Improved formic acid oxidation using electrodeposited Pd–Cd electrocatalysts in sulfuric acid solution

In the present research, nanostructured Pd–Cd alloy electrocatalysts with different compositions were produced using the electrodeposition process. The morphology of the samples was studied by scanning electron microscopy analysis. Also, the elemental composition of the samples was determined by energy-dispersive X-ray spectroscopy and elemental mapping tests. Tafel polarization and electrochemical impedance spectroscopy methods were employed to determine the electrochemical corrosion properties of the synthesized samples in a solution containing 0.5 M sulfuric acid and 0.1 M formic acid. The linear sweep voltammetry, cyclic voltammetry, and chronoamperometry techniques were also employed to evaluate the electrocatalytic activity of prepared samples toward the oxidation of formic acid. In this respect, the influence of some factors such as formic acid and sulfuric acid concentrations and also potential scan rate was investigated. Compared to the pure Pd sample, the Pd–Cd samples were more reactive for the oxidation of formic acid. Besides, the sample with a lower amount of Pd (Pd_1·3Cd) demonstrated much higher electrocatalytic activity than the Pd_7·1Cd and Pd_2·1Cd samples. The observed high mass activity of 15.06 A mg^?1_Pd for the Pd_1·3Cd sample which is 21.1 times higher than Pd/C is an interesting result of this study.     

用迁移率和载流子浓度研究碲镉汞中的深能级

获得了一种研究碲镉汞深能级的方法。通过分析迁移率 载子浓度与温度的关系，可以得到关于深能级的重要依据。     

高阻值Cd1-xZnxTe晶体的生长及其性能测试

通过适当的工艺措施，采用Bridgman法生长了直径为30mm的X射线及γ射线探测器级的Cd.9Zn0．1Te晶锭．测试结果表明：该晶锭结晶质量良好，位错密度低，成分均匀，杂质含量低，红外透过率和电阻率都十分接近本征Cd.9Zn0．1Te的值．并从晶体的生长特性、缺陷和杂质的角度，分析了生长高性能晶体的条件，研究了生长Cdl-xZnxTe晶体的x值与缺陷和杂质浓度之间的关系．     

Alleviation Effect of Lanthanum on Cadmium Stress in Seedling Hydroponic Culture of Kidney Bean and Corn

Since1970s,rare earths(RE)have been exten-sively used as micro-fertilizers for crops in China.Ithas already been proved that REcani mprove the pro-duction and quality of crops.However,there havebeen a fewinvestigations about using RE as regulatorin pollution ecology.For example,An et al[1]studiedthe effects of O3on wheat growth and the protectiveeffect of RE.Yan and Zhou et al[2,3]discussed theprotective effect of RE on plants under acid rainstress.Jia et al[4]and Hu et al[5]reported th…     

湿法炼锌制镉碱渣综合回收实践

采用高温高酸氧化浸出工艺对湿法炼锌粗镉生产过程产出的制镉碱渣进行处理。通过“电解液+锰粉氧化浸出”与“电解液直接浸出”制镉碱渣小试工艺试验对比,获得高温高酸氧化浸出的工艺参数为：浸出温度85~90 ℃、浸出时间8 h以上、液固质量比~4 g/g,锌、镉高温高酸氧化浸出率分别达到96.88%、95.35%。通过工业化实践,将某锌冶炼厂长期堆存的制镉碱渣有效处理,实现锌、镉等有价金属的回收,提高金属回收率,同时避免含隔渣长期堆存带来的环保风险,具有较好的经济和环境效益。     

TAM胶粘剂中铅镉汞铬砷有害元素的同时测定

研究了HF +HCl消解样品 ,试液用ICP -AES法同时测定TAM胶粘剂中铅、镉、汞、铬、砷的新方法。在选定的最佳条件下测铅、镉、汞、铬、砷的检出限分别为 0 .0 0 15、0 .0 0 0 8、0 .0 0 11、0 .0 0 17、0 .0 0 0 9μg·L- 1 ,回收率为 93 .5 %～ 10 8.3 % ,RSD为 0 .62 %～ 5 .65 %。该法准确、快速、简便 ,应用于TAM胶粘剂的测定 ,结果满意     

硫硒化镉大红釉的研究

综述了硫硒化镉大红釉的研究状况，分析了各种充硒化镉釉制备方法的优缺点。提出了独特的硫硒化镉系列色釉的制备工艺－－多熔块反应法。     

球形零价铁生物炭吸附Cd(II)的性能和机制

本研究提供了一种一步热解法制备纳米零价铁生物炭的方法。将海藻酸铁在高温缺氧条件下热解制备了球形零价铁生物炭复合材料（ZVIBC），考察了Cd(II)溶液pH、初始浓度、吸附时间、背景离子、空气中老化时间对ZVIBC吸附Cd(II)性能的影响，通过FTIR、XRD、XPS、EDS等方法对ZVIBC以及ZVIBC-Cd(II)进行了表征，研究了ZVIBC对Cd(II)的吸附机理。结果显示：pH对ZVIBC吸附Cd(II)有显著的影响，4为最佳吸附pH条件。ZVIBC吸附Cd(II)的过程符合Langmuir模型，拟合的饱和吸附量为240 mg/g。主要吸附机理为：活性官能团（O—H、C—O、C=C、C=O、COO）与Cd(II)形成配合物，以及Cd(II)与Fe2+生成Cd(OH)2沉淀。     

钾对土壤镉有效性的影响及其机理

分析了不同用量钾肥对土壤镉有效性的影响,采用盆栽与等温吸附试验,研究了镉污染赤红壤上,施用钾肥对小油菜生物量、镉吸收量与土壤溶液中钾、镉含量及土壤镉吸附等的影响.结果表明:无论是低镉还是高镉污染水平,与对照相比,小油菜干质量均以高钾用量增幅最大,两季平均增加分别为16.6%(低镉)和17.7%(高镉).在低、高镉两种污染水平下,增加钾肥的施用量,土壤溶液中钾含量明显增加,小油菜体内钾含量也明显增加.钾肥施用量为195 mg/kg时,土壤溶液中镉含量最高,较对照分别增加2.80%(低镉)与23.7%(高镉);而小油菜体内镉含量较对照平均分别增加10%(低镉)和45.9%(高镉).钾离子与镉共存时,明显改变土壤吸附镉的能力,与钠体系相比,钾体系赤红壤的总吸附容量降低了31.3%.钾与镉共存时,土壤对镉的吸附作用明显影响小油菜对镉的吸收,是控制土壤镉有效性的关键因子.     

含氮大分子吸附剂的制备及其对Cd(II)的吸附

利用三聚氯氰的温度梯度反应活性,在较低温度下,用多乙烯多胺与三聚氯氰进行亲核取代反应,合成出一种以三嗪环为连接点的不溶含氮大分子颗粒吸附剂(N-MGA),并将其用于去除水体中的Cd(Ⅱ).通过元素分析、FTIR和SEM对N-MGA进行表征,同时对Cd(Ⅱ)的吸附进行吸附动力学、等温吸附模型拟合和吸附机理进行研究,考察了溶液pH对Cd(Ⅱ)吸附性能的影响、吸附剂的吸附-解吸再生循环性能及结构稳定性.结果表明,该吸附剂对Cd(Ⅱ)的吸附机理是利用吸附剂氨基上氮的孤对电子与Cd(Ⅱ)的配位络合作用进行吸附,且吸附过程符合准二级动力学模型和Langmuir吸附等温线模型,最大吸附量可达539.1 mg/g,且对Cd(Ⅱ)的吸附较为容易,吸附能力较强;在Cd(Ⅱ)初始质量浓度为3636.5和70.0 mg/L时,对Cd(Ⅱ)的吸附率分别可达97.5％和99.9％,且10次吸附-解吸再生循环中吸附率维持在97.0％～98.2％,解吸率均在97.6％以上,吸附剂回收率均在92.0％以上.