基于电化学方法检测工作场所气体颗粒物中重金属的研究

发布时间：2018-10-11 08:12

【摘要】：随着工业生产的规模的不断扩大，重金属污染亦随之加重。然而，许多重金属加工企业往往忽视工作场所的环境污染，造成职业病患者人数逐年上升。究其原因，环境中气体颗粒物中所含的重金属是引发此类职业病的重要原因，因此对气体颗粒物的重金属进行有效的监测是环境科学和安全技术工程领域颇具价值的课题。电化学分析技术作为一种灵敏度高、操作简单、重现性好的测量方法，在痕量重金属的检测中占有重要地位。本文借鉴了溶液中重金属离子的检测原理，将其应用到气体颗粒物中。也就是，将气体颗粒物中重金属元素进行消解处理，使其分散在水溶液中。我们以电化学方法构建出一种专门检测溶液中重金属的新型传感器，并运用差分脉冲溶出伏安法对矿山、化工企业等工作场所气体颗粒物中的铅、镉、锌等重金属离子进行了检测。对传感器检测的实验条件、参数、重现性和线性关系进行了优化。在电位增量3 mV，脉冲幅度40 mV，脉冲宽度40ms，脉冲周期80 ms，HAc-NaAc缓冲液(0.1 mol/L，pH 4.0)作为反应条件下，传感器检测溶液中的Pb~(2+)和Cd~(2+)，其背景电流极小且稳定，在1μg/L～1 mg/L浓度范围内检测电流与离子浓度之间呈现出显著的线性关系。在5～1000μg/L范围内溶出峰电流与Pb~(2+)浓度的相关系数达到了0.999以上。选择1.0 V作为铅的沉积电位，Pb~(2+)的浓度与沉积时间也呈现出强相关。通过循环伏安扫描和恒电位扫描对工作电极进行活化，从而改善了电极的重现性，实验偏差明显减小。研究了汞膜电极的重复性，表明长期储存在蒸馏水中的汞膜电极能够重复使用，且在一周内保持良好的活性。上述检测所得到的结果与原子吸收法、原子发射光谱的结果进行比照，其相对误差低于5 %，，这意味着我们所构建的传感器能够有效地对气体颗粒中所含的重金属进行检测。此种检测方法具有灵敏度高，设备成本低和操作简便等特点，有望在环境保护、安全工程等行业得以广泛应用。
[Abstract]:With the continuous expansion of industrial production, heavy metal pollution is also aggravated. However, many heavy metal processing enterprises often ignore the environmental pollution in the workplace, resulting in an increase in the number of occupational disease patients. The reason is that the heavy metals contained in the gas particles in the environment is an important cause of this occupational disease. Therefore, the effective monitoring of heavy metals in the gas particles is a valuable subject in the field of environmental science and safety technology engineering. Electrochemical analysis, as a sensitive, simple and reproducible method, plays an important role in the detection of trace heavy metals. In this paper, the principle of heavy metal ion detection in solution is used as reference, and it is applied to gaseous particulate matter. In other words, heavy metal elements in gaseous particles are dissolved and dispersed in aqueous solution. We have developed a new type of sensor for the detection of heavy metals in solution by electrochemical method, and used differential pulse stripping voltammetry to detect lead and cadmium in gaseous particulates in mines, chemical enterprises and other workplaces. Zinc and other heavy metal ions were detected. The experimental conditions, parameters, reproducibility and linear relationship of sensor detection are optimized. Under the conditions of potential increment of 3 mV, pulse amplitude 40 mV, pulse width 40 Ms, pulse period 80 ms,HAc-NaAc buffer solution (0. 1 mol/L,pH 4.0) as reaction conditions, the background current of Pb~ (2) and Cd~ (2) in the solution is very small and stable. There was a significant linear relationship between the detection current and ion concentration in the concentration range of 1 渭 g/L~1 mg/L. The correlation coefficient between the peak current and the concentration of Pb~ (2) in the range of 5 渭 g / L is more than 0.999. The concentration of Pb~ (2) was strongly correlated with the deposition time when 1. 0 V was chosen as the deposition potential of lead. The working electrode was activated by cyclic voltammetry and potentiostatic scanning, thus the reproducibility of the electrode was improved, and the experimental deviation was obviously reduced. The repeatability of mercury film electrode was studied. It was shown that the mercury membrane electrode stored in distilled water for a long time could be reused and maintained good activity within one week. The results obtained above are compared with those obtained by atomic absorption spectrometry and atomic emission spectroscopy. The relative error is less than 5%, which means that the sensor we constructed can effectively detect heavy metals in gas particles. This method has the characteristics of high sensitivity, low equipment cost and easy operation. It is expected to be widely used in environmental protection, safety engineering and other industries.
【学位授予单位】：天津理工大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：O657.1;R134.4

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