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氯胺消毒对三卤甲烷类消毒副产物的控制研究 总被引:5,自引:0,他引:5
在氯消毒研究的基础上,研究氯胺对消毒副产物的控制,将氯与氨氮的比值降至5,能够使单独氯消毒所生成消毒副产物减少89%,二溴一氯甲烷也不再检出;消毒副产物的生成量与氯胺的投加量呈很好的线性关系;接触时间对消毒副产物的生成量影响很小,24 h增加缓慢;pH升高至8消毒副产物的总量比pH为7时减少82.3%,一溴二氯甲烷不再检出;氯胺代替氯消毒能够很好地控制溴代消毒副产物种类和总量. 相似文献
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自行设计了气固相光催化实验系统,以铝材为担载体,TCM和TCE为模拟污染物,在常温、常压下,对辐射光源、气体相对湿度、污染物反应浓度等因素对TCM和TCE的光催化降解反应的影响进行了研究.结果表明,在研究所采用的实验条件下,辐射光源采用254 nm时的降解效率要比采用365 nm时高10%左右;气体相对湿度为40%时光催化降解效率最高;随着污染物反应浓度的增加,TCM的降解效率降低,而TCE的降解效率增加.初步的反应动力学研究结果表明,TCM和TCE在二氧化钛表面的光催化降解反应可采用Langmuir-Hinshelwood动力学方程来表征. 相似文献
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以揭示回灌过程中CHCl3耦合胶体效应影响下的二次形成作用为研究目标,通过批实验分析有、无胶体条件下不同水化学条件对CHCl3生成速率及生成量的影响,并结合切向流超滤技术和原子力电镜扫描(AFM)表征手段分析CHCl3-SiO2胶体协同作用模式.结果表明,CHCl3的生成量随着反应时间的增加而增大,并在特定的反应时间内,高氯/TOC比率、高pH值、低离子强度均会促进CHCl3的二次形成.SiO2胶体的存在会影响反应前体物的吸附,使各时刻CHCl3生成作用均受到抑制,并对水中的CHCl3有强吸附作用.结果可为人工回灌过程中CHCl3的二次形成作用提供科学参考. 相似文献
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Liao CH Wantawin C Lu MC Huang CI 《Environmental science and pollution research international》2004,11(4):254-259
BACKGROUND: The spent waste of aliphatic chlorinated solvents has caused severe deterioration of groundwater quality. Trichloromethane (TCM), which shows health and toxicological effects on human beings, was selected as a model compound to be dechlorinated through a redox system. METHODS: The Fe0-based system including Fe0/H2O, Fe0/UV, Fe0/H2O2, and Fe0/UV/H2O2 was explored to evaluate its performance in dechlorinating TCM. H2O2 was dosed at later reaction time points to initiate Fenton or photo-Fenton reactions. The first two systems demonstrate the reductive dechlorination of TCM by Fe0-released electrons, while the latter two show dechlorination of TCM by both electron reduction and hydroxyl radical oxidation. The system parameters of TCM remaining, Cl- buildup, Fe2+ accumulation, H2O2 residue, and ORP were measured to describe different redox characteristics of TCM dechlorination. The Cl- buildup was used as a way to describe the degree of TCM dechlorination in an open reaction system. RESULTS: Reductive dechlorination efficiencies of TCM were 5% and 6% for the systems of Fe0/H2O and Fe0/UV, respectively. In contrast, the Fe/H2O2 and Fe0/UV/H2O2 systems were capable of dechlorinating TCM reductively and oxidatively by 14% and 15%, respectively. The presence of UV light was found to retard the dissolution of Fe2+, but it enhanced the rate of chloride buildup, based on the comparison of Fe0/H2O and Fe0/UV systems. In addition, WV irradiation plays only a minor role in the Fe0/UV/H2O2 system, in view of TCM dechlorination. Application of small amount of H2O2 results in the increase of Fe2+ accumulation rate in the Fe0/H2O2 system. CONCLUSIONS: TCM was dechlorinated mostly through post Fenton oxidation; reductive reaction represents a less efficient way to dechlorinate TCM. The efficiencies of overall TCM dechlorination for the two systems of Fe0/H2O2 and Fe0/UV/ H2O2 are comparable to each other, and this implies that the presence of UV irradiation imposes no significant enhancement. RECOMMENDATIONS AND OUTLOOKS: It is highly recommended to initiate effective redox dechlorination of TCM with the system of Fe0/H2O2, where the H2O2 in excess is applied at a later reaction time point. 相似文献
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以氨基酸为代表的溶解性含氮有机物在水源水中广泛存在,成为制水工艺消毒副产物的主要前体物之一.选取色氨酸(Trp)为含氮前体物模型,考察了其在消毒工艺中产生受控消毒副产物的途径及影响因素.结果表明,Trp氯化过程经取代,脱羧,水解等一系列反应,可生成卤乙酸(HAAs),三卤甲烷(THMs)等消毒副产物.THMs和HAAs的生成量随加氯量增加;随接触时间的延长逐渐增加.温度的升高,HAAs的生成量先增大后减少;碱性条件有利于THMs和HAAs的生成.氯胺消毒和遮光条件下可明显减少THMs和HAAs的产生. 相似文献
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