Simultaneous Degradation, Dehalogenation, and Detoxification of Halogenated Antibiotics by Carbon Dioxide Radical Anions

Despite the extensive application of advanced oxidation processes(AOPs)in water treatment,the efficiency of AOPs in eliminating various emerging contaminants such as halogenated antibiotics is constrained by a number of factors.Halogen moieties exhibit strong resistance to oxidative radicals,affecting the dehalogenation and detoxification efficiencies.To address these limitations of AOPs,advanced reduction processes(ARPs)have been proposed.Herein,a novel nucleophilic reductant—namely,the carbon dioxide radical anion(CO_(2)^(·-))—is introduced for the simultaneous degradation,dehalogenation,and detoxification of florfenicol(FF),a typical halogenated antibiotic.The results demonstrate that FF is completely eliminated by CO_(2)^(·-),with approximately 100%of Cland 46%of Freleased after 120 min of treatment.Simultaneous detoxification is observed,which exhibits a linear response to the release of free inorganic halogen ions(R^(2)=0.97,p<0.01).The formation of halogen-free products is the primary reason for the superior detoxification performance of this method,in comparison with conventional hydroxyl-radical-based AOPs.Products identification and density functional theory(DFT)calculations reveal the underlying dehalogenation mechanism,in which the chlorine moiety of FF is more susceptible than other moieties to nucleophilic attack by CO_(2)^(·-).Moreover,CO_(2)^(·-)-based ARPs exhibit superior dehalogenation efficiencies(>75%)in degrading a series of halogenated antibiotics,including chloramphenicol(CAP),thiamphenicol(THA),diclofenac(DLF),triclosan(TCS),and ciprofloxacin(CIP).The system shows high tolerance to the pH of the solution and the presence of natural water constituents,and demonstrates an excellent degradation performance in actual groundwater,indicating the strong application potential of CO_(2)^(·-)-based ARPs in real life.Overall,this study elucidates the feasibility of CO_(2)^(·-)for the simultaneous degradation,dehalogenation,and detoxification of halogenated antibiotics and provides a promising method for their regulation during water or wastewater treatment.

Progress in Analytical Methods of Halogenated Disinfection By-Products

Ensuring the health and safety of drinking water is crucial for both nations and their citizens.Since the 20th century,the disinfection of drinking water,effectively controlling pathogens in water sources,has become one of the significant advances in public health.However,the disinfectants used in the process,such as chlorine and chlorine dioxide,react with natural organic matter in the water to produce disinfection by-products(DBPs).Most of these DBPs contain chlorine,and if the source water contains bromine or iodine,brominated or iodinated DBPs,collectively referred to as Halogenated disinfection byproducts(X-DBPs),are formed.Numerous studies have found that X-DBPs pose potential risks to human health and the environment,leading to widespread concern.Mass spectrometry has become an important means of discovering new types of X-DBPs.This paper focuses on the study of methods for analyzing X-DBPs in drinking water using mass spectrometry.

Determination of the Toxicities of 16 Halogenated Benzenes to Photobacterium Phosphoreum and 2D- and 3D-QSAR Studies

In this paper we take photobacterium phosphoreum （T3） as the experimental bacteria, and determine the half-inhibitory concentration （-1gEC50） against the photobacterium phosphoreum of 16 halogenated benzenes. Using B3LYP method of DFT in the Gaussian 03 program, we obtain the structural and thermodynamic descriptors of 16 halogenated benzenes by fully-optimized calculation at the 6-311G＊＊ level. Taking the structural and thermodynamic descriptors as theoretical descriptors, the 2D QSAR model （R2 = 0.983） was established, which can be utilized to predict -lgEC50 of halogenated benzene according to the corrected linear solvation energy theory based on the experimental data of-lgECs0. In addition, the relationship between the toxicity and 3D spatial structure of the compound is studied by comparing the molecular similarity index analysis （CoMSIA） of 3D-QSAR method. By cross validation, the correlation coefficient q2 of CoMSIA model is 0.687, and the conventional correlation coefficient R2 = 0.958. The model is stable and reliable with great predictive ability. The 3D-QSAR model shows that the toxicity of halogenated benzene compound is mainly affected by the characteristics of hydrophobie field of the substituted halogens.

A QSRR Study on the Relative Retention Time of Halogenated Methyl-phenyl Ethers

Halogenated methyl-phenyl ethers （anisoles） are ubiquitous organic compounds in the environment. In the present study, geometrical optimization and electrostatic potential calculations have been performed for 42 halogenated anisoles at the HF/6-31 G^＊ level. A number of statistically based parameters have been obtained. By multiple regression method, linear relationships between the gas-chromatographic relative retention time （RRT） and structural descriptors have been established for the training set of 32 halogenated anisoles. The result showed that the parameters derived from electrostatic potentials （ESPs） together with the molecular volume （Vmc） could be well used to express the quantitative structure-RRT relationships of halogenated anisoles. The best two-variable regression model gives a correlation coefficient of 0.980 and a standard deviation of 0.07, and the leave-one-out cross-validated correlation coefficient is 0.975. The goodness of the model has been further validated through exploring the predictive power for the testing set of 10 halogenated anisoles.

Prediction of Infinite Dilution Activity Coefficients of Halogenated Hydrocarbons in Water

Geometrical optimization and electrostatic potential calculations have been performed for a series of halogenated hydrocarbons at the HF/Gen-6d level. A number of electrostatic potentials and the statistically based structural descriptors derived from these electrostatic potentials have been obtained. Multiple linear regression analysis and artificial neural network are employed simultaneously in this paper. The result shows that the parameters derived from electrostatic 2 potentials σtot^2, V s and ∑ Vs^＋, together with the molecular volume （Vine） can be used to express the quantitative structure-infinite dilution activity coefficients （γ^∞） relationship of halogenated hydrocarbons in water. The result also demonstrates that the model obtained by using BFGS quasiNewton neural network method has much better predictive capability than that from multiple linear regression. The goodness of the model has been validated through exploring the predictive power for the external test set. The model obtained via neural network may be applied to predict γ^∞ of other halogenated hydrocarbons not present in the data set.

High halogenated nitrobenzene hydrogenation selectivity over nano Ir particles

The selective hydrogenation of halogenated nitrobenzene over noble metal catalysts(Pd, Pt, and Ir) has attracted much attention owing to its high efficiency and environmental friendliness. However, the effect of size on the catalytic performance varies among different metal catalysts. In this study, sub-nano(<3 nm) Ir and Pd particles were prepared, and their catalytic properties for hydrogenation of halogenated nitrobenzene were evaluated.Results show that high selectivity(N 99%) was achieved over small Ir nanoparticles, in which the selectivity over the Pd with same size was much lower than that on Ir nanoparticles. Meanwhile, Ir and Pd have different hydrogen consumption rates and reaction rates. Density functional theory calculations showed that p-chloronitrobenzene(CNB) has different adsorption properties on Ir and Pd. The distance between oxygen(cholorine) and Ir is much shorter(longer) than that between oxygen and Pd. The reaction barriers of dechlorination of p-CNB and p-chloroaniline over different Ir models are much larger than those on Pd. Especially,lower coordination of Ir leads to larger barriers of dechlorination reaction. These theoretical results explain the difference between Ir and Pd on hydrogenation of halogenated nitrobenzene.

Magnetic graphene oxide-anchored Ni/Cu nanoparticles with a Cu-rich surface for transfer hydrogenation of nitroaromatics

The bimetallic nanoparticles compositing of Ni-rich core and Cu-rich shell(Ni/Cu NPs)were successfully synthesized by a liquid-phase thermal decomposition method.The content of copper and nickel in Ni/Cu NPs was controllable by adjusting the ratio of two metal precursors,copper formate(Cuf)and nickel acetate tetrahydrate(Ni(OAc)_(2)·4H_(2)O).Ni/Cu NPs were further anchored on graphene oxide(GO)to prepare a magnetic composite catalyst,called Ni/Cu-GO.The dispersibility of Ni/Cu NPs in solution was enhanced by GO anchoring to prevent the sintering and aggregation during the reaction process,thereby ensuring the catalytic and cycling performance of the catalyst.The catalytic transfer hydrogenation(CTH)reaction of nitroaromatics was investigated when ammonia borane was used as the hydrogen source.Cu dominated the main catalytic role in the reaction,while Ni played a synergistic role of catalysis and providing magnetic properties for separation.The Ni_(7)/Cu_(3)-GO catalyst exhibited the best catalytic performance with the conversion and yield of 99%and 96%,respectively,when 2-methyl-5-nitrophenol was used as the substrate.The Ni_(7)/Cu_(3)-GO catalyst also exhibited excellent cyclic catalytic performance with the 5-amino-2-methylphenol yield of above 90%after six cycles.In addition,the Ni_(7)/Cu_(3)-GO catalyst could be quickly recycled by magnetic separation.Moreover,the Ni_(7)/Cu_(3)-GO catalyst showed good catalytic performance for halogen-containing nitroaromatics without dehalogenation.

Effect of monotoxicity and mixtoxicity of nitroaromatics to the green algae, Scienedesmus obliquus

In general, many pollutants co\|exist in natural aquatic ecosystems. They affect each other and occur different results, such as synergism, addition and antagonism. So the research at mixtoxicity of contaminants to aquatic organism is more important than monotoxicity. In this paper, 50% effectual inhibition concentration 48h \%EC\%\-\{50\} values of 6 kinds of nitroaromatic compounds to the green algae, \%Scenedesmus obliquus,\% were investigated. Mixtoxic experiments, in which any combination of 2,4\|DNT and other 6 kinds of compounds, indicate: (1) synergisms between 2,4\|DNT and 4\|NAn, as well as 4\|NAnis, 1,4\|DNB; (2) antagonisms between 2,4\|DNT and 4\|NT, as well as 4\|NPh, 4\|NCB.

Clicking ferrocene to halogenated boron-doped diamond surfaces

The halogenated boron-doped diamond （BDD） surfaces were reacted with sodium azide through a nucle- ophilic substitution reaction. The resulting azide-terminated BDD surfaces were used to trigger the ＂click＂ reaction. Because of the attractive electrochemical properties of ferrocene-containing molecules, such as fast electron transfer rates, reversible redox activities, and favorable redox potentials, we show that ferrocene derivatives can be grafted onto non-oxidized diamond surfaces by ＂click chemistry＂. These redox-active ferrocene-containing layers on a BDD surface, because of their ability to store and release charges reversibly, have the potential to be used as hybrid molecular/semiconductor memory devices.

Protecting-group-free amination of halogenated nitrobenzaldehyde with palladium catalyst

"One-step"method for the synthesis of secondary aliphatic amine substituted nitrobenzaldehyde was developed.In the presence of Pd catalyst,halogenated nitrobenzaldehyde could be smoothly coupled with secondary aliphatic amine to give the target product in hexamethylphosphamide(HMPT) media without the protection of aldehyde groups.

Quantitative structure－activity study on the reductive dehalogenation potency of the halogenated aromatics

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Ant Colony Optimization as a Powerful Tool for Descriptor Selection in QSPR Study of Infinite Dilution Activity Coefficients of Halogenated Hydrocarbons in Water

A quantitative structure-property relationship （QSPR） study was suggested for the prediction of infinite dilution activity coefficients of halogenated hydrocarbons, γ∞ , in water at 298.15 K. After optimization of 3D geometry of the halogenated hydrocarbons with semi-empirical quantum chemical calculations at the AM1 level, different descriptors （1514 descriptors） were calculated by the HyperChem and Dragon softwares. A major problem of QSPR is the high dimensionality of the descriptor space; therefore, descriptor selection is the most important step. In this paper, an ant colony optimization （ACO） algorithm was proposed to select the best descriptors. Then the selected descriptors were applied for model development using multiple linear regression. The average absolute relative deviation and correlation coefficient for the training set were obtained as 4.36% and 0.951, respectively, while the corresponding values for the test set were 5.96% and 0.929, respectively. The results showed that the applied procedure is suitable for the prediction of γ∞ of halogenated hydrocarbons in water.

QSRR Study on the Relationship between the Chromatographic Capacity Factor and Lipophilicity and Structure Parameters of Halogenated Thiophenols

The capacity factors （k＇） of fourteen types ofhalogenated thiophenols in different phases of methanol-water eluent were determined by reversed phased high-performance liquid chromatography （RP-HPLC） and the relationships between the logarithm of capacity factor lgK＇ and methanol ratio ψ were analyzed. A fair linear relationship is found between lgK＇ and ψ, and the correlation coefficients R2 of the constructed linear equations are all greater than 0.990. Relationship between the chromatographic data lgKw＇ when extrapolated to pure water and n-octanol/water partition coefficient lgKow obtained by the group contribution method has shown a good linear correlation with R2= 0.956. The structure parameters of fourteen halogenated thiophenols were calculated by using DFT, and the correlation equation of lgKw＇ and structure parameters was obtained by using SPSS, lgKw＇ = -0.409 ＋ 0.039a and R2 = 0.981, meaning that lgKw＇ is mainly determined by the polarizability α.

上海淀山湖表层沉积物中卤代阻燃剂时空分布

通过方差分析、主成分分析和商值法探究了上海淀山湖28个表层沉积物中56种卤代阻燃剂(HFRs)的时空分布特征、污染源及潜在生态风险.结果表明,上海快速工业化和城市化进程导致典型水源地淀山湖表层沉积物中3种HFRs出现明显累积,其中替代型溴代阻燃剂(Σ_(22)ABFRs,21.418ng/g)浓度已超出传统溴代阻燃剂(Σ_(23)PBDEs,10.344ng/g)约2倍.十溴联苯醚(BDE209,7.890ng/g),十溴二苯乙烷(DBDPE,17.990ng/g)和得克隆(Σ_(Syn+Anti)DP,1.176ng/g)是最主要的同系物.这些HFRs的高值点主要出现在环湖生活生产活动较密集的淀山湖西南区域,季节性差异不显著.主成分分析法揭示出商用十溴、五溴和八溴二苯醚及其替代品的使用,以及含新型阻燃剂的塑料制品的使用是主要来源.基于商值法的风险评估揭示出五溴联苯醚、BDE209、DBDPE、2,4,6-三溴苯氧基乙烷(BTBPE)和2-乙基己基-2,3,4,5-四溴苯甲酸酯(TBB)在绝大多数沉积物中对底栖生物均呈现中等风险,BDE209在个别采样点出现高风险,表明未来对这些卤代阻燃剂的环境监管仍需加强.

高含卤阻燃剂污染特征及分析方法研究进展

高含卤阻燃剂(highly halogenated flame tetardants,HHFRs)是指氯系或溴系阻燃剂中含卤量在60%以上的阻燃剂,因含卤量高,阻燃性能优越,HHFRs在塑料及高分子材料等中得到了广泛应用。与常规阻燃剂相比,HHFRs在环境中更具持久性,浓度较高时在室内外大气与灰尘、土壤、沉积物、生物体甚至人体血清、母乳中频繁检出,且降解后形成毒性更强的脱卤转化产物。毒理学证据表明HHFRs呈显著的内分泌干扰效应,造成神经发育损伤等。为科学评估及预测HHFRs的潜在环境与健康风险,获取准确可靠的定性定量数据是关键。然而,由于HHFRs具有沸点高且在光热作用下易发生脱卤等特性,使得复杂环境基质中痕量HHFRs的分析仍具有挑战性,从而阻碍了对其环境行为及毒效机制的深入认识。汇总了国内外近期关于十溴联苯醚(BDE-209)、十溴二苯乙烷(DBDPE)、得克隆(DP)、四溴双酚A/S衍生物(TBBPA/S-DBPE)、三(2,4,6-三溴苯氧基)-1,3,5-三嗪(TTBP-TAZ)及三(三溴新戊基)磷酸酯(TTBNPP)等几种典型HHFRs的样品前处理及仪器分析检测等方面的进展,并结合其理化性质及环境赋存特征等进行了评述,梳理出了当前分析方法的优缺点,并对今后的研究方向进行了展望。

不同阻燃剂对尼龙材料加工改性的研究进展

尼龙具有优异的力学性能以及耐腐蚀、耐油性、耐热性等优点,可广泛应用于军工、深海等高端领域。但尼龙材料具有可燃性,在燃烧过程中会产生大量的烟雾、有毒气体和熔体滴落,对人类的生命和财产造成损害。总结了阻燃尼龙基体的加工方式和卤系阻燃剂、磷系阻燃剂、氮系阻燃剂等常用传统阻燃剂改性尼龙材料的技术发展、应用和困境,分析不同种类阻燃剂对尼龙性能的影响机制,并重点论述了生物基阻燃剂及碳基阻燃剂2种先进尼龙阻燃改性方法的优势、发展及潜在应用。

大学有机化学教材引入卤键的必要性研究

卤键是存在于分子间或分子内的一种非共价吸引相互作用,近年来逐渐成为化学、生物、材料等学科研究的热门领域之一。2013年,IUPAC已给出了卤键的明确定义。而在大学有机化学教材中,很多重要的有机化学反应都有卤素分子的参与。通过采用量子化学计算,本文证明了卤素分子参与的相关有机化学反应中都有卤键的存在,并指出在教材中引入卤键概念对于学生准确理解和熟练掌握这些重要反应的必要性。

离子色谱法测定电线电缆材料中卤素含量的不确定度评定

卤素含量是影响电线电缆材料性能的关键指标之一,因此需精确测定以实现精细的产品质量控制和职业安全。离子色谱法通常用于量化卤素含量,其准确性和真实性取决于各种因素,如仪器精度、样品制备和标准物质选择。剖析了影响离子色谱分析结果的变量,建立了一个不确定度评估模型,并用实际样品对不确定度进行了量化。实验结果表明,仪器精度和样品制备是使用离子色谱法测量电线电缆材料中卤素含量的不确定度的主要来源。通过微调实验条件和加强质量控制,减少不确定度并提高测量的精度和可靠性是可行的。

无卤阻燃聚烯烃电缆料及其与阻燃剂相容性的研究进展

随着城市化的进行,电力电缆取代架空线路进行能源输送和分配的需求不断增加,聚烯烃正逐渐成为电力电缆的主要基体材料。聚烯烃属于易燃材料,为了减少电缆引起的火灾事件并考虑到环保要求,在材料中加入无卤阻燃剂是目前提高聚烯烃电缆材料阻燃性能的主要方式。首先归纳了无卤阻燃聚烯烃电缆的基体材料和基料改性方法,其次介绍了无卤阻燃剂的分类和阻燃机理,最后综述了提高基体和无卤阻燃剂相容性的最新研究进展。

硬质聚氨酯泡沫材料用无卤阻燃剂的研究进展

聚氨酯常用卤系阻燃剂存在燃烧时释放卤化氢腐蚀性气体及有毒有害物质的问题,危害人体健康。近年来,无卤阻燃剂以无卤、低烟、环保的优势,已逐渐替代卤系阻燃剂用于硬质聚氨酯泡沫阻燃。该文介绍了添加型阻燃剂和反应型阻燃剂最新研究进展,重点概括了添加型无机阻燃剂(如金属氢氧化物及氧化物、无机磷系、无机硅系及其协同阻燃剂、纳米材料)、添加型有机阻燃剂(如有机氮系、有机磷系、有机硅系及有机硅系及其协同阻燃剂)、膨胀型阻燃剂(可膨胀石墨、氮、磷膨胀型阻燃剂)及含氮、磷、硅的反应型阻燃剂的特点、阻燃机理及其对硬质聚氨酯泡沫阻燃性能的影响;对聚氨酯泡沫用无卤阻燃剂阻燃机理进行了阐述;最后,对聚氨酯泡沫用无卤阻燃剂今后发展的热点进行了展望。