零价纳米铁在水污染修复中的研究现状及讨论

详细介绍了零价纳米铁在水污染修复中的研究现状,包括可以修复的污染物种类、作用机理和影响因素等.纳米铁可以去除水体中有机污染物、无机污染物和重金属等,影响因素主要包括溶解氧、pH、污染物初始浓度、纳米铁的投加量、粒径、超声波的协同作用和纳米铁的修饰作用等.还探讨了目前纳米铁在地下水污染修复研究和实际应用中存在的问题     

城市景观水体富营养化污染及治理技术初探

介绍了城市景观水体的功能特点;从景观水体的污染物来源,分析了景观水体富营养化的原因;针对城市景观水体的污染特点,综述了景观水体富营养化的污染源控制措施、物理治理技术、化学治理技术和生物修复技术。城市景观水体富营养化原因复杂,单一的技术难以达到修复效果,需要采用多种技术联用的综合治理方法,才能达到恢复景观水体的生态平衡。     

竹丝复合生物反应器处理城市景观水体

为探索景观水体等低污染水体处理方法和竹丝生物载体开发的可行性,以竹丝复合生物反应器处理低污染景观水体;对外加葡萄糖碳源对COD降解的影响,反应器内生物相,反应器内竹丝填料和活性污泥的作用等进行了初步研究.结果表明,向反应器中补充少量的葡萄糖有利于水体中COD的降解,最佳补充量为0.05 g·L-1;而且发现竹丝复合生物反应器中竹丝填料上的微生物对污染物的降解占主导地位;对接种后反应器内指示性微生物观察结果发现,竹丝生物载体是一种能很快吸附和保护接种微生物的材料,非常适合低污染水体的处理和修复.     

橡胶硫化废气的净化处理

提出了一种能有效净化硫化废气的新型涡旋脉冲式反应器的结构设计。有直径为西450的PVC反应器进行了胶管硫化罐硫化废气净化试验。系统地考察了操作温度、液气比对污染物脱除率的影响。结果表明：涡旋脉冲式反应器可以高效率地脱除废气中的主要污染物，在适宜的操作条件下，酚类污染物的脱除率可达96％以上。     

膜生物反应器应用于饮用水处理

饮用水的生物处理需要有效地除去水中阴离子微污染物。然而，在不改变水质和不增加新的污染物或除去水中必须元素的条件下，除去目标污染物的专门技术尚未成熟。一些新技术包括：压力推动膜生物反应器；气体传递膜生物反应器；离子交换膜生物反应器。这些技术综合了膜分离和微污染物离子的生物降解，可以有效地减少水的二次污染。     

新型膜生物反应器处理印染废水研究进展

印染废水含有多种染料、浆料、表面活性剂等复杂化学物质,属难处理的工业废水之一,新型膜生物反应器法是一种处理印染废水的重要方法。膜生物反应器法是将传统的生物处理印染废水技术和膜分离技术相结合,从而更加高效彻底的去除废水中的污染物。而新型膜生物反应器则是根据膜生物反应器的不足对其进行改进。主要介绍海藻式膜生物反应器、生物铁式膜生物反应器填料式、填料式膜生物反应器等的研究现状及进展,并对今后的发展方向提出了建议。     

包埋厌氧氨氧化菌的影响因素与研究现状

与传统的活性污泥法相比，采用包埋厌氧氨氧化技术可以提高反应器中的细胞浓度、缩短启动时间、促进固液分离、提高系统耐冲击性能。本文主要介绍了微生物固定化技术的各种方法及其优缺点，进一步阐述载体材料、污泥形态、交联剂和其它环境因素等对包埋厌氧氨氧化细菌的影响，并对该技术在处理水体中污染物的研究现状进行了总结。最后，对包埋厌氧氨氧化技术的发展前景进行了预测，并讨论了其存在的制约因素。     

黑臭水体需氧量计算模型研究及应用

曝气技术是黑臭水体整治的一项有效措施。综述了曝气技术在国内外黑臭水体治理上的应用,研究了黑臭水体需氧量计算的三种方法,利用组合推流反应器模型思想,结合生物膜降解污染物机理,设计建立了一种适用于黑臭河道湖泊需氧量计算模型-改进型组合推流反应器。利用该模型计算商丘某河道需氧量,结果表明整治期间总需氧量为6 305 kgO2,黑臭水体整治前20天需氧量大,占总需氧量的83.1%,因此在黑臭河道治理前期需及时补充溶解氧,为微生物降解污染物提供溶解氧条件。     

超声波气升式内循环反应器流体力学性能研究

研究了超声波对气升式内循环反应器流体力学性能的促进作用,重点考察比较了有无超声波时气升式反应器性能及超声功率对反应器气含率、液体循环速度、混合时间等的影响。实验证明,超声波的加入对气含率未见影响,有使液体循环速度逐渐减小的趋势,而对混合时间的影响较复杂。在小气速下,小功率超声波促进流体的径向混合,随着超声功率的增加,超声振动阻碍流体的径向混合,因而存在一个最佳的超声功率,并且超声波对混合时间的影响随着表观气速的增加而逐渐减小。提出了该反应器流体力学关联式。     

超声波微混合反应器混合性能的研究

介绍了超声波微混合反应器的原理,利用Dushman反应与硼酸盐的酸碱中和反应对反应器的混合效果进行表征。研究了进料流速、进料管径、超声波脉冲频率对溶液混合效果的影响。实验结果表明,超声波微混合反应器的微观混合性优于传统的双进料搅拌反应器。     

臭氧/超声联合降解水中对氨基苯酚的动力学

采用臭氧/超声联合降解含对氨基苯酚模拟废水.研究了对氨基苯酚降解的影响因素和动力学,考察了反应液初始pH 值、反应物初始浓度、臭氧投量、反应温度对臭氧/超声降解对氨基苯酚反应速率的影响.结果表明,对氨基苯酚初始浓度为1000 mg·L^-1时,pH 11.0,臭氧投量88 mg·min^-1,超声密度0.3 W·ml^-1,常温下反应30 min后对氨基苯酚去除率达99％以上.对氨基苯酚的臭氧/超声降解符合表观一级动力学,得到幂指数方程描述反应动力学.     

Organic reactions in water or biphasic aqueous systems under sonochemical conditions. A review on catalytic effects

Catalysis in aqueous systems under sonochemical conditions has become an irreplaceable method in green synthetic chemistry after more than two decades of studies in this domain. The present review has the aim of describing the state-of-the-art with a comprehensive view of advantages and limitations as well as new potential applications. Catalytic procedures in water assisted by ultrasound and/or hydrodynamic cavitation are environmentally friendly with milder conditions, shorter reaction times and higher yields. Sonochemical processes can reduce the formation of hazardous by-products, the generation of waste and also produce energy savings. Cavitational implosion generates mechanical and chemical effects such as cleaning of catalyst surface and formation of free radicals by sonolysis of water. The present overview of sonochemical reactions in water (oxidation, bromination, aza-Michael, C–C couplings, MCR and aldol reactions) should provide useful models for furthering the progress of organic synthesis using harmless and greener sound energy.     

三氯乙腈的合成、应用与市场

介绍了三氯乙腈的合成方法及应用,分析了其产销现状及前景。     

Comparative study on the sonophotocatalytic degradation of hazardous waste

The enhanced sonophotocatalytic degradation of Chrome Intra Orange G (C.I. 18745), an azo dye, in aqueous solution under UV light has been carried out using solvothermally sensitized ZnO nanoparticles as catalyst. The effects of sonolysis, sonocatalysis, photocatalysis and sonophotocatalysis have been examined to study the influences on the degradation rates by varying the initial dye concentration, dye solution pH, catalyst morphology and loading to ascertain the synergistic effect on the degradation techniques. ZnO sonophotocatalysis was always faster than the respective individual processes. Ultrasound may modify the rate of photocatalytic degradation by promoting the deaggregation of the catalyst and ultrasound-induced increase of its active surface area, by increasing the amount of reactive radical species through cavitation leading to water splitting and formation of H₂O₂ by both photocatalysis and sonolysis. To further verify the direct relation of the effective surface area offered by ZnO to its reaction rate, sonophotocatalysis experiments were conducted using nanorods of different dimensions and aspect ratios. Higher aspect ratio values correspond to an enhancement of the sonophotocatalytic activity.     

Effect of sonolysis on kinetics and physicochemical properties of treated chitosan

Low molecular weight chitosan with weight‐average molecular weight from 161 to 22,000Da were obtained by sonolysis. Optimal conditions for sonolysis were described. The influence of sonolysis condition and the molecular parameters of initial chitosan on the degradation rate and degradation rate constant were investigated in detail. Weight‐average molecular weight (M_w) and molecular weight dispersion (M_w/M_n) of samples were measured by gel permeation chromatography. The structure of degraded chitosan were characterized by Fourier transform infrared, X‐ray diffraction, and electrospray ionization mass spectrometry. For a given sonolysis time, the decrease in molecular weight has been found to be greatest at lowest reaction temperature and lowest chitosan concentration. Molecular weight of samples decreased exponentially with increasing sonication time at early stages. The action mode of ultrasound on the splitting of molecular chain of chitosan has been discussed. The degree of deacetylation of the main hydrolysis products almost unchanged compared with the initial chitosan. The decrease of molecular weight led to transformation of crystal structure but the chemical structures of residues were not modified. Ultrasonic treatment on chitosan is an alternative, safe method to prepare chitosan having different molecular weights, which are more suitable for biomedical and food applications. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Electrochemical and sonoelectrochemical processes applied to the degradation of the endocrine disruptor methyl paraben

Methyl paraben is commonly employed as a preservative in pharmaceutical preparations, personal care products and some processed foods. However, the ester constitutes a potential pollutant in aquatic environments and has been classified as an endocrine disruptor. This study describes the degradation of methyl paraben (100 mg L^?1 in 0.05 mol L^?1 aqueous potassium sulfate at pH 5.7) by means of an electrochemical process (employing a boron-doped diamond anode) either alone or coupled with sonolysis. Electrolyses were performed at 25, 30 and 35 ± 1 °C during 120 min using applied constant current densities of 10.8 and 21.6 mA cm^?2. The hybrid sonoelectrochemical processes were conducted under similar conditions with the application of ultrasound at a frequency of 20 kHz and a power intensity of 523 W cm^?2. Although mineralization of methyl paraben could be achieved using either process, in comparison with the electrochemical method, the hybrid technique showed a higher mineralization efficiency (around 60 %) with approximately 50 % removal of total organic carbon, thereby confirming the synergistic effect of sonolysis.     

The gas phase hydrodechlorination of chlorobenzene over nickel/silica

The gas phase hydrodechlorination of chlorobenzene over the temperature range 473 K⩽T⩽573 K has been studied using a 1.5% (w/w) Ni/SiO₂ catalyst. Reproducible turnover frequencies are quoted and the effects of varying such process variables as reaction time and temperature, contact time, chlorobenzene and hydrogen partial pressures are presented. The catalyst was 100% selective in promoting hydrodechlorination and the aromatic ring remained intact in every instance. Under reaction conditions far removed from equilibrium conversions, the catalyst exhibited no appreciable short term deactivation while the maintenance of long term activity was also established. Chlorine coverage of the catalyst surface under reaction conditions was probed indirectly by monitoring, via pH changes in an aqueous NaOH trap, HCl desorption after completion of the catalytic step. The hydrogenolysis of bromobenzene, 2‐chlorophenol and 3‐chlorotoluene under the same reaction conditions were considered for comparative purposes where the turnover frequencies decrease (at 573 K) in the order 2‐chlorophenol>3‐chlorotoluene>chlorobenzene>bromobenzene; reactivity is discussed in terms of thermodynamic limitations and reactant/catalyst interactions. Reaction orders with respect to hydrogen and chlorobenzene partial pressures were obtained at different reaction temperatures and the experimental rate data are adequately represented by an extended power rate expression that approximates the Langmuir–Hinshelwood model for non‐competitive adsorption. © 1999 Society of Chemical Industry     

Permeation of Telone C‐35 EC™ and chloropicrin through protective gloves

Telone is a potent volatile liquid chlorinated hydrocarbon pesticide based on 1,3‐dichloropropene that is applied without dilution for fumigation purposes, and so poses an inhalation and air pollution threat, as proven by past monitoring. 1,3‐Dichloropropene also causes allergic skin effects, is absorbed through the skin, and metabolites have been shown to be excreted after skin absorption, so making it a skin exposure threat too, one that may become most important in the situations of adequate respirator protection or cleaning up spills. It is often coformulated with agents like chloropicrin, a chemical warfare agent, to substitute for methyl bromide fumigant. The aim of the study was to assess if nitrile and laminated gloves provided adequate protection against Telone C‐35 EC?, using an ASTM‐type I‐PTC‐600 permeation cell containing disposable (Safeskin?) and chemically‐resistant (Sol‐Vex?) nitrile and laminated (Barrier? and Silver Shield?) glove materials with hexane liquid collection. Analyses of cis‐ and trans‐1,3‐dichloropropene and chloropicrin in the collection fluid at various times were performed on a moderately polar capillary column, using gas chromatography–electron capture detection by the internal and external standards methods. Both nitrile materials were degraded by the formulation and pure chloropicrin, and so were unsuitable for protection. Both laminated glove materials offered some protection with Silver Shield? the better, since less mass had permeated by 8 h, but the extent of protection was still inadequate, as illustrated by a risk assessment of the skin exposure situation. It is recommended that Viton gloves be worn rather than the laminated ones when Telone C‐35 EC? is handled. Laminated gloves may protect against pure chloropicrin. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 100: 18–25, 2006     

新法氘代溴苯-d_5的合成与表征

以氘代苯（Ｃ６Ｄ６）及单质溴（Ｂｒ２）为原料,铁粉（Ｆｅ）及单质碘（Ｉ２）为催化剂,同时改进了常规溴苯合成中粗产物的后处理工序,最终合成出了产率达７２．５％ 、氘代率达９９．２％ 的氘代溴苯（Ｃ６Ｄ５Ｂｒ）。采用付立叶变换红外光谱仪及激光拉曼光谱仪对Ｃ６Ｄ５Ｂｒ的振动光谱特性进行了研究,此外亦采用相对重量校正因子１Ｈ－核磁共振波谱法对样品氘代率的测定进行了探讨。     

Heterocyclic synthesis with nitriles: A new approach to Thiophene and Thieno-[2,3-d]-pyrimidine derivatives

α-Cyano-β-thiocyanatomethyl cinnamonitrile ( 1 ) was transformed into 5-acetyl-2-amino-4-phenylthiophen-3-carbonitrile ( 3 ) on refluxing in acetic/sulphuric acid mixture. Compound 3 reacted with trichloroacetonitrile, formamide, carbon disulphide and ethylorthoformate.