优化处理红宝石中轻微玻璃态物质的清理实验

针对目前市场上出现的一些因优化处理而产生轻微玻璃残余物的天然红宝石,经适当浓度的氢氟酸(浓度23%)浸泡后,位于红宝石内裂隙和表面凹坑中的轻微玻璃态残余物被溶解,达到清理玻璃态残余物的目的,并利用电感耦合等离子体-原子发射光谱仪(ICP-AES)分析含玻璃材料的溶液中Si和Al的浓度分别为28.60μg/mL和2.795μg/mL,进而估算玻璃态残留物的损失量以判定热处理过程中非人为加入的玻璃态物质在红宝石中的充填程度。利用红外光谱仪对玻璃残留物清理前后的红宝石红外光谱进行对比研究得出:清理前,红外光谱显示在1 100~1 000 cm-1内有1个单峰宽谱带,谱峰为1 050 cm-1,是由νas(Si—O—Si)非对称伸缩振动引起的,表明残留物为非晶质体,750~600 cm-1之间位于744 cm-1的吸收峰为νs(Si—O—Si)对称伸缩振动引起;清理后,未检测到玻璃残余物特征的Si—O振动峰,仅具950~600 cm-1范围内的宽谱带,为刚玉Al—O基频振动谱带736、622 cm-1,体现晶质金属氧化物的特征,表明样品中玻璃态物质已被清除,实验后红宝石可被划归为经人工优化范畴。宝石显微镜下观察到清理实验后红宝石中原先被玻璃残余物所掩盖的显著内裂隙及表面凹坑。     

金标样定值中全金量的湿法分析

含金试样经王水溶解,溶液经活性炭吸附-碘量法测定溶液中的金;残渣经氢氟酸和王水再溶解,活性炭富集-火焰原子吸收测定残渣中的金;两项结果相加作为样品中金的总量。方法用于金的地质标样定值分析,结果与标准值吻合(E<3s)。     

改性海泡石回收锌渣酸浸液中镓的实验

采用改性海泡石从锌渣酸浸液中提取、回收稀散金属镓,取得了良好的试验结果。分别考察了溶液的酸度、海泡石的用量及提取时间对提取率的影响,并对镓的解吸和海泡石的再生性进行了研究。结果表明:试验料液pH值等于3,海泡石的量为3.0 g,提取时间30 min的条件下,镓的提取率大于95%,其他干扰离子Cd2 、Zn2 、Pb2 及Cu2 的提取率小于10%。提取镓后的海泡石,用2.0 mol/L HCl解吸,镓的解吸率大于99%,且解吸后的海泡石仍可循环再利用。     

碱熔-阳离子交换树脂分离ICP-MS法测定厚覆盖区地球化学调查样品中硼锗溴钼锡碘钨

多目标地球化学填图是多目标区域地球化学调查中重要的区域性基础性工作之一,为了更好地反映出地球化学背景变化,要求分析方法具有更高的准确度、精密度以及更低的检出限。地球化学调查样品中的硼锗溴钼锡碘钨主要采用单独或分组熔矿的方法进行制备和测定,操作流程长且涉及6种测定方法。本文基于前人研究,对以上7种元素的分析方法进行系统总结,采用过氧化钠-氢氧化钠碱熔,分取溶液加入柠檬酸,利用阳离子交换树脂,静态交换2～3h,除去溶液中大量的阳离子减少基体干扰,利用电感耦合等离子体质谱法(ICP-MS)测定硼锗溴钼锡碘钨含量。结果表明：7种元素的检出限分别为0.66、0.096、0.78、0.11、0.15、0.29、0.27μg/g,相对标准偏差(RSD,n=11)在2.1%～7.5%之间,均小于10%。该方法操作简便、快速,应用成本低,并且整合了相关6种分析配套方法,应用于测定厚覆盖区地球化学调查样品,精密度和准确度均满足《多目标区域地球化学调查规范(1∶250000)》(DZ/T 0258—2014)要求。     

Electron accepting capacity of dissolved organic matter as determined by reaction with metallic zinc

Information about the chemical electron accepting capacity (EAC) of dissolved organic matter (DOM) is scarce owing to a lack of applicable methods. We quantified the electron transfer from metallic Zn to natural DOM in batch experiments at DOC concentrations of 10–100 mg-C L^− 1 and related it to spectroscopic information obtained from UV-, synchronous fluorescence, and FTIR- spectroscopy. The electron donating capacity of DOM and pre-reduced DOM was investigated using Fe(CN)₆³⁻ as electron acceptor. Presence of DOM resulted in release of dissolved Zn, consumption of protons, and slower release of hydrogen compared to reaction of metallic Zn with water at pH 6.5. Comparison with reaction stoichiometry confirmed that DOM accepted electrons from metallic Zn. The release of dissolved Zn was dependent on pH, DOC concentration, ionic strength, and organic matter properties. The reaction appeared to be completed within about 24 h and was characterized by pseudo first order kinetics with rate constants of 0.5 to 0.8 h^− 1. EAC per mass unit of carbon ranged from 0.22 mmol g^− 1 C to 12.6 mmol g^− 1 C. Depending on the DOM, a calculated 28–127% of the electrons transferred from metallic Zn to DOM could be subsequently donated to Fe(CN)₆³⁻. EAC decreased with DOC concentration, and increased with aromaticity, carboxyl, and phenolic content of the DOM. The results indicate that an operationally defined EAC of natural DOM can be quantified by reaction with metallic Zn and that DOM properties control the electron transfer. Shortcomings of the method are the coagulation and precipitation of DOM during the experiment and the production of hydrogen and dissolved Zn by reaction of metallic Zn with water, which may influence the determined EAC.     

蛋白质和核糖核酸在阿哈湖沉积物中的变化特征

阿哈湖沉积物中的蛋白质和核糖核酸（RNA）随时间和沉积深度的增加逐渐被分解，其含量分别在沉积深度为17cm和19cm以后明显降低，而它们的分解产物氨基酸和核苷酸却有不同的变化规律，氨基酸在沉积深度为27－30cm的孔隙水中含量较高，这种变化规律与微生物对氨基酸和核苷酸利用的差异有关，由于地质聚合作用及矿物和有机聚合物对蛋白质的吸附作用的影响，蛋白质在沉积深度为17cm以后仍保留了一定的含量。     

Cu2+和Cd2+在蒙脱石-胡敏酸复合体上的吸附及其竞争

土壤和水体中的腐殖酸常常与粘土矿物紧密结合成为特殊的复合体.这种粘土矿物-腐殖酸复合体对重金属的吸附作用既有别于粘土矿物,更有别于腐殖酸.以蒙脱石和胡敏酸分别作为粘土矿物和腐殖酸的代表,通过一系列实验研究了Cu2+、Cd2+在单一体系和共存体系条件下在蒙脱石-胡敏酸复合体上的吸附作用,同时探讨了二者的竞争特点.实验结果表明,在单一体系条件下,蒙脱石-胡敏酸复合体对Cu2+的吸附量始终明显大于Cd2+,且二者的吸附量均随其初始浓度的增大而呈线性增大;而在Cu2+和Cd2+共存体系条件下,Cu2+的吸附量始终略大于Cd2+的吸附量,即复合体对Cu2+的吸附有较好的选择性.在吸附过程中,复合体中的蒙脱石与Cd2+和Cu2+的阳离子交换作用处于主导地位.无论是在单一体系还是在共存体系中,Cd2+优先替换电价相同而半径略大的Ca2+,而Cu2+则优先替换半径相近、电价低的Na+.因此,Cd2+的存在使Cu2+在复合体上的吸附量明显地减小,而Cu2+的存在对Cd2+的吸附几乎没有影响.这些实验结果将有助于深入探讨重金属离子在土壤、水体等环境中的迁移-固定行为.     

敞口酸溶-电感耦合等离子体质谱法同时测定地质样品中45个元素

改进了三酸(HCl-HNO3-HF)或四酸(HCl-HNO3-HF-HClO4)溶矿对难溶元素分解不彻底及对易挥发元素测定结果不稳定的现象,建立了地质样品中15个稀土元素及其常规微量元素一次溶矿、一次测定的分析方法,提高了分析质量。采用HCl-HNO3-HF-HClO4-H2SO4混合酸一次分解样品,用50%的逆王水复溶提取后定容,以Rh为内标元素,三通在线进样方式,电感耦合等离子体质谱法同时测定地质样品中45个元素的含量。讨论了分解方法对易挥发元素、难溶元素的影响,对岩石标准物质(GBW07106)、水系沉积物标准物质(GBW07303)和土壤标准物质(GBW07429)的测定值与标准值相一致,方法精密度为0.03%～4.97%。方法准确度高,简单、快捷、实用。     

Eutectoid and cotectoid petrographic types of acid volcanic and subvolcanic rocks of the continental margin volcanic belts as exemplified by East Asia

Using continental-margin volcanic belts of East Asia as an example, the petrography and geochemistry of acid volcanic and subvolcanic rocks are considered. Cotectoid and eutectoid types are distinguished among them. The eutectoid type is characterized by a disequilibrium mineralogical composition, which includes phenocrysts of early “gabbro” paragenesis (pyroxenes, calcic plagioclase, occasional olivine and amphibole) and “granite” paragenesis (K-Na feldspar, quartz, biotite) and groundmass corresponding to dry quartz-feldspathic eutectics. A linear correlation is noted between the amount of phenocrysts of gabbro paragenesis and SiO₂ content. The entire petrochemical diversity of the eutectoid-type rocks is determined by the quantitative proportions between the gabbro paragenesis and bulk composition. The cotectoid rocks are dominated by sparsely-phyric and aphyric rocks lacking melanocratic inclusions and xenogenic minerals. In the cotectoid-type rocks, the compositions of the phenocrysts and groundmass are complementary with the bulk rocks composition, indicating their equilibrium cotectic crystallization.     

葡聚糖对酸性矿山废水中次生铁矿物形成的影响

采用H2O2氧化Fe2＋并供应4种不同浓度葡聚糖的方法,探讨在H2O2氧化体系中葡聚糖对次生铁矿物形成的影响。结果表明：葡聚糖对次生矿物的形成具有明显的抑制作用;随着葡聚糖浓度的提高,次生矿物内的Fe含量降低,而S含量没有显著变化,且所有处理的K含量均较低;没有葡聚糖处理的次生矿物XRD特征峰与黄钾铁矾吻合,而添加葡聚糖后形成的次生矿物的特征峰与施氏矿物吻合,但是所有处理的次生矿物的结晶度都不高;随着葡聚糖浓度的提高,次生矿物的颗粒尺寸降低,比表面积增加。因此,葡聚糖能够抑制次生矿物的合成,并且阻止次生矿物由施氏矿物向黄钾铁矾的转变。