硝基甲苯对小鼠睾丸生殖细胞DNA的损伤作用

为提供硝基甲苯的环境遗传毒理学依据和建立鱼类生殖细胞的培养方法,采用昆明小鼠睾丸支持细胞/生殖细胞共培养法以及彗星实验,研究了2,4-二硝基甲苯(2,4-DNT)、2,6-二硝基甲苯(2,6-DNT)、对硝基甲苯(4-NT)对小鼠睾丸生殖细胞DNA的损伤作用.结果表明,3种受试硝基甲苯化合物均能够诱导小鼠睾丸生殖细胞DNA单链断裂,而且其受损率与剂量对数具有明显的剂量-效应关系.2,4-DNT、2,6-DNT以及4-NT的各个剂量浓度引起细胞DNA损伤的程度,与对照组相比,均具有显着性差异(p<0.01,p<0.05).受试化合物的毒性顺序为2,6-DNT>2,4-DNT>4-NT,DNA的损伤作用二硝基甲苯大于单硝基甲苯.提示在体外条件下,2,4-DNT、2,6-DNT和4-NT具有生殖毒性,可以引起小鼠睾丸生殖细胞DNA损伤.     

Remediation of 2,4-dichlorophenol-contaminated groundwater using nano-sized CaO2 in a two-dimensional scale tank

• Nano CaO₂ is evaluated as a remediation agent for 2,4-DCP contaminated groundwater. • 2,4-DCP degradation mechanism by different Fe²⁺ concentration was proposed. • 2,4-DCP was not degraded in the system for solution pH>10. • The 2,4-DCP degradation area is inconsistent with the nano CaO₂ distribution area. This study evaluates the applicability of nano-sized calcium peroxide (CaO₂) as a source of H₂O₂ to remediate 2,4-dichlorophenol (2,4-DCP) contaminated groundwater via the advanced oxidation process (AOP). First, the effect and mechanism of 2,4-DCP degradation by CaO₂ at different Fe concentrations were studied (Fenton reaction). We found that at high Fe concentrations, 2,4-DCP almost completely degrades via primarily the oxidation of •OH within 5 h. At low Fe concentrations, the degradation rate of 2,4-DCP decreased rapidly. The main mechanism was the combined action of •OH and O₂^•−. Without Fe, the 2,4-DCP degradation reached 13.6% in 213 h, primarily via the heterogeneous reaction on the surface of CaO₂. Besides, 2,4-DCP degradation was significantly affected by solution pH. When the solution pH was>10, the degradation was almost completely inhibited. Thus, we adopted a two-dimensional water tank experiment to study the remediation efficiency CaO₂ on the water sample. We noticed that the degradation took place mainly in regions of pH<10 (i.e., CaO₂ distribution area), both upstream and downstream of the tank. After 28 days of treatment, the average 2,4-DCP degradation level was ≈36.5%. Given the inadequacy of the results, we recommend that groundwater remediation using nano CaO₂: (1) a buffer solution should be added to retard the rapid increase in pH, and (2) the nano CaO₂ should be injected copiously in batches to reduce CaO₂ deposition.     

Aufnahme von 2,4,6-Trinitrotoluol in Pflanzen

Soil contaminations with the explosive 2,4,6-TNT are a major problem at many sites of former ammuniton plants in Germany. But only little is known about its environmental or metabolic fate in soil or plants. A field study was conducted on a former ammunition plant in Stadtallendorf/Hessen. Three areas with different TNT concentrations were planted with 8 different crops. After harvest plants were analyzed for TNT, ADNTs and DNTs. Soil contamination decreased in the rhizosphere compared to unplanted areas and there was a transfer of TNT from soil to the plants. Accumulation in plants was dependent on soil contamination and also specific for different plant parts or plant species. The contamination spectrum of TNT and derivatives was different in soil or plant tissue, respectively. After acid hydrolysis of bean roots, 2,6-DNT and 2,4-DNT could be identified in the extract.     

杀灭菊酯对土壤过氧化氢酶活性的影响

为了探讨杀灭菊酯(Fenvalerate)对土壤过氧化氢酶作用的可能机制,采用室内模拟试验研究了杀灭菊酯对土壤过氧化氢酶活性和酶促反应特征参数的影响,并采用分子荧光光谱法研究了杀灭菊酯对离体过氧化氢酶构象的影响.结果表明,1)随着培养时间的延长,杀灭菊酯对土壤过氧化氢酶和离体过氧化氢酶活性的影响均表现为抑制→激活→恢复,与土壤过氧化氢酶相比,离体过氧化氢酶的抑制最低点发生前移;2)24h培养时间下,土壤过氧化氢酶抑制率与杀灭菊酯浓度呈显著正相关;3)24h培养时间下,随杀灭菊酯浓度的增加,酶促反应米氏常数Km逐渐增大,过氧化氢酶活性、酶促反应最大反应速率Vmax、Vmax/Km均逐渐减小,且各参数与杀灭菊酯浓度均显著相关,表明过氧化氢酶酶促反应特征参数可以表征杀灭菊酯对土壤过氧化氢酶活性的影响程度,其作用机理为混合型抑制;4)分子荧光光谱结果表明,随着杀灭菊酯浓度的增加,离体过氧化氢酶在352nm波长处的相对荧光强度不断增强,其分子构象发生了变化,分子渐趋疏松.     

硝基芳香烃降解菌株的分离、鉴定和应用

从被二硝基甲苯(DNT)和三硝基甲苯(TNT)污染的土壤中分离到5个高效降解硝基芳香烃类化合物的菌株TD1、TD2、TD3、TD4和TD5。16S rDNA序列分析表明,TD1、TD2、TD3和TD4属于节杆菌属(Arthrobacter),TD5属于不动杆菌属(Acinetobacter)。菌株复配试验表明,TD1、TD2、TD3、TD4和TD5的体积比例为2:2:2:1:1时对含有DNT和TNT的炸药废水的CODC r去除率最好。最佳复配的菌液投加到装有合适填料载体的生物反应器中用于处理炸药废水,运行47d后出水CODC r不超过200 mg/L,硝基苯类化合物的浓度在2 mg/L以下。     

Fenton process for degradation of selected chlorinated aliphatic hydrocarbons exemplified by trichloroethylene, 1,1-dichloroethylene and chloroform

The degradation of selected chlorinated aliphatic hydrocarbons (CAHs) exemplified by trichloroethylene (TCE), 1,1-dichloroethylene (DCE), and chloroform (CF) was investigated with Fenton oxidation process. The results indicate that the degradation rate was primarily affected by the chemical structures of organic contaminants. Hydroxyl radicals (·OH) preferred to attack the organic contaminants with an electron-rich structure such as chlorinated alkenes (i.e., TCE and DCE). The dosing mode of Fenton’s reagent, particularly of Fe²⁺, significantly affected the degradation efficiency of studied organic compound. A new “time-squared” kinetic model, C = C _o exp(?k _obs t ²), was developed to express the degradation kinetics of selected CAHs. This model was applicable to TCE and DCE, but inapplicable to CF due to their varied reaction rate constants towards ?OH. Chloride release was monitored to examine the degree of dechlorination during the oxidation of selected CAHs. TCE was more easily dechlorinated thanDCE and CF.Dichloroacetic acid (DCAA) was identified as the major reaction intermediate in the oxidation of TCE, which could be completely removed as the reaction proceeded. No reaction intermediates or byproducts were identified in the oxidation of DCE and CF. Based on the identified intermediate, the reaction mechanism of TCE with Fenton’s reagent was proposed.     

高级催化氧化法去除水中邻苯二甲酸酯的研究进展

普遍认为,邻苯二甲酸酯类物质（Phthalic Acid Esters,PAEs）是内分泌干扰物质（Endocrine Disrupting Chemicals,EDCs）,被广泛应用于增塑剂、化妆品中,具有致畸性,致癌性,致突变性以及拟/抗雌激素活性、拟/抗甲状腺激素活性等内分泌干扰特性。邻苯二甲酸酯类物质很容易扩散到环境中,在土壤、大气、水环境中均有检出,是环境中常见污染物,严重威胁人体健康和生态环境,已经引起国内外的广泛关注。在综述邻苯二甲酸酯类物质的物理化学性质、毒性影响、国内外天然水体、地下水和生活污水中的污染现状的基础上,讨论消除水环境中PAEs污染的强化混凝、吸附、膜处理、生物处理和高级氧化技术。高级氧化技术因其能够快速有效地去除饮用水和污水中不同种类的有机污染物而备受关注,且发展迅速。重点介绍了高级催化氧化法对水环境中PAEs的去除,包括催化湿式过氧化物氧化过程,催化臭氧氧化过程,光催化氧化过程,超声波、微波辅助催化氧化过程以及高级纳米催化氧化过程。其中,Fenton催化氧化技术在氧化过程中通过使用催化剂或协同紫外光等方式产生高度反应性羟基自由基,可无选择性地将PAEs完全降解为无毒无害的小分子物质,对PAEs的氧化去除效果最好。虽然在高级氧化过程中应用催化剂可大大提高氧化效率和降解程度,但催化氧化法耗能较大、催化剂消耗量大、受水体pH值的影响,且研究大多限于实验室阶段,未能大量投入工业应用,需要进一步发展创新。因此,开发新型高效催化剂、提高催化剂选择性、优化催化氧化反应条件、优化设计催化反应器、与其他技术耦合是水体中PAEs类环境激素污染控制技术的发展方向。     

Kinetics of microwave-enhanced oxidation of phenol by hydrogen peroxide

Aqueous solutions of phenol were oxidized by hydrogen peroxide assisted by microwave (MW) irradiation. A simple kinetic model for the overall degradation of phenol in the presence of excess H₂O₂ is proposed in which the degradation rate of phenol is expressed as a linear function of the concentrations of phenol and H₂O₂. A detailed parametric study showed that the degradation rate of phenol increased with increasing [H₂O₂] until saturation was observed. Phenol degradation followed apparent zero-order kinetics under MW radiation or H₂O₂ oxidation. However, after 90 min of irradiation, the observed kinetics shifted to pseudo first order. The overall reaction rates were significantly enhanced in the combined MW/H₂O₂ system, mainly because microwave could accelerate H₂O₂ to generate hydroxyl radical (^·OH) and other reactive oxygen intermediates. The observed synergetic effects of the MW/H₂O₂ process resulted in an increased in the net reaction rate by a factor of 5.75. When hydrogen peroxide is present in a large stoichiometric excess, the time required to achieve complete mineralization is reduced significantly.     

Fenton degradation of dialkylphthalates: products and mechanism

Contamination of wastewater by organic pollutants is a major worldwide issue. For instance plastic additives such as phthalates are found in wastewater. Efficient techniques are thus needed to clean wastewaters. The Fenton reaction involving H₂O₂ and Fe(II) salts can be used to treat polluted water. During the Fenton reaction pollutants are decomposed directly by hydroxyl radicals. In some cases toxic by-products are produced. Here dimethyl phthalate, diethyl phthalate, and dipropyl phthalate by-products formed during the Fenton reaction were studied. Fenton degradation of selected phthalates yielded numerous transformation products such as hydroxylated phthalates. The hydroxylation reaction occurred at the aromatic ring of phthalates and yielded mono- and dihydroxylated phthalates. For monohydroxylated phthalate, 3-hydroxy- and 4-hydroxydialkylphthalates are the main transformation products. In addition to hydroxylated derivatives, aliphatic chain degraded mono- and dihydroxylated phthalates were also detected.     

Dual-reaction-center catalytic process continues Fenton’s story

• Dual-reaction-center (DRC) system breaks through bottleneck of Fenton reaction. • Utilization of intrinsic electrons of pollutants is realized in DRC system. • DRC catalytic process well continues Fenton’s story. Triggered by global water quality safety issues, the research on wastewater treatment and water purification technology has been greatly developed in recent years. The Fenton technology is particularly powerful due to the rapid attack on pollutants by the generated hydroxyl radicals (•OH). However, both heterogeneous and homogeneous Fenton/Fenton-like technologies follow the classical reaction mechanism, which depends on the oxidation and reduction of the transition metal ions at single sites. So even after a century of development, this reaction still suffers from its inherent bottlenecks in practical application. In recent years, our group has been focusing on studying a novel heterogeneous Fenton catalytic process, and we developed the dual-reaction-center (DRC) system for the first time. In the DRC system, H₂O₂ and O₂ can be efficiently reduced to reactive oxygen species (ROS) in electron-rich centers, while pollutants are captured and oxidized by the electron-deficient centers. The obtained electrons from pollutants are diverted to the electron-rich centers through bonding bridges. This process breaks through the classic Fenton mechanism, and improves the performance and efficiency of pollutant removal in a wide pH range. Here, we provide a brief overview of Fenton’s story and focus on combing the discovery and development of the DRC technology and mechanism in recent years. The construction of the DRC and its performance in the pollutant degradation and interfacial reaction process are described in detail. We look forward to bringing a new perspective to continue Fenton’s story through research and development of DRC technology.     

Study on degradation process of famotidine hydrochloride in aqueous samples

The kinetics of famotidine (FAM) transformation under the influence of various factors, important from the environmental point of view, was investigated in aqueous solutions. The degradation processes using UV, H₂O₂, UV/H₂O₂, H₂O₂/Fe²⁺, and UV/H₂O₂/Fe²⁺ were studied. Direct photolysis and H₂O₂-assisted photolysis showed a pseudo-first-order kinetics, while the Fenton and the photo-Fenton processes fit second-order kinetics. The provided experiments proved a high resistance of FAM to direct photolysis. Its stability depends highly on the pH of the reaction solutions. The rate of FAM direct photolysis in acidic solutions was almost negligible. The reaction rate of FAM photolysis at pH 8–9 was 3.7 × 10^?3 min^?1 with DT₅₀ about 3 h 7 min. It was found that the presence of H₂O₂ in the reaction environment enhances the rate of photolysis of FAM. The observed rates of reaction were 5.1 × 10^?3 min^?1 and 3.7 × 10^?3 min^?1 in acidic and basic solutions, respectively. The used Fenton systems appeared to be the most efficient in FAM removal. The rate of reaction depends on concentration of Fe²⁺ and H₂O₂. It was observed that the presence of UV-light enhances the reaction rate by two to six times in comparison to the classical Fenton system. Additionally, FAM behavior in natural water under solar irradiation was examined. The irradiation experiments were carried out in batch experiments with simulated sunlight.     

三维电极电化学反应器组合Fenton试剂深度处理焦化废水

采用三维电极电化学反应器组合Fenton试剂法对经过二级生化处理后的焦化废水进行深度处理。在三维电极参数一定的条件下,考察了影nfi]TOC去除率的影响因素,探讨了该反应体系的降解动力学及降解机理。正交试验结果表明,反应体系中各参数的最佳值分别为p（H202投加量）=300mg·L-1,pH3．4,反应时间为90min,c（FeS04-7H20投加量）为3．5mmol·L-1,TOC去除率可达到61．7％。焦化废水的降解反应表现为一级动力学。紫外吸收光谱分析结果,废水中有机物彻底发生了降解矿化,这为三维电极组合Fenton试剂工艺在焦化废水深度处理中的工程应用提供了一定的理论指导。     

Hydroxyl radical intensified Cu2O NPs/H2O2 process in ceramic membrane reactor for degradation on DMAc wastewater from polymeric membrane manufacturer

• Cu₂O NPs/H₂O₂ Fenton process was intensified by membrane dispersion. • DMAc removal was enhanced to 98% for initial DMAc of 14000 mg/L. • Analyzed time-resolved degradation pathway of DMAc under ·OH attack. High-concentration industrial wastewater containing N,N-dimethylacetamide (DMAc) from polymeric membrane manufacturer was degraded in Cu₂O NPs/H₂O₂ Fenton process. In the membrane-assisted Fenton process DMAc removal rate was up to 98% with 120 min which was increased by 23% over the batch reactor. It was found that ·OH quench time was extended by 20 min and the maximum ·OH productivity was notably 88.7% higher at 40 min. The degradation reaction rate constant was enhanced by 2.2 times with membrane dispersion (k = 0.0349 min⁻¹). DMAc initial concentration (C₀) and H₂O₂ flux (J_p) had major influence on mass transfer and kinetics, meanwhile, membrane pore size (r_p) and length (L_m) also affected the reaction rate. The intensified radical yield, fast mass transfer and nanoparticles high activity all contributed to improve pollutant degradation efficiency. Time-resolved DMAc degradation pathway was analyzed as hydroxylation, demethylation and oxidation leading to the final products of CO₂, H₂O and NO₃⁻ (rather than NH₃ from biodegradation). Continuous process was operated in the dual-membrane configuration with in situ reaction and separation. After five cycling tests, DMAc removal was all above 95% for the initial [DMAc]₀ = 14,000 mg/L in wastewater and stability of the catalyst and the membrane maintained well.     

有机磷酸酯阻燃剂降解方法的研究进展

有机磷阻燃剂(OPFRs)已取代溴代阻燃剂广泛应用于各行业,并很容易通过挥发、磨损等方式进入各环境介质中.目前,已在水体、土壤等环境介质中检测到了 OPFRs的存在.本文总结了目前已有的OPFRs在环境中的降解方式,据其原理主要可分为化学法和生物法,化学法主要包含Fenton/类Fenton氧化法、紫外-双氧水法(UV...     

Unprecedented total mineralization of atrazine and cyanuric acid by anodic oxidation and electro-Fenton with a boron-doped diamond anode

This article reports the complete mineralization of atrazine. Atrazine has been the most widely used s-triazine herbicide. Atrazine occurs in natural waters and presents a potential danger for public health because atrazine is considered as an endocrine disruptor. The use of chemical, photochemical and photocatalytic advanced oxidation processes (AOPs) to decontaminate waters containing atrazine only allowed its conversion into the cyanuric acid as ultimate end products, since it cannot be completely degraded by hydroxyl radicals (^•OH) produced by these techniques. The same behavior was previously reported for anodic oxidation and electro-Fenton with Pt anode, although better performances were found using boron-doped diamond (BDD) anode but without explaining the role of generated ^•OH. Here, the oxidative action of these radicals in such electrochemical AOPs has been clarified by studying the mineralization process and decay kinetics of atrazine and cyanuric acid in separated solutions by anodic oxidation with BDD and electro-Fenton with Pt or BDD anode using an undivided cell with a carbon-felt cathode under galvanostatic conditions. Results showed that electro-Fenton with BDD anode was the more powerful treatment to degrade both compounds. Almost total mineralization, 97% total organic carbon (COT) removal, of atrazine was only feasible by this method with a faster removal of its oxidation intermediates by ^•OH formed at the BDD surface than that formed in the bulk from Fenton reaction, although the latter process caused a more rapid decay of the herbicide. Cyanuric acid was much slowly mineralized mainly with ^•OH produced at the BDD surface, and it was not degraded by electro-Fenton with Pt anode. These results highlight that electrochemical advanced oxidation processes (EAOPs) using a BDD anode are more powerful than the classical electro-Fenton process with Pt or PbO₂ anodes.     

Fe—C微电解法＋H2O2组合工艺处理对氯硝基苯废水

利用废铁屑对对氯硝基苯废水进行预处理 ,可以使废水中的对氯硝基苯转化为氨基氯苯 ,然后在废水中加入H2 O2 ,使H2 O2 与废水中的Fe2 + 构成Fenton试剂 ,反应生产OH·自由基 ,OH·自由基具有强烈的氧化性 ,将氨基氯苯和对氯硝基苯中的苯环打开 ,形成断链 ,再进一步将其矿化分解     

The role of black carbon as a catalyst for environmental redox transformation

Black carbon (BC) is an important class of geosorbents that control the fate and transport of organic pollutants in soil and sediment. We previously demonstrated a new role of BC as an electron transfer mediator in the abiotic reduction of nitroaromatic and nitramine compounds by Oh and Chiu (Environ Sci Technol 43:6983-6988, 2009). We proposed that BC can catalyze the reduction of nitro compounds because it contains microscopic graphitic (graphene) domains, which facilitate both sorption and electron transfer. In this study, we assessed the ability of different types of BC--graphite, activated carbon, and diesel soot--to mediate the reduction of 2,4-dinitrotoluene (DNT) and 2,4-dibromophenol (DBP) by H(2)S. All three types of BC enhanced DNT and DBP reduction. H(2)S supported BC-mediated reduction, as was observed previously with a thiol reductant. The results suggest that BC may influence the fate of organic pollutants in reducing subsurface environments through redox transformation in addition to sorption.     

常温下过硫酸盐氧化降解水中对氯苯胺

研究了常温下初始pH值对过硫酸盐氧化降解水中对氯苯胺(PCA)动力学过程的影响,并探讨了PCA降解的机理.结果表明,室温下,PCA的降解符合准一级动力学方程;pH值为3、5、7、9和11时,其一级动力学常数k分别为0.03×10-4、0.12×10-4、0.28×10-4、0.26×10-4和0.27×10-4s-1;酸性体系不利于PCA的降解,pH 7时PCA的降解速率最大,半衰期为6.88 h.通过LC/MS和GC/MS鉴定得到PCA降解的4种主要中间产物,分别为对氯硝基苯、对苯醌、1-(4氯苯)-3苯基脲和5-氯-2-(4氯苯二氮烯)苯酚,并在此基础上探讨了过硫酸盐氧化降解PCA的可能途径.     

二甲亚砜作探针试剂研究Fenton反应条件

随着高级氧化技术成为废水处理的研究热点,羟基自由基的产生、测定及测定条件等相关问题的探索,成为发展高级氧化技术的重要条件及其重要组成部分。以分光光度法为主要分析方法,以二甲亚砜作为·OH的探针试剂,对Fenton反应及其反应的最佳条件进行研究。结果表明,在实验条件下,H2O2初始浓度为11.5mmol/L,Fe2+/H2O2的浓度比值在1:23左右,pH范围为3～4时,·OH产率最高。     

Modeling and optimization of Nile blue sulfate mineralization by heterogeneous fenton oxidation

Artificial neural network and response surface methodology have been used to develop a model for simulation and optimization of the removal of Nile blue sulfate by heterogeneous Fenton oxidation. Experimental data were used to train an artificial neural network model with linear transfer function at the output layer and a tangent sigmoid transfer function at the hidden layer. A Box–Behnken design was employed to assess the effects of input process parameters on the total organic carbon removal. First order kinetics and lumped kinetics models were used to describe the reaction; a high regression coefficient indicated that the latter fitted best. The formation of non-oxidizable compounds was shown by liquid chromatography–mass spectrometry.