【作者】 欧红香；

【导师】 王谦；

【作者基本信息】 江苏大学 ， 清洁能源与环境保护， 2012， 博士

【摘要】 工业生产过程中产生的金属污染物对人类的健康和生态环境带来严重危害,吸附法在金属污染物治理中有着重要作用。生物材料以其原料来源广、形貌多样、价廉和环境友好等特点在吸附分离、功能材料等领域广为应用。本论文以不同形貌微生物作为生物材料来源,采用不同预处理方式和表面修饰方法制备了不同形貌的吸附材料,并用于几种典型金属污染物的吸附分离,主要研究结果如下：(1)培养、收集丝状真菌M7和KC,经低温冷冻干燥,制备M7-1、KC-2两种生物吸附剂。采用多种方法对其理化性能进行表征,结果表明两种真菌生物吸附剂细胞表面富含羟基、羧基等多种有利于金属离子吸附的活性官能团。考察了溶液pH、吸附时间和初始离子浓度等因素对M7-1、KC-2吸附性能的影响。M7-1吸附Cu(Ⅱ)和Pb(Ⅱ)的最佳pH分别为5.0和6.0；而KC-2吸附Pb(Ⅱ)和Ag(Ⅰ)的最佳pH分别为5.0和3.0。两种生物吸附剂的初始吸附速率随金属离子种类和初始浓度改变而发生变化。准二级吸附动力学模型能很好地描述M7-1、KC-2两种生物吸附剂对金属离子的吸附,表明吸附过程以化学吸附作用为主。M7-1、KC-2的吸附量随金属离子的初始浓度增加而增大。Langmuir吸附等温模型对M7-1、KC-2对金属离子的吸附平衡数据具有较好的拟合效果,表明两种生物吸附剂对金属离子的吸附以单分子层吸附为主。所制备的两种真菌生物吸附剂对金属离子有良好的吸附性能。(2)培养、收集芽孢杆菌,经低温冷冻干燥制备了生物吸附剂B1,利用溶胶-凝胶技术制备了表面包硅生物吸附剂B1Si,采用牺牲模板法制备了中空硅吸附剂B1SiS,并将B1、B2Si和B1SiS三种材料用于Pb(Ⅱ)的吸附分离研究。理化性能分析表征结果表明：B1和B1Si均保留了菌体的丰富官能团,B1Si机械性能增强；B1Si和B1SiS为无定形非晶体,表面包硅增大了B1Si和B1SiS的比表面积,并产生微孔结构。考察了溶液pH、吸附剂用量、离子浓度和吸附时间等对三种材料吸附性能的影响,以及吸附动力学、吸附等温模型和吸附热力学机理及行为。研究结果表明：在溶液pH分别为5.0、5.5和5.5时,B1、B1Si和B1SiS吸附Pb(Ⅱ)的效果最佳,吸附剂用量达到1.0 g/L后,吸附去除率提高有限,240 min后吸附过程趋于平衡。准二级吸附动力学模型较好地描述了三种吸附材料对Pb(Ⅱ)的吸附动力学行为；Langmuir吸附等温模型能很好地描述三种吸附材料的吸附平衡性能,B1、B1Si和B1SiS在318 K下对Pb(Ⅱ)的最大饱和吸附量分别为67.57、93.46和72.45 mg/g；热力学方程的拟合表明三种吸附材料对Pb(Ⅱ)的吸附是一个吸热和自发的过程。B1Si和B1SiS具有良好的解吸再生性能,共存离子Na(Ⅰ)和Ca(Ⅱ)基本不影响吸附材料对Pb(Ⅱ)的吸附性能。(3)采用改进的Stober法制备包硅酵母(SiY),并将其作为表面印迹载体材料,结合溶胶-凝胶技术和表面离子印迹技术制备基于包硅酵母的Pb(Ⅱ)表面离子印迹聚合物(IIP/SiY)。采用不同表征方法对IIP/SiY理化性能进行表征,结果表明：-NH2、-OH等是印迹聚合及离子吸附过程中的重要活性基团；SiY具有微孔结构和较大的比表面积,在SiY表面及微孔内的印迹聚合及模板离子洗脱等使IIP/SiY保持了较大的比表面积和孔体积。IIP/SiY对Pb(Ⅱ)吸附的最佳溶液pH为6.0。准二级吸附动力学模型较好地描述了IIP/SiY和NIP/SiY对Pb(Ⅱ)的吸附动力学行为,吸附速控步同时受粒子内扩散和液膜扩散影响。Langmuir等温模型成功拟合了IIP/SiY和NIP/SiY吸附Pb(Ⅱ)的等温平衡数据,318 K时IIP/SiY的单分子层饱和吸附容量为86.21 mg/g。选择性实验表明IIP/SiY对目标离子Pb(Ⅱ)具有更高的吸附量和选择性,解吸再生实验表明IIP/SiY可定量洗脱,具有良好的解吸再生性能。更多还原

【Abstract】 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(Ⅱ) and Pb(Ⅱ) adsorption onto M7-1 were 5.0 and 6.0, while the values for adsorption of Pb(Ⅱ) and Ag(Ⅰ) 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(Ⅱ) 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(Ⅱ) 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(Ⅱ) 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(Ⅰ) and Ca(Ⅱ), had little effects on the adsorption of Pb(Ⅱ) 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(Ⅱ) 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(Ⅱ) adsorption on IIP/SiY. Pb(Ⅱ) 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(Ⅱ) 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(Ⅱ) ion. Pb(Ⅱ) adsorbed onto IIP/SiY could be eluted quantitatively and IIP/SiY was reusable.更多还原