SBIR Phase I: A Real Time Analyzer for Chlorinated Hydrocarbons

这项小企业创新研究第一阶段计划将测试一种检测氯化碳氢化合物的新方法，并特别适用于监测土壤、底土和渗透区。氯化烃是分布最广、化学寿命最长的一类危险废物。这种化合物的密度比水大，并通过地下水和渗透带向下迁移。通常很难验证地下修复方法的有效性，因为修复活动（如土壤洗涤和溶剂萃取）可能会加剧迁移。因此，需要改进的方法来监测这些化合物的浓度。任何新的分析技术都必须是现场可部署的，提供快速（实时）响应，并且必须在存在大量无机氯化物背景的情况下对氯化碳氢化合物有选择性。这将是一种监测方法，可以在修复过程中连续测定当地氯化溶剂浓度的变化。该方法可以与锥形贯入仪一起使用，也可以在固定位置（包括井顶空间区域）实施。包括氯化有机化合物的蒸汽通过用于排除液体的膜取样，然后在放电中分解。用近红外二极管激光光谱法测量了放电产生的HCI浓度。光纤将激光从地面上的微型二极管激光器带到测量区域，该激光器可以在多个测量点之间复用。这种方法保证了快速的时间响应和较低的运行成本。预计氯代烃的Ppm检测限为1秒响应时间，测量动态范围为104。拟议的技术被设计为与锥体穿透法兼容，以利用已经围绕使用锥体穿透仪创建的修复诊断市场。在数千个需要修复的地点，土壤和地下水中的污染物中有35%至40%是氯代烃。

This Small Business Innovation Research Phase I program will test a novel method for detecting chlorinated hydrocarbons, and has particular application to monitoring soil, subsoil, and vadose zones. Chlorinated hydrocarbons comprise one of the most widespread, chemically long-lived classes of hazardous waste The compounds are denser than water and migrate downward through groundwater and vadose zones. It is often difficult to verify the effectiveness of subsurface remediation methods because remediation activities--such as soil washing and solvent extraction--may exacerbate the migration. Thus, improved methods are required to monitor concentrations of these compounds. Any new analysis technique must be field deployable, provide rapid (real time) response, and must be selective for chlorinated hydrocarbons in the presence of large backgrounds of inorganic chlorides. This will be a monitoring method that can provide continuous determination of changes in the local concentrations of the chlorinated solvents during remediation. The approach can be engineered for use with cone penetrometers or can be implemented in fixed locations including well headspace areas. Vapor including chlorinated organic compounds is sampled through a membrane used to exclude liquids, then is decomposed in an electric discharge. The concentration of discharge-produced HCI is measured by near-infrared diode laser spectroscopy. Fiber optics bring the laser light to the measurement region from a miniature diode laser that is kept above ground and that can be multiplexed among numerous measurement points. This approach guarantees rapid time response and low operating costs. Ppm detection limits for chlorinated hydrocarbons with a 1 second response time and a measurement dynamic range of 104 are anticipated. The proposed technology is designed to be compatible with cone penetrometry in order to take advantage of the market for remediation diagnostics that has already been created around the use of cone penetrometers. Chlorinated hydrocarbons account for 35 to 40% of contamination in soil and ground water at thousands of sites requiring remediation.