水体中有机污染物的分离富集及降解方法的研究

【作者】 肖克；

【导师】 司士辉；

【作者基本信息】 中南大学 ， 分析化学， 2010， 硕士

【摘要】 分子印迹技术(MIT)是具有特异选择性的新兴识别技术,用分子印迹聚合物(MIP)作为固相萃取柱的固定相可以选择性地分离和富集待测物分子,提高分析方法的灵敏度。内电解法和Fenton氧化法是处理难降解有机废水的有效方法,具有良好的开发应用前景。本文考察了分子印迹固相萃取技术对除草剂阿特拉津的分离富集效能,并系统地研究了增强型内电解法、Fenton氧化法、以及增强型内电解__Fenton法降解有机废水的性能和操作条件,从而为难降解有机废水的治理提供了理论和实践依据。研究结果表明：1.分子印迹固相萃取柱的制备及分离富集效能研究：采用阿特拉津为模板制备了分子印迹聚合物,并将其制成固相萃取柱。结合能力实验表明,装柱后分子印迹聚合物的最大吸附量是装柱前的26倍,结合用时仅为装柱前的1／64,装柱过程大大提高了分子印迹聚合物的结合能力和效率。分子印迹固相萃取柱和C。8柱对水质中阿特拉津的分离富集效果的对比研究表明,在相同的实验条件下,与C18柱相比,分子印迹固相萃取柱的萃取效果及样品净化能力优势明显。2.增强型内电解法处理对硝基苯酚废水的研究：采用化学共沉淀法与化学镀法相结合制备了镀铜磁性粒子(CCMPs),并用SEM,XRD和磁强计对其进行表征。采用增强型内电解法,以对硝基苯酚为目标污染物,考察了铁屑与镀铜磁性粒子质量比、磁场强度、初始pH值、曝气量和Na2SO4投加量对COD去除率的影响,并对对硝基苯酚的降解机理进行分析。在铁屑与镀铜磁性粒子质量比为10,磁场强度为0.04 T,初始pH值为4.0,曝气量为15 L/min,Na2SO4投加量为2000 mg／L的条件下,反应3.5 h,对硝基苯酚降解完全,废水COD去除率达到72%。在相同的实验条件下,其处理效果明显优于传统铁屑／活性炭法及铁屑法。3.Fenton试剂处理难降解有机废水的影响因素分析：采用Fenton氧化法对硝基苯类化合物废水进行降解研究。运用正交实验确定各操作条件对污染物的降解影响大小顺序依次为：溶液初始pH值>H202投加量>Fe2+投加量>反应温度>反应时间。进一步的单因素实验得出最佳操作条件：H202投加量为80 mmol/L,Fe2+投加量为8 mmol/L,溶液初始pH值为3.0,反应温度为25℃,反应时间为60 min。在此条件下,废水COD去除率达到53.6%。4.增强型内电解__Fenton法处理难降解有机废水的研究：采用增强型内电解__Fenton法处理难降解有机废水。以硝基苯类化合物为目标污染物,进行操作参数条件的优化,分析了影响COD去除率的原因,并在最佳操作条件下对比增强型内电解__Fenton法、增强型内电解法、Fenton法以及分子印迹固相萃取技术对水体中有机污染物的降解去除效果。实验结果表明,和其它三种方法相比,增强型内电解Fenton法高效、经济,具有较大优势。更多还原

【Abstract】 Molecularly imprinting technology (MIT) is a new technology with the characteristics of special selectivity and recognition. Combined the Molecularly imprinted polymer (MIP) with solid phase extraction (SPE), the sensitivity of analytical methods would be improved greatly because of the special capacity of separation and enrichment of MIP. Internal electrolysis and Fenton oxidation processes are effective technologies and have good prospect of development and application for the treatment of refractory organic wastewaters. In present study, the separation and enrichment of atrazine using SPE technique were studied in detail, and the degradation of organic wastewater by Enhanced Internal Electrolysis, Fenton oxidation and Enhanced Internal Electrolysis__Fenton combined process were investigated, the operational parameters and the degradation effect of each process were studied in detail. The results obtained in this study could provide some important theory and practice guides for the treatment of refractory organic wastewaters. All the experimental results were showed as follows:1.The preparation and evaluation of separation and enrichment efficiency of molecularly imprinted solid phase extraction (MISPE) column. In this study, MIP using atrazine as the template was prepared, a glass tube packed the particles of the MIP was employed as MISPE column. The test of binding capacity indicated that the maximum of absorption capacity of MISPE column was twenty-six times than that of MIP, and the binding time of MISPE column was cut to about one sixty-fourth of what the MIP had, so the binding performance of MIP was greatly enhanced. The comparative study of MISPE column and C18 column on separation and enrichment of atrazine showed that the MISPE column had distinct advantage for extraction and clean-up samples.2.The treatment of p-Nitrophenol (PNP) wastewater using Enhanc-ed Internal Electrolysis process. In this study, the copper-coated magnetic particles (CCMPs) were prepared by the combination of a chemical co-precipitation method with an electroless plating method and characterized by scanning electron microscope, X-ray diffraction and magnetization measurements. The Enhanced Internal Electrolysis process was employed for treating the PNP wastewater. The effects of quality rate of iron scraps to copper-coated magnetic particles, magnetic intensity, initial pH, aeration rate, and Na2SO4 dose on COD removal efficiency have been studied systematically. The degradation mechanism of PNP was also analyzed. The results of bath experiments indicated that with quality rate of iron scraps to copper-coated magnetic particles as 10, magnetic intensity as 0.04 T, initial pH as 4.0, aeration rate as 15 L/min, and Na2SO4 dosage as 2000 mg/L, after a reaction time of 3.5 h, the PNP was completely degraded and the removal efficiency of COD could reach as high as 72%. Under the same conditions, the treating effect of Enhanced Internal Electrolysis process was much better than that of traditional Fe/C process or Zero-valent Iron process.3.The analysis of factors influencing the degradation of refractory organic wastewater by Fenton reagent. In this study, Fenton oxidation process have been investigated to degrade NBCs wastewater. The operating conditions for the degradation of pollutants were determined via orthogonal experiment, and the effect of various operating parameters follows in the following decreasing order:initial pH>H2O2 dosage> Fe2+ dosage>temperature>reaction time. The optimal operating parameters were determined by single factor experiment and showed as follows:[H2O2]=80 mmol/L, [Fe2+]=8 mmol/L, initial pH=3.0, tempera-ture=25℃, reaction time=60 min. Under the conditions mentioned above, the removal efficiency of COD could reach 53.6%.4. The treatment of refractory organic wastewater using Enhanced Internal Electrolysis__Fenton combined process. In this study, Enhanced Internal Electrolysis__Fenton combined process was employed to treat refractory organic wastewater. The NBCs were used as the target pollutants and the operational parameters were optimized respectively first, and the reasons affecting the COD removal efficiency were analyzed. Experiments were conducted under optimum conditions to compare the difference among the treating effectiveness of the organic pollutants of Enhanced Internal Electrolysis__Fenton combined process, Enhanced Internal Electrolysis process, Fenton oxidation process and MISPE process.The results showed that the Enhanced Internal Electrolysis__Fenton combined process appears superior to other three processes in relation to the treatment efficiency and cost.更多还原