College of Geology and Environment, Xi'an University of Science and Technology, Xi'an, Shaanxi 710054, China.
College of Geology and Environment, Xi'an University of Science and Technology, Xi'an, Shaanxi 710054, China; Shaanxi Provincial Key Laboratory of Geological Support for Coal Green Exploitation, 710054, China; Key Laboratory of Coal Resources Exploration and Comprehensive Utilization, Ministry of Land and Resources, China.
Sci Total Environ. 2022 Aug 1;832:154925. doi: 10.1016/j.scitotenv.2022.154925. Epub 2022 Mar 30.
Radon gas is a cancer risk and exists naturally in certain soils, such as loess, which is an important raw earth construction material in arid regions such as northwestern China and southern USA. Accordingly, the radon exhalationed from building materials is of increasing concern; however, there is little research on radon exhalation from loess. In this study, the pore structure and radon exhalation characteristics of heat-treated loess were investigated by nitrogen adsorption tests, swept surface electron microscopy, and radon measurements. The rate of radon exhalation increases linearly with temperature until 400 °C and then decreases exponentially. Changes in the internal pore structure (pore type, surface morphology, and specific surface area) of loess are strongly correlated with the radon exhalation rate. The volume of micropores (<2 nm diameter) is an important influence on radon exhalation ability, which is closely related to the fractal dimension of the micropore structure after heating. The results provide guidance for predicting the radiation risk posed by radon diffusing from loess.
氡气是一种致癌风险，存在于某些土壤中，如黄土，黄土是中国西北和美国南部等干旱地区重要的原生土建筑材料。因此，建筑材料中释放的氡越来越受到关注；然而，关于黄土中氡的释放研究甚少。本研究通过氮气吸附试验、扫描表面电子显微镜和氡测量，研究了热处理黄土的孔隙结构和氡释放特性。氡的释放率随温度呈线性增加，直到 400°C，然后呈指数下降。黄土内部孔隙结构（孔隙类型、表面形貌和比表面积）的变化与氡释放率密切相关。微孔（<2nm 直径）的体积对氡的释放能力有重要影响，这与加热后微孔结构的分形维数密切相关。研究结果为预测从黄土中扩散的氡辐射风险提供了指导。
