比色法在无机材料分析中的应用及注意事项

1比色法的应用 比色法是利用溶液颜色的深浅来确定待测物质含量的一种方法。在无机材料低含量成分分析中，与常用的滴定法、重量法比较，比色法具有较高的准确度和灵敏度。例如，TiO2滴定法，存在操作麻烦、终点颜色难以辨认的缺点。矾土、普通矿渣、铁矿石中的TiO2、MnO，粘土、水泥中的TiO2，石灰石中的SiO2、Al2O3、Fe2O3，硅砂中的Fe2O3等等，这些成份含量低，一般在5％以下，若采用滴定法分析，0．05ml的滴定量就造成较大的误差，     

碱熔-电感耦合等离子体原子发射光谱(ICP-AES)法测定水泥标准物质中的氧化物含量

电感耦合等离子体原子发射光谱(ICP-AES)法与内标法的结合扩展了ICP-AES法的分析范围。采用氢氧化钠熔融样品,ICP-AES-内标法测定各类水泥标准物质样品中SiO_2、Al_2O_3、TFe_2O_3、MgO、TiO_2等氧化物的含量。实验结果表明,标准物质测定值与标准值吻合,6次平行样品测定相对标准偏差小于1.4%。方法一次熔样,纵向测定主常量元素,操作简单,快速,准确,为水泥标准物质的研制提供了另一种定值方式。     

透辉石与透闪石的利用

透辉石是一种钙镁的偏硅酸盐矿物,其化学式为CaMg[Si_2O_6],理论化学成分为:Cao25.9％,Mgo 18.5％,SiO_255.6％。混入物有Feo和Mno,有时有Al_2O_3、Fe_2O_3、Cr_2O_3、V_2O_5及TiO_2。 透闪石也是一种钙镁的偏硅酸盐矿物,其化学式为Ca_2Mg_5[Si_5O_(11)]_2[OH]_2。理论化学成分为:CaO 13.8％、MgO 24.6％、SiO_2 58.8％、H_2O 2.8％。有时有FeO、MnO及Al_2O_3等类质同像的混入物。     

X射线荧光光谱法测定硅石中主次量元素组分

以Li_2B_4O_7、LiBO_2和LiF(质量比为45∶10∶5)为混合熔剂,NH_4NO_3为氧化剂,LiBr为脱模剂,熔融制作样片,采用硅质砂岩、石英岩标准样品和配制标准样品作为校准样品,建立了熔融制样-X射线荧光光谱法(XRF)测定硅石中主次量成分(SiO_2、Al_2O_3、TFe_2O_3、MgO、CaO、K_2O、MnO、TiO_2、P_2O_5)的快速分析方法。对样品制备以及分析测试过程中的条件进行了优化,在最优条件下,对标准样品(GBW03112、GBW07835)进行重复测定,相对标准偏差RSD<2%。同时对3个混合配制的硅石标准样品进行分析,结果与参考值无显著性差异。     

陕南镇巴地区牛蹄塘组页岩沉积环境分析

页岩的形成环境对于页岩储层评价和甜点预测具有重要意义。文章应用元素地球化学分析方法探讨陕西西乡—镇巴地区牛蹄塘组页岩沉积环境。①B含量和Sp值、Fe_2O_3/Ti O_2-Al_2O_3/(Al_2O_3+Fe_2O_3)图解、Mn_O/Ti O_2均指示牛蹄塘组沉积于大陆边缘浅海环境;②Sr/Cu、CIA和高BaXS均反映该区牛蹄塘组沉积期间气候温暖湿润,生物繁盛,水体古生产力高;③V/Cr、V/(V+Ni)、Ni/Co、Th/U、δU及草莓状黄铁矿富集表明牛蹄塘组页岩在缺氧的还原条件下沉积;④红柱石晶体、Si O_2/Al_2O_3比值及高丰度Mo、V表征牛蹄塘组页岩硅质矿物除陆源碎屑外,大部分为生物成因,仅在地层底部有少量热液成因硅。     

氧化物添加剂对氧化锌阀片电性能的影响

本文研究了添加一种或多种氧化物如Nb_2O_5、Sb_2O_3、Bi_2O_3、CoO、MnO_2、Cr_2O_3、NiO和Al_2O_3的氧化锌阀片的V-I特性,讨论了以上添加物的种类、数量及烧成温度对非线性V-I特性的影响.在所有研究的阀片中,由下面的配方制成的试样具有很好的非线性(α≈40)和大约150J/cm~3的能量承受力.87.325wt%ZnO+0.1%Nb_2O5+3.5%Sb_2O_3+6%Bi_2O_3+0.55%CoO+0.7%MnO_2+0.9%Cr_2O_3+0.9%NiO+0.025%A1(NO_3)_3     

硅铝磷酸盐玻璃——水泥回转窑内砖面釉料

此玻璃含量(重量％)为:14Al_2O_3,32.93SiO_2及53.02 P_2O_5。熔融相的公式为:Si_2AlO(PO_4)_3或4SiO_2·Al_2O_3·3P_2O_5。此玻璃能和SiO_2相(特别是方石英或鳞石英)相容,也能和莫来石相容。制造此种玻璃的配合料的组成,是在三元图上ABC三角形的组成(重量％)范围内。(A)10.5Al_2O_3,84.5SiO_2,5P_2O_5;(B)28.6     

粉煤灰空心微珠轻质保温隔热材料

波兰某大学的PAWLOWSKIS等学者,发现燃煤火力发电厂排出的粉煤灰中含有相当数量的球状空心颗粒,他们把这种空心微小颗粒叫做microspheres或cenosphere,中文称为粉煤灰空心微珠。粉煤灰空心微珠是以SiO、Al_2O_3、Fe_2O_3为主要成分,SiO_2含量占49.5—61.0％,Al_2O_3占26.0—30.0％,Fe_2O_3占4.2—10.8％。粉煤灰空心微珠内还含有CO_2气体58—85％,N_2气体15—41％。在显微镜下观     

蒸汽相水解法制备磁性光催化剂Fe_3O_4/SiO_2/TiO_2及其光催化性能

采用蒸汽相水解法,以Fe3O4纳米磁性颗粒为磁核,在其表面包覆一层SiO2来阻止光腐蚀,然后将锐钛矿相纳米氧化钛沉积在Fe3O4/SiO2颗粒表面,从而制得核壳结构的Fe3O4/SiO2/TiO2磁性复合光催化材料。用X射线粉末衍射仪(XRD)、场发射扫描电镜(FE-SEM)、高分辨率透射电子显微镜(HR-TEM)、探针式震动磁强计等手段对所制备的产物的结构、形貌、磁强度性能进行表征。以300W汞灯为光源,用亚甲基蓝和酸性红模拟污水中的有机染料来评价复合光催化剂的性能。结果表明,磁性纳米微球中TiO2的含量越大,其光催化性能越好,含TiO2质量分数50%的F3O4/SiO2/TiO2磁性纳米微球可在180min内降解亚甲基蓝模拟染料废水,降解率达99%,在80min内降解酸性模拟染料废水,降解率达98%。     

新疆东天山红云滩铁矿床磁铁矿标型和硫同位素特征及其意义

红云滩铁矿床是新疆东天山阿奇山-雅满苏构造带中一个富铁矿床,矿体赋存于石炭系雅满苏组安山质凝灰岩和晶屑凝灰岩中,呈层状、似层状或透镜状产出,矿区分为东西两个矿段。矿石以块状和浸染状为主,脉状次之,局部有条带状和网脉状。矿石矿物主要为磁铁矿,脉石矿物组合为绿泥石、石榴石、透闪石、阳起石、绿帘石和石英等。根据野外及镜下观察,可将红云滩矿床分为两期3个成矿阶段,按阶段分别为(1)火山喷溢成矿阶段,(2)矽卡岩+磁铁矿阶段,(3)石英-硫化物+磁铁矿阶段,磁铁矿主要形成于矽卡岩+磁铁矿阶段。磁铁矿的电子探针数据显示FeO含量变化较大,在88. 80%～93. 19%之间,具有低的TiO_2含量(0～0. 21%),较高的SiO_2(0～1. 77%)、MgO(0～1. 19%)、CaO(0～1. 51%)、Al_2O_3(0～0. 94%)含量,显示出热液型磁铁矿特征。TiO_2-Al_2O_3-(MgO+MnO)、TiO_2-Al_2O_3-MgO和(Ca+Al+Mn) vs (Ti+V)图解表明,磁铁矿形成与火山沉积和火山热液活动有密切关系。红云滩铁矿床黄铁矿硫同位素变化范围较大,δ~(34)S值在-3. 8‰～4. 7‰之间,指示成矿物质主要来自深部岩浆系统。红云滩铁矿床的形成在时间上和空间上均与海底火山活动密切相关,结合矿床地质特征,认为红云滩铁矿为火山喷溢-火山热液型矿床。     

新疆东天山寨北山铜矿区火山岩地球化学特征及地质意义

新疆东天山觉罗塔格构造带南缘寨北山铜矿区出露的下石炭统雅满苏组火山岩以中酸性火山岩为主,岩石类型包括安山玢岩和流纹岩,夹少量玄武安山岩以及同成分的火山碎屑岩。岩石主要为钙碱性系列,具富铝(Al_2O_3=12.23%~18.17%,平均15.5%)、低钛(TiO_2=0.12%~1.1%,平均0.55%)的特征;稀土元素整体上呈现轻稀土相对富集、重稀土相对亏损的右倾型稀土配分模式,富集K、Rb、Pb、Th等大离子亲石元素(LILE)、亏损Nb、Ta、Ti等高场强元素(HFSE);Ta/Yb值、Zr/Nb值、Zr/Y值分别为0.10~0.27、15.97~38.34和4.11~12.55。其可能形成于早石炭世古康古尔洋向南俯冲作用的岛弧环境,为俯冲洋壳与地幔楔岩石交代反应的产物。铜矿体赋存于雅满苏组火山岩中,虽与铁矿的赋矿地层雅满苏组时代相同,但赋矿火山岩岩石类型和地球化学特征不同,铜矿床含矿岩体可能是板片俯冲下大洋板片熔融,在岩浆熔融上升过程中同时析出金属,与地幔楔发生交代作用,在合适位置富集成矿。     

西藏山南努日地区比马组火山岩地球化学特征及成因

桑日群火山岩带是拉萨地块南缘火山—岩浆弧中一条非常重要的火山岩带,被认为是新特提斯洋壳沿拉萨地块南缘北向俯冲消减作用的产物,是俯冲作用的代表性岩浆记录,对了解新特提斯洋的演化历史以及拉萨地块的构造演化具有重要的意义。资料显示,位于桑日群上部的比马组在走向上岩石组合不尽相同。本文选取山南努日地区比马组中酸性火山岩为研究对象,研究显示,努日地区比马组火山岩为高SiO_2、Al_2O_3,低TiO_2、MgO、Yb,富集大离子亲石元素和轻稀土元素,亏损中稀土元素及高场强元素Nb、Ti、Ce、P的一套钙碱性火山岩系列,地球化学特征及Sr-Nd同位素显示该套火山岩是晚白垩世新特提斯洋向北俯冲、消减过程中地壳岩石发生部分熔融形成,其形成构造环境为活动大陆边缘陆侧的岛弧环境。     

Enhanced arsenic removal using mixed metal oxide impregnated chitosan beads

Mixed metal oxide impregnated chitosan beads (MICB) containing nanocrystalline Al₂O₃ and nanocrystalline TiO₂ were successfully developed. This adsorbent exploits the high capacity of Al₂O₃ for arsenate and the photocatalytic activity of TiO₂ to oxidize arsenite to arsenate, resulting in a removal capacity higher than that of either metal oxide alone. The composition of the beads was optimized for maximum arsenite removal in the presence of UV light. The mechanism of removal was investigated and a mode of action was proposed wherein TiO₂ oxidizes arsenite to arsenate which is then removed from solution by Al₂O₃. Pseudo-second order kinetics were used to validate the proposed mechanism. MICB is a more efficient and effective adsorbent for arsenic than TiO₂-impregnated chitosan beads (TICB), previously reported on, yet maintains a desirable life cycle, free of complex synthesis processes, toxic materials, and energy inputs.     

北羌塘地区冬布勒山基性、超基性岩特征及构造意义

冬布勒山基性、超基性岩产于若拉岗日逆冲断裂带北侧,近东西向展布,岩石组合为超镁铁岩及变质玄武岩,与千枚岩、硅质岩、碳酸盐岩共生,呈岩块状镶嵌于上三叠统若拉岗日岩群砂泥质复理石、中基性火山岩及灰岩中。超镁铁岩浆来自亏损的地幔,并受壳源物质混染;玄武岩贫钾富钠,属钙碱性、碱性系列,为过渡型洋脊玄武岩,它们为蛇绿岩残片,与西侧大横山、弯岛湖蛇绿混杂岩带、东部康特金—岗齐曲蛇绿混杂岩带处于同一构造带,东连金沙江蛇绿岩带,是古特提斯洋壳向北俯冲消减过程中形成的增生楔。     

河南汝州—宝丰—鲁山地区铝土矿Li、Ti、Ga、Zr、Nb和LREE的矿化特征

文章对河南省汝州—宝丰—鲁山地区铝土矿进行了稀有金属、稀土元素和稀散元素("三稀")矿化调查,发现了Li、Ti、Ga、Zr、Nb和LREE矿化信息,并显示了V、Rb和Th的异常富集信息,这为该地区铝土矿—"三稀"的综合勘查开发提供了参考。该地区铝土矿样品中的Al_2O_3与TiO_2、Zr和Nb_2O_5呈正相关关系,与Ga含量整体上呈负相关关系;铝土矿的元素含量存在一定的空间分布规律,南部张店—张八桥成矿带的Al_2O_3、Zr含量及A/S比值较高,中部观音堂—大营成矿带的TiO_2、La和Ce含量较高。综上认为,南部张店—张八桥成矿带是汝州—宝丰—鲁山地区铝土矿成矿区内铝土矿—"三稀"资源潜力较大的区段。     

东昆仑灶火河地区晚奥陶世侵入岩地球化学特征、锆石U-Pb年龄及其伸展构造环境的确定

灶火河地区位于东昆仑伯喀里克—香日德成矿带,为确定该区花岗闪长岩的形成时代、源区性质和构造背景,对其进行了LA-ICP-MS锆石U-Pb年代学和同位素及地球化学研究。结果显示岩体侵位时间为(449. 9±1. 4) Ma,属于晚奥陶世。岩石Si O2含量为71. 99%～63. 67%,Na2O含量为2. 61%～3. 43%、K2O含量为3. 56%～5. 81%,Al2O3含量为13. 31%～15. 28%,铝饱和指数A/CNK=0. 94～1. 04,介于偏铝质和过铝质之间。稀土元素分布模式为轻稀土富集,具弱负Eu异常。相对原始地幔明显富集Zr、Ga、Y和Hf等高场强元素并强烈亏损Ba、Sr、P和Ti等特征,Zr含量远高于该带内分异或者未分异的I型花岗岩,以上特征表明灶火河地区晚奥陶世侵入岩属A型花岗岩,结合岩石成岩年龄、地球化学特征以及区域构造演化,认为其为陆-陆碰撞或岛弧岩浆作用之后伸展构造环境下的花岗岩。     

Effect of inorganic, synthetic and naturally occurring chelating agents on Fe(II) mediated advanced oxidation of chlorophenols

This study examines the feasibility and application of Advanced Oxidation Technologies (AOTs) for the treatment of chlorophenols that are included in US EPA priority pollutant list. A novel class of sulfate/hydroxyl radical-based homogeneous AOTs (Fe(II)/PS, Fe(II)/PMS, Fe(II)/H₂O₂) was successfully tested for the degradation of series of chlorophenols (4-CP, 2,4-CP, 2,4,6-CP, 2,3,4,5-CP). The major objective of the present study was to evaluate the effectiveness of three representative chelating agents (citrate, ethylenediaminedisuccinate (EDDS), and pyrophosphate) on Fe(II)-mediated activation of three common peroxide (peroxymonosulfate (PMS), persulfate (PS), and hydrogen peroxide (H₂O₂)) at neutral pH conditions. Short term (4 h) and long term (7 days) experiments were conducted to evaluate the kinetics and longevity of different oxidative systems for 4-chlorophenol degradation. Results showed that each of the iron-chelating agent couple was superior in activating a particular oxidant and consequently for 4-CP degradation. In case of Fe(II)/PMS system, the inorganic chelating agent pyrophosphate showed effective activation of PMS whereas very fast dissociation of PMS was recorded in the case of EDDS without any apparent 4-CP degradation. In Fe(II)/H₂O₂ system, EDDS was proven to be the most effective whereas pyrophosphate showed negligible activation of H₂O₂. Fe(II)/Citrate system showed moderate activation of all three oxidants. PMS was found to be the most universal oxidant, which was activated by all three iron-chelating agent systems and Fe(II)/Citrate was the most universal chelating agent system, which was able to activate all three oxidants to a certain extent.     

Evaluation of distribution, mobility and binding behaviour of heavy metals in surficial sediments of Louro River (Galicia, Spain) using chemometric analysis: a case study

Contents of total and extractable heavy metals, carbonates, MnO and Fe₂O₃, organic matter, and matrix components such as SiO₂, Al₂O₃, CaO, Na₂O, MgO, TiO₂, K₂O and P₂O₅ are used along with principal component analysis (PCA) for studying distribution, mobility and binding behaviour of Cd, Cr, Cu, Ni and Pb in the Louro River (Galicia, Spain). Eleven surficial sediment samples were taken along the beds of the river course. Total metal concentrations were obtained after microwave-assisted digestion whilst extractable metal contents were obtained following a three-stage sequential extraction scheme (i.e. soluble, reducible and oxidisable fractions). Loading plots of heavy metals bound to carbonates, Fe–Mn oxides, organic matter and aluminosilicates allowed determination of binding behaviour. Correlations found indicate that Pb and Cu are mainly discharged from urban wastes, whereas Cr and Ni are from electroplating and galvanizing industries. The occurrence of diffuse pollution sources along the river can account for the binding behaviour of Cd. Metal mobility decreased in the order: Cd>Pb>Cu>Ni>Cr. Despite total contents indicating moderate-to-high heavy metal pollution in this river, metals are mostly distributed in the residual fraction, hence showing a low risk of mobility.     

Iron amendment and Fenton oxidation of MTBE-spent granular activated carbon

Fenton-driven regeneration of methyl tert-butyl ether (MTBE)-spent granular activated carbon (GAC) involves an Fe amendment step to increase the Fe content and to enhance the extent of MTBE oxidation and GAC regeneration. Four forms of iron (ferric sulfate, ferric chloride, ferric nitrate, ferrous sulfate) were amended separately to GAC. Following Fe amendment, MTBE was adsorbed to the GAC followed by multiple applications of H₂O₂. Fe retention in GAC was high (83.8-99.9%) and decreased in the following order, FeSO₄·7H₂O > Fe₂(SO₄)₃·9H₂O > Fe(NO₃)₃·9H₂O > FeCl₃. A correlation was established between the post-sorption aqueous MTBE concentrations and Fe on the GAC for all forms of Fe investigated indicating that Fe amendment interfered with MTBE adsorption. However, the mass of MTBE adsorbed to the GAC was minimally affected by Fe loading. Relative to ferric iron amendments to GAC, ferrous iron amendment resulted in lower residual iron in solution, greater Fe immobilization in the GAC, and less interference with MTBE adsorption. MTBE oxidation was Fe limited and no clear trend was established between the counter-ion (SO₄²⁻, Cl⁻, NO₃⁻) of the ferric Fe amended to GAC and H₂O₂ reaction, MTBE adsorption, or MTBE oxidation, suggesting these processes are anion independent.     

Efficiency of aluminum-iron coagulants when purifying water of clayey and humic matter

The paper has investigated coagulation activity of aluminum-iron coagulants (weight ratio of Al₂O₃ to Fe₂O₃ equals 9; 4, and 2.5) in the course of treating model water having various content of clayey (6.5–40 mg/dm³) and humic (27–75 deg) substances compared with sulfates of aluminum and iron. It has been found that for the said conditions the most effective reagent is AZhK 9 whose use makes it possible, given its lower consumption (by ～10%), to lower the content of residual aluminum by 10–15%. For reducing the latter it is possible to employ aluminum-iron reagents and with a larger fraction of iron oxide as part of the coagulant, but only when treating waters with an increased content of clayey particles.