【作者】 李楠；

【导师】 任月明；

【作者基本信息】 哈尔滨工程大学 ， 环境工程， 2013， 硕士

【摘要】 重金属离子和细菌都是水体中常见的污染物，并且可能对人体造成很大的危害，及时对其加以去除是十分必要的。本文采用溶胶-凝胶法制备了锰铁氧体（MnFe₂O₄）及银锰铁氧体(Ag_0.003Mn_0.827Fe2O_3.8285)两种磁性尖晶石材料，分别将其用于吸附剂去除水中重金属离子和杀菌剂杀灭水中的大肠杆菌。对水中Cr（Ⅵ）﹑Ni（Ⅱ）、Pb（Ⅱ）和Cu（Ⅱ）等重金属的去除效果较好，在一定的实验条件下，对大肠杆菌也可以全部杀灭。采用现代测试手段SEM、EDS、XRD、FTIR、XPS等对MnFe₂O₄吸附剂和Ag_0.003Mn_0.827Fe2O_3.8285杀菌剂进行了结构和性能测试。结果表明，本实验合成的两种材料都呈多孔结构，MnFe₂O₄具有标准的锰铁氧体晶体结构，表面存在-COOH、-OH、Mn-O、Fe-O等官能团。在Ag_0.003Mn_0.827Fe2O_3.8285材料的EDS、XRD、XPS等表征图谱中，都可以发现Ag的存在，说明制备过程中已经成功的把银离子掺杂到银锰铁氧体的结构中。分别考察了溶液pH值、吸附时间和重金属离子初始浓度等因素对MnFe₂O₄去除水中Cr（Ⅵ）﹑Ni（Ⅱ）、Pb（Ⅱ）和Cu（Ⅱ）四种离子的影响效果。结果显示，吸附Cr（Ⅵ）和Ni（Ⅱ）的最佳pH值分别为2.0和7.0，吸附Pb（Ⅱ）和Cu（Ⅱ）的最佳pH值均为6.0。MnFe₂O₄去除水中Cr（Ⅵ）和Ni（Ⅱ）的反应分别在4.0h和2.0h达到平衡，Pb（Ⅱ）和Cu（Ⅱ）在MnFe₂O₄吸附剂表面达到吸附平衡需要3.0h。动力学和热力学研究表明，四种离子的吸附数据都符合准二级反应动力学模型和Langmuir等温吸附模型。吸附过程属于单层吸附，以化学吸附为主。MnFe₂O₄吸附剂对Cr（Ⅵ）﹑Ni（Ⅱ）、Pb（Ⅱ）和Cu（Ⅱ）四种离子的饱和吸附量分别为38.00mg/g﹑171.71mg/g﹑73.47mg/g和63.94mg/g。采用SEM、EDS、XRD、FTIR、XPS等代化测试手段对MnFe₂O₄吸附Pb（Ⅱ）和Cu（Ⅱ）的机理进行了深入分析，结果表明铅和铜均以离子的形式被吸附于MnFe₂O₄表面，与MnFe₂O₄表面的羟基基团和羧基基团发生了络合反应。MnFe₂O₄吸附剂经回收并在盐酸溶液中解吸再生后，可以循环使用五次以上，并且保持吸附效率基本不变。研究了Ag_0.003Mn_0.827Fe2O_3.8285杀菌材料杀灭水中大肠杆菌的影响因素：包括不同银离子掺杂量的杀菌剂﹑杀菌剂投加量﹑大肠杆菌浓度﹑光照﹑离子溶出﹑羟基抑制剂﹑反应时间﹑溶液pH值﹑反应温度等。实验结果表明，Ag_0.003Mn_0.827Fe2O_3.8285对于大肠杆菌有明显的杀灭效果，反应不需要任何光照，反应过程中没有羟基自由基的产生。杀菌实验在pH值为7.0的中性溶液中得到最佳效果，在碱性溶液中完成杀菌反应需要更长的时间，而当溶液呈酸性时非常不利于反应的进行。升高温度能够促进杀菌反应的发生，增加Ag_0.003Mn_0.827Fe2O_3.8285的投加量或降低大肠杆菌的初始浓度，都可以缩短反应时间。在常温下的中性溶液中，当Ag_0.003Mn_0.827Fe2O_3.8285的投加量为0.5g/L时，完全去除浓度为2×10⁷CFU/mL的大肠杆菌需要2h的时间。使用后的Ag_0.003Mn_0.827Fe2O_3.8285杀菌剂经过超声清洗可重复使用，经过5次循环实验后，对大肠杆菌的去除率仅降低了1.41%。通过SEM﹑AFM﹑SOD酶活力等表征分析，Ag_0.003Mn_0.827Fe2O_3.8285杀灭大肠杆菌的反应机理可归纳为，细菌附着在Ag_0.003Mn_0.827Fe2O_3.8285材料表面，通过与材料互相接触反应，细菌的形态结构生理功能都受到破坏，造成细菌死亡。更多还原

【Abstract】 Heavy metal ions and bacteria are common pollutants in water bodies, and harmful tohuman body. It is necessary to remove them in a timely manner. The MnFe₂O₄andAg_0.003Mn_0.827Fe2O_3.8285were both synthesized by sol–gel method. respectively for adsorbentto remove heavy metals in water ions and fungicide to kill the E. coli in water.Then the surface properties of the them were explored by SEM, EDS, XRD, FTIR andXPS. The results showed that the two samples both had widely distributed porous structure.The exist of Ag was found in EDS, XRD and XPS of Ag_0.003Mn_0.827Fe2O_3.8285.The adsorptionof Cr（Ⅵ）﹑Ni（Ⅱ）、Pb（Ⅱ） and Cu（Ⅱ） from aqueous solution on magnetic porous spinelMnFe₂O₄was investigated. Single batch technique was employed to test pH effect, sorptionkinetics and isotherm. The results showed that the optimum pH value of Cr（Ⅵ） and Ni（Ⅱ） was2.0and7.0, the equilibrium time was4.0h and2.0h, respectively. The Pb（Ⅱ） and Cu（Ⅱ）removal was also strongly pH–dependent with an optimum pH value of6.0, and theequilibrium time was3.0h. The adsorption process could be described by apseudo–second–order model. The equilibrium data were corresponded well with Langmuirisotherm. The maximum adsorption capacities for Cr（Ⅵ）, Ni（Ⅱ）, Pb（Ⅱ） and Cu（Ⅱ） were38.00mg/g,171.71mg/g,73.47mg/g and63.94mg/g, respectively. The interaction mechanismand the regeneration were also explored. The adsorbed Pb（Ⅱ） and Cu（Ⅱ） were in the form ofthe complex with oxygen in carboxyl groups and hydroxyl groups banding on MnFe₂O₄surface. The sorbent could be reused for five times with high removal efficiency.The inactivation of Escherichia coli （E.coli） from aqueous solution onAg_0.003Mn_0.827Fe2O_3.8285was investigated. Batch experiments were conducted to investigatethe effect of silver content, does of Ag_0.003Mn_0.827Fe2O_3.8285, light, reaction time, concentrationof E.coli, temperature, pH value, ons dissolve and hydroxy inhibitor. TheAg_0.003Mn_0.827Fe2O_3.8285was found to be highly effective at killing E. coli without light andcould completely inactivate2×10⁷cfu/mL E. coli within2h. The optimal removal effect wasobtained when pH was7.0. Meanwhile, more inactivation of E. coli was observed at alkalinepH than at acid pH in Ag_0.003Mn_0.827Fe2O_3.8285suspension. Higher temperature was beneficialto increased the bactericidal efficiency. Moreover, the mechanism of bactericidal action for the Ag_0.003Mn_0.827Fe2O_3.8285wasinvestigated by scanning SEM and AFM. The results showed that lots of E. coli adhered to thesurfaces of Ag_0.003Mn_0.827Fe2O_3.8285closely and the cell membrane of the bacterium has beendisrupted after reaction. The enzymatic activity of E. coli was also reduced after mixed withAg_0.003Mn_0.827Fe2O_3.8285for a period interaction as measured. The Ag_0.003Mn_0.827Fe2O_3.8285could be reused for five times with high removal efficiency. This work provides a potentialeffective material to be used in the antimicrobial applications.更多还原