CdTe量子点荧光猝灭法测定赤泥中痕量镍

Cd Te量子点具有荧光强度高和稳定性好的优点,应用Cd Te量子点荧光猝灭法分析基体复杂的样品,需要有效分离对测定干扰的金属元素和高效富集待测元素。本文以巯基乙酸(TGA)作稳定剂,采用水相合成法制备了巯基乙酸修饰的Cd Te量子点,基于镍离子在p H=10.0硼砂缓冲溶液中对Cd Te量子点的荧光具有较强猝灭作用,建立了一种测定赤泥中痕量镍的荧光光度方法。荧光猝灭反应的最佳实验条件为:Cd Te量子点的浓度3.0×10-4mol/L,反应温度为室温,反应时间10 min,在此条件下镍离子浓度在2.0×10-7~7.8×10-5mol/L范围内与Cd Te量子点的相对荧光强度呈良好的线性关系;方法检出限为1.5×10-7mol/L。本方法针对Fe3+、Co2+、Cu2+等主要基体金属元素允许量低的问题,采用25%的2-羟基-4-仲辛氧基二苯甲酮肟(N530)磺化煤油萃取回收滤液中的Ni2+,镍回收率达到99%以上;赤泥中痕量镍的测定结果与催化光度法相符,加标回收率为98.3%-104.2%。     

砂质碎屑储层钙质夹层形成机理及其主控因素分析

砂岩储层中局部钙的富集是影响储层物性的重要因素之一,因此揭示钙形成的主控因素及形成机理,对油田后期的高效开发无疑具有重要意义。在砂质碎屑岩中,钙的富集一般以"钙尖"的形式产出,有顶底钙形式、也有团块状等等。本文通过物理化学分析手段,剖析钙离子的来源,钙离子富集条件及钙质沉淀机理及其主控因素。研究结果表明,钙离子主要在同生、表生与深埋成岩作用期析出,各类酸性水是其催化条件。在同生与表生作用期,在湖(海)平面下降,河道变迁等条件下,通过蒸发作用,化学反应平衡左移,形成含钙化合物沉淀。利用苏里格气田东区目的层丰富的地下水地球化学组成分析资料,经综分析表明,目的层钙质夹层形成地质条件复杂,为深埋成岩、同生与表生混合作用下的产物,其中深埋成岩作是其主要形成时期,而其余少量钙质夹层则是在同生或表生期形成,并进一步明确了深埋成岩作用是苏里格气田东区钙质夹层富集的主控因素。     

酸溶法测定硫铁矿中的全硫

在野外地质队实验室仪器少的条件下,用酸溶的方法分析硫铁矿中全硫,简单、快速、易操作,取得良好的结果。     

高硫酸盐矿山废水的处理方法研究进展

高硫煤矿闭坑后成为埋藏在地表以下深部的产酸污染场,对相邻含水层和周边环境造成了潜在危害,且因采动效应影响和矿井空间分布复杂导致相邻含水层的污染过程与污染程度评价困难。以某闭坑矿区为研究对象,选取SO₄ ²⁻作为特征污染物,考虑多煤层采动裂隙对含水层结构的破坏影响,运用数值模拟技术对闭坑矿区酸性矿井水中SO₄ ²⁻污染迁移特征进行研究,并分析流体扩散系数对含水层污染物运移的影响。结果表明：SO₄ ²⁻在二叠系童子岩组砂岩含水层中水平迁移面积随时间增大而增大,增大速率逐渐减小,垂向渗透系数扩大10倍,空间变异性增强;闭坑5、10、15 a后,最大水平迁移距离分别为215、414、612 m,最大垂向迁移距离分别达到50、65、70 m;而扩散系数越大,产酸时间越长,SO₄ ²⁻迁移距离和污染范围将随之增大,相较于水平方向,垂向上SO₄ ²⁻浓度变化对扩散系数的敏感度更高。基于模拟结果,结合闭坑矿区实际条件,针对性提出了“源头减量−过程阻断−末端治理”的综合防控与治理方案。研究结果将为该闭坑煤矿酸性矿井水污染治理与防控提供理论基础,也为其他同类矿井提供科学借鉴。

     

区域地震范围内地壳介质的低频响应

本文对于计算Pnl波格林函数的广义地震射线方法进行了改进。包括:1.简化了地震射线的描述方法;2.将射线按其运动学相似性进行分组计算,从而较大地提高了计算速度;3.进一步推广用于计算SH波部分的响应。对于1983年山东菏泽地震和1985年云南禄劝地震,用综合地震图方法模拟了763型长周期地震仪的Pnl波记录,求出两个地震的断层面解答,其结果与有关研究所得该地区构造应力场的图象基本一致。     

Kinetics of redox cycling of iron coupled with fulvic acid

The kinetics of conversion of iron(III) (hydr)oxides to ferrous iron mediated by fulvic acid have been investigated in order to improve the understanding of the redox cycling of iron at the oxic-anoxic boundary in natural waters. Under the conditions similar to natural waters, fulvic acid is able to reduce the iron(III) (hydr)oxide. The kinetics of the reaction depend on the reactivity of iron(III) (hydr)oxides and the reducing power of the fulvic acid. The rate of reaction is 60 nm/h obtained under following conditions: total concentration of Fe(III) 1.0 × 10^–4 M, pH 7.5, fulvic acid 5 mg/L. The rate is considered as a net result of reduction and oxidation in the > Fe^III-OH/Fe(II) wheel coupled with fulvic acid. In a real natural water system, reductants other than fulvic acid may be of importance. The results obtained in the laboratory, however, provide evidence that the Fe(OH)₃(s)/Fe(II) redox couple is able to act as an electron-transfer mediator for the oxidation of natural organic substances, such as fulvic acid by molecular oxygen either in the absence of microorganisms or as a supplement to microbial activity.     

Fatty acid profiles of benthic environment associated with artificial reefs in subtropical Hong Kong

Artificial reefs can enhance habitat heterogeneity, especially in seabed degraded by bottom-dredging and trawling. However, the trophodynamics of such reef systems are not well understood. This study provided baseline data on trophic relationships in the benthic environment associated with artificial reefs in late spring and mid summer of subtropical Hong Kong, using fatty acid profiles as an indicator. Data from sediments collected at the reef base, materials from sediment traps deployed on top and bottom of the reefs, total particulate matter from the water column and oyster tissues from reef surface were subjected to principal component analysis. Results showed variations of fatty acid profiles in the total particulate matter, upper sediment trap and oyster tissue samples collected in the two samplings, indicating seasonal, trophodynamic changes within the reef system. The wastes produced by fish aggregating at the reefs can also contribute a source of biodeposits to the nearby benthic environment.     

Analytical model of well leakage pressure perturbations in a closed aquifer system

Deep saline aquifers are commonly used for disposal and storage of various surface fluids. The target injection zone must be hydraulically isolated from overlying zones in order to ensure containment of the injected fluids. Improperly plugged nonoperational abandoned wells that penetrate the injection zone are the main potential leakage pathways. Leakage through such wells may cause an observable pressure signal in a zone overlying the injection zone; such a signal can be used to detect the leakage. In this paper we develop an analytical model to evaluate the pressure change induced by leakage through a well in a multilayer system. Unlike previous analytical models on the topic, our model uses a closed system, which may significantly affect the strength and behavior of the pressure signal induced by leakage. The analytical model is first presented for a two-layer system centered at the leaky well location. We evaluate the leakage-induced pressure change using the Laplace transform of Duhamel’s superposition integral, yielding the solution in the Laplace domain. We then derive a late-time asymptotic solution using the final value theorem, which suggests that the leakage rate becomes constant after sufficient time. We then obtain the multilayer solution by extending the two-layer solution and presenting it in matrix form in the Laplace domain. We apply the solution to three examples. In the first example, we apply the analytical model to a two-layer system, investigating its behavior and comparing the results with a numerical solution. In order to demonstrate behavior and potential applications of the multilayer analytical model, we present two multilayer examples: one with identical layers and another, replicating a CO₂ storage site, with dissimilar layers. The leakage-induced pressure change does not necessarily decrease as the distance increases from the injection zone toward the surface.