试纸法快速检测工业废水中重金属铜离子

介绍了一种可以快速、便捷、灵敏地进行现场半定量和定量测定水体中重金属Cu2+浓度的络天青-氨基化纤维素试纸。该试纸的检出限为0.1 mg/L,在pH值为6.0⁷.0时,检测的线性范围为0.17.0时,检测的线性范围为0.1¹0.0 mg/L,反应时间为120 s。该方法可与微型光谱仪或Cu2+标准比色板联用,可以同时进行定量或者半定量检测。该试纸弥补了显色剂易从试纸上脱落的不足,增强了试纸的稳定性与准确性。该方法可应用于工业废水中Cu2+的测定,与原子吸收分光光度法的测定结果相比较,两者基本一致。     

Ag2S/ZnS异质纳米材料的制备及尺寸调变

采用溶液-固-固法合成Ag2S/ZnS异质纳米材料;采用X射线衍射仪(XRD)、透射电子显微镜(TEM)和高分辨透射电子显微镜(HR?TEM)等对产物的物相组成、形貌和微观结构进行了表征;采用UV-Vis对材料的带隙进行表征.结果表明,通过热解银前驱体((C4H9)2NCS2Ag)的时间来改变硫化银催化剂颗粒的大小,从而调节Ag2S/ZnS异质纳米材料的直径,通过调节Ag离子和Zn离子的摩尔比来改变Ag2S/ZnS异质纳米材料的长度.得到的产物均具有火柴状结构,火柴的头部为硫化银纳米颗粒,火柴的杆部为硫化锌纳米线,且其长度、直径不一;当长度和直径在(3.57±0.83)nm和(4.20±0.86)nm时的带隙值分别为4.09 eV和4.06 eV.     

牛奶中抗生素快速检测试纸的研制

制作了牛奶中抗生素的快速检测试纸。探讨了TTC浓度、菌液浓度、浸泡时间等条件对试纸检测结果的影响。实验结果证明,抗生素检测试纸制作的最佳条件为:将中速滤纸浸泡在2%浓度的TTC试剂中5 min,干燥30 min。应用本试纸测试市售散装牛奶和袋装牛奶中氯霉素的含量,并与国标法检测结果相比较基本一致。检测试纸具有简便、快速、成本低等优点。     

胶原纤维接枝杨梅单宁负载纳米Ag的制备及其抗菌性能研究

以胶原纤维(CF)接枝杨梅单宁(BT)为载体,制备了一种新型纳米银(nAg)抗菌剂(CF-BTx-nAg).BT为一种天然的酚类化合物,将其接枝到胶原纤维上,可提高Ag的负载量、控制纳米Ag的粒径及分布.通过扫描电镜(SEM)、红外光谱(FTIR)、透射电镜(TEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)等手段对该抗菌剂的物化性能进行表征,发现该抗菌剂具有规则的纤维结构,纳米Ag颗粒的平均粒径为3.25 nm且分散均匀.抗菌实验结果表明,不同BT接枝度的CF-BTx-nAg对大肠杆菌均具有较好的抑制能力,其中CF-BT0.2-nAg的抑制能力最强.当CF-BT0.2-nAg与～105cfu/mL的大肠杆菌菌悬液在310 K、150 r/min下连续培养(Ag质量浓度为8 mg/L),培养4 h后已检测不到活细菌的存在.CF-BT0.2-nAg对大肠杆菌的最低抑菌质量浓度(MIC)≤4mg Ag/L,且CF-BT0.2-nAg至少可重复使用5次,表现出优良的抗菌性能.     

洗虾粉的快速检测方法

本文旨在通过研究,提出普通市民易于掌握且快速、简易的非法洗虾粉检测法。通过计算和实验得到制备试纸所需高锰酸钾和催化剂稀硫酸的浓度比,得到最有效的处理试纸方法,不需借助大量专业工具仅凭借试纸就可以实施特定检测。     

试纸法快速检测水中重金属铬

传统的重金属铬检测方法步骤繁琐,耗时较长,检测成本偏高.研制了水中重金属铬检测试纸,并提供了一种简便、快捷、反应灵敏、精度较高的检测方法.该法可适用于环境水中常见铬污染物的半定量测定,通过与国标法对比实验,证实了试纸法具有可靠的灵敏性.     

羟基磷灰石纳米棒的可控制备及其催化一氧化碳氧化性能

采用简单的一步水热法,以赖氨酸为沉淀剂,通过改变赖氨酸浓度,合成不同尺寸的羟基磷灰石(HAP)纳米棒,负载质量分数3%Ag制备Ag/HAP催化剂。利用Ag与HAP之间的强相互作用将Ag纳米粒子分散在HAP载体表面,使其具有较好的催化活性。活性测试发现,赖氨酸浓度为0. 20 mol·L~(-1)时,制备的Ag/HAP催化剂催化性能最好,在空速为60 000 mL·(g·h)~(-1)条件下,CO的完全转化温度为190℃。XRD和SEM表征结果表明,赖氨酸浓度对Ag/HAP催化剂的结构和性能影响较大。UV-vis、H_2-TPR和XPS测试结果表明,活性组分Ag主要以Ag~0和Ag~+的形式存在于HAP载体上,其中Ag0作为主要催化活性中心,使Ag/HAP催化剂在CO氧化反应中保持较高的活性。     

动态

美国 Environmental Test System(ETS)公司生产的环保试纸有两种不同的构形,一种与尿试纸相似由单层浸泡试剂的滤纸构成,作半定量分析;另一种是将试纸夹在两层带刻度的透明塑料膜之间构成,可进行定量测定。现已有的20多种试纸,可测定各种环境中的游离氯、总氯、游离溴、总溴、氰尿酸、总碱度、pH、总硬度、铁、铜,H_2O_2、SO_2、SO_3、细菌和霉菌等,还有可测定机动设备散热器中水的冰点和防冻剂浓度的两联试纸。上述试纸均可检测到 ppm水平,使用方便、快速,特别适合现场应用和工作人员自检。有些试纸还适用于食品加工,如细菌和霉菌     

Ag+对含砷金精矿生物浸出的影响

研究了Ag+对含砷金精矿生物浸出的影响,测量了浸出液中铁、银、砷浓度及氧化还原电位(Eh)的变化,考察了Ag+对细菌密度的影响,并对浸渣进行了光谱表征. 结果表明,Ag+对含砷金精矿的生物浸出有一定的促进作用且在高浓度Fe3+条件下催化作用明显;低Ag+浓度下含砷金精矿的生物浸出率提高约10%,但Ag+浓度过高将影响细菌生长,导致浸出速率下降. Ag+催化含砷金精矿生物浸出是Ag+取代矿物表面的砷并生成Ag2S,之后被Fe3+氧化分解,重新产生Ag+,从而加速矿物的氧化分解.     

纳米Ag/TiO2掺杂改性环氧树脂复合材料的光催化性能研究

运用原位合成法,通过改变聚合温度、Ag/TiO2的质量比、溶剂浓度等参数完善纳米Ag/TiO2环氧树脂复合材料的合成步骤.以亚甲基蓝为底物对制备的树脂涂层进行光催化测试,通过MB溶液吸光值的变化探究掺杂纳米Ag/TiO2对环氧树脂的光催化性能的改善,并对其硬度、附着力等级、抗冲击强度等基本性能与纯环氧树脂作比较,最终得...     

从卤化银废液中回收银并制备硝酸银标准溶液

利用铁与浓盐酸反应产生的H2与AgCl、AgI废液反应，可得到粗制银粉；将粗制银粉与硝酸反应转化成硝酸银后，加入紫铜，制得99．99％以上的纯银粉；再用纯银粉制备硝酸银标准溶液，从而实现了卤化银废液的有效回收。     

Electrode reaction of silver on a silver bromide crystal

The electrode reactions of silver on a silver bromide single crystal were observed employing a current step method with a small amount of electricity passed. Special attention was paid to the preparation of the electrode contact. From the overvoltage change, the kinetic parameters, i_O, Fv and a_O were obtained in the temperature range 300–400°C. It is concluded that the reactions proceed with two steps, the one is a formation of interfacial silver ions, through a charge transfer process and the other the incorporation of the formed ion into the electrolyte crystal, which is a specific character for the solid electrolyte system. In this system, the iterfacial silver ion seems to be incorporated through a vacant site of lattice with an accompanying surface diffusion.     

银镀层中银离子的迁移现象(二)

文章的第2部分论述了银镀层发生离子迁移的实验方法和检测方法.实验方法有环境实验法和溶液实验法;检测方法包括光学观察,绝缘电阻值测量,感应电特性,SEM观察,组成分析,放射化分析,软X射线观察,AFM观察和激光显微镜观察等.     

Studies on the silver/silver oxide electrode

The electrochemical behaviour of silver/silver oxides electrodes in 1 N KOH or 1 N KOH + methanol have been studied by measuring current-potential and impedance-potential curves under the potential sweep in the cathodic direction starting from the AgO formation region.Two specific anodic current peaks A and X were observed in current-potential curves. It was concluded that X was due to the incomplete oxidation of Ag₂O to AgO under the anodic sweep or due to the partial decomposition of AgO layer, and A was due to the catalytic reaction of AgO with methanol followed by the electrochemical oxidation of Ag₂O to AgO.The values of the impedance tend to decrease in the vicinity of the peak A at the low frequency, which may be attributed to the reduction of AgO with methanol.     

Antibacterial silver

The antibacterial activity of silver has long been known and has found a variety of applications because its toxicity to human cells is considerably lower than to bacteria. The most widely documented uses are prophylactic treatment of burns and water disinfection. However, the mechanisms by which silver kills cells are not known. Information on resistance mechanisms is apparently contradictory and even the chemistry of Ag(+) in such systems is poorly understood.Silver binds to many cellular components, with membrane components probably being more important than nucleic acids. It is difficult to know whether strong binding reflects toxicity or detoxification: some sensitive bacterial strains have been reported as accumulating more silver than the corresponding resistant strain, in others the reverse apparently occurs. In several cases resistance has been shown to be plasmid mediated. The plasmids are reported as difficult to transfer, and can also be difficult to maintain, as we too have found. Attempts to find biochemical differences between resistant and sensitive strains have met with limited success: differences are subtle, such as increased cell surface hydrophobicity in a resistant Escherichia coli.Some of the problems are due to defining conditions in which resistance can be observed. Silver(I) has been shown to bind to components of cell culture media, and the presence of chloride is necessary to demonstrate resistance. The form of silver used must also be considered. This is usually water soluble AgNO(3), which readily precipitates as AgCl. The clinically preferred compound is the highly insoluble silver sulfadiazine, which does not cause hypochloraemia in burns. It has been suggested that resistant bacteria are those unable to bind Ag(+) more tightly than does chloride. It may be that certain forms of insoluble silver are taken up by cells, as has been found for nickel. Under our experimental conditions, silver complexed by certain ligands is more cytotoxic than AgNO(3), yet with related ligands is considerably less toxic. There is evidently a subtle interplay of solubility and stability which should reward further investigation.     

脉冲无氰镀银及镀层抗变色性能的研究

采用赫尔槽试验筛选出一种阴离子表面活性剂及含氮杂环化合物作为脉;中无氰镀银的添加剂,并初步确定了无氰镀银的工艺条件及脉冲条件一通过正交试验进一步化化脉冲条件及镀银添加剂含量分别为：脉宽1ms、占空比10％、平均电流密度0．6A／dm^2、阴离子表面活性剂及含氮杂环化合物含量分别为12mg/L、110mg/L测定了该镀银层的耐蚀性、抗变色性能及与基体的结合力,并用扫描电镜对其微观形貌进行了观察。结果表明,脉冲无氰镀银层的抗变色性能优于直流无氰镀银层;光亮镍打底后再脉冲无氰镀银,可获得更加光亮、结晶细致的镀银层,且抗变色性能及耐蚀性均增强.     

Comparative voltammetric behaviour of the silver/silver oxide electrode prepared on vitreous carbon and silver substrates

The voltammetric behaviour of vitreous carbon/chemically precipitated silver hydroxide layer and silver/electrochemically formed silver oxide layer electrodes are compared. As the former type of electrode is free from silver substrate contributions during the oxidation-reduction cycles (ORC) the voltammetric data indicate the occurrence of soluble Ag(I) species in the gel-like silver hydroxide matrix. Soluble species can be formed during the ORC as a consequence of AgOH formation at the early stages of the oxidation and reduction processes. Nucleation and growth of new phases produce a non-homogeneous layer structure and a decrease in the amount of active material participating in the ORC under preset conditions.     

The kinetics of silver iodide film formation on the silver anode

The potentiodynamic formation of AgI films by reaction (1) on an Ag rotating disc electrode was studied and the results were compared to previous work regarding the formation of anodic AgBr and Ag₂S films,

In dilute iodide solutions, a very porous AgI film is formed at a rate controlled by the diffusion of I^? to the electrode surface. At higher iodide concentrations, and particularly in high conductivity supporting electrolytes, a porous AgI film forms at a rate initially limited by ionic migration in solution followed by diffusion of I^? in the pores of the AgI film.In 1 M NaI solutions, when AgI becomes rather soluble, thick granular AgI films form at a rate limited by the solid-state migration of ions in the bulk of the film. On the basis of the low-field model of film growth, the ionic conductivity of these AgI films has been determined to be 8.7 × 10^?5 Scm^?1     

Surface roughness of thin silver films pulse-plated using silver cyanide-thiocyanate electrolyte

We investigated the effect of the pulse current density, current-on time and current-off time on the surface roughness of a silver thin film that was pulse-plated using a silver cyanide-thiocyanate electrolyte. The interface width, which is defined by the root mean square of the fluctuations in the height of the surface, is found to decrease rapidly with the current-off time and to increase with current-on time. However, it should be noted that when the value of current-off time is sufficiently large, the interface width decreases with pulse current density. These experimental results indicate that by appropriate selection of the current-on time and current-off time, we can fabricate silver electrodeposits with minimal surface roughness. We have discussed the influence of these three parameters on the interface width from the viewpoint of the cathode potential and adsorption.