【作者】 李梦耀；

【导师】 钱会；

【作者基本信息】 长安大学 ， 地下水科学与工程， 2008， 博士

【摘要】 五氯苯酚（PCP）为优先污染物和持久性有机污染物，具有长期残留性、生物蓄积性、半挥发性和高毒性四个显著特点。黄土在我国北方地区广泛分布，以黄土为母质所形成的黄土性土壤是这些地区农、林、牧业、城市建设、工业的重要场地，因此研究五氯苯酚及其钠盐（PCP-Na）在黄土性土壤中的迁移转化及其治理方法，揭示五氯苯酚在黄土中的吸附、迁移规律，考察其对地下水的影响程度，寻找去除水体中五氯苯酚及其钠盐的方法及途径，对于评价PCP／PCP-Na的环境危害，减小对地下水的污染，保护地下水资源以及含氯酚废水的处理都具有十分重要的理论意义和实际应用价值。本文阐述了持久性有机污染物——五氯苯酚的结构、性质、来源及其危害；土壤及黄土性土壤的组成、结构、理化性质及水理性质。综述了五氯苯酚及其钠盐在土壤／沉积物中的吸附、迁移；含五氯苯酚及其钠盐污染废水治理等领域的国内外研究的最新进展。在此基础上，以西安黄土为例，采取静态与动态试验相结合的方法，研究了五氯苯酚在黄土性土壤中的吸附与解吸性能。试验测定吸附热力学和动力学曲线，确定平衡吸附热力学及动力学模型；通过计算吸附有关热力学状态函数，分析吸附及解吸机理；建立五氯苯酚在黄土性土壤中迁移转化的数学模型，试验测定模型参数，将五氯苯酚浓度分布的数学模型计算值和试验测定值进行对比，验证迁移转化数学模型的可靠性。同时，基于五氯苯酚及其钠盐污染废水的治理，研究对比了五氯酚钠在活性炭、HDX-8型大孔吸附树脂、D311A型阴离子交换树脂上的吸附与解吸性能，吸附的动力学、热力学模型与参数。并将Fe（Ⅱ）、Fe（Ⅲ）分别固载到LS-5000螯合树脂上，与H₂O₂一起构成异相Fenton试剂，进行五氯酚钠的Fenton试剂-光协同催化氧化降解研究，获得了降解五氯酚钠的最佳工艺条件，解决了Fenton试剂-光催化氧化降解过程中因Fe（Ⅲ）／Fe（Ⅱ）水解产生的光效率降低、五氯苯酚分析困难、在废水处理过程引入新的污染等问题，在此项研究的基础上设计了处理五氯苯酚废水的初步工艺流程。研究成果对黄土地区地下水的保护及五氯苯酚废水处理具有重要的理论及实际意义。主要研究结论：1．五氯苯酚在黄土性土壤中的吸附动力学符合Elovich方程和双常数方程；静态吸附量为53．9mg／kg，吸附速率为21．5mg／（kg．h）。2．五氯苯酚在黄土性土壤中的吸附为自发热力学放热过程；吸附作用力主要为氢键力；吸附等温线可用Freundlich方程和Langmuir方程描述。3．黄土性土壤对水溶性五氯酚钠滞留能力较差。五氯苯酚很容易穿过黄土，不可避免地对地下水造成污染。4．五氯苯酚（钠盐）在黄土性土壤中的迁移受到了水动力弥散、吸附／解吸的共同作用，降解作用的影响可忽略。其中吸附作用符合亨利线性模式q=K_dC，试验测得吸附系数K_d=0．0847cm³／g；迟滞因子R=1．46；弥散系数D=0．00466m²／d。数学模型的计算结果与实验测定结果吻合较好，表明水动力弥散模型可较好地用来对五氯苯酚在黄土性土壤中的运移进行模拟。5．D311A型阴离子交换树脂对五氯苯酚吸附为离子交换作用，吸附速率快、吸附量大，解吸速率快，解吸率高，穿透慢，是吸附法治理含五氯苯酚（钠盐）废水的优选吸附剂。6．光照时间、过氧化氢浓度、载Fe（Ⅱ）／Fe（Ⅲ）螯合树脂用量、初始浓度等对五氯苯酚降解率都有影响。7．载Fe（Ⅱ）螯合树脂与H₂O₂构成的异相Fenton试剂光协同催化氧化降解五氯苯酚的最佳工艺条件为：0．2g载Fe（Ⅱ）螯合树脂+24μg／ml过氧化氢+16μg／ml五氯苯酚+150min紫外光照，在此条件下，五氯苯酚的降解率为94．2％。影响因素强度大小次序为：光照时间＞载Fe（Ⅱ）螯合树脂质量＞五氯苯酚初始浓度＞过氧化氢浓度。8．Na⁺、K⁺、Mg²⁺、Cl^-、SO₄^2-等50倍于五氯苯酚质量浓度时，对降解率几乎不产生影响，Zn²⁺、NH₄⁺、NO₃^-等5倍于五氯苯酚质量浓度时，对降解率产生较大影响。9．Fe（Ⅱ）、Fe（Ⅲ）在五氯酚钠的光催化氧化降解过程中表现出一定的相似性。更多还原

【Abstract】 Due to the significant characteristics:long-term remains,bioaccumulation,semi-volatilized and hightoxicity,Pentachlorophenol（PCP）has been attributed to the Priority Pollutants and Persistent OrganicPollutants.In the west of China,the Loess possesses a great share in the land distributions,thus the soilcontaining Loess is an important factors for the utilization of agriculture,forest,animal husbandry,urbanconstruction and industrial development.In this way,more and more attentions have been paid to theresearches of pentachlorophenol and its sodium salts（PCP-Na）in Loess,such as the migration,the impacton the groundwater,and the management methods of pentachlorophenol and its sodium salts（PCP-Na）inXi’an Loess.From our points,those subjects have very important theoretical and practical values,forinstance,revealing the adsorption and migration laws of pentachlorophenol in the Loess,announcing theinfluence degree of pentachlorophenol and its sodium salts on the groundwater,seeking for the ways andmeans to remove pentachlorophenol and its sodium salts from water,grasping migration and distributionlaws of PCP / PCP-Na,evaluating the environmental hazards,reducing the pollution of groundwater,protecting the groundwater resources and treating pentachlorophenol wastewater,etc.In the present thesis,the structures,properties,resource and harm of PCP / PCP-Na have beengleaned,the adsorption and migration of pentachlorophenol and its sodium salts in the soil / sediments hasbeen reviewed.The latest developments of treatment of pentachlorophenol and its sodium salts wastewaterhave been summarized.To our the best knowledge,The several pivotal subjects related with those field arefurther pay close attention to by using the Loess of Xi‘an,the detail items includes:theadsorption/desorption properties and laws of PCP-Na in the Loess have been ascertained by combination ofstatic and dynamic method,the curves of adsorption thermodynamic and dynamic have been detected anddetermined.the migration transformation mathematical model of PCP-Na in the Loess and its modelparameters have been obtained,and the result showed that the model parameters have a good cohererencewith the experimental value,which further verify the validity of migration transformation mathematicalmodel.Besides,the adsorption and desorption of PCP-Na wastewater on the activated carbon,HDX-8 resin,D311A anion exchange resin have been investigated,moreover,adsorption kinetic and thermodynamic alsohave been determined.In addition,by choosing the resin chelated by Fe（Ⅱ）and Fenton reagent andFenton agent,the degradation of PCP-Na wastewater by combination of Fenton method and photocatalytic have been studied.The optimal reaction condition have been attained.Those routes solve the severaldifficult problems,i.e.,lower reactive efficiency;rub on the analysis of PCP-Na wastewater and bringingthe external pollution.Correspondingly,the treatment processes of PCP-Na wastewater have been designed.Those results can facilitate the protection of groundwater and the treatment of PCP-Na wastewater.Certainly,some important and practical significance of research conclusions have been attained.1.The adsorption of PCP-Na in the Loess abides by the Elovich equation and the tow-parametersequations.Thereinto,the constant of adsorption quantity is 53.9mg/kg and the adsorption rate is 21.5mg/（kg.h）.2.The adsorption of PCP-Na in the Loess belongs to an exothermal spontaneous reaction,and themain force can be attributed to the hydrogen bond.Adsorption isotherm can be described with Freundlichequation and Langmuir equation,respectively.3.The Loess soil has not a function for the enrichment of PCP-Na,and the PCP-Na penetrates theLoess soil easily.Inevitably,the groundwater will be contaminated by the PCP-Na.4.The migration of PCP-Na has been affected by the hydrodynamic diffusion and adsorption/desorption simultaneously,but the influence of degradation can be ignored.Additionally,It has been foundthat adsorption abides by the Herry equation:q=K_dC,thereinto,the adsorption constant K_d=0.0847cm³/g,the retard factor R=1.46,the diffusion coefficient D=0.00466m²/d.Moreover,the results determined formthose modes has a well coherence with the experiments”,which indicated that the diffusion modes can beused to simulate the migration of PCP-Na in The Loess soil well.5.The most effective adsorbent for the treatment of PCP-Na wastewater by adsorption method isD311A ion exchange resin.The main merits include the faster adsorption rate,the larger adsorptioncapacity,the quick desorption procedure,the higher desorption efficiency and slow penetrating rate.6.The illumination time,concentrations of H₂O₂,resin chelated by Fe（Ⅱ）,Fe（Ⅲ）and the initialconcentration have an effect on the degradation of PCP-Na.7.In the presence of catalysts of resin chelated by Fe（Ⅱ）and Fenton reagent,the optimal conditionfor the degradation of PCP-Na include 0.2g resin chelated by Fe（Ⅱ）;24μg/ml H₂O₂;16μg/ml PCP-Na;and 150min illumination time,and the degradation efficiency attained 94.2%.The sensitivity orders ofthose factors are:illumination time＞quantity of resin chelated by Fe（Ⅱ）,Fe（Ⅲ）＞the initial concentrationof PCP-Na＞the initial concentrations of H₂O₂. 8.The concentration of Na⁺、K⁺、Mg²⁺、Cl^-、SO₄^2-more than 50 times of PCP-Na have not effect onthe degradation efficiency.However,the concentration of Zn²⁺、NH₄⁺、NO₃^-just 5 times of PCP-Na willhave an obvious effect.9.Fe（Ⅱ）、Fe（Ⅲ）have a similar effect on the photo-catalytic degradation of PCP-Na.更多还原