Free cupric ions in contaminated agricultural soils around a copper mine in eastern Nanjing City, China

To determine the environmental free metal ion activity was a recent hot issue. A method to measure low-level free cupric ion activity in soil solution extracted with 0.01 mol/L KNO3 was developed by using cupric ion-selective electrode （ISE） and calibrating with Cu-buffer solution. Three copper buffers including iminodiacetic acid （IDA）, ethylenediamine （EN）, and glycine （Gly） were compared for calibrating the Cu-ISE curves in the range of free cupric ions （pCu^2＋） 7-13. The Cu-EN buffer showed the best electrode response and thus was applied as the calibration buffer. The pCu^2＋ of 39 contaminated agricultural soils around a copper mine was measured, ranging from 5.03 to 9.20. Most Cu in the soil solutions was found to be complexed with dissolved soil organic matters, averaging 98.1%. The proportion of free Cu^2＋ ions in the soil solutions decreased with the increasing of solution pH. Soluble Cu and free Cu^2＋ ions concentrations were analyzed by multiple linear regressions to evaluate the effects of soil properties on metal levels and speciation. The results showed that soil solution pH was the most significant factor influencing pCu^2＋ （with R^2 value of 0.76）, while not important for the soluble Cu concentration.     

硅微粉的提纯实验研究

采用选择性絮凝法对硅微粉进行提纯处理,分别探索了分散剂、絮凝剂种类及用量、pH值和沉降时间等因素对提纯效果的影响,实验结果表明,当聚乙烯吡咯烷酮、油酸钠的投加量分别80 g/t和1 824 g/t硅微粉,体系pH5.3,沉降时间50 min时,硅微粉中二氧化硅的含量从74%提高到了90.9%,提纯效果显著。     

Experimental investigation into different selectively coated receivers and silver-coated selective surface compound parabolic reflector using regression modelling for industrial heating

The paper explores the experimental results of the prototype compound parabolic trough made of mild steel and silver-coated selective surface. This prototype has been tested with top cover. The performance of the collector has been evaluated with two kinds of receivers coated with three types of black coatings. First receiver is of copper coated with black copper, second receiver is of mild steel coated with black copper and third receiver is of copper coated with black zinc. From actual field experiments, it has been observed that the efficiency of the system achieved with copper receiver coated with black copper is comparatively higher than the other two types of receivers. A simple regression analysis is used to correlate the thermal performance parameters of the system.     

柴油机SCR催化器载体结构参数优化

提出一种柴油机选择催化还原（SCR）催化器载体结构参数优化的设计方法,根据车用柴油机排量,将SCR催化器载体分为4类,选取载体体积、长度、目数、壁厚和涂层厚5个结构参数为设计变量,以高NO。转化率及低压力损失为优化目标,利用拉丁超立方实验设计选择样本点进行数值模拟,在构建的Kriging近似模型基础上,对载体结构参数采用改进的非支配排序遗传算法NSGA—II（non—dominatedsortinggeneticalgorithm—II）进行优化设计。结果表明：Kriging近似模型的拟合精度较高,结合NSGA—II算法对SCR催化器载体结构参数进行优化是可行的、有效的,不同排量下的优化结果均能够较好地满足设计要求。     

商业SCR烟气脱硝催化剂钙中毒研究

使用2种不同浓度的前驱体溶液(Ca(NO3)2和Ca(CH3COO)2溶液)浸渍新鲜商业SCR(selective catalytic reduction)烟气脱硝催化剂,并对浸渍中毒后催化剂的性能进行了研究。实验结果表明,物理中毒在本研究中占主导位置,化学中毒并不明显。采用离子色谱、氮气吸附-脱附分析、红外光谱分析、X射线衍射分析、扫面电镜分析等多种表征技术对中毒后催化剂进行了表征。结果表明,中毒后催化剂孔结构性质发生了变化,特别是Ca(CH3COO)2溶液浸渍催化剂,内部孔道堵塞较为严重。X射线衍射分析和扫描电镜分析也从另一方面说明了CaCO3的出现及积累导致催化剂脱硝效率降低。此外,催化剂红外光谱分析从表面活性位的角度说明了本研究催化剂化学中毒现象并不明显。     

改进钒基SCR脱硝催化剂的抗碱金属中毒性能

以锐钛矿型二氧化钛和钛钨粉(5%WO3-TiO2)为载体,制备了系列钒和钨负载量不同的钒钛催化剂,考察碱金属和碱土金属(钾、钠和钙)对催化剂在氨选择性催化还原(NH3-SCR)氮氧化物反应中催化活性的影响。钾、钠和钙对钒钛催化剂的中毒影响大小顺序为钾钠钙。提高钒钛催化剂中钒的含量可显著提高催化剂的SCR活性和抗碱金属中毒性能,但高钒负载量(4.5%V2O5)造成催化剂氮气选择性明显下降,氧化亚氮生成显著增加。钨的添加有利于提高钒钛催化剂的低温活性和抗碱金属中毒性能,对氮气选择性无明显影响。     

铁铈钛复合氧化物催化剂的制备及其选择性催化还原NO的性能

采用共沉淀法制备了一种新型催化剂——铁铈钛复合氧化物催化剂,研究了Fe掺加量、体积空速以及H2O和SO2的加入对其选择性催化还原NO性能的影响;采用XRD和SEM等手段对催化剂的结构和形貌进行了表征。表征结果显示,Fe的掺加使催化剂表面的颗粒更均匀,提高了催化剂的分散度。实验结果表明：以Ce（NO3）3,Fe（NO3）3?9H2O,TiOSO4?2H2O为原料、按n（Ce）∶n（Fe）∶n（Ti）=0.2∶0.8∶1配比制得的Ce0.2Fe0.8TiOx为催化剂,在反应温度250 ℃、反应时间3 h、体积空速25 000 h-1的条件下,NO去除率为99.8%,N2选择性为100%;Fe的掺加显著提高了Ce0.2Fe0.8TiOx催化剂的抗H2O和SO2的能力。     

玻璃减薄蚀刻液中氟硅酸的选择性脱除方法

光电玻璃减薄蚀刻液中氟硅酸(H2SiF6)的累积,是导致蚀刻液无法连续使用而转化为废液的主要原因。尝试对蚀刻废液中氟硅酸进行选择性脱除工艺,探索刻蚀液循环利用的有效处理方法。鉴于氟硅酸的碱金属盐具有溶解度较低的特点,研究考察了利用钠盐或钾盐为沉淀剂,将废液中的H2SiF6以氟硅酸盐的形式沉淀去除,为实现蚀刻液的循环利用提供可能。结果表明,KCl相比NaCl对H2SiF6处理效果更好,但生成的K2SiF6的结晶颗粒过细,难以自然沉降,过滤效果较差;而Na2SiF6结晶沉降特性较好,且使用NaCl为沉淀剂具有价廉易得等特点,可作为氟硅酸的理想沉淀剂。H2SiF6去除率与碱金属盐H2SiF6摩尔计量比正相关,当摩尔计量比NaCl/H2SiF6=2,H2SiF6含量10%的模拟废液,其H2SiF6去除率可达到90%以上。     

SCR脱硝尿素中微量元素的质谱法测定

建立了电感耦合等离子体质谱(ICP-MS)法测定SCR脱硝尿素中Na、Mg、Al、P、K、Ca、Cr、Fe、Ni、Cu、Zn、Pb等12种微量元素的分析方法.通过向碰撞/反应池(CRC)系统中引入氦气消除多原子离子质谱干扰,采用混合内标元素45Sc、89Y、209Bi消除基体效应.结果表明,各元素在一定范围内线性关系良好,方法的检出限为0.2～23.6 ng/L,样品的加标回收率在89.6％ ～ 108.4％之间,RSD在1.6％ ～3.8％之间.方法能准确测定SCR脱硝尿素中的多个微量元素,可用于SCR脱硝尿素的质量控制和安全评价.     

离子选择电极法测定水中氟离子影响因素的探讨

离子选择电极法测定水中氟离子的监测方法,因其操作简单、干扰少、不必进行预处理等优点,广泛应用于环境监测领域。但国家标准检测方法对检测过程条件控制及影响因素等没有明确写明。本文结合实验和文献资料,对检测过程中出现的结果偏差进行了探讨。