镀铬液中Cr3+离子交换分离、过铬酸戊醇体系萃取分光光度法测定

介绍了用离子交换法分离镀铬液中Cr3+离子,在硝酸介质中Cr3+被H2O2氧化为蓝色的过铬酸(H2CrO6),然后被戊醇萃取.建立了镀铬液中直接测定微量三价铬的新方法.其桑德尔灵敏度为0.098μg/cm2,Cr3+含量在1.0×10-5g/ml～1.2×10-4g/ml范围内符合比耳定律,能准确测定镀铬液中Cr3+离子.     

铝及其合金阳极氧化电解着色液中Sn~(2+)和 Ni~(2+)的连续测定

铝及其合金的阳极氧化膜的 GKC 青铜包系列电解着色液已研究开发并成功地用于生产。此着色液是锡、镍混合盐型。用碘量法测定着色液中二价锡会受到 GKC—Ⅰ或 GKC—Ⅱ严重干扰,而他二价锡结果偏高。故着色液中二价锡分析似有研究改进的必要。另外,文献未提及电解着色液中镍的分析方法。鉴于此,本文对电解着色液中二     

存在严重杂质干扰的酸性镀锌溶液的分析

当酸性镀锌溶液存在严重杂质干扰时，传统分析方法就无法准确测定镀液中各主盐的含量。给出了一组新型分析方法，分别测定了原料KCl的纯度，并测定了镀液中ZnCl2、KCl及H3BO3的含量。通过与传统方法测试结果比较表明，新方法步骤简便、快捷，消耗低，精确度高，在实际生产中取得了很好的效果。     

减少H2O2干扰测定稳定性ClO2含量的方法

用碘量法测定稳定性ClO2溶液中的ClO2含量时,当稳定液中过碳酸盐过量,测定结果会偏高.作者提出将待测样酸化后加入稍过量的K2Cr2O7与其中的H2O2反应以消除其影响,再用碘量法测定的新方法.方法操作简便,结果可靠,为较准确地检测含过量过碳酸盐的稳定性ClO2溶液中的ClO2真实含量提供了新的途径.     

铝阳极氧化膜在SeO_3~(2-)溶液中电解着色

铝阳极氧化膜在SeO_3~(2-)溶液中电解着色时在一定工艺条件下出现饱和色。增加着色电压、电流及槽液中SeO_3~(2-)浓度均不能加深饱和色;而改变槽液温度、活化条件可改变饱和色,但最深色调为桔红色。若在SeO_3~(2-)着色液中添加Cu~(2+)不再显示饱和色,可得到从浅黄到灰色等着色膜。通过分析膜层中Se及Cu含量,说明了Cu与Se发生了共沉积。     

钝化液中硝酸含量的测定(铬酸铅分离法)

钝化液中硝酸含量的测定是某厂化验室长期存在的生产关键问题。钝化液中含有硝酸、硫酸及三氧化铬,其中硝酸含量的测定因三氧化铬含量较高(200克/升),致使长期没有可靠的分析方法而影响生产。虽然有一个方法,但因 CrO_3含量较高,他们用 BaCrO_4分离法,因 BaCrO_4溶度积较大(SpBaCrO_4=     

铝阳极氧化膜在SeO2-3溶液中电解着色

铝阳极氧化膜在SeO3^2-溶液中电解着色时在一定工艺条件下出现饱和色。增加着色电压、电流及槽液中SeO3^2-浓度均不能加深饱和色；而改变槽液温度、活化条件可改变饱和色，但最深色调为桔红色。若在SeO3^2-着色液中添加Cu^2 不再显示饱和色，可得到从浅黄到灰色等着色膜。通过分挤膜层中Se及Cu含量，说明了Cu与Se发生了共沉积。     

石墨炉原子吸收光谱法测定2种植物叶中重金属含量

本文采用石墨炉原子吸收光谱法分别测定茶叶和银杏叶2种植物叶中Pb、Cd和Cr等3种重金属含量,首先对干的叶子做预处理,然后采用微波消解,最后用石墨炉原子吸收法分别测定消解样品中Pb、Cd和Cr三种元素的含量。茶叶、银杏叶中铅的含量分别0.459 mg/kg、2.45 mg/kg,镉的含量分别为0.0425 mg/kg、1.22 mg/kg,铬的含量分别为0.461 mg/kg、5.18 mg/kg,三种元素的加标回收率均在92.0%-97.3%,相对标准差均小于2.5%。表明利用石墨炉原子吸收测定茶叶、银杏叶中的铅、镉和铬的分析方法是准确的。     

COD快速测定方法的应用

作者介绍的COD快速测定法是利用强酸性消解液在加热和催化剂存在的条件下,水中还原性的物质被K2Cr2O7氧化,K2Cr2O7本身被还原生成Cr3 ,而Cr3 浓度与水样中的COD浓度成正比,通过比色测定Cr3 或Cr6 的吸光度值,从而间接快速测定水中COD的方法.该方法省时、节能,试剂用量小,能同时测定大批量水样.     

深海气田富含乙二醇产出水分析方法的建立及应用

南海西部海域深海气田产出液中乙二醇含量高达70%以上,其与水互溶特性使产出水中各离子含量测定结果存在较大偏差,严重干扰产出水样分析结果,影响到产水来源判断及MRU处理系统正常运行的诊断。本文通过不同实验分析方法比对及标准分析方法步骤优化和干扰物排除等分析手段,建立了深海气田富含乙二醇产出液的分析方法。研究结果表明,采用电位滴定法测定富含乙二醇产出水Cl^-含量;指示剂滴定法测定富含乙二醇产出水CO₃^2-、HCO₃^-含量;分光光度法测定富含乙二醇产出水SO₄^2-含量;ICP光谱法测定金属元素等,实验操作过程较简单、准确度高。通过对生产工艺节点液样进行离子含量监测,为气田生产及时诊断MRU处理系统正常有效防止天然气水合物并正确判断深海气田产水来源提供基础数据支撑,以保障深水气田的正常运行。     

Three-liquid-phase extraction and separation of V(V) and Cr(VI) from acidic leach solutions of high-chromium vanadium–titanium magnetite

A new method by liquid–liquid–liquid three phase system, consisting of acidified primary amine N1923(abbreviated as A-N1923), poly(ethylene glycol)(PEG) and (NH_4)_2SO_4 aqueous solution, was suggested for the separation and simultaneous extraction of V(V) and Cr(VI) from the acidic leach solutions of highchromium vanadium–titanium magnetite. Experimental results indicated that V(V) and Cr(VI) could be selectively enriched into the A-N1923 organic top phase and PEG-rich middle phase, respectively, while Al(III)and other co-existing impurity ions, such as Si(IV), Fe(III), Ti(IV), Mg(II) and Ca(II) in acidic leach solutions,could be enriched in the(NH_4)_2SO_4 bottom aqueous phase. During the process for extraction and separation of V(V) and Cr(VI), almost all of impurity ions could be removed. The separation factors between V(V) and Cr(VI) could reach 630 and 908, respectively in the organic top phase and PEG middle phase, and yields of recovered V(V) and Cr(VI) in the top phase and middle phase respectively were all above 90%.Various effects including aqueous p H, A-N1923 concentration, PEG added amount and(NH_4)_2SO_4 concentration on three-phase partitioning of V(V) and Cr(VI) were discussed. It was found that the partition of Cr(VI) into the PEG-rich middle phase was driven by hydrophobic interaction, while extraction of V(V) by A-N1923 resulted of anion exchange between NO_3~- and H_2V_(10)O_(28)~(-4). Stripping of V(V) and Cr(VI) from the top organic phase and the middle PEG-rich phase were achieved by mixing respectively with NaNO_3 aqueous solutions and Na OH-((NH_4)_2SO_4 solutions. The present work highlights a new approach for the extraction and purification of V and Cr from the complex multi-metal co-existing acidic leach solutions of high-chromium vanadium–titanium magnetite.     

Adsorption of chromium(VI) from aqueous solution by Artist’s Bracket fungi

The objective of this study was to investigate Artist’s Bracket (AB) fungi for the removal of Cr(VI) from aqueous solutions. The effects of pH, adsorbent dosage, temperature, contact time and initial concentration of Cr(VI) were evaluated. The optimal pH value for the removal of Cr(VI) was at pH 2. Moreover, the results showed that the adsorption of Cr(VI) decreased by increasing the initial Cr(VI) concentration and pH. The absorption of Cr(VI) on AB can be described by both Freundlich and Langmuir isotherm models. In addition, both pseudo-first-order and pseudo-second-order kinetic model well described the adsorption of Cr(VI) onto AB.     

New Red-Shade Ceramic Pigments Based on Y2Sn2−xCrxO7−δ Pyrochlore Solid Solutions

New high-stability red-shade ceramic pigments based on pyrochlore solid solutions Y₂Sn_{2− x} Cr _x O_7−δ ( x = 0–1, 0 < δ= 0–1/2 x ) were developed employing conventional solid-state reaction synthesis. The relationship between their optical properties and microstructure was analyzed by X-ray diffractometry and ultraviolet–visible-light spectroscopy. Decomposition of the structure with formation of the perovskite YCrO₃ observed for chromium substitutions x ≥ 5 was attributed mainly to high concentration of defects. The structural and optical parameters of the materials were found to correlate with the concentration of a species with higher oxidation state than Cr(III), such as Cr(IV) or Cr(V).     

Kinetics, thermodynamic and equilibrium study of Cr(VI) adsorption from aqueous solutions by NCL coal dust

The waste material NCL coal dust was used as adsorbent for removal of Cr(VI) from aqueous solutions under batch adsorption experiments. The maximum removal of 99.97% was recorded at pH 2. The time required to attain equilibrium was found to be 60 min. Adsorption kinetics was described by the Lagergren equation. The value of the rate constant of adsorption was found to be 0.0615 min^?1 at 16 mg dm^?3 initial concentration and 298 K. The applicability of the Langmuir and Freundlich equations for the present system was also tested at different temperatures: 298, 313, and 328 K. Both thermodynamic parameters and temperature dependence indicated the endothermic nature of Cr(VI) adsorption on coal dust. The results showed that NCL coal dust is a promising adsorbent for the removal of Cr(VI) from aqueous solutions.     

核桃青皮醇提物对棉织物染色性能的研究

为解决天然染料核桃青皮染色色调单一的问题,以颜色特征值和染色牢度为指标,通过单因素和正交实验优化了影响染色效果的温度、时间、pH值及核桃青皮色素染液的质量浓度等因素,比较了单金属盐的不同媒染方法和双金属盐复配对纯棉织物染色性能的影响。结果表明,核桃青皮色素染色的优化条件为：温度90oC、质量浓度71.40 g/L、染浴pH=4.0、时间140 min。核桃青皮提取液染色棉织物色谱的范围广,耐摩擦牢度好;耐皂洗牢度上单金属盐媒染是后媒＞前媒＞同浴＞直接染色,双金属盐复配及Fe3+、Fe2+、Cu2+、Al3+、Cr6+等单金属盐媒染的耐皂洗色牢度均能达到3级以上。X-射线衍射分析表明棉织物内部结构未受影响,Fe3+、Fe2+、Cr6+、Sr2+、Na+和K+等单金属盐和Fe2+/Cu2+、Fe2+/Ti4+、Cu2+/Ti4+、Cu2+/Sn2+、Al3+/Cr6+、Cr6+/Ti4+和Cr6+/Sn2+等双金属盐媒染后的棉织物紫外线防护能力增强。     

Reduction of hexavalent chromium by copper

The galvanic reaction of metallic copper in Cr(VI)-laden aqueous solutions of varying pH was examined by in situ u.v.–visible spectrophotometry, rotating disc electrode chronopotentiometry and cyclic voltammetry. The galvanic reaction in 0.2 M H₂SO₄ solutions was pseudo first order in Cr(VI) concentration. Experiments with both magnetically stirred solutions and a copper mesh or a copper film in a rotating disc electrode configuration revealed the reaction to be diffusion-controlled with respect to Cr(VI) transport to the copper surface. Finally, cyclic voltammetry data in Cr(VI)-laden media of varying pH underline the important role of protons in the galvanic reaction.     

低浓度甲烷催化燃烧特性及Cr催化剂的研究

采用浸渍法制备了不同Cr2O3含量的Cr2O3/γ-Al2O3系列催化剂,研究了Cr2O3/γ-Al2O3催化剂焙烧温度、甲烷浓度及反应空速对甲烷催化活性的影响,并考察了催化剂的抗硫中毒能力.结果表明,该法制备的Cr2O3/γ-Al2O3系列催化剂具有较好的低温催化活性,且随Cr2O3含量的增加,催化剂活性先增加后降低;Cr2O3含量为20％的Cr2O3/γ-Al2O3催化剂的甲烷催化燃烧活性与甲烷浓度呈正相关,与反应空速呈负相关关系.实验表明,400℃焙烧制备的Cr2O3含量为20％的Cr2O3/γ-Al2O3催化剂具有较好的甲烷低温催化活性,且具有较强的抗硫中毒能力.     

Experimental design and batch experiments for optimization of Cr(VI) removal from aqueous solutions by hydrous cerium oxide nanoparticles

Hydrous cerium oxide (HCO) was synthesized by intercalation of solutions of cerium(III) nitrate and sodium hydroxide and evaluated as an adsorbent for the removal of hexavalent chromium from aqueous solutions. Simple batch experiments and a 2⁵ factorial experimental design were employed to screen the variables affecting Cr(VI) removal efficiency. The effects of the process variables; solution pH, initial Cr(VI) concentration, temperature, adsorbent dose and ionic strength were examined. Using the experimental results, a linear mathematical model representing the influence of the different variables and their interactions was obtained. Analysis of variance (ANOVA) demonstrated that Cr(VI) adsorption significantly increases with decreased solution pH, initial concentration and amount of adsorbent used (dose), but slightly decreased with an increase in temperature and ionic strength. The optimization study indicates 99% as the maximum removal at pH 2, 20 °C, 1.923 mM of metal concentration and a sorbent dose of 4 g/dm³. At these optimal conditions, Langmuir, Freundlich and Redlich–Peterson isotherm models were obtained. The maximum adsorption capacity of Cr(VI) adsorbed by HCO was 0.828 mmol/g, calculated by the Langmuir isotherm model. Desorption of chromium indicated that the HCO adsorbent can be regenerated using NaOH solution 0.1 M (up to 85%). The adsorption interactions between the surface sites of HCO and the Cr(VI) ions were found to be a combined effect of both anion exchange and surface complexation with the formation of an inner-sphere complex.     

立方ZrW2O8结构类型热收缩固溶体Zr1-χMχW2-yM'yO8-z/2的研究进展

综合介绍了最近十多年,立方ZrW2O8结构类犁固溶体Zr1-xMxW2-yM'yO8-z/2(M:Hf4+,Ti4+,Sn4+,Al3+,In3+,Fe3+,Cr3+,Mn2+,RE3+;M':Mo6+, V5+)的研究进展和主要研究成果.由生成等价和低价离子取代而制备的固溶体Zr1-xMxW2-yM'yO8-z/2,可调整立方ZrW2O8,结构类型热收缩材料的有序-无序相变温度、晶胞参数,提高离了电导率,热稳定性和机械强度,不失为一种改善热收缩材料性能的途径.此外,还列举了多种合成立方ZrW2O8 结构类型固溶体和制备陶瓷材料的方法.     

35CrMo和00Cr13Ni5Mo硫化氢环境应力腐蚀开裂

用慢应变速率拉伸实验和U形试样浸泡实验、电化学极化技术并结合微观分析手段,在湿硫化氢介质中研究了35CrMo和00Cr13Ni5Mo两种钢的应力腐蚀开裂行为规律。结果表明,35CrMo和00Cr13Ni5Mo钢在实验条件下均具有一定应力腐蚀开裂（SCC）敏感性,其敏感性随着溶液pH的降低和H₂ S浓度的增大而增大;00Cr13Ni5Mo 在实验条件下抗SCC的能力均高于同条件下的35CrMo,在pH3.0的溶液中,二者性能比较接近,在pH4.5的溶液中,00Cr13Ni5Mo 耐H₂S环境SCC的性能明显提高,高于35CrMo,这主要是因为00Cr13Ni5Mo中的耐蚀合金元素增强了其钝化膜的稳定性、降低了氢脆作用所致。