Electrochemical Behavior of Single CuO Nanoparticles: Implications for the Assessment of their Environmental Fate

The electrochemical behavior of copper oxide nanoparticles is investigated at both the single particle and at the ensemble level in neutral aqueous solutions through the electrode‐particle collision method and cyclic voltammetry, respectively. The influence of Cl^? and NO₃^? anions on the electrochemical processes occurring at the nanoparticles is further evaluated. The electroactivity of CuO nanoparticles is found to differ between the two types of experiments. At the single‐particle scale, the reduction of the CuO nanoparticles proceeds to a higher extent in the presence of chloride ion than of nitrate ion containing solutions. However, at the multiparticle scale the CuO reduction proceeds to the same extent regardless of the type of anions present in solution. The implications for assessing realistically the environmental fate and therefore the toxicity of metal‐based nanoparticles in general, and copper‐based nanoparticles in particular, are discussed.     

ASBR与脉冲进水SBR组合工艺处理垃圾渗滤液

为了研究厌氧-好氧工艺处理垃圾渗滤液的脱氮性能,采用ASBR联合脉冲进水SBR(脉冲SBR)处理高氨氮实际垃圾渗滤液。ASBR的水力停留时间为2d;中间水箱调节脉冲SBR的进水C/N(3～5)和NH4+-N浓度;脉冲SBR采用3次等量进水模式,运行周期分为4个缺氧段和3个好氧段,不投加外碳源,缺氧4利用污泥内碳源进行反硝化。结果表明,串联运行时期(157d)系统获得了高效的脱氮性能。ASBR进水COD为7 338～10 445mg.L-1,去除率在83%以上;脉冲SBR进水NH4+-N浓度分4个阶段逐步提高至912.0±41.7mg.L-1,总氮(TN)去除率在90%以上,出水总氮小于40mg.L-1;系统COD和总氮去除率分别在87%和97%以上。单个缺氧4进程内的内源反硝化速率(DNR)会由快变慢,而其平均理论内源反硝化速率(TDNRm)达到了1.531mgN.h-1.gMLVSS-1。在不使用物化预处理和不投加外碳源的情况下实现了对渗滤液的深度脱氮。     

Influence of zinc on electrochemical discharge activity of Mg-6%Al-5%Pb anode

Mg-6%Al-5%Pb (mass fraction) anodes with different contents of zinc were prepared by melting and casting. The electrochemical discharge behavior of these anodes in 3.5% NaCl solutions was investigated by galvanostatic test and electrochemical impedance spectroscopy (EIS). The microstructures and the corroded surfaces of these anodes were studied by scanning electron microscopy (SEM) and emission spectrum analysis (ESA). The phase structures and the corrosion products of the anodes were analyzed by X-ray diffraction (XRD). The results show that zinc promotes the grain refinement of Mg-6%Al-5%Pb anode and makes the average discharge potential of Mg-6%Al-5%Pb anode more negative during galvanostatic test. Mg-6%Al-5%Pb anode with the addition of 1% (mass fraction) zinc has the best electrochemical performance. The activation mechanism of zinc to Mg-6%Al-5%Pb anode is as follows: The hydrolyzation of dissolved Zn²⁺ ions reduces the pH value of the solution near the surface of the anode and accelerates the dissolution of Mg(OH)₂ film; The precipitated Zn(OH)₂ with similar structure as Mg(OH)₂ combines with Mg(OH)₂ film easily and makes it break down.     

氯酸盐复合吸收剂同时脱硫脱硝试验研究

通过一种新型的NaClO/NaClO2复合吸收剂,在小试级别的喷淋塔装置内进行同时脱硫脱硝试验研究.通过考察各种工艺运行参数对脱除效率的影响,确定了NaClO/NaClO2复合吸收液同时脱硫脱硝的工艺条件:NaClO浓度为4mmol/L,NaClO2浓度为2mmol/L,吸收液初始pH值为5.5,液气比为25L/m3,烟气流量为20m3/h,反应温度为50℃.最佳工艺条件下,平均脱硫脱硝率可分别达到99.7%,93.9%.NaClO/NaClO2复合吸收剂成本比单纯使用NaClO2要低,而脱硝效率有较大提高.     

焦化废水的亚硝化反硝化研究

为了确证脱酚焦化废水亚硝化型硝化及以焦化废水中的氨酚为电子供体实现亚硝酸盐的反硝化的可行性，以模拟SBR法的好氧与厌氧过程，对脱酚后的焦化废水实现了亚硝化型硝化，产生的亚硝酸盐浓度达到117.6mg/L，以未脱酚的焦化废水中的酚，氨为电子供体，实现了亚硝酸盐的反硝化。     

电化学方法脱除高岭土中铁、钛杂质的研究

除去高岭土中铁、钛等杂质，有利于它的广泛应用．对淮北地区高岭土进行电化学处理，并对处理前后的试样进行了SiO2，Al2O3，Fe2O3和TiO2含量的测定，发现在保持SiO2和Al2O3总量基本不变的前提下，Fe2O3，TiO2的脱除率分别达到60．0％和31．7％．同时配合透射电子显微镜、X-衍射和EDX能谱对样品进行分析．结果表明，电化学处理后的高岭土颗粒明显细化，铁、钛含量明显减少．     

混凝土中变形与光圆钢筋腐蚀速率试验研究

为了比较含氯离子的混凝土中变形钢筋及光圆钢筋腐蚀特征和腐蚀速度的不同，制作了同时含有变形和光圆2种钢筋并掺加了质量为水泥质量3％的盐ω（NaCl）的混凝土试件，然后进行了近一年的室外自然气候暴露试验．试验期间利用电化学线性极化法和试件腐蚀失重称量方法测试了2种钢筋的腐蚀速度；并分析和总结了它们的腐蚀特征．试验结果表明光圆钢筋的腐蚀机理主要是微电池腐蚀，腐蚀形态比较均匀，平均腐蚀失重率比变形钢筋大；而变形钢筋腐蚀机理主要是宏电池腐蚀，腐蚀主要发生在钢筋表面某几个局部区域，局部最大坑蚀深度约为光圆钢筋最大坑蚀深度的1．7倍．     

关于燃煤电厂脱除NOx的技术分析

本文简要介绍了燃煤电厂NOx形成的原因。在对火电厂炉内和烟气中脱氮技术分析的基础上,针对我国国情和现阶段我国烟气净化的发展状况,提出了烟气脱氮技术在我国的实施建议。     

微波诱导催化还原脱硫脱硝实验研究

针对我国电厂烟气治理的现状,进行了微波诱导催化还原脱硫、脱硝实验研究。该方法具有同时脱除烟气中污染物二氧化硫、氮氧化物的能力。利用微波装置和活性炭研究了模拟烟气同时脱硫脱硝,利用此技术可以将96%的一氧化氮和二氧化硫一步分解为环境友好的氮气和可以回收的有价值的单质硫。利用正交实验设计,对一些主要反应参数对脱硫脱硝的影响进行了分析。