高锰酸钾预氧化对剑水蚤DBPsFP的去除特征研究

以剑水蚤为试验对象,研究在不同条件下,高锰酸钾预氧化对剑水蚤代谢产物在氯化消毒过程中消毒副产物前体物的去除特征.研究表明:随高锰酸钾投加量的增加,水合氯醛(CH)、1,1,1-三氯丙酮(1,1,1-TCP)、三氯甲烷(TCM)总体呈上升趋势,二氯乙酸(DCAA)逐渐减少,而三氯硝基甲(TCNM)、1,1-二氯丙酮(1,1-DCP)、二氯乙腈(DCAN)和三氯乙酸(TCAA)先上升后下降,在本试验高锰酸钾投量范围内,高锰酸钾浓度为5mg/L时 CH、TCNM、DCAN、TCAN、DCAA、TCAA和1,1-DCP的去除效果最佳,去除率最高可达72.2%;延长预氧化时间,DCAN、DCAA、TCAA浓度逐渐降低,TCM、CH浓度逐渐升高,TCNM、TCAN、1,1,1-TCP浓度先升高后降低,而1,1-DCP浓度先迅速下降后逐渐升高,预氧化时间宜控制在20min;pH<7可有效抑制TCM的生成.pH=7时TCAA达到最小值,而1,1-DCP含量最高,pH>7有助于1,1-DCP的减少,CH、DCAA、DCAN、TCAN、TCNM和1,1,1-TCP随pH的增加而减少.在pH=9时生成量均最小, 最高去除率为80%;最佳温度为30℃,随着温度的升高,DCAA、TCAA和TCM浓度有所增加,1,1-DCP、DCAN和1,1,1-TCP生成量减少,在20℃时,CH的浓度最小,而TCAN的浓度最大.     

高锰酸盐复合药剂预氧化对摇蚊幼虫DBPsFP的去除控制研究

以花翅摇蚊幼虫为试验对象,研究高锰酸盐复合药剂预氧化对摇蚊幼虫代谢产物在氯化消毒过程中消毒副产物前体物的去除控制.研究表明:在p H由5升高到9时,三氯乙酸(TCAA)与二氯乙酸(DCAA)的浓度呈逐渐减少趋势;p H由5升高到7时,三氯甲烷(TCM)和三氯乙腈(TCAN)的浓度减幅最大,1,1-二氯丙酮(1,1-DCP)和1,1,1-三氯丙酮(1,1,1-TCP)则在p H为8时浓度达到最低值;随着药剂投加量的增加,TCM呈现出持续稳定增长趋势,DCAA呈总体下降趋势,而TCAN、1,1-DCP、1,1,1-TCP和TCAA则先增加后减少,高锰酸盐的投加量为3mg·L-1时,消毒副产物去除效果显著;延长预反应时间,TCM呈总体上升趋势,1,1-DCP、DCAA、TCAA呈下降趋势,TCAN、1,1,1-TCP呈先增加后减少的趋势,综合考虑最佳预氧化时间为30 min;投加混凝剂能够有效控制消毒副产物前体物的生成,随着混凝剂的不断增加,TCM、1,1,1-TCP呈先增加后减少的趋势,TCAN、1,1-DCP、DCAA、TCAA浓度则逐渐降低,在投量为40 mg·L-1时,达到最低值.     

饮用水中典型微生物消毒过程中消毒副产物的生成规律

以饮用水中典型微生物--大肠杆菌（Escherichia coli）为试验对象,研究pH值、氯化时间、氯投量及细菌浓度对大肠杆菌在氯化消毒过程中生成消毒副产物（DBPs）的影响,并分析何种氯化条件下,DBPs控制效果最佳.研究表明：随氯投量增加,二氯乙腈（DCAN）呈先上升后下降趋势;随氯化时间延长,三氯丙酮（1,1,1-TCP）和DCAN先增加后减少;在pH值从5升高到9时,1,1,1-DCP、三氯硝基甲烷（TCNM）、二氯乙酸（DCAA）和三氯乙酸（TCAA）持续降低;细菌污染水源事件在近年常有报道,当水源水中细菌浓度增加时,饮用水中三氯甲烷（TCM）、TCNM、DCAA和TCAA浓度增加,但DCAN、三氯乙腈（TCAN）、二氯丙酮（1,1-DCP）和1,1,1-TCP不一定增加.为了达到低毒性的目的,氯投量浓度不宜太高,同时控制氯化时间为6h和pH>8.     

模拟泳池水中氯化消毒副产物的生成规律

以模拟泳池水为研究对象,研究不同的氯化时间、氯投加量、pH值、反应温度条件对泳池水在氯化消毒过程中生成消毒副产物（DBPs）的影响.研究结果表明：延长氯化反应时间,二氯乙酸（DCAA）、三氯乙酸（TCAA）和三氯甲烷（TCM）的浓度不断升高,二氯乙腈（DCAN）、三氯硝基甲烷（TCNM）和1,1,1-三氯丙酮（1,1,1-TCP）的浓度则先升高再降低.DBPs浓度在氯化反应的前24h增幅较大,48h后趋于平缓;随着氯投加量的增加,DCAA、TCAA、TCM、TCNM和1,1,1-TCP浓度一直呈上升趋势,而DCAN浓度则先升高再降低.在氯投加量为2mg/L时,DBPs的浓度较低;在pH值从6升高到8的过程中,DCAA、TCAA、DCAN和1,1,1-TCP浓度先升高再降低,TCM和TCNM浓度则一直升高.pH值在6~7范围内可有效控制DBPs的形成;随着反应温度的升高,DCAA、TCAA、TCM和TCNM浓度持续升高,DCAN和1,1,1-TCP则逐渐降低.综上所述,应合理调节泳池水的氯化消毒条件,在保证舒适度的同时有效控制DBPs的生成.     

高锰酸钾预氧化对大肠杆菌DBPsFP的去除

以大肠杆菌为试验对象,采用高锰酸钾（KMnO₄）预氧化法,研究了不同的高锰酸钾浓度、氯化时间、pH值、预氧化时间及反应温度在氯化消毒过程中对大肠杆菌消毒副产物生成潜能（DBPsFP）的去除影响.研究表明：随着KMnO₄浓度的增加,二氯乙腈（DCAN）、三氯乙腈（TCAN）、1,1,1-三氯丙酮（1,1,1-TCP）及三氯乙醛（CH）浓度先降低,后升高,1,1-二氯丙酮（1,1-DCP）浓度先升高,后降低;三氯甲烷（TCM）浓度逐渐降低.在KMnO₄浓度2mg/L时,DCAN、TCAN、1,1,1-TCP浓度降至最低,对大肠杆菌DBPsFP的氧化去除效果最好;延长氯化时间,TCAN,1,1-DCP浓度逐渐升高,而DCAN,CH和1,1,1-TCP浓度先升高后降低.TCM浓度先升高后趋于稳定;pH值由5升高到9时,1,1,1-TCP、TCAN浓度不断地降低;DCAN浓度先降低,再升高;而1,1-DCP、CH浓度先升高,再降低;延长预氧化时间,TCAN、DCAN、TCM的浓度逐渐降低;1,1-DCP、1,1,1-TCP的浓度先升高,再降低;CH的浓度先升高,之后趋于稳定;随着反应温度的升高,1,1-DCP、DCAN的浓度逐渐升高;1,1,1-TCP浓度则逐渐降低;TCAN、TCM的浓度先升高再降低,而CH浓度则先降低再升高.综上,在KMnO₄浓度2mg/L,氯化时间48h,碱性条件（pH > 8）,预氧化时间30min时最有利于大肠杆菌DBPsFP的去除.     

水中典型含氮有机物氯化生成消毒副产物的潜能研究

选取了受污染原水中广泛存在的12种含氮有机物（除草剂、杀虫剂、氨基酸、工业品等）,开展了氯化和氯胺化培养生成典型消毒副产物的实验,目的是通过对水中脲类除草剂、嗪类除草剂和其他含氮化合物培养生成不同消毒副产物的生成量,讨论不同种类含氮化合物生成含碳和含氮消毒副产物规律以及考察不同消毒副产物的可能前体物.研究发现,脲类除草...     

铜均相和非均相催化氯化消毒反应研究

在不同的入水pH值条件下,考察了铜离子存在时的均相情况和铜氧化物存在时的非均相情况下,水中余氯的分解和消毒副产物的生成规律.结果表明,与不含铜的情况相比,铜的存在,无论是均相还是非均相,对余氯的分解均有促进作用.不同的pH值条件下,铜均相和非均相对挥发性氯化消毒副产物三卤甲烷(THMs)的生成和非挥发性氯化消毒副产物二氯乙酸(DCAA)和三氯乙酸(TCAA)生成的影响不同,这主要是由于pH值影响了水中可溶性铜离子的浓度造成的.随着pH值的升高,在铜均相和非均相催化下,水中可溶性铜离子的浓度均降低.可溶性铜离子的浓度会影响水中消毒副产物的生成.对于挥发性氯化消毒副产物THMs来说,当铜离子浓度小于2.5 mg·L-1时,随着铜离子浓度增加,对THMs生成的促进作用加强;当铜离子浓度大于2.5 mg·L-1后,对THMs生成的促进作用减弱;对于非挥发性氯化消毒副产物DCAA和TCAA,随着铜离子浓度增加,DCAA的生成量逐渐增加,TCAA的生成量逐渐减少.     

我国地表水中典型DBPs的暴露水平及生态风险

氯消毒过程中可能生成有毒有害的副产物,会对水生态系统和环境健康产生直接和间接的次生危害.三卤甲烷（THMs）和卤乙酸（HAAs）是地表水中检出率最高的消毒副产物（DBPs）,其毒性效应受到广泛关注.本文检索整理了三氯甲烷（TCM）、三溴甲烷（TBM）、二氯乙酸（DCAA）和三氯乙酸（TCAA）在我国地表水暴露浓度和对水生生物的毒性效应浓度,了解我国重点流域地表水环境中TCM、TBM、DCAA和TCAA的浓度水平,分别利用急、慢性毒性数据推导预测无效应浓度（PNEC）,并使用风险商（RQ）和概率生态风险评价法（PERA）对我国重点流域水环境中TCM、TBM、DCAA和TCAA进行多层次生态风险评估.结果表明,我国地表水环境中TCM、TBM、DCAA和TCAA暴露浓度范围为n.d.~51μg/L.以致死和生长、繁殖等为测试终点的急、慢性毒性数据,构建物种敏感度分布（SSD）曲线,推导出TCM、TBM、DCAA和TCAA的PNEC值分别为0.586,0.857,0和44.880mg/L;0.006,0.064,0.956和0.012mg/L.基于急、慢性毒性数据计算出的RQ小于1.我国重点流域中TCM和TCAA对1%的水生生物造成生长、繁殖等慢性毒性影响的概率分别为78.86%和20.61%,存在潜在的生态风险.     

Fatty acids and algal lipids as precursors of chlorination by-products

Six common algal fatty acids (FAs) with different numbers of double bonds, lipophilic fractions and proteins extracted from the diatom Navicula pelliculosa and algal cells were chlorinated to evaluate their potential in generating disinfection by-products (DBPs). The result showed that the more double bonds in the FAs, the higher the amounts of chloroform and dichloroacetic acid (DCAA) produced, but such a pattern was not observed for trichloroacetic acid (TCAA). Based on the previously reported composition of fatty acids in algal lipids, the DBP generation potentials of algal lipids were calculated. These predicted values were much lower than those measured in the chlorinated algal lipophilic fraction, suggesting unknown lipophilic fraction(s) served as potent DBPs precursors. Another calculation attempted to predict DBP production in algal cells based on algal lipid and protein composition, given quantified measured DBP production per unit algal lipid and proteins. The analysis showed that the observed DBP production was similar to that predicted (< 35% difference), suggesting that algal biochemical compositions may serve as a bioindicator for preliminary estimation of chloroform, DCAA and TCAA formation upon chlorinating algae.     

饮用水处理中活性炭吸附卤乙酸的特性

采用静态和动态试验研究了活性炭对卤乙酸的物理吸附特性。静态试验表明：在单吸附质条件下,二氯乙酸和三氯乙酸的吸附等温线在低浓度区（Ｃｅ〈５０μｇ／Ｌ）表现为单层吸附,在高浓度区表现为多层吸附。活性炭对三氯乙酸的吸附能力高于二氯乙酸。在饮用水处理常见的浓度范围内,活性炭对三氯乙酸的吸附容量约为二氯乙酸的２倍。在多吸附质条件下,对三氯乙酸的吸附容量只略的降低,对二氯乙酸的吸附容量则显著下降,这与有机物的     

南水北调丹江口水库水氯(胺)化消毒副产物产生特性与消毒工艺对比

系统研究了南水北调中线工程水源——丹江口水库水在氯(胺)化消毒条件下,常规消毒副产物的产生特性,考察了消毒方式、消毒剂投加量、接触时间、p H和溴离子浓度等因素的影响,并对消毒工艺参数进行了优化.结果发现,丹江口水库水经氯化消毒可产生三氯甲烷、二氯一溴甲烷等常规含碳和较低浓度二氯乙腈、三氯硝基甲烷等含氮消毒副产物,而氯胺化消毒仅产生三氯甲烷和三氯硝基甲烷等消毒副产物(disinfection by-products,DBPs).自由氯消毒过程产生的各类型DBPs浓度约为氯胺消毒的7.5倍,短时自由氯转氯胺方式DBPs产生量介于两者之间;随着自由氯投加量增加,各类型消毒副产物均呈现增加趋势,投加量大于2 mg·L-1后DBPs增加量较少.随氯胺投加量增加,三氯甲烷生成量变化不大,投加量大于2mg·L-1后可产生三氯硝基甲烷等副产物.随反应时间延长,自由氯的衰减速率明显大于氯胺,同时消毒副产物增长量明显快于氯胺消毒.随着p H升高,自由氯消毒后三卤甲烷含量呈现增加趋势,而氯胺消毒后变化不明显.随溴离子浓度的增加,自由氯和氯胺消毒后副产物类型均向溴代DBPs转变,同时总生成量明显增加,自由氯消毒DBPs增长量明显大于氯胺消毒过程.丹江口水库水采用氯胺化消毒可以降低消毒副产物的生成风险,如采用自由氯消毒方式,水厂需根据实际常规处理工艺重点控制自由氯的投加量等参数.     

Characterization of disinfection byproduct formation potential in 13 source waters in China

The formation potential of four trihalomethanes (THMFP) and seven haloacetic acids (HAA7FP) in 13 source waters taken from four major water basin areas in China was evaluated using the simulated distribution system (SDS) chlorination method. The specific ultraviolet absorbance (SUVA254: the ratio of UV254 to dissolved organic carbon (DOC)), which ranged between 0.9 and 5.0 L/(mg m), showed that the organic compounds in di erent source waters exhibited di erent reactivities with chlorine. The HAA7FP of source waters ranged from 20 to 448 g/L and the THMFP ranged from 29 to 259 g/L. The HAA7FP concentrations were higher than the THMFP concentrations in all but one of the samples. Therefore, the risks of haloacetic acids (HAAs) should be of concern in some source waters. TCM (chloroform) and BDCM (bromodichloromethane) were the major THM constituents, while TCAA (trichloroacetic acid) and DCAA (dichloroacetic acid) were the major HAA species. Br-THM (brominated THM species) were much higher than Br- HAA (brominated HAA species), and the formation of Br-DBP (Br-THM and Br-HAA) should be of concern when the bromide concentration is over 100 g/L.     

高藻水臭氧预氧化过程有机物转化及消毒副产物生成势

研究了高藻水预氧化处理过程中,不同臭氧氧化程度及不同pH值条件下,藻类有机物释放与转化规律以及氯化消毒副产物(DBPs)的生成特性.结果表明,臭氧投加量为28.92 mg·L-1时藻去除率达36%.随着臭氧投加量的增加,藻的去除率进一步增加,类腐殖酸先增加后持续减少,溶解性微生物代谢产物、类富里酸和类芳香蛋白物质持续减少;低投加量的臭氧对二氯乙腈(DCAN)、三氯乙腈(TCAN)生成势有明显的控制作用,但会增加三氯硝基甲烷(TCNM)以及1,1,1-三氯丙酮(1,1,1-TCP)前体物,随臭氧投加量增大,DBPs生成势显著增大.酸性条件下臭氧对藻的去除效果最好,UV254以及总有机碳(DOC)均随pH的增大有所上升,但变化较小;臭氧氧化可降解溶解性微生物代谢产物,降解效果受pH影响较小,类腐殖酸有机物随pH值增大而减少;DCAN、TCAN生成势随pH增大有所降低,TCNM生成势在pH=10条件下最高,1,1,1-TCP生成势在pH=7条件下最高.     

膜生物反应器处理城市污水的后续次氯酸钠消毒研究

针对膜生物反应器（membrane bioreactor,MBR）处理城市污水的后续次氯酸钠消毒,分别开展了不同氯的投加剂量对指示微生物（总大肠菌群和粪大肠菌群）的灭活效果、消毒副产物（disinfection by-products,DBPs）生成量以及消毒后出水发光菌急性毒性研究.结果表明,在工程应用中MBR处理工...     

Formation potentials of typical DBPs and changes of genotoxicity for chlorinated tertiary effluent pretreated by ozone

The effects of ozonation on the formation potential of typical disinfection byproducts (DBPs) and the changes of genotoxicity during post chlorination of tertiary effluent from a sewage treatment plant were investigated. Ozonation enhanced the yields of all detected chlorine DBPs except CHCl3. At a chlorine dose of 5 mg/L, the three brominated THMs and five HAAs increased, while chloroform decreased with the increase of ozone dose from 0 to 10 mg/L (ozone dose in consumption base). At a chlorine dose of 10 mg/L, the two mixed bromochloro species THMs and two dominant HAAs (DCAA and TCAA) firstly increased and then decreased with the increase of ozone dose, with the turning point approximately occurring at an ozone dose of 5 mg/L. The genotoxicity detected using umu test, on the other hand, was removed from 7 μg 4-NQO/L to a negligible level by ozonation under an ozone dose of 5 mg/L. Chlorination could further remove the genotoxicity to some extent. It was found that SUVA (UV absorbance divided by DOC concentration) might be used as an indicative parameter for monitoring the removal of genotoxicity during the oxidation.     

氯酚类化合物对紫背浮萍生长及叶绿素含量的影响

以我国本土水生植物紫背浮萍为受试物种,利用其生长抑制和叶绿素含量的变化评价了3种氯酚类化合物的毒性效应.结果显示:2,4-二氯酚(2,4-DCP), 2,4,6-三氯酚(2,4,6-TCP)和五氯酚(PCP)对紫背浮萍的96h IC50值分别为12.73,8.49,1.12mg/L.根据化学物质对水生生物毒性分级标准,3种物质均为高毒.2,4-DCP,2,4,6-TCP和PCP对紫背浮萍基于叶绿素含量变化的最大可接受浓度(MATC)分别为2.24,1.58, 0.35mg/L,对应的急慢性毒性比(ACR)分别为5.68,5.37和3.20.     

Formation potentials of typical disinfection byproducts and changes of genotoxicity for chlorinated tertiary e uent pretreated by ozone

The effects of ozonation on the formation potential of typical disinfection byproducts (DBPs) and the changes of genotoxicity during post chlorination of tertiary effluent from a sewage treatment plant were investigated. Ozonation enhanced the yields of all detected chlorine DBPs except CHCl3. At a chlorine dose of 5 mg/L, the three brominated THMs and five HAAs increased, while chloroform decreased with the increase of ozone dose from 0 to 10 mg/L (ozone dose in consumption base). At a chlorine dose of 10 mg/L, the two mixed bromochloro species THMs and two dominant HAAs (DCAA and TCAA) firstly increased and then decreased with the increase of ozone dose, with the turning point approximately occurring at an ozone dose of 5 mg/L. The genotoxicity detected using umu test, on the other hand, was removed from 7 μg 4-NQO/L to a negligible level by ozonation under an ozone dose of 5 mg/L. Chlorination could further remove the genotoxicity to some extent. It was found that SUVA (UV absorbance divided by DOC concentration) might be used as an indicative parameter for monitoring the removal of genotoxicity during the oxidation.     

Enhanced ozonation of dichloroacetic acid in aqueous solution using nanometer ZnO powders

Nanometer zinc oxide (ZnO) powders were used as a catalyst to enhance the ozonation for the degradation of dichloroacetic acid (DCAA) in aqueous solution. The batch experiments were carried out to investigate the e ects of key factors such as catalyst dosage, ozone dosage, solution pH and tert-butyl alcohol (t-BuOH) on the degradation e ciency of DCAA. Density functional theory (DFT) was adopted to explore the mechanism of generating hydroxyl radical (.OH) on the ZnO surface. The results showed that adsorption and ozonation processes were not e ective for DCAA removal, and the addition of ZnO catalyst improved the degradation e ciency of DCAA during ozonation, which caused an increase of 22.8% for DCAA decomposition compared to the case of ozonation alone after 25 min. Under the same experimental conditions, the DCAA decomposition was enhanced by increasing catalyst dosage from 100 to 500 mg/L and ozone dosage from 0.83 to 3.2 mg/L. The catalytic ozonation process is more pronounced than the ozonation process alone at pH 3.93, 6.88, and 10. With increasing the concentration of t-BuOH from 10 to 200 mg/L, the degradation of DCAA was significantly inhibited in the process of catalytic ozonation, indicating that ZnO catalytic ozonation followed .OH reaction mechanism. Based on the experimental results and DFT analysis, it is deduced that the generation of .OH on the ZnO surface is ascribed to the adsorption of molecule ozone followed by the interaction of adsorbed ozone with active sites of the catalyst surface. It is also concluded that ZnO may be an e ective catalyst for DCAA removal, which could promote the formation of .OH derived from the catalytic decomposition of ozone.     

羟基氧化铁催化臭氧氧化对滤后水卤乙酸生成势的影响

考察了滤后水经过单独臭氧氧化和羟基氧化铁(FeOOH)催化臭氧氧化后5种卤乙酸生成势(HAA5FP)的生成情况.研究了氧化时间、溴离子浓度、滤后水pH值、碱度和O3投量对2种氧化方式下HAA5FP的影响规律.发现该滤后水氯化后的HAA种类为二氯乙酸(DCAA)、三氯乙酸(TCAA)及溴离子存在时有二溴乙酸(DBAA).无溴离子存在时,催化臭氧氧化在5～20min内使得HAA5FP比臭氧氧化后的降低9.5%～18.3%.溴离子浓度增加使HAA5FP减少,催化臭氧氧化后HAA5FP也比臭氧氧化后低更多.中性pH时,催化臭氧氧化比臭氧氧化有更明显的控制HAA5FP的优势.重碳酸盐碱度升高使HAA5FP降低,且2种氧化后HAA5FP的差别减小.O₃/TOC比值为0.45～1.43的臭氧投量范围内,催化臭氧氧化后HAA5FP比臭氧氧化后减少11.2%～28.0%.催化臭氧氧化对滤后水HAA5FP的影响与FeOOH催化臭氧生成羟基自由基的特点密切相关.     

Pd/Ti电极上2,4,6-三氯酚还原脱氯:条件优化及降解途径

利用电沉积法制备了Pd/Ti电极,用于2,4,6-三氯酚(2,4,6-TCP)的电还原脱氯.采用单因素实验和响应面分析法,探讨了2,4,6-TCP脱氯试验条件;根据实验结果,拟合出了脱氯中各步骤的反应速率常数.结果表明,2,4,6-TCP初始浓度为80mg/L时,优化的脱氯参数为电流为5mA,支持电解质Na2SO4浓度为0.05mol/L,阴极电解液初始pH值为2.40.在优化条件下, 2,4,6-TCP在80min内完全脱氯; 2,4,6-TCP的还原脱氯符合准一级反应动力学,主要脱氯途径为2,4,6-TCP→2,6-DCP→2-CP→苯酚.