Enhanced degradation of carbon tetrachloride by surfactant-modified zero-valent iron

Sorption of carbon tetrachloride （CT） by zero-valent iron （ZVI） is the rate-limiting step in the degradation of CT, so the sorption capacity of ZVl is of great importance. This experiment was aimed at enhancing the sorption of CT by ZVI and the degradation rate of CT by modification of surfactants. This study showed that ZVI modified by cationic surfactants has favorable synergistic effect on the degradation of CT. The CT degradation rate of ZVI modified by cetyl pyridinium bromide （CPB） was higher than that of the unmodified ZVI by 130%, and the CT degradation rate of ZVI modified by cetyl trimethyl ammonium bromide （CTAB） was higher than that of the unmodified ZVI by 81%. This study also showed that the best degradation effect is obtained at the near critical micelle concentrations （CMC） and that high loaded cationic surfactant does not have good synergistic effect on the degradation due to its hydrophilicity and the block in surface reduction sites. Furthermore degradation of CT by ZVI modified by nonionic surfactant has not positive effect on the degradation as the ionic surfactant and the ZVI modified by anionic surfactant has hardly any obvious effects on the degradation.     

Science Letters： Simultaneous removal of nitrate and heavy metals by iron metal

INTRODUCTION Nitrate and heavy metals commonly found ingroundwater pollutants constitute significant healthrisk to humans and a burden on the environment.Mixtures of these compounds often exist in soils andgroundwater at numerous contaminated sites. Highnitrate (NO3 ) levels in drinking water supplies sig- ?nificantly endanger human health, as they are directlyresponsible for methemoglobinemia in infants (bluebaby syndrome) and may play a role in the develop-ment of som…     

直接还原铁在一重炼钢生产中的应用

介绍了一重炼钢过程中原材料的使用情况,分析了直接还原铁代替部分废钢的可行性,对直接还原铁在一重的应用前景进行了论述.     

硝酸法处理废硬质合金回收金属钴和碳化钨

介绍了用硝酸法处理废硬质合金，回收金属钴和碳化钨的方法，并且设计了对废气氛氧化物的处理方法，消除了对环境的污染。是一种工艺简单，投资省，成本低，能耗少，污染小的回收工艺。     

载铁颗粒活性炭的制备及其表征

本文以废活性炭为原料,氧化铁为添加剂,通过高温煅烧的方法制备载铁颗粒活性炭（IOCGAC）。结果表明,IOCGAC制备的最佳工艺参数为:煅烧终温为900℃,升温速率为6℃·min^-1,m(氧化铁)/m（废活性炭）为4∶6,恒温时间为0.5 h,所得产品的比表面积达630.5m²·g^-1,收率为50.9%。对其进行SEM,IR,XRD表征分析,结果表明活性炭的表面负载了一层致密的铁氧化物,且主要以α-     

分光光度法测定茶叶与红枣中铁的含量

采用邻二氮菲分光光度法测定茶叶与红枣中铁的含量。结果显示,铁标准溶液在0～2μg/mL浓度范围内,标准曲线呈较好的线性关系,茶叶及红枣中铁含量均较高。研究结果可为人们合理饮用茶叶、食用红枣、补充微量铁提供参考。     

添加化学助滤剂 改善铁精矿过滤效果

在铁精矿的过滤过程中添加了不同的助滤剂进行试验。结果表明,一些助滤剂,如1631—WHL—2,TX—10一PEO有好的助滤效果。同时对助滤机理进行了探讨。     

羟基氧化铁催化臭氧氧化降解苯胺废水

以实验室制备的羟基氧化铁（FeOOH）为催化剂催化臭氧氧化处理苯胺废水,对比催化臭氧氧化与单独臭氧降解苯胺的效率,实验结果表明,FeOOH催化臭氧氧化能加快对苯胺的降解速率,并且矿化程度高.说明FeOOH对臭氧氧化水中的苯胺具有明显的催化作用.探讨了氧气的进气流量、苯胺的初始浓度、水溶液的pH、催化剂的投加量等因素对催化氧化苯胺的影响.研究表明：氧气的进气流量为30L/h、初始浓度300mg/L时、pH值7.3、催化剂的投加量为2g/L、反应15min后,苯胺的去除率可达98.2%,COD的去除率可达70%.在催化体系中加入自由基捕获剂叔丁醇后,催化臭氧氧化反应明显受到抑制,间接证明了FeOOH催化臭氧氧化苯胺遵循自由基反应机理.     

Rapid dechlorination of chlorinated organic compounds by nickel/iron bimetallic system in water

Detoxification of chlorinated organic compounds via reaction with nickel/iron powder was implemented in aqueous solution. Compared to iron, nickel/iron bimetallic powder had higher hydrodechlorination activities for both atrazine (ATR) and p-chlorophenol (pCP); nickel/iron (2.96%, w/w) was shown to have the largest specific surface area and the optimum proportion for the dechlorination of both ATR and pCP. Electrochemical measurements showed that the adsorbed hydrogen atom on the nickel must have been the dominant reductive agent for the dechlorination of both ATR andpCP in this system.     

Combined treatment of landfill leachate with fecal supernatant in sequencing batch reactor

A laboratory-scale sequencing batch reactor （SBR） is used to treat landfill leachate containing high concentration of ammonium nitrogen with municipal fecal supernatant. The SBR system is operated in the following sequential phases： fill period, anoxic period, aeration period, settling period, decant and idle period. The results indicated that the average removal efficiencies of COD, BOD5, TN, NH4^＋-N were 93.76%, 98.28%, 84.74% and 99.21%, respectively. The average sludge removal loading rates of COD, BOD5, TN and NH4^＋-N were 0.24 kg/（kg SS.d）, 0.08 kg/（kg SS.d）, 0.04 kg/（kg SS.d） and 0.036 kg/（kg SS.d）, respectively. Highly effective simultaneous nitrification and denitrification was achieved in the SBR system. The ratio of nitrification and denitrification was 99% and 84%, respectively. There was partial NO2^- denitrification in the system.     

甲基橙指示SnCl2还原无汞测铁法的改进

对用甲基橙指示预氧化还原无汞测铁法的实验条件进行了探讨，改进了无汞测铁法的一些具体操作步骤，使无汞测铁法的实验现象更加明显，测定精度更高，并与经典的SnCl2-HgCl2预还原测铁法进行比较，结果令人满意。     

甲基橙指示SnCl2还原无汞测铁法的改进

对用甲基橙指示预氧化还原无汞测铁法的实验条件进行了探讨,改进了无汞测铁法的一些具体操作步骤,使无汞测铁法的实验现象更加明显,测定精度更高,并与经典的SnCl2-HgCl2预还原测铁法进行比较,结果令人满意.     

零价铁还原降解活性艳红X-3B的动力学研究

研究了不同表面积的零价铁还原降解活性艳红X-3B的动力学,结果表明零价铁对活性艳红X-3B的脱色反应符合准一级动力学过程,且随着铁粉的表面积增大及溶液的pH降低,反应动力学常数增大.     

The mechanism of Fe (III)-catalyzed ozonation of phenol

Fe (III)-catalyzed ozonation yielded better degradation rate and extent of COD (Chemical Oxygen Demand) or oxalic acid as compared with oxidation by ozone alone. Two parameters with strong effects on the efficiency of ozonation are pH of the solution and the catalyst (Fe³⁺) dosage. The existence of a critical pH value determining the catalysis of Fe (III) in acid conditions was observed in phenol and oxalic acid systems. The best efficiency of catalysis was obtained at a moderate concentration of the catalyst. A reasonable mechanism of Fe (III)-catalyzed ozonation of phenol was obtained based on the results and literature. Project (No. [2003]-AM10: 15) supported by Sino-Finnish Scientific and Technological Cooperation Project     

锰镍比对Fe-Mn-Ni系TWIP合金铸铁组织和力学性能的影响

通过制备4种不同锰镍比的TWIP合金铸铁,研究了锰镍比对Fe-Mn-Ni系TWIP合金铸铁组织和力学性能的影响。试验结果表明:随着锰镍比从3∶2、2∶1、3∶1和4∶1逐渐增加,铸铁铸态组织中的碳化物含量增加。在1 050 ℃保温10 h后进行水淬,就能使碳化物分解,获得单相奥氏体基体组织。经过热处理后,锰镍比为3∶2的TWIP合金铸铁力学性能最佳,其抗拉强度为885 MPa,伸长率为29.7%。     

Simulation of top-down crack propagation in asphalt pavements

Top-down crack in asphalt pavements has been reported as a widespread mode of failure.A solid understanding of the mechanisms of crack growth is essential to predict pavement performance in the context of thickness design,as well as in the design and optimization of mixtures.Using the coupled element free Galerkin (EFG) and finite element (FE) method,top-down crack propagation in asphalt pavements is numerically simulated on the basis of fracture mechanics.A parametric study is conducted to isolate the effects of overlay thickness and stiffness,base thickness and stiffness on top-down crack propagation in asphalt pavements.The results show that longitudinal wheel loads are disadvantageous to top-down crack because it increases the compound stress intensity factor (SIF) at the tip of top-down crack and shortens the crack path,and thus the fatigue life descends.The SIF experiences a process "sharply ascending—slowly descending—slowly ascending—sharply ascending again" with the crack propagating.The thicker the overlay or the base,the lower the SIF; the greater the overlay stiffness,the higher the SIF.The crack path is hardly affected by stiffness of the overlay and base.     

复合淬火高性能ADI曲轴的研制

通过球铁曲轴的等温淬火和表面超音频淬火复合处理的工艺研究,把等温淬火和超音频淬火两种热处理技术有机地结合在一起,应用于球铁曲轴上,获得了曲轴心部为上贝氏体、残余奥氏体和微量的下贝氏体,保证了心部的高强韧性;表面淬硬层为高密度位错马氏体的综合组织,提高了表层的高耐磨性。其抗拉强度达1 200MPa以上、延长率达到4%~6%、表面硬度达50~58HRC。因此具有优良的力学性能,完全可以取代钢件曲轴应用于中、高端内燃机曲轴。     

微波消解-火焰原子吸收光谱法测定黄花菜、薇菜和核桃仁中的铜、锌、铁、锰

采用微波消解样品,用火焰原子吸收光谱法测定了黄花菜、薇菜和核桃仁中的铜、锌、铁、锰的含量。试验结果令人满意,加标回收率为95.9~105.6%,相对标准偏差为0.16~1.74%。     

无线传感网络路由协议研究新动向

无线传感器网络因其明显的性能优势和巨大的应用前景而受到学术界和工业界越来越广泛的重视。在无线传感器体系结构中,网络层路由协议是无线传感网络的核心问题。文章阐述了无线传感器网络的特点,路由协议的要求,并对重要的路由协议工作原理进行了技术分析,从协议性能的角度比较了各个路由协议的特点,最后在文中对WSN路由协议的研究仍存在的问题和挑战进行了论述,指出了未来无线传感器网络路由协议的研究方向。     

"图南"与"逍遥"--《庄子.逍遥遊》解读

《逍遥》以鲲化为鹏而“图南”开篇，这与题意及收篇的“树之于无何有之乡，广莫之野，彷徨乎无为其侧、逍遥乎寝卧其下”存在着十分明显的矛盾。自晋郭象《注》到令人陈鼓应的《庄子今注今释》，都未能对此作出符合庄子原意的令人信服的解说。通过对《逍遥》文本结构的读解，并结合《庄子》全书中关于“游”的思想的考察，提出以下观点：鲲鹏不是“逍遥游”者，不是庄子理想的人格形象，而是庄子要否定对象；蜩、学鸠与斥Yan不是像有些学者认为的是“下土”、“世俗的人”或“侏儒之群”，它们是庄子心目中的“游”者，是庄子肯定的对象。