导　　师： 何振江;杨冠玲

学科专业： G0207

授予学位： 博士

作　　者： ;

机构地区： 华南师范大学

摘　　要： 随着经济的发展,环境问题日益受到人们的关注.二氧化硫作为主要的大气污染物,对环境造成严重的危害,有必要对其污染状况作连续监测.在我们国家,长期以来定点大气环境质量监测仪器依靠进口,国内没有任何企业从事大气环境质量监测仪器研究;进口仪器价格昂贵,每套大气环境质量监测仪器价格昂贵,由于没有国内技术支持,每套每年得维护费用不菲.这不利用于中国环保仪器技术和环保产业的发展.因此在中国开展大气质量监测仪器技术研究,不仅可以降低购买国外仪器的费用和维护费用,而且有利于环保仪器技术的提高,同时促进环保产业的发展,具有重要的现实和经济意义.二氧化硫检测仪器是定点大气环境质量监测仪器系统的一个主要部分.在所有检测二氧化硫的技术中,采用紫外荧光原理检测大气中二氧化硫浓度是世界多个国家、世界卫生组织的标准化方法,包括我们国家.在广州市环保局的大力支持下,立项开展大气质量监测系统研究.作为其中的一个部分,我们开展了定点大气二氧化硫紫外吸收荧光检测理论与仪器技术研究. With the development of economic, environment pollution problem arise people's concerns. One of major pollutants, sulfur dioxide, has done great harm to our environment, so it is more and more necessary to operate an continuous monitoring for pollution by sulfur dioxide. In our country, all monitoring systems for atmospheric pollutants, including sulfur dioxide have imported for a long time, such situation do no good to national environment protection technology and environmental protection industry, we should develop our environment protection technology including detection of sulfur dioxide in air. Among all methods for detecting sulfur dioxide, ultraviolet fluorescence method is popular in many countries, including our country, and also is promoted by Word Health Organization. By the great support from Guangzhou Environment Protection Administration, we start the theories and technique studies on ultraviolet fluorescence for detecting sulfur dioxide in air based on photon counting method. The achievements include.- /(1/) On the base of single wavelength and small light beam fluorescence detection theory, fluorescence detection theory using multiple excitation wavelength and limited excitation light beam is presented; the results show the later can improve the fluorescence response of sulfur dioxide. /(2/) Two physical model for studying the performance of cell, the key part, are developed; numerical calculation results indicate the effect of both radius of cross section and absorption coefficient of the surface of cell on cell's signal-noise ratio, and there is a reasonable radius value for cell to reach the best ratio of signal to noise without an bigger radius; those results are helpful for the design optimization of cell; /(3/) Two experimental system are designed and many factors having an effect on system's performance are studied; using the first experimental system with the detector H6240-02 PMT, the results show that the photon counts is linear to the concentration of sulfur dioxide from 0 to 97ppm in volume; using another experimental system with the detector H6180-01 PMT, the detector response is linear from 18ppb to l00000ppb; the response of SO2 fluorescence signal is about 7counts//ppb.s ,and the detection limit is about 8 ppb, with an integration time of one minute . /(4/) The major source of measurement error at low ppb concentrations is fluctuations of excitation light. The dependence of fluorescence response of zero air on temperature and flux is not obvious. Fluorescence response at 48000ppb and lOOOOOppb increased with the increase of the flux, however is lower with the higher temperature at 48000ppb. /(5/) The differences on fluorescence counts between ambient air and zero air are studied. /(6/) The origin of background counts, the spreading of excitation light and fluorescence are analyzed. /(7/) One data acquisition soft was developed by use of National Instrument's virtual development language.

关 键 词： 二氧化硫 紫外荧光检测

分 类 号： [X831]

领　　域： [环境科学与工程]