Tuchowska Magdalena, Muir Barbara, Kowalik Mariola, Socha Robert P, Bajda Tomasz
Faculty of Geology, Geophysics and Environmental Protection, AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Krakow, Poland.
Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Niezapominajek 8, 30-239 Krakow, Poland.
Materials (Basel). 2019 Jul 13;12(14):2253. doi: 10.3390/ma12142253.
Montmorillonite-the most popular mineral of the smectite group-has been recognized as a low-cost, easily available mineral sorbent of heavy metals and other organic and inorganic compounds that pollute water. The aim of this work was to determine the sorption mechanism and to identify the reaction products formed on the surface of montmorillonite and organo-montmorillonite after sorption of molybdates (Mo(VI)) and tungstates (W(VI)). Montmorillonites are often modified to generate a negative charge on the surface. The main objective of the study was to investigate and compare the features of Na-montmorillonite (Na-M), montmorillonite modified with dodecyl trimethyl ammonium bromide (DDTMA-M), and montmorillonite modified with didodecyl dimethyl ammonium bromide (DDDDMA-M) before and after sorption experiments. The material obtained after sorption was studied by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The XRD pattern showed the presence of a new crystallic phase in the sample that was observed under an SEM as an accumulation of crystals. The FTIR spectra showed bands related to Mo-O and W-O vibration (840 and 940 cm, respectively). The obtained results suggest that molybdenum(VI) and tungsten(VI) ions sorb onto the organo-montmorillonite in the form of alkylammonium molybdates and tungstates.
蒙脱石——蒙脱石族中最常见的矿物——已被公认为是一种低成本、易于获取的矿物吸附剂，可吸附污染水体的重金属以及其他有机和无机化合物。本研究的目的是确定吸附机制，并识别钼酸盐（Mo(VI)）和钨酸盐（W(VI)）吸附后在蒙脱石和有机蒙脱石表面形成的反应产物。蒙脱石通常经过改性以在其表面产生负电荷。该研究的主要目的是研究和比较钠基蒙脱石（Na-M）、用十二烷基三甲基溴化铵改性的蒙脱石（DDTMA-M）以及用双十二烷基二甲基溴化铵改性的蒙脱石（DDDDMA-M）在吸附实验前后的特性。吸附后得到的材料通过X射线衍射（XRD）、傅里叶变换红外光谱（FTIR）、扫描电子显微镜（SEM）和X射线光电子能谱（XPS）进行研究。XRD图谱显示样品中存在一种新的晶相，在SEM下观察到该晶相为晶体的聚集体。FTIR光谱显示了与Mo-O和W-O振动相关的谱带（分别为840和940 cm）。所得结果表明，钼（VI）和钨（VI）离子以烷基铵钼酸盐和钨酸盐的形式吸附到有机蒙脱石上。
