磁性CeO2-Fe3O4复合材料光催化/吸附去除水中As(III)

原水砷污染问题严重威胁饮用水水质安全,随着生活饮用水标准的提高,致使多地饮用水中砷超标问题突显.本研究利用CeO₂半导体的光催化活性及CeO₂和Fe₃O₄对As（V）的强亲和力,合成了双组份磁性CeO₂-Fe₃O₄复合材料,并采用SEM、XRD、BET和VSM等手段进行表征,考察复合材料的光催化/吸附除砷效果;研究了初始pH值、共存离子等因素对吸附除砷效果的影响;采用等温吸附模型、吸附动力学模型等手段进行吸附特性研究.实验结果表明,在光催化过程中,·OH和·O₂^-为主要的活性氧化物种.在紫外照射下,As（Ⅲ）能完全被氧化为毒性较低的As（V）,同时将As（V）高效吸附于CeO₂-Fe₃O₄粒子表面.在中性条件下,CeO₂-Fe₃O₄粒子对砷的饱和吸附量为122.19 mg·g^-1.共存离子Cl^-和SO₄^2-对As（V）的吸附没有显著影响,而CO₃^2-、SiO₃^2-和PO₄^3-与As（V）存在明显的竞争吸附,使As（V）的吸附去除效果明显降低.吸附动力学和吸附等温线模拟分别符合准二级动力学方程和Freundlich吸附等温线,表明As（V）的吸附以化学吸附为主导.CeO₂-Fe₃O₄复合吸附剂可快速实现固液分离,容易再生且重复利用性较好,具有广泛的应用前景.     

锰铁复合磁性材料制备及其对零价汞吸附性能研究

燃煤工业是我国人为汞排放的主要来源,寻求合理有效的途径来控制汞排放至关重要.本文将氧化性强的过渡金属锰离子引入Mn/γ-Fe₂O₃晶格中,制备出锰铁复合磁性材料（Fe_3-xMn_x）_1-δO₄,以其来模拟Hg⁰在燃煤废气中的吸附过程,并通过比表面积和孔隙率、X衍射分析、SEM、磁性分析、氧化还原等材料表征方法研究（Fe_3-xMn_x）_1-δO₄的吸附性能,同时重点研究（Fe_3-xMn_x）_1-δO₄在不同掺杂量、温度、空速等操作条件下对Hg⁰的吸附能力.结果显示,制备所得的（Fe_3-xMn_x）_1-δO₄的比表面积均在120 m²·g^-1以上,较大的比表面积和孔体积可以为Hg⁰的吸附反应提供更多的活性区域,促进反应进行.SEM表征也显示（Fe_3-xMn_x）_1-δO₄的微观特征呈现球状颗粒物,拥有较大的表面积,能够提供更多的吸附活性位.在磁性铁氧化物中引入过渡金属锰,其对汞的氧化能力明显增强;在100~200℃的反应温度窗口,此时温度大小与（Fe_3-xMn_x）_1-δO₄对汞的吸附能力成正比,达到200℃时,500 min内平均穿透率可达到9%;空速对（Fe_3-xMn_x）_1-δO₄吸附汞的能力影响较小.     

改性活性炭除亚砷酸盐的性能研究

制备了2种负载铁锰氧化物的改性活性炭（FM-GAC-1、FM-GAC-2）并研究其对水中的亚砷酸盐的去除性能.考察了2种改性活性炭除三价砷的吸附等温线、反应动力学及pH、温度、水中共存离子对其去除三价砷的影响,发现FM-GAC-1和FM-GAC-2对三价砷均有较好的去除效果,吸附容量分别为32.37、 26.67 mg·g^-1.吸附速率符合拟二级反应动力学,化学反应控制过程是改性活性炭除砷的限速步骤.pH值偏酸性有利于吸附的进行,温度升高,吸附容量有所下降,该吸附过程是自发的放热过程.同时,水体中的共存阴离子在其浓度值为三价砷的200倍时,SiO^2-₃、 PO^2-₃、NO^-₃对FM-GAC-1吸附三价砷有明显影响; SiO^2-₃、CO^2-₃对FM-GAC-2吸附三价砷有显著影响.总体上讲,FM-GAC-1较FM-GAC-2有更为优异的去除三价砷性能.     

活性炭纤维对活性染料的吸附动力学研究

研究了活性炭纤维从水溶液中吸附4种活性染料（活性艳红K-2BP、活性翠蓝KN-G、活性金黄K-3RP、活性黑KN-B）的吸附特性,从动力学角度探讨了吸附机理.结果表明,活性炭纤维对4种染料的平衡吸附量q_e均随着初始浓度和温度的增加而升高,相同条件下,q_e的大小顺序为：活性艳红＞活性金黄＞活性黑＞活性翠蓝.吸附过程符合伪二级吸附速率方程,染料分子的空间结构、大小和极性是影响初始吸附速率的主要因素.活性炭纤维对4种染料的吸附活化能都比较低,依次为16 .42、3 .56、5 .21和26 .38 kJ·mol^-1,说明吸附过程以物理吸附为主.     

不同铁源对剩余污泥厌氧系统中蓝铁石生成的影响

以污水处理厂剩余污泥为研究对象,污泥经酸/碱预处理（pH=3.0/pH=10.0）后,分别以FeOOH、FeCl₃及Fe₂O₃为外加铁源,进行厌氧发酵,探究铁源对厌氧系统中蓝铁石晶体生成的影响.结果表明：FeCl₃和FeOOH可以高效地被还原为Fe²⁺,其铁还原效率（E_Fe）最高为56.24%~80.10%,且酸处理效果优于碱处理（3.00%~13.31%）,而Fe₂O₃的E_Fe相对较低,最高分别为31.94%（pH=3.0）和50.1%（pH=10.0）.FeOOH和Fe₂O₃的投加,可促进胞外聚合物（EPS）中蛋白质含量的提升,增强胞外电子传递能力,但Fe₂O₃因其结晶度高,阻碍了铁还原微生物对铁源的利用,导致铁还原效率低.上清液PO₄^3-浓度、污泥Fe-P比例与E_Fe呈负相关,E_Fe越高则PO₄^3-浓度、Fe-P比例越低.FeOOH组上清液PO₄^3-浓度下降幅度最大,反应第9 d PO₄^3-浓度最低,仅为对照组的10.30%（pH=3.0）和17.20%（pH=10.0）,其次是FeCl₃组（22.83%/27.87%）,Fe₂O₃组最终剩余较多PO₄^3-（65.02%/56.33%）;FeOOH、FeCl₃和Fe₂O₃酸/碱组的Fe-P比例分别为32.19%/21.20%、34.41%/23.09%和20.92%/11.99%.铁源的添加提高了污泥的磷回收率（R_p）,并且酸预处理效果优于碱处理,其中FeCl₃组R_p最高,是对照组的2.91倍,其次是FeOOH组（2.63倍）和Fe₂O₃组（2.12倍）.XRD分析表明,FeOOH和FeCl₃酸/碱预处理组均生成了蓝铁石晶体.     

AMD污泥复合材料吸附As (Ⅴ)的机制及其影响因素

污泥基吸附剂被广泛用于水和土壤中各种污染物的治理,是资源化利用的有效途径.以酸性矿山废水（AMD）污泥为骨料,玉米秸秆为还原剂,膨润土为载体,采用固相还原法制备污泥复合材料,并比较了不同原料配比和不同煅烧温度制备的复合材料吸附As （Ⅴ）的性能,探究了溶液pH、吸附剂投加量和竞争离子等对材料吸附As （Ⅴ）的影响,使用SEM-EDS、XRD、FT-IR、BET和XPS等分析技术对材料性能进行表征,探讨其吸附机制.结果表明,在900℃时AMD污泥：玉米秸秆：膨润土=2 ：1 ：1制备出的材料吸附As （Ⅴ）效果最好,材料表面生成大量Fe₃O₄、Fe₂ O₃和Fe⁰颗粒.该材料对As （Ⅴ）的吸附符合准二级动力学模型和Freundlich吸附等温模型,最大吸附容量为164.5mg ·g^-1,比原始AMD污泥提高了4.4倍.静电吸附、含氧官能团络合作用、铁氧化层的吸附和Fe⁰释放出Fe²⁺/Fe³⁺形成Fe （OH）₂/Fe （OH）₃,与砷酸盐的共沉淀等是复合材料吸附As （Ⅴ）的主要作用机制.     

Ni2+生物吸附动力学及吸附平衡研究

研究了金属离子Ni²⁺在酿酒酵母上的生物吸附特性,内容包括生物吸附动力学和吸附等温线.生物吸附动力学结果表明,当Ni²⁺初始浓度为65.6 mg/L时,Ni²⁺在酿酒酵母上的生物吸附可以分为2个阶段,第1阶段为物理吸附,在10　min内快速达到平衡.Ni²⁺在酵母上的吸附过程可以很好地用准二级动力学方程来描述 （R²=0.999）,动力学参数k₂为0.018 4 g/(mg·min),q_e为5.96 　mg/g.吸附等温线结果表明,Ni²⁺在酿酒酵母上的生物吸附可以用Langmuir和Freundlich方程来描述,最大吸附量q_max为6.32 　mg/g.酿酒酵母可用于处理低浓度的含Ni²⁺废水.     

有机改性蒙脱土对萘的吸附机制和影响因子

我国场地土壤中多环芳烃（PAHs）污染或PAHs-重金属复合污染是常见的污染类型,对公众健康与环境构成巨大威胁.本研究利用耗散型石英晶体微天平（QCM-D）技术和批量吸附实验,探究实验室制备的2种有机改性黏土对萘的吸附机制,以及萘与Cu²⁺共存时黏土颗粒吸附情况.结果表明,25℃时,十六烷基三甲基溴化铵改性蒙脱土（CTAB-SMF）的吸附等温线符合Freundlich模型（R²>0.92,n>1）,说明其对萘的吸附位点具有多样性,在较高萘平衡浓度（c_e=1 mmol ·L^-1）下吸附分配系数K_d为SMF的13.4倍;3-巯基丙基三甲氧基硅烷改性蒙脱土（TMSP-SMF）的吸附等温线符合Langmuir模型（R²>0.96）,在较高萘平衡浓度（c_e=1 mmol ·L^-1）下吸附分配系数K_d为SMF的1.14倍.说明2种有机改性黏土对萘的吸附效果优于SMF颗粒.3种黏土颗粒对萘的吸附焓在-30~-10 kJ ·mol^-1之间,均为自发物理吸附.溶液离子强度升高抑制了SMF吸附萘,但对改性黏土吸附萘无显著影响.萘平衡浓度较低（c_e=0.1 mmol ·L^-1）时,Cu²⁺的存在使TMSP-SMF对萘的吸附效果增加了3倍;同时萘能促进2种改性黏土对Cu²⁺的吸附.本研究通过原位在线QCM-D检测了黏土对萘的吸附机制,结果与批量吸附实验结果一致：CTAB-SMF对萘的吸附位点主要为黏土层间的改性剂基团,TMSP-SMF则位于黏土颗粒表面的改性剂基团.本项研究结果显示,QCM-D技术是一种有效的原位在线表征黏土膜吸附有机污染物的方法,2种有机改性的黏土颗粒可作为应用于PAHs或PAHs-重金属复合污染场地的修复材料.     

锰氧化物负载施氏矿物去除酸性矿山废水中As(III)的性能及机理

施氏矿物是天然的砷吸附剂,但其存在酸性条件下对As(III)吸附性能较弱且无法对As(III)氧化降毒的缺陷. 采用液相沉淀法成功制备出锰氧化物负载施氏矿物(MnO_x@Sch),研究锰负载量、初始pH值和共存离子对MnO_x@Sch去除As(III)的影响,并采用吸附动力学结合XPS、FTIR及TEM等表征探究该过程的机理. 结果表明:在初始pH=3、投加量为0.5 g·L^-1、As(III)初始浓度为1 mg·L^-1的条件下,As(III)与MnO_x@Sch反应后的剩余浓度仅为2.42~3.38 μg·L^-1.MnO_x@Sch去除As(III)受初始pH影响较小,H₂PO₄^-共存时As(III)去除存在明显的抑制作用. MnO_x@Sch 去除As(III)的过程符合准二级动力学方程和颗粒内扩散方程. 液相化学组分和固相产物表征分析显示MnO_x@Sch对As(III)的去除机理可概括为As(III)氧化、静电吸附和络合配位及配体交换. 研究结果可为施氏矿物及其改性材料应用于酸性矿山废水砷污染治理提供理论依据.     

纳米Fe3O4负载的浮游球衣菌去除重金属离子的工艺研究

以纳米Fe₃O₄负载浮游球衣菌（Sphaerotilus natans）制备复合生物吸附剂,对此吸附剂进行表征并考察了其吸附水中重金属离子的性能.红外光谱分析表明,此复合生物吸附剂表面的主要活性基团为酰胺基（—CONH—）和羟基（—OH）.吸附性能研究表明,菌含量和流量是影响复合生物吸附剂吸附重金属离子的主要因素,在Cu²⁺初始浓度c₀<20 mg/L,菌含量1.5 g/L（菌/ Fe₃O₄＝3∶2）,流量0.96 L/h 时吸附剂对Cu²⁺的吸附效果最好;用稀盐酸对复合生物吸附剂进行再生,吸附剂可重复使用10次以上,再生液可重复使用3次; 吸附选择性为：Pb²⁺ > Cu²⁺ > Zn²⁺>Cd²⁺.     

Effects of two sludge application on fractionation and phytotoxicity of zinc and copper in the soil

The potential harm of heavy metals is a primary concern in application of sludge to the agricultural land. A pot experiment was conducted to evaluate the effect of two sludges on fractionation of Zn and Cu in soil and their phytotoxicity to pakchoi. The loamy soil was mixed with 0%, 20%, 40%, 60% and 80% (by weight) of digested sewage sludge (SS) and composted sludge (SC). The additions of both sludges caused a significant raise in all fractions, resulting in that exchangeable (EXCH) and organic bound (OM) became predominance of Zn and organic bound Cu occupied the largest portion. There was more available amount of Zn and Cu in SS treatments than SC treatments. During the pot experiment, the concentration of Zn in EXCH, carbonate (CAR) and OM and Cu in EXCH and OM fractions decreased in all treatments, so their bioavailability reduced. Germination rate and plant biomass decreased when the addition rate was high and the best yield appeared in 20% mixtures at the harvest of pakchoi. The two sludges increased tissue contents of Zn and Cu especially in the SS treatments. Zn in pakchoi was not only in relationship to ΔEXCH and ΔCAR forms but also in ΔOM forms in the sludge-soil mixtures. Tissue content of Cu in pakchoi grown on SC-soils could not be predicted by ΔEXCH. These correlation rates between Zn and Cu accumulation in pakchoi and variation of different fractions increased with time, which might indicate that sludges represented stronger impacts on the plant in long-term land application.     

Intraspecific differences in effects of co-contamination of cadmium and

A hydroponic experiment was carried out to study intraspecific differences in the effects of different concentrations of cadmium (Cd)(0-10 mg/L) and arsenate (As(V)) (0-8 mg/L) on the growth parameters and accumulation of Cd and As in six wheat varieties Jing-9428, Duokang-1, Jingdong-11, Jing-411, Jingdong-8 and Zhongmai-8. The endpoints of wheat seedlings, including seed germination,biomass, root length and shoot height, decreased with increasing the Cd and As concentrations. Significant differences in seed germination, biomass, root length, shoot height and the accumulation of Cd and As were observed between the treatments and among the varieties (p ＜ 0.05). The lethal dosage 50% were about 20, 80, 60, 60, 80 and 20 mg As/L for Jing-9428, Duokang-1, Jingdong-11,Jing-411, Jingdong-8 and Zhongmai-8, respectively, and the corresponding values for Cd were about 30, 80, 20, 40, 60 and 10 mg Cd/L, respectively. Among the six varieties, Duokang-1 was found to be the most resistant to Cd and As toxicity, and Zhongmai-8 was the most sensitive to Cd and As co-contamination. The resistance of the six varieties was found dependant on the seedling uptake of Cd and As. Duokang-1 was the most suitable for cultivation in Cd and As co-contaminated soils.     

Toxic effects of acetochlor, methamidophos and their combination on nifH gene in soil

Toxic effects of two agrochemicals on nifH gene in agricultural black soil were investigated using denaturing gradient gel electrophoresis （DGGE） and sequencing approaches in a microcosm experiment. Changes of soil nifH gene diversity and composition were examined following the application of acetochlor, methamidophos and their combination. Acetochlor reduced the nifH gene diversity （both in gene richness and diversity index values） and caused changes in the nifH gene composition. The effects of acetochlor on nifH gene were strengthened as the concentration of acetochlor increased. Cluster analysis of DGGE banding patterns showed that nifH gene composition which had been affected by low concentration of acetochlor （50 mg/kg） recovered firstly. Methamidophos reduced nifH gene richness that except at 4 weeks. The medium concentration of methamidophos （150 mg/kg） caused the most apparent changes in nifH gene diversity at the first week while the high concentration of methamidophos （250 mg/kg） produced prominent effects on nifH gene diversity in the following weeks. Cluster analysis showed that minimal changes of nifH gene composition were found at 1 week and maximal changes at 4 weeks. Toxic effects of acetochlor and methamidophos combination on nifH gene were also apparent. Different nifH genes （bands） responded differently to the impact of agrochemicals： four individual bands were eliminated by the application of the agrochemicals, five bands became predominant by the stimulation of the agrochemicals, and four bands showed strong resistance to the influence of the agrochemicals. Fifteen prominent bands were partially sequenced, yielding 15 different nifH sequences, which were used for phylogenetic reconstructions. All sequences were affiliated with the alpha- and beta-proteobacteria, showing higher similarity to eight different diazotrophic genera.     

Arsenic uptake by arbuscular mycorrhizal maize （Zea mays L.） grown in an arsenic-contaminated soil with added phosphorus

The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As) uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment.Non-mycorrhizal and zero-P addition controls were included.Plant biomass and concentrations and uptake of As,P,and other nutrients,AM colonization,root lengths,and hyphal length densities were determined.The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium.Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments,but shoot and root biomass of AM plants was depressed by P application.AM fungal inoculation decreased shoot As concentrations when no P was added,and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition,respectively.Shoot and root uptake of P,Mn,Cu,and Zn increased,but shoot Fe uptake decreased by 44.6%,with inoculation, when P was added.P addition reduced shoot P,Fe,Mn,Cu,and Zn uptake of AM plants,but increased root Fe and Mn uptake of the nonmycorrhizal ones.AM colonization therefore appeared to enhance plant tolerance to As in low P soil,and have some potential for the phytostabilization of As-contaminated soil,however,P application may introduce additional environmental risk by increasing soil As mobility.     

Degradation of metabolites accumulated of benzo[a]pyrene by coupling Penicillium Chrysogenum with KMnO4

Several main metabolites of benzo[a]pyrene （BaP） formed by Penicillium chrysogenum, Benzo[a]pyrene-1,6-quinone （BP 1,6- quinone）, trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene （BP 7,8-diol）, 3-hydroxybenzo[a]pyrene （3-OHBP）, were identified by high-performance liquid chromatography （HPLC）. The three metabolites were liable to be accumulated and were hardly further metabolized because of their toxicity to microorganisms. However, their further degradation was essential for the complete degradation of BaP. To enhance their degradation, two methods, degradation by coupling Penicillium chrysogenum with KMnO4 and degradation only by Penicillium chrysogenum, were compared; Meanwhile, the parameters of degradation in the superior method were optimized. The results showed that （1） the method of coupling Penicillium chrysogenum with KMnO4 was better and was the first method to be used in the degradation of BaP and its metabolites; （2） the metabolite, BP 1,6-quinone was the most liable to be accumulated in pure cultures; （3） the effect of degradation was the best when the concentration of KMnO4 in the cultures was 0.01% （w/v）, concentration of the three compounds was 5 mg/L and pH was 6.2. Based on the experimental results, a novel concept with regard to the bioremediation of BaP-contaminated environment was discussed, considering the influence on environmental toxicity of the accumulated metabolites.     

Impact of atrazine and nitrogen fertilizers on the sorption of chlorotoluron in soil and model sorbents

Sorption of chlorotoluron in ammonium sulfate, urea and atrazine multi-solutes system was investigated by batch experiments. The results showed application of nitrogen fertilizers to the soil could affect the behavior of chlorotoluron. At the same concentration of N, sorption of chlorotoluron decreased as the concentration of atrazine increased on the day 0 and 6 in soil, respectively. The sorption of chlorotoluron increased from 0 to 6 d when soils were preincubated with deionized water, ammonium sulfate and urea solution for 6 d. That indicated incubation time was one of the most important factors for the sorption of chlorotoluron in nitrogen fertilizers treatments. The individual sorption isotherms of chlorotoluron in rubbery polymer and silica were strictly linear in single solute system, but there were competition sorption between pesticides or between pesticides and nitrogen fertilizers. That indicated the sorption taken place by concurrent solid-phase dissolution mechanism and sorption on the interface of water-organic matter or water-mineral matter.     

Distribution and ecological effect of mercury in Laogang landfill, Shanghai, China

Laogang landfill near Shanghai is the largest landfill in China, and receives about 10000 t of daily garbage per day, Samples of topsoil and plants were analyzed to evaluate mercury pollution from the landfill. For topsoil samples, there were significant correlations among total mercury （HgT）, combinative mercury （Hgc） and gaseous mercury （HgG）, and content of total organic carbon （TOC）, but, no significantly relationship was found between Hg content and filling time. Hg content changes in vertical profiles with time showed that the average Hgv of profiles 1992, 1996, and 2000 was similar, but their average HgG was quite different. HgT was significantly correlated with Hgc in profile 1992 and 2000, and Hgv was significantly correlated with Hg6 in profile 1996. HgG/Hgv ratio in profile samples decreased in the order of （HgG,/HgT）1992〉（HgG/HgT）1996〉〉（HgG/HgT）2000. A simple outline of Hg release in landfill could be drawn： with increasing of filling time, degradation undergoes different biodegradation, accordingly, gaseous mercury goes through small, more, and small proportion to total mercury. Distribution of Hg in plants was inhomogeneous, following the order of leaf〉root〉stem. The highest value of leaf may be associated with higher atmospheric Hg from landfill. Ligneous plants （e.g. Phyllostachys glanca, Prunus salicina and Ligustrum lucidum） are capable of enriching more Hg than herbaceous plants.     

EDTA-enhanced phytoremediation of lead contaminated soil by Bidens maximowicziana

Phytoremediation is a potential cleanup technology for the removal of heavy metals from contaminated soils.Bidens maximowicziana is a new Pb hyperaccumulator,which not only has remarkable tolerance to Pb but also extraordinary accumulation capacity for Pb.The maximum Pb concentration was 1509.3 mg/kg in roots and 2164.7 mg/kg in overground tissues.The Pb distribution order in the B. maximowicziana was:leaf>stem>root.The effect of amendments on phytoremediation was also studied.The mobility of soil Pb and the Pb concentrations in plants were both increased by EDTA application.Compared with CK(control check),EDTA application promoted translocation of Pb to overground parts of the plant.The Pb concentrations in overground parts of plants was increased from 24.23-680.56 mg/kg to 29.07-1905.57 mg/kg.This research demonstrated that B.maximowicziana appeared to be suitable for phytoremediation of Pb contaminated soil,especially,combination with EDTA.     

Potential of plant polyphenol oxidases in the decolorization and removal of textile and non-textile dyes

In this study an effort has been made to use plant polyphenol oxidases; potato （Solanum tuberosum） and brinjal （Solanum melongena）, for the treatment of various important dyes used in textile and other industries. The ammonium sulphate fractionated enzyme preparations were used to treat a number of dyes under various experimental conditions. Majority of the treated dyes were maximally decolorized at pH 3.0. Some of the dyes were quickly decolorized whereas others were marginally decolorized. The initial first hour was sufficient for the maximum decolorization of dyes. The rate of decolorization was quite slow on long treatment of dyes. Enhancement in the dye decolorization was noticed on increasing the concentration of enzymes. The complex mixtures of dyes were treated with both preparations of polyphenol oxidases in the buffers of varying pH values. Potato polyphenol oxidase was significantly more effective in decolorizing the dyes to higher extent as compared to the enzyme obtained from brinjal polyphenol oxidase. Decolorization of dyes and their mixtures, followed by the formation of an insoluble precipitate, which could be easily removed simply by centrifugation.     

Decomposition of alachlor by ozonation and its mechanism

Decomposition and corresponding mechanism of alachlor, an endocrine disruptor in water by ozonation were investigated. Results showed that alachlor could not be completely mineralized by ozone alone. Many intermediates and final products were formed during the process, including aromatic compounds, aliphatic carboxylic acids, and inorganic ions. In evoluting these products, some of them with weak polarity were qualitatively identified by GC-MS. The information of inorganic ions suggested that the dechlorination was the first and the fastest step in the ozonation of alachlor.