去除农药废水中铜、锌离子的方法研究

研究了NaOH、Na2S沉淀法和微电解-沉淀絮凝法去除农药废水中的铜、锌离子。探讨了三种处理方法的控制因素及其对铜、锌离子去除效果的影响。最终确定处理方案为：调节含铜、锌废水pH值为8后,每升废水分别加入Na2S0.59g和0．48g,处理后溶液中铜、锌离子含量分别为6mg／L和1mg／L,可进入生化配水池稀释10倍后,铜、锌离子含量均小于1mg／L,对微生物降解无影响,达到排放标准。     

从低品位含碲废料中回收碲的研究

根据原料的物相分析和组成测定结果,表明该物料具有特殊性。此低品位含碲物料中含有大量的锌及其化合物,由于锌与碲化合物的化学性质相似,所以采用常规的酸或碱浸工艺均难以使Zn与Te分离。因此,在保证技术指标的条件下,必须以最短流程实现锌、铜与碲的分离,这是该工艺的技术关键。     

钕-铁-硼合金电镀锌的一种方法

所发明的钕-铁-硼合金电镀锌的方法为：将钕-铁-硼基体用除油剂除油，经水洗浸入盐酸水溶液中除锈，再经水洗后放人碱溶液中进行阴极处理，水洗后再放入稀盐酸溶液中进行弱腐蚀处理，水洗干净后在下列组成的钾盐光亮镀锌电解液中电镀锌，氯化锌35～100g／L；氯化钾180～220g／L；硼酸30～35g／L；B2—11光亮剂8～12mL／L。     

荧光分光光度法测定痕量锌

荧光试剂水杨醛缩邻氨基苯酚在六亚甲基四氨盐酸缓冲溶液介质中,能与锌离子形成稳定络合物使其荧光强度增强且荧光增强的程度与锌质量浓度成正比,据此建立了测定痕量锌离子的直接荧光分析方法。研究了试剂与锌的荧光反应的最佳测定条件,讨论了共存离子的影响。在入ex／em=405／517mn处,锌量在0．7—158．0μg／L范围内呈良好的线性关系。平行测定Zn2＋（100ug／L）标准溶液11次,RSD为1．98％,方法检出限为0．23μg／L。该方法重复性好、灵敏度高,简便、快速,试剂合成方法简单。可用于水样中锌的测定,回收率为101％-102％。     

锌灰制备活性氧化锌新工艺

以炼锌厂废锌灰为原料，经硫酸浸取制备活性氧化锌，考察了工艺条件对锌浸出率的影响。实验结果表明：锌灰在50℃浸取，酸用量40g／L，可使锌的溶出率达92．8％。碱式碳酸锌最佳水解温度为40℃，水解时间为2h，pH为7．5时，溶液中锌质量浓度为10g／L，得到96％以上的水解率。采用该工艺制得的氧化锌符合HG／T2572-1994。     

钛板为负极载体的酸性二次电池性能研究

在国内首次自组装了以Pt／C气体扩散电极为正极,Ti板为负极材料的新型酸性锌空气电池,进行了新电池性能测试。结果如下,实验以电流密度为20mA／cm。来恒流充放电,首次放电压平台在0．92V,充电平台在2．65V左右,充电电压在不断上升,可能是由于氧气析出后破环了Pt／C电极结构引起;在新型锌空电池的锌负极表现出优良的性能,在整个电池性能改变时,锌负极的沉积与溶出所需电压基本维持稳定状态,实验进行了七个循环,显示出酸性锌空气电池是可行的。     

仿金镀液中氯化铵的作用机理探讨

研究了氰化物仿金镀液中氯化铵的作用机理和监控方法。实验表明，当氯化铵的质量浓度≤1g／L时，镀层的颜色不够均匀，高电流密度区呈暗红色，氯化铵≥4g／L时，镀层发红。仿金镀液中不加氯化铵时，锌络离子的组成为[Zn（CN）4]^2-，锌的沉积速度较慢，镀层发红。向镀液中加2g／L-3g／L氯化铵，锌络离子转化为[Zn（CN）3NH3]^-，锌的沉积速度相对变快，镀层为仿金色。向镀液中过量加入氯化铵时，锌络离子转化为[Zn（CN）2（NH3）2]，锌的沉积速度重新变慢，镀层发红。用霍尔槽实验能够定性测定仿金镀液中氯化铵的浓度。     

稀土镧盐改性液体复合热稳定剂的性能研究

通过热烘法、电导率法、热重分析（TG）研究了液体镧盐与钙、锌、钡之间的热稳定剂协同效应。结果表明,稀土镧盐可减缓锌烧,但La／Ca／Zn三元复合热稳定剂用于PVC时,其初期着色现象明显：稀土镧用于高锌配方中发挥优良的抗锌烧性能,当锌含量3％,稀土镧4％时,PVC试片40min后才出现锌烧;La／Ba／Zn三元复合体系有显著的协同效应,La4．5％,Ba4．5％,Zn1％时,180℃下,静态热稳定时间可达45min,PVC的塑化时间、塑化温度、平衡扭矩分别为159S、177℃、18．4N·m。     

氯化物溶液中电镀锌镍合金

提出氯化物镀液中锌镍合金电镀配方，镀液中Ｎｉ＾２＋浓度不同，镀层镍含量不同。在４５－５５℃－５５℃，Ｄｋ为５－２５ｍＡ／ｃｍ＾２，镀液Ｎｉ＾２＋／Ｚｎ＾２＋／Ｚｎ＾２＋为６％－３７％时，能获得满意的镀层。结果表明，锌镍合金镀层性能优于纯锌镀层。     

锌/钴双金属氰化络合物催化环氧丙烷聚合机理

用以二乙二醇二乙醚为有机配体的锌／钴双金属氰化络合物进行了环氧丙烷的聚合，并用扩展X射线精细结构分析方法研究了催化剂激活和环氧丙烷聚合过程中锌离子和钴离子的区域结构变化。结果表明，锌／钴双金属氰化络合物催化环氧丙烷的聚合是一个活性聚合体系。在环氧丙烷聚合过程中锌离子由与3．0个氧原子配位转变为与5．7个氧原子配位，表明聚合活性中心为5．0个氧原子配位的螯合锌离子。     

Enhancement of Catalytic Activity on Pd/C and Te–Pd/C During the Oxidative Dehydrogenation of Sodium Lactate to Pyruvate in an Aqueous Phase Under Pressurized Oxygen

The oxidative dehydrogenation of sodium lactate to sodium pyruvate in an aqueous phase proceeded favorably using Pd/C and that doped with Te at 358 K with no adjustment in solution pH under pressurized oxygen, although previous reports had stated that this reaction would not proceed using Pd/C while Pd/C doped with either Pb, Bi or Te showed the activity at atmospheric pressure, 363 K, and a pH of 8.     

Alumina supported Mo–V–Te–O catalysts for the ammoxidation of propane to acrylonitrile

The effect of Te addition over Mo–V–O catalysts supported on alumina is discussed for the ammoxidation of propane to acrylonitrile. Catalyst composition and atmosphere of activation are evaluated. Catalysts are characterized before and after catalytic reaction by XPS, XRD and in situ Raman spectroscopies. The absence of Te in catalysts formulation and the presence of a high amount of vanadium induce the presence of V⁵⁺ species and the formation of V₂O₅ oxide; associated with a decrease in acrylonitrile selectivity. The presence of Mo-based polyacids structures decreases the selectivity to acrylonitrile. V⁵⁺ sites are responsible of propane activation and of the subsequent -H abstraction to form the intermediate propylene. Then, a Mo–V rutile-like structure in which vanadium species are reduced as V⁴⁺, is responsible for nitrogen insertion and acrylonitrile formation. The formation of such structure is favoured when Te is added to catalysts and is promoted during propane ammoxidation.     

Formation of an intermetallic compound Pd3Te with deactivation of Te/Pd/C catalysts for selective oxidation of sodium lactate to pyruvate in aqueous phase

The addition of a trace amount of Te promoted the activity of Pd/C in the liquid-phase oxidation of lactic acid, but the Te/Pd/C catalyst, for which Pd₃Te crystalline phase extended over the bulk at a higher Te-doping above Te/Pd = 0.3 (atom), was again inactive. A powder XRD evidence for Pd₃Te is given.     

仿生酶菌协同体系预处理木质素机理及特性

白蚁-真菌自然共生体系可有效转化木质纤维素类生物质,其本质在于对木质素物理结构的破坏和官能团的修饰,减少木质素对酶的非生产性吸附,从而提升酶解糖化效率,为生物质高效能源化利用提供新思路。本文基于白蚁肠道中存在的分解木质素酚类单元的漆酶（La）和蚁巢内降解木质纤维素的蚁巢伞菌（Te）,构建La和Te协同预处理木质素体系,比较La和典型的木质素降解菌黄孢原毛平革菌（PC）对木质素模型化合物碱木素的预处理特性。结果表明,在降解La预处理的碱木素过程中,Te产生的漆酶（La）和木质素过氧化物酶（LiP）活性最大值较未处理的碱木素样品分别提升43.3%、58.5%,PC产生的漆酶（La）和锰过氧化物酶（MnP）活性最大值较未处理的碱木素样品分别提升35.9%、31.6%。漆酶预处理强化了Te、PC对碱木素官能团的修饰和物理结构的破坏。傅里叶红外转换光谱分析（FTIR）表明酶菌协同体系处理后碱木素特征官能团的吸收峰显著降低。扫描电镜（SEM）和压汞测试结果表明酶菌协同体系对碱木素表面结构破坏严重,La和Te协同（La+Te）体系预处理后的碱木素平均孔径比单一La和单一Te分别显著提升31.1%、45.6%。经La+Te体系预处理后的碱木素最大酶吸附量较未处理的碱木素减少了51.5%,由于非生产性吸附显著减少,后续纤维素酶的转化率较未处理的碱木素样品提高了71.5%。本文证明了通过漆酶与真菌协同作用可有效改变碱木素物化特性,从而有效促进后续纤维素的酶解糖化,为木质纤维素类生物质高效利用提供指导。     

Evidence for a change in valence state for tellurium adsorbed on a Pt(111) electrode

Information about structure and chemical composition of irreversibly deposited tellurium on Pt(111) in sulphuric acid solution has been gathered ex-situ by LEED and XPS as a function of emersion potential. From the chemical shift of the Te 3d_5/2 level, a change in the valence state from Te(0) to Te(IV) with positive-going electrode potential is deduced, the total amount of Te on the surface remaining constant. XP spectra also reveal the presence of Te(II) on the surface, which may be a consequence of partial double layer collapse in the emersed state. The maximum coverage of Te(0) is around 0.4 ML, as derived by XPS and LEED. The coadsorption of anions accompanying the valence transition from Te(0) to Te(IV) has also been studied. It is demonstrated that the very first potential cycle in the region of the surface redox peak, i.e. between +0.65 and +0.45 V versus Ag/AgCl, brings about drastic changes in the adlayer properties. Although XPS has provided strong evidence for a change in the valence state of adsorbed Te on Pt(111), this system has demonstrated the limitations of the ex-situ approach to obtain electrochemical information.     

N和硫属元素掺杂及共掺杂TiO_2第一性原理计算

采用密度泛函理论(DFT)计算了N、S、Se和Te掺杂及共掺杂金红石TiO2的电子结构。针对DFT方法存在对过渡金属氧化物带隙能的计算结果与实际值严重偏离的缺陷,采用DFT+U(Hubbard系数)方法对掺杂体系的电子结构进行了计算。优化结构的结果表明,掺杂造成二氧化钛的体积膨胀和晶格畸变很明显。相比较于其他元素而言,Te更难掺杂进二氧化钛中是由于其大的原子半径和较大的取代能。能带总态密度图和分态密度图的分析表明,Ti 3d和O 2d轨道与N 2p、S 3p、Se 4p和Te 5p强烈地杂化在一起。与S、Se、Te单掺杂后带隙能比较,由计算的结果(S:2.43;Se:2.42;Te:2.46)可以看出,N/S、N/Se和N/Te共掺杂能明显地改善材料的电子结构及带隙。DFT+U计算结果与实验测量结果较好地吻合。     

Electrochemical characterization of the underpotential deposition of tellurium on Au electrode

Electrochemical characterization of the underpotential deposition (UPD) of tellurium on Au substrate has been performed in this paper. The mechanism of Te deposition and its voltammetry dependence on the Te ion concentration were studied, and it suggests that variations in the metal ion concentration may affect the UPD process kinetics. The effect of tellurium adsorbates on UPD behavior of Te has also been investigated. The results show that the tellurium adsorbates could be irreversibly adsorbed upon the Au substrate surface under the open-circuit conditions. Subsequent removal of the Te adsorbates was also proved to be very difficult within the Au double-layer region, and a standard electrochemical cleaning procedure is necessary to remove the Te adsorbates completely. When the potential was cycled into the Au oxidation region, a substantial loss of Te adsobates was observed, which occurs simultaneously with the Au oxidation features. Scan rate dependent cyclic voltammetry experiments reveal that the peak current in the Te UPD peak is not a linear function of the scan rate, ν, but of a 2/3 power of the scan rate, ν^2/3. It is in good consistent with a two-dimension nucleation and growth mechanism.     

Enhanced thermoelectric power factor and low thermal conductivity in one-dimensional Te/Ag2Te composites

We reports the synthesis and characterization of Te/Ag₂Te nanorod composites with various Ag₂Te contents. The composite samples were prepared by mixing Te and Ag₂Te nanorods synthesized by polyvinylpyrrolidone (PVP)-assisted solution-phase mixing. The thermoelectric properties of the prepared composites vary according to the Ag₂Te content. Furthermore, the samples exhibit an enhancement in electrical conductivity and a reduction in the Seebeck coefficient with increasing Ag₂Te content. The maximum power factor (350.71 µV/K at room temperature) is observed for the sample containing 30% Ag₂Te. The samples were assembled as 1D nanostructures, which led to a decrease in thermal conductivity owing to the strong phonon scattering effect. The maximum thermoelectric figure of merit (ZT) at room temperature, 0.34 was obtained for the sample with 30% Ag₂Te content. This value is 480% larger than that obtained for the pristine Te nanorod samples.     

Electrodeposition Behaviour of Cadmium Telluride from 1-ethyl-3-methylimidazolium Chloride Tetrafluoroborate Ionic Liquid

Voltammetry at a glassy carbon electrode was used to study the electrochemical deposition of Cd–Te from the Lewis basic 1-ethyl-3-methylimidazolium chloride/tetrafluoroborate air-stable room temperature ionic liquid between 80 °C and 140 °C. Deposition of tellurium alone occurs through a four-electron reduction of Te(iv) to Te which could be further reduced to Te(-ii) at a more negative potential. The Cd–Te electrodeposits could be obtained by the underpotential deposition (UPD) of Cd on the deposited Te. The UPD of Cd on Te was, however, limited by a slow charge transfer rate. Samples of Cd–Te electrodeposits were prepared on tungsten and titanium substrates and characterized by energy dispersive spectroscope (EDS), scanning electron microscope (SEM), and X-ray powder diffraction (XRD). The results showed that an excess amount of Cd(ii) was required in order to prepare CdTe codeposits with a Cd/Te atomic ratio approached 1/1. The deposit composition was independent of the deposition potential within the Cd UPD range. Raising the deposition temperature increased the UPD rate of Cd and promoted the formation polycrystalline CdTe.     

cdSe_xTe_(1-x)薄膜电极光溶解性能的研究

用循环伏安法对半导体Cdse_xTe_(1-x)薄膜电池的光溶解性能进行了研究。在1mol/L KCl溶液中测量光溶解产物的阴极还原特性,考察了在多硫化钠,多硫化钾及铁氰化钾溶液中的光腐蚀行为。用此方法还研究了薄膜电极表面的光刻蚀过程和pH的影响,并用X射线光电子能谱分析光刻进行不同时间后,电极表面发生的变化。