Department of Civil and Environmental. Universidad de la Costa, CUC, Calle 58 # 55-66, Barranquilla, Atlántico, Colombia.
Department of Civil and Environmental. Universidad de la Costa, CUC, Calle 58 # 55-66, Barranquilla, Atlántico, Colombia; Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
Chemosphere. 2020 Jun;248:125946. doi: 10.1016/j.chemosphere.2020.125946. Epub 2020 Jan 28.
Sediments from coal mine drainages (CMDs) contain large quantities of suspended pollutants (possibly numerous chemical substances) along with sulfates and hazardous elements (e.g., chromium, zinc, copper, lead) that irreversibly accumulate in the water. As this accumulation can continue for decades after discontinuation of coal extraction, it is necessary to employ multidisciplinary approaches to control the threat in such zones. The quantity of amorphous material in some CMDs was evaluated by X-ray powder diffraction (XRD) using the Rietveld-based SIROQUANT software package. Modern Dual Beam Focused Ion Beam (FIB), field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscope (H-TEM), and energy-dispersive X-ray spectrometer (EDS) were used to evaluate the occurrence and transformation of nanophases (NPs). FIB is used to determine the 3D distribution of different species (internal structure) within individual NPs, whereas EDS is used to observe NP features (e.g., shape, constituent, range, assembly, and form of polymerization). The mineralogy of the sediment from the Brazilian CMDs, including the proportions of quartz, clays, Al-Fe-oxides, and amorphous NPs, appears to be related to the nature of the mineral matter in the relevant coal cleaning rejects (CCRs). The sediments of CMDs from the Brazilian coal area derived at a lower-pH range have different amorphous compositions as compared to those derived at a higher pH range. These special amorphous compositions are shown to be related to several other sediment properties such as particle surface area. The information gleaned in this study will be useful for further geochemical evaluation of CMDs in other parts of the world.
煤矿排水 (CMD) 中的沉积物含有大量悬浮污染物（可能包括许多化学物质）以及硫酸盐和有害元素（例如铬、锌、铜、铅），这些物质会在水中不可逆转地积累。由于在停止采煤几十年后，这种积累仍会持续，因此需要采用多学科方法来控制这些地区的威胁。使用基于 Rietveld 的 SIROQUANT 软件包通过 X 射线粉末衍射 (XRD) 评估了一些 CMD 中的无定形物质的数量。现代双束聚焦离子束 (FIB)、场发射扫描电子显微镜 (FE-SEM)、高分辨率透射电子显微镜 (H-TEM) 和能量色散 X 射线光谱仪 (EDS) 用于评估纳米相 (NPs) 的发生和转化。FIB 用于确定单个 NPs 内不同物质的 3D 分布（内部结构），而 EDS 用于观察 NPs 的特征（例如形状、成分、范围、组装和聚合形式）。巴西 CMD 沉积物的矿物学，包括石英、粘土、Al-Fe-氧化物和无定形 NPs 的比例，似乎与相关洗煤废料 (CCR) 中矿物质的性质有关。与源自较高 pH 范围的沉积物相比，源自较低 pH 范围的 CMDs 沉积物具有不同的无定形组成。这些特殊的无定形组成与其他一些沉积物特性有关，例如颗粒表面积。本研究获得的信息将有助于对世界其他地区的 CMD 进行进一步地球化学评估。
