| Metal pollutants produced from industrial processes have produced severer effects on human health and ecosystem. Adsorption has been one of the important methods applied to metal pollutants treatment. The major advantages of biomaterials include:aboundant source, wide sources, diverse morphologies, low cost and environment friendly, then biomaterials have been intensively investigated and applied to such field as adsorption/separation and functional materials. Different microbial biomass were used as the sources of biomaterials and treated with several pretreatment methods and surface-modified materials. Then different adsorbents were synthesized and applied to adsorb and separate metal pollutants from aqueous solutions. The main conclusions were followed:(1) Biomass of filamentous fungus M7 and KC were cultured and collected. The two biosorbents, M7-1 and KC-2, were prepared by freeze-drying of the biomass. Differents methods were applied for the physical and chemical properties' characterization. Results indicated that abundant functional groups such as hydroxyl and carboxyl groups existed on cell surface, which were attributed to metal adsorption. The effects of such factors as solution pH, contact time and initial ion concentration on adsorption performance of M7-1 and KC-2 were investigated. The optimum values of solution pH for Cu(â…¡) and Pb(â…¡) adsorption onto M7-1 were 5.0 and 6.0, while the values for adsorption of Pb(â…¡) and Ag(â… ) onto KC-2 were 5.0 and 3.0 respectively. The nature and initial concentration of metal ions affected the initial adsorption rates of the two fungal adsorbents. The kinetic data of the two biosorbents were better fitted by pseudo-second-order kinetic model, which indicated the chemical adsorption nature. The adsorption capacities of M7-1 and KC-2 increased with the increasing of initial ion concentration. Langmuir isotherm had the better correlation coefficients for M7-1 and KC-2, indicating the monolayer adsorption process. M7-1 and KC-2 were effective to adsorb metal ions.(2) Biomass of Bacillus sp. was cultured and collected. Three kinds of adsorbents were prepared with different technologies:B1 by freeze-drying, B1Si by coating silica with sol-gel methods, and hollow silica adsorbent (BISiS) by calcinating the bio-template, and were applied to Pb(â…¡) adsorption. Different methods were applied for physical and chemical performance characterization. The results indicated that B1 and B1Si maintained the abundant functional groups, and silica coating improved the mechanical strength of B1Si; B1Si and B1SiS were amorphous; and the silica particles on B1Si and B1SiS enlarged the specific surface and produced micropores. The effects of solution pH, sorbent dosage, ion concentration and contact time on adsorption capacity were investigated. The adsorption kinetic, isotherm, and thermodynamic mechanisms of the three adsorbents were determined. Results indicated that optimum values of solution pH for Pb(â…¡) adsorption on B1, B1Si and B1SiS were 5.0,5.5 and 5.5, respectively; after the mass of adsorbent reached 1.0 g/L the adsorption ratio obtained limited improvement; and after 240 min Pb(â…¡) adsorption on the three kinds of sorbents reached balance. Pseudo-second-order kinetic model better fitted the kinetic data and Langmuir isotherm could describe the adsorption process better. The maximum adsorption capacities of B1, B1Si and B1SiS at 318 K were 67.57,93.46 and 72.45 mg/g, respectively. Thermodynamics parameters confirmed the spontaneous and endothermic nature of adsorption process. B1Si and B1SiS were recyclable adsorbents. The coexisting ions, Na(â… ) and Ca(â…¡), had little effects on the adsorption of Pb(â…¡) onto the three sorbents.(3) SiY was synthesized with yeast cells as bio-template by modified Stober method and applied as the supporter of surface-imprinting(SIP) technology. Pb(â…¡) surface-imprinting polymers(IIP/SiY) were prepared with sol-gel and SIP technologies. Physical and chemical characterization of IIP/SiY with several methods indicated that amino and hydroxyl groups played important roles during the processes of imprinting polymerization and adsorption; SiY obtained micropore structure and a large specific surface area; and IIP/SiY maintained the large specific surface area and pore volume because of the surface-imprinting polymerization on SiY and elution of objective ion. The optimum solution pH was 6.0 for Pb(â…¡) adsorption on IIP/SiY. Pb(â…¡) adsorption onto IIP/SiY followed well with pseudo-second-order kinetic and rate controlling step was affected both by intraparticle diffusion and film diffusion. The isothermal equilibrium data of Pb(â…¡) adsorption on IIP/SiY and NIP/SiY were well fitted by Langmuir isotherm model. The monolayer maximum capacity of IIP/SiY was 86.21 mg/g. Results of selective experiments indicated that IIP/SiY had better adsorption ability and selectivity for Pb(â…¡) ion. Pb(â…¡) adsorbed onto IIP/SiY could be eluted quantitatively and IIP/SiY was reusable.
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