【作者】 叶龙；

【导师】 尤宏；

【作者基本信息】 哈尔滨工业大学 ， 环境科学与工程， 2014， 博士

【摘要】 高氯酸盐被广泛应用于军事、烟火、皮革加工等领域。ClO4–可以与I–竞争并导致人体甲状腺功能紊乱，这会给人体健康带来危害。它具有溶解度高、吸附性低及稳定性强的特点，是可快速扩散的持久型无机污染物。我国作为军事、航天大国和主要的焰火生产与消费国家，可以预期存在着高氯酸盐的环境污染问题，应该积极开展与之相关的研究。本文建立了一种水中痕量ClO4–的检测方法，并首次对哈尔滨地区高氯酸盐分布进行调查分析，研发出一种光催化还原去除水中ClO4–的方法，这对于面对潜在的环境风险以及制定应急措施具有重大的现实意义。在建立水中痕量ClO4–的检测方法的过程中，首先通过考察抑制电流、淋洗液浓度、淋洗液流速和柱温对离子色谱法检测ClO4–的影响并确定最佳检测条件；然后以ClO4–的回收率为评价标准，确定PWAX型固相萃取柱的最佳富集条件；最后，将固相萃取富集ClO4–的过程与离子色谱法检测ClO4–联立，即固相萃取-离子色谱法检测水样中痕量ClO4–。结果表明，当预处理体积为1L，水样中ClO4–的浓度为1-15μg/L，Cl–和SO42–的浓度均小于或等于30mg/L时，固相萃取-离子色谱法可以代替离子色谱串联质谱法测定水样中的ClO4–浓度，方法检出限为0.15μg/L，最低检出限为0.60μg/L，ClO4–回收率在99.7%-100.5%之间。通过检测哈尔滨地区浅层地下水、地表水、雨水、雪以及表层土壤在各个时期所含ClO4–的浓度，对哈尔滨地区高氯酸盐分布特征及其影响因素进行分析总结。研究发现，雪和表层土壤中的ClO4–主要来自春节期间烟花爆竹的燃放，只有春节期间取得的雪样中可以检测到ClO4–（0.02-0.15μg/L），且ClO4–平均浓度在除夕之夜达到最高值（0.13μg/L）。哈尔滨地区的松花江和阿什河中常年含有ClO4–，在松花江和阿什河漫滩区的浅层地下水中ClO4–浓度通常高于远离漫滩区的浅层地下水中ClO4–浓度。此外，春季时期浅层地下水和地表水中ClO4–浓度要高于秋季。采用溶胶凝胶法研制了负载型Cu-TiO2/SiO2催化剂，通过对比催化剂对ClO4–的还原效果筛选出最优催化剂——Cu2+和TiO2的质量比为0.5%时制得的Cu-TiO2/SiO2催化剂（Cu0.5）。以Cu0.5作为催化剂，考察O2、催化剂浓度、空穴清除剂浓度、光生电子（e–）、pH、羟基自由基、反应温度以及水中几种常见离子对光催化还原ClO4–的影响。结果表明，在无氧条件下，当以Cu0.5为催化剂（10g/L），空穴清除剂柠檬酸的初始浓度为0.15mmol/L（pH=3.63），再以2mL/min的速度向系统中持续投加浓度为1.5mmol/L的柠檬酸，反应温度为368±0.5K，当ClO4–浓度为0.001mmol/L，经过260min的反应后，ClO4–的去除率可以达到95%左右。当ClO4的初始浓度不同时，ClO4还原反应均符合一级反应动力学。在光催化还原ClO4–的过程中，ClO3–和Cl–分别为中间产物和最终产物，ClO4–被光催化系统中的e–和CO2还原，其中CO2是柠檬酸被h+氧化过程中生成的中间产物。更多还原

【Abstract】 Perchlorate is widely used in military industry, fireworks industry, leatherworking and so on. It interferes with the uptake of iodine into the thyroid and mayaffect human health. It is one of the persistent inorganic pollutants and has some feature such as high solubility, low absorbability and high stability. China is not only a great power in aviation and spaceflight military affairs field but also a main producing country of fireworks, so there may be the problem of perchlorate pollution and the concerning research should be carried out. An analytical method about the determination of trace perchlorate in groundwater was built. The perchlorate distribution in Harbin and a method about removing perchlorate from water were studied. All these researches have great realistic significance to the potential environmental risks and development of relevant contingency planning emergency measures.The analytical method of the determination of trace perchlorate in groundwater is studied. At first, the optimumdetecting conditions were found by studying the influences of suppressor current, eluent concentration, eluent velocity and column temperature on detecting perchlorate by using ion chromatography (IC). Then, the optimumgathering conditions of PWAX were found. PWAX is one kind of solid phase extraction (SPE) column. At last, the course of perchlorate gathering and detecting perchlorate by using IC were combined, namely determination of trace perchlorate in water by SPE-IC. The results indicate that when the perchlorate concentration in water ranges from1μg/L to15μg/L, and thechloridionconcentration and sulfate concentration are both smaller than30mg/L, the limit of detection is0.60μg/L and the recovery ranges from99.7%to100.5%.Seasonal variation and influencing factors of perchlorate distribution in groundwater, surface water, rain, snow and surface soilwere studiedin differentperiods in Harbin and its vicinity, China. Results indicate that perchlorate only can be detected in snow during the spring festival and the perchlorate concentration ranged from0.02μg/L to0.15μg/L. In addition, the mean concentration can reach the maximum (0.13μg/L).Perchlorate concentrations in groundwater and surface water decrease after rainy season in summer.Groundwater samples collected in the floodplain areas of the Songhua River and the Ashi River containedhigher perchlorate concentrations than that far away with the rivers.Cu–TiO2/SiO2catalystswere prepared by the sol–gel dip-coating method. The catalyst has the best catalyticactivity when the nominal mass ratio of Cu2+to TiO2is0.5%(Cu0.5).The influences of oxygen, catalyst concentration, hole scavengerconcentration, e, pH, hydroxyl radical, reaction temperature and common ions on photocatalytic perchlorate reduction were studied. Results indicate that the efficiency of perchlorate reductioncan reach95%after260min irradiation (368±0.5K) when the initial perchlorate concentration and citric acidconcentration are0.001mmol/L and0.15mmol/L, citric acid (1.5mmol/L) is added to the system at a constant speed2mL/min. The reaction of perchlorate reduction matches first-order dynamical reaction equation when the initial perchlorate concentrations are different.Cl is identified as the end product and ClO3is the intermediate in the course of perchlorate reduction. Perchlorate is reduced by e and CO2, CO2is the intermediate when citric acid is oxidated by photogenerated hole.更多还原