Oxidation of Polychlorinated Biphenyls (PCBs) in Supercritical Water

摘要：劳伦斯·L·塔夫拉里德斯研究所：锡拉丘兹大学建议编号：0115650该项目的目标是通过开发基础知识来推进超临界水氧化(SCWO)过程的现有技术，这些基础知识可用于定义一种有效且对环境安全的方法来销毁从受污染的土壤/沉积物或处置场所提取的有毒多氯联苯(PCB)。多氯联苯是一种剧毒的有机污染物，被122个国家列入最近被称为“脏十几种”的禁用化学物质名单。209个多氯联苯同系物的数量大约是元素周期表中元素数量的两倍，是氯苯数量的17倍，为研究提供了象棋一样的可能性。系统选择的同系物和最常用的工业多氯联苯混合物将在SCW纯净和甲醇溶液中进行氧化。重点将放在甲醇溶液上，因为观察到甲醇对多氯联苯的脱氯有促进作用。还将研究从多氯联苯污染的现实世界沉积物中通过SC-CO2/MeOH提取获得的几种溶液，以将PI正在开发的土壤修复技术的提取和氧化步骤结合起来。这种方法将使人们能够在没有动力学研究和没有反应速率促进剂的情况下，在不那么恶劣的条件下设计和优化运行具有竞争力的超临界水处理大规模多氯联苯和其他相关污染物的装置。在实验结果的基础上，建立了反应动力学和反应路径以及结构-反应活性关系。多氯联苯在超临界水中的氧化实验将在高压等温推流管式反应器中进行，该反应器能够在温度高达873K、压力高达60兆帕的条件下连续运行。方法是选择热力学、动力学和工艺参数，以便找到最佳条件，以便在最小侵害性条件下实现安全和有效销毁多氯联苯这一战略目标。考虑的主要参数为温度(673~874K)、压力(25~35 MPa)、停留时间(1~240 S)和溶质浓度(甲醇中的溶质浓度为0.1~10g/L，超临界水中的溶质浓度为10-3~10 mmol/L)。这一知识将通过出版物和演示文稿向研究界传播，并将为学生，包括生活在多氯联苯污染土地上的美洲原住民提供示范培训/教育。

ABSTRACTPI: Lawrence L. Tavlarides Institution: Syracuse UniversityProposal Number: 0115650The goal of this project is to advance the existing technology of the supercritical water oxidation (SCWO) process by developing fundamental knowledge which can be used to define an efficient and environmentally safe way to destroy toxic polychlorinated biphenyls (PCBs) extracted from contaminated soil/sediments or from disposal sites. PCBs are highly toxic organic pollutants (POPs) included by 122 nations on a recently banned list of chemicals known as the "dirty dozen." The 209 PCB congeners are approximately twice the number of the elements in the Periodic Table and 17 times the number of chlorobenzenes, offering chess0like possibilities of investigations. Systematically selected congeners and the most used industrial PCB mixtures will be oxidized in SCW both neat and methanolic solutions. Emphasis will be on the methanolic solutions due to observed rate-enhancing quality of MeOH on PCB dechlorination. Several solutions obtained by SC-CO2/MeOH extraction from PCB polluted real world sediments will also be studied to couple the extraction and oxidation steps of a soil remediation technology being developed by the PI. This approach will permit one to design and optimally operate competitive SCWO large-scale units for PCBs and other related pollutants under less severe conditions than those proposed without kinetic studies and without reaction rate enhancers. Based on experimental results, reaction kinetics and pathways and structure-reactivity relationships will be developed.PCB oxidation experiments in supercritical water will be conducted in a high-pressure, isothermal plug-flow tubular reactor capable of continuous operation at temperatures up to 873 K and pressures up to 60 MPa. The approach is to select thermodynamic, kinetic and process parameters in order to find the optimum conditions for achieving the strategic goal of safe and efficient PCB destruction under the least aggressive conditions. The main parameters considered are temperature (673 - 874 K), pressure (25 - 35 MPa), residence time (1-240 s), and solute concentration (0.1 - 10 g/L in MeOH, and 10-3 - 10 mmol/L in SCW). This knowledge will be disseminated to the research community through publications and presentations and will provide a model training/education to students, including Native Americans living on PCB contaminated lands.