【摘要】 工业废水排放是造成水系中重金属元素Cd污染的重要因素，如排放不当可能会造成严重的环境污染，人长期食用Cd污染环境中的农作物或者水生生物，会引起各类疾病，对身体造成严重的伤害，所以及时检测重金属元素Cd含量对工业废水的处理与排放十分重要。与传统检测方法比，能量色散X射线荧光（EDXRF）分析具有速度快、不损坏样品、操作简单、仪器体积小等优点，更加适合应用在工业废水处理现场，实现对工业废水中重金属元素的快速检测，为工业废水的处理提供依据。开展EDXRF法现场快速检测工业废水中Cd元素含量影响因素的研究，检测对象是未经处理流动的工业废水，为了不影响工艺流程，废水样品将流过一段工艺管道，EDXRF检测装置将安装在工艺管道外部，推导了管道为方形管道，X射线源和探测器分别垂直位于方形管道两个相邻平面时，X射线荧光分析的数学模型，仿真分析了不同管道几何参数和“源-样-探”几何位置对待测元素Cd特征X射线照射量率的影响，通过蒙特卡罗方法模拟验证理论分析的准确性，并得出方形管道样品的最佳激发-探测装置及其优化参数。文中根据建立的数学模型进行MATLAB仿真研究，工业废水溶液设定为Cd元素浓度为100 000μg·mL^-1,介质为浓度为1.09 mol·L^-1的HNO₃的溶液，设定入射光射线能量为40 keV,带入参数计算，得到管道壁材料、管道壁厚、探测器高度、 X射线源水平距离对标样中待测元素Cd特征X射线照射量率变化趋势的影响。同时建立蒙特卡罗模型，模拟研究了源出口到样品侧面水平距离与准直器直径、“源-样”距离、“样-探”距离、探测器高度、管道壁厚度和管道壁材料对样品中待测元素Cd特征峰净峰面积和峰背比的影响，得到管道壁厚度在工艺允许的条件下尽可能的薄，常见管道材料选择聚丙稀酸脂塑料作为管道材料更佳，“样-探”距离为1mm,“源-样”距离和探测器高度在客观条件，比如器件几何尺寸，器件固定条件等允许的情况下，越小越好，当源出口到样品侧面水平距离为2.8 mm,准直器直径为2 mm, Cd的特征峰的峰背比和净峰面积会有一个最佳值。更多还原

【Abstract】 Industrial wastewater discharge is an important factor causing heavy metal element Cd pollution in water systems. Improper discharge may cause serious environmental pollution. Long-term consumption of crops or aquatic organisms in Cd-contaminated environments will cause various diseases and cause serious harm to the body. Therefore, timely detection of the heavy metal element Cd content is very important for treating and discharging industrial wastewater.Compared with traditional detection methods, energy-dispersive X-ray fluorescence（EDXRF） analysis has the advantages of fast speed, no damage to samples, simple operation, and small instrument size. It is more suitable for application in industrial wastewater treatment sites to detect heavy metal elements in industrial wastewater rapidly. Detection provides a basis for the treatment of industrial wastewater. This article conducts research on factors affecting the on-site rapid detection of Cd element content in industrial wastewater using the EDXRF method. The detection object is untreated flowing industrial wastewater. In order not to affect the process flow, the wastewater sample will flow through a section of the processingpipeline, and the EDXRF detection device will be installed. Outside the processing pipeline, this paper deduces the mathematical model of X-ray fluorescence analysis when the pipeline is square and the X-ray source and detector are vertically located on two adjacent planes of the square pipeline. The simulation analyzes different pipeline geometric parameters and “source-sample”-Explore the influence of the geometric position of the element to be measured on the characteristic X-ray irradiation rate of Cd, verify the accuracy of the theoretical analysis through Monte Carlo method simulation, and obtain the optimal excitation-detection device and its optimized parameters for the square pipe sample.This article conducts MATLAB simulation research based on the established mathematical model. The industrial wastewater solution is set to have a Cd element concentration of 100 000 μg·mL^-1, the medium is an HNO₃ solution with a concentration of 1.09 mol·L^-1, and the incident light ray energy is set to 40 keV, which is brought into parameter calculation, the effects of pipe wall material, pipe wall thickness, detector height, and horizontal distance of the X-ray source on the changing trend of the characteristic X-ray intensity of the element Cd in the standard sample were obtained. At the same time, a Monte Carlo model was established to simulate and study the source outlet ofthe sample. The simulation study was conducted to investigate the influence of the horizontal distance from the source outlet to the sample side, collimator diameter, “source-sample” distance, “sample-detector” distance, detector height, pipe wall thickness, and pipe wall material on the net peak area and peak-to-background ratio of the Cd characteristic peak in the sample. It is found that the pipe wall thickness should be as thin as possible under allowable process conditions, and the commonly used pipe material is better to be polypropylene acid ester plastic. The “sample-detector” distance is 1 mm. The “source-sample” distance and detector height should be as small as possible under objective conditions, such as the device’s geometric size and the device’s fixing conditions. When the horizontal distance from the source outlet to the sample size is 2.8 mm and the collimator diameter is 2 mm, the peak-to-background ratio and net peak area of the Cd characteristic peak will reach an optimal value.更多还原