Studies On Separation, Adsorption And Immobilization Of The Accumulation Of Heavy Metals Of Sheathed Bacteria

A sheathed bacteria which was strongly resistant to to heavy metals,was separated from the active sludge.Its life cycle and the tolerance scope to heavy metals were studied. As a bioabsorbent,its basic studies of sheathed bacteria were carried on,such as the technological conditions to adsorb heavy metals,the method of the immobilized cell preparation et al.It provided proofs for the application of sheathed bacteria in the treatment of heavy metals wastewater.The main results were listed as follows:By enrichment culture in the urea medium,combining with separation and purification by lineation in selective medium containing heavy metals,a sheathed bacteria FSK08 which was synchronously resistant to Pb²⁺and Zn²⁺was obtained from the active sludge.FSK08 was identified by physiological and biochemical characteristics analysis and 16S rRNA sequence analysis.By observing the morphological characteristics of different growth stages in CGY and Stoke medium,the growth rule and the life cycle of sheathed bacteria were grasped, providing a theoretical basis for sheathed bacteria's adsorption to heavy metals.Through the tolerance experiment to heavy metals,identified the poisonous effect to Pb²⁺and Zn²⁺ as well as the tolerance scope to heavy metals by the sheathed bacteria.The impact factors of adsorption of Pb²⁺and Zn²⁺,such as pH,temperature,strain age,adsorption time were studied and the optimum conditions of the adsorption of Pb²⁺ and Zn²⁺were obtained.By using acid,alkali,heat treatment to pretreat sheathed bacteria and compared the impact on the adsorption of Pb²⁺by sheathed bacteria before and after pretreatment to improve the adsorption capacity.To separate the cell wall,the sheathed bacteria was broken by the ultrasonic wave. Studies separately on the the adsorption of Pb²⁺by the sheath,the cell wall,the intracellular polymer PHB of sheathed bacteria,preliminarily understood the mechanism of the adsorption of Pb²⁺by sheathed bacteria.The immolibized effects of three materials,gelatin,sodium alginate and PVA were evaluated for immobilizing sheathed bacteria.Considered the character cost,mass transfer capability of immobilized cell,it was found that the PVA saturated boric acid method was the method fit for immobilization of sheathed bacteria.To achieve better immobilized effects,optimized the immobilized conditions by adjusting the concentration of PVA,the concentration of sodium alginate and the immobilized time.