聚合氯化铝-壳聚糖复合絮凝剂对腐殖酸的絮凝特性研究

研究了聚合氯化铝-壳聚糖(PAC-CTS)絮凝剂的絮凝特性,进行了聚合氯化铝-壳聚糖复合絮凝剂和单独聚合氯化铝对水中溶解态腐殖酸的去除实验。结果表明:复合絮凝剂在投加量为80 mg/L时即可达到与单独聚合氯化铝投加量为150 mg/L时的去除效果,同时前者适应的pH值范围更宽;与投加量和pH值相比,水样浊度和絮凝搅拌速度是影响絮凝效果的次要因素;另外红外光谱分析发现复合絮凝剂中壳聚糖与聚合氯化铝之间存在相互作用。     

垃圾焚烧发电烟气中NO_x污染控制技术综述

垃圾焚烧技术由于其自身特点,有望成为未来中国城市垃圾处置的主要方式。而焚烧烟气中NO_x污染的控制是垃圾焚烧技术得以广泛应用的重要前提。目前处理NO_x的主流方法为SNCR和低温SCR。SNCR将还原剂直接喷入炉膛内,易操作,但脱硝效率较低。低温SCR采用低温低尘布置,能耗小,但硫酸氢铵的生成制约了低温催化剂的广泛应用。需进一步研发低温具有良好抗硫性能的催化剂,并在工程应用中优化反应器和脱硫工艺的设计,以减少NH_4HSO_4的生成,增加催化剂在线加热装置,从而延长催化剂的寿命。     

Removal of Cs from water and soil by ammonium-pillared montmorillonite/Fe3O4 composite

To remove cesium ions from water and soil, a novel adsorbent was synthesized by following a one-step co-precipitation method and using non-toxic raw materials. By combining ammonium-pillared montmorillonite (MMT) and magnetic nanoparticles (Fe₃O₄), an MMT/Fe₃O₄ composite was prepared and characterized. The adsorbent exhibited high selectivity of Cs⁺ and could be rapidly separated from the mixed solution under an external magnetic field. Above all, the adsorbent had high removal efficiency in cesium-contaminated samples (water and soil) and also showed good recycling performance, indicating that the MMT/Fe₃O₄ composite could be widely applied to the remediation of cesium-contaminated environments. It was observed that the pH, solid/liquid ratio and initial concentration affected adsorption capacity. In the presence of coexisting ions, the adsorption capacity decreased in the order of Ca^2 + > Mg^2 + > K⁺ > Na⁺, which is consistent with our theoretical prediction. The adsorption behavior of this new adsorbent could be expressed by the pseudo-second-order model and Freundlich isotherm. In addition, the adsorption mechanism of Cs⁺ was NH₄⁺ ion exchange and surface hydroxyl group coordination, with the former being more predominant.     

La0.8Ca0.2FeO3/MgAl2O4丝网整体催化剂用于低浓度甲烷催化燃烧

开发了涂覆在金属丝网基体上的La_(0.8)Ca_(0.2)FeO_3/MgAl_2O_4复合整体催化剂,用于低浓度甲烷(0.5%,体积分数)催化燃烧反应.首先用沉积-沉淀法制备了La_(0.8)Ca_(0.2)FO_3(LCF)钙钛矿与Mg Al_2O_4尖晶石复合的粉末催化剂LCF/Mg Al2O4,用程序升温微反应器(TPRS)测定了粉末活性,结合XRD、BET、SEM、TPR的表征结果,筛选出了最佳复合物质的量比和最适焙烧温度.当LCF与Mg Al_2O_4复合后,抗烧结能力增强,以拟一级反应速率常数(k,L·g~(-1)·s~(-1))计的活性提高了1倍左右.然后采用浆料涂覆法,在表面改性的金属丝网蜂窝基体上分层涂覆了作为第二载体的MgAl_2O_4和LCF/Mg Al_2O_4复合粉体涂层,考察了复合粉体球磨前焙烧的温度、第二载体及活性层涂覆量的影响.最后在空速GHSV=40000 h~(-1)条件下测试了甲烷催化燃烧反应的活性.与陶瓷基体相比,涂覆在金属丝网基体上的LCF/MgAl_2O_4活性在600℃时提升了48.1%.500 h长运转试验发现,催化剂活性在初期的200 h下降了20.3%,然后基本保持稳定.     

基于复合语言表达的装备维修合同商评价与选择

目的科学选择最优装备维修合同商。方法提出装备维修合同商的综合评价指标,建立一种同时使用比较语言和单一语言表达的装备维修合同商选择评价模型。利用层次分析法确定指标权重,采用复合语言对备选合同商的各项指标进行评价,将复合语言转换为犹豫模糊语言术语集(HFLTS),通过有序加权平均(OWA)算子计算HFLTS的模糊包络,最后应用逼近理想点(TOPSIS)法进行了合同商的评价和选择。结果通过实例验证了该选择方法的实用性和有效性。结论为军方合理选择最优装备维修合同商提供了重要模型借鉴。     

小麦秸秆驱动菱铁矿热解制备磁性生物质碳及其吸附Cd2+活性

以小麦秸秆和菱铁矿为原料,在500℃下热处理改性,制备了一种C-Fe_3O_4复合材料.采用FTIR、XRD、SEM、BET、磁化率仪对C-Fe_3O_4复合材料(以下统称复合材料)进行表征.考察了接触时间、初始pH、初始Cd~(2+)浓度、离子强度对Cd~(2+)去除率的影响,结合吸附前后表征结果分析了复合材料对Cd~(2+)的吸附机制.结果表明:复合材料及单独煅烧制备的小麦秸秆炭的比表面积分别为23.38 m~2·g~(-1)和7.20 m~2·g~(-1),孔容积分别为1.04×10-1cm~3·g~(-1)和2.23×10-2cm~3·g~(-1),平均孔径分别为17.74 nm和12.38 nm;红外光谱显示复合材料和小麦秸秆炭表面富含羧基、羟基等具有金属离子吸附活性的官能团;磁化率测试结果显示复合材料的质量磁化率为42 900×10~(-8)m~3·kg~(-1).复合材料对Cd~(2+)的吸附动力学用准二级动力学模型拟合度最好;吸附等温线符合Freundlich模型;pH在3.0~6.0之间,吸附容量随pH增大而升高,pH在6.0~9.0之间,吸附容量趋于稳定;pH在4.0~9.0之间,解析量随pH增大而减少;离子强度从1 mmol·L~(-1)增至100 mmol·L~(-1),Cd~(2+)的吸附容量略有减少,解析率由0.51%提升至8.5%;说明复合材料主要通过表面络合作用及离子交换去除溶液中的Cd~(2+).此外,复合材料的磁化性能使其在固液分离方面比一般的吸附材料具有很大优势.     

多核复合聚铝絮凝剂对水体残留铝的影响

采用分别添加金属离子Fe~(3+)和Zn~(2+)的方法制备多核复合型絮凝剂聚合氯化铝铁(PAFC)和聚合氯化铝锌(PAZC),并与市售聚合氯化铝(PAC)比较处理高岭土模拟水样后出水残留铝浓度,得出复合絮凝剂具有更低的出水余铝量及更宽的pH适用范围以及更低的投加量。达到85%COD去除率,PAZC、PAFC和PAC用量分别为5、10和20 mg/L;处理后出水残余铝量分别为0.04、0.09和0.14 mg/L;处理成本分别为0.020、0.028和0.048元/t。     

Use of best linear unbiased prediction for hot spot identification in two-way compositing

Compositing of individual samples is a cost-effective method for estimating a population mean, but at the expense of losing information about the individual sample values. The largest of these sample values (hotspot) is sometimes of particular interest. Sweep-out methods attempt to identify the hotspot and its value by quantifying a (hopefully, small) subset of individual values as well as the usual quantification of the composites. Sweep-out design is concerned with the sequential selection of individual samples for quantification on the basis of all earlier quantifications (both composite and individual). The design-goal is for the number of individual quantifications to be small (ideally, minimal). Previous sweep-out designs have applied to traditional (i.e., disjoint) compositing. This paper describes a sweep-out design suitable for two-way compositing. That is, the individual samples are arranged in a rectangular array and a composite is formed from each row and also from each column. At each step, the design employs all available measurements (composite and individual) to form the best linear unbiased predictions for the currently unquantified cells. The cell corresponding to the largest predicted value is chosen next for individual measurement. The procedure terminates when the hotspot has been identified with certainty.     

安全监控系统的防雷技术研究

雷电对安全监控系统的电子设备是非常有害的，所以必须对其进行防御。为了科学系统地设计安全监控系统的防雷方案，本文从电磁兼容的角度对雷击种类及其破坏机理的分析，掌握了雷电的耦合途径及防雷关键所在，从切断电磁耦合途径的思路入手对安全监控系统的防雷技术进行了分析与设计。利用避雷针、避雷器及屏蔽接地等方法对安全监控系统的雷击防护进行了设计，经工程实践证明本文的避雷措施是行之有效的。     

微波催化氧化处理正丁酸废水Ni-Co-Ce-O催化剂的制备及表征

采用微波催化氧化处理正丁酸模拟废水，以COD去除率为评价指标，对固相-焙烧法制备的3个系列共45种催化剂进行筛选，通过正交实验对催化剂制备工艺进行优化，并对优选出的催化剂进行XRD和SEM表征。结果表明，NiO+Co₂O₃+CeO₂（Ni∶Co=1∶1、NiO+Co₂O₃/CeO₂=1∶4）为筛选出的最优催化剂；Ni-Co-Ce-O催化剂最优制备条件为Ni：Co摩尔比1∶2、（NiO+Co₂O₃）/CeO₂质量比5%、研磨时间40 min、焙烧温度450℃、焙烧时间3 h，此条件下制备的催化剂催化效能最高，COD去除率达67%。