the adsorption of lead ions but low temperature was good for copper ions. The existence of Na⁺, K⁺ and Mg²⁺ promoted the removal of lead ions. However, the removal of lead ions was independent of Cu²⁺ and Ca²⁺, but Cu²⁺ at high initial concentration enhanced the removal. Opposition to lead ions, the metal ions such as Na⁺, K⁺, Mg²⁺, Ca²⁺ and Pb²⁺ were competitive with copper ions. The lmol/L HCl solution could desorbed the Pb²⁺ and Cu²⁺ from the hydrophobic EPS, and the desorption rate were 76.12% and 94.13% for Pb²⁺ and Cu²⁺ respectively. The hydrophobie EPS could accumulate Pb²⁺ and Cu²⁺, which were at low concentration, and the accumulated capacity on Pb²⁺ was excel to that on Cu²⁺. Lead ions reacted with -COOH and -OH on the hydrophobic EPS primarily by IR testify. It was speculated that copper ions combined with -COOH and -OH on the hydrophobic EPS.