Lu Yushen, Dong Wenkai, Wang Wenbo, Ding Junjie, Wang Qin, Hui Aiping, Wang Aiqin
Key Laboratory of Clay Mineral Applied Research of Gansu Province, Center of Eco-material and Green Chemistry, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China.
University of the Chinese Academy of Sciences, Beijing 100049, China.
Nanomaterials (Basel). 2018 Nov 8;8(11):925. doi: 10.3390/nano8110925.
A series of environment-friendly clay minerals-α-Fe₂O₃ iron-red hybrid pigments-were prepared by a simple one-step hydrothermal reaction process using natural nanostructured silicate clay minerals as starting materials. The influence of structure, morphology and composition of different clay minerals on the structure, color properties, and stability of the pigments was studied comparatively by systematic structure characterizations with X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmittance electron microscope (TEM), X-ray fluorescence spectroscopy (XRF), X-ray photoelectron spectroscopy (XPS) and CIE- Colorimetric analyses. The results showed that the clay minerals act as green precipitants during the hydrothermal reaction to induce in-situ transformation of Fe(III) ions into Fe₂O₃ crystals. Meanwhile, they also act as the "micro-reactor" for forming Fe₂O₃ crystals and the supporter for inhibiting the aggregation of Fe₂O₃ nanoparticles. The color properties of iron-red hybrid pigments are closely related to the surface charges, surface silanol groups, and solid acid sites of clay minerals. The clay minerals with higher surface activity are more suitable to prepare iron-red pigments with better performance. The iron-red hybrid pigment derived from illite (ILL) clay showed the best red color performance with the color values of = 31.8, = 35.2, = 27.1, C* = 44.4 and h° = 37.6, and exhibited excellent stability in different chemical environments such as acid, alkaline, and also in high-temperature conditions.
以天然纳米结构硅酸盐粘土矿物为原料，通过简单的一步水热反应过程制备了一系列环境友好型粘土矿物-α-Fe₂O₃铁红混合颜料。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）、透射电子显微镜（TEM）、X射线荧光光谱（XRF）、X射线光电子能谱（XPS）和CIE比色分析等系统结构表征方法，比较研究了不同粘土矿物的结构、形态和组成对颜料的结构、颜色性能和稳定性的影响。结果表明，粘土矿物在水热反应过程中作为绿色沉淀剂，诱导Fe(III)离子原位转化为Fe₂O₃晶体。同时，它们还作为形成Fe₂O₃晶体的“微反应器”和抑制Fe₂O₃纳米颗粒聚集的载体。铁红混合颜料的颜色性能与粘土矿物的表面电荷、表面硅醇基团和固体酸位点密切相关。表面活性较高的粘土矿物更适合制备性能较好的铁红颜料。源自伊利石（ILL）粘土的铁红混合颜料表现出最佳的红色性能，颜色值为 = 31.8， = 35.2， = 27.1，C* = 44.4和h° = 37.6，并且在不同的化学环境如酸性、碱性以及高温条件下均表现出优异的稳定性。
