Coordinated water stabilizes indigo-sepiolite hybrid pigments: Evidence from acid modification
Coordinated water stabilizes indigo-sepiolite hybrid pigments: Evidence from acid modification
复制标题
DOI：
10.1016/j.clay.2023.106877
复制
发表时间：
2023-05
影响因子：
5.6
通讯作者：
Li Li-Li;Guanzheng Zhuang;Peng Yuan
中科院分区：
文献类型：
--
作者：
Li Li-Li;Guanzheng Zhuang;Peng Yuan
海泡石的微孔结构能固定有机染料，形成稳定的杂化颜料。前人的研究表明，微孔隙和配位水可能是靛蓝-海泡石杂化颜料优异的颜色和稳定性的原因。本文揭示了配位水在酸改性形成杂化颜料中的作用。采用硝酸对海泡石进行改性，改性后的海泡石在不同条件下使用。以靛蓝和酸改性海泡石为原料，制备了一系列靛蓝-海泡石颜料。采用X射线衍射、傅里叶变换红外光谱、透射电子显微镜和N2吸附-脱附等方法对样品的微观结构进行了表征和分析。通过反射光谱和CIE颜色参数对杂化颜料的颜色性能进行了评价。用浓硝酸和二甲基亚砜对颜料的化学稳定性进行了研究。此外，还研究了在典型博物馆中模拟30年光照条件下颜料的光稳定性。酸改性后的海泡石具有较大的比表面积和孔容。然而，酸改性导致较差的颜色性能和稳定性，由于与八面体Mg 2+结合的配位水的去除。这些发现证实了配位水分子是通过形成氢键来稳定靛蓝-海泡石混合颜料的关键。
Sepiolite can form stable hybrid pigments by immobilizing organic dyes in its microporous structure. Previous investigations demonstrated that the micropores and coordinated water might be responsible for the exceptional color and stability of indigo-sepiolite hybrid pigments. This work reveals the roles of coordinated water in forming hybrid pigments by acid modification. Raw sepiolite was modified by nitric acid at different conditions before use. Then a series of indigo-sepiolite pigments were prepared by indigo and acid-modified sepiolite. Their microstructures were characterized and analyzed by X-ray diffraction, Fourier transform infrared, transmission electron microscopy, and N2adsorption-desorption. The color properties of hybrid pigments were evaluated by reflectance spectra and CIE color parameters. Investigations into the chemical stability of pigments were conducted using concentrated HNO3and dimethyl sulfoxide. In addition, the photostability of pigments exposed to simulated 30-year illumination in a typical museum was studied. Acid modification of sepiolite contributed to a larger specific surface area and pore volume. However, acid modification resulted in worse color properties and stability due to the removal of coordinated water bonded with octahedral Mg2+. These findings confirmed that coordinated water molecules were the key to stabilizing indigo-sepiolite hybrid pigments by forming hydrogen bonds.