Preparation of Transparent Suspension of Lamellar Magnesium. Hydroxide Nanocrystals Using a High-Gravity Reactive Precipitation Combined with Surface Modification
Preparation of Transparent Suspension of Lamellar Magnesium. Hydroxide Nanocrystals Using a High-Gravity Reactive Precipitation Combined with Surface Modification
复制标题
层状镁透明悬浮液的制备。
DOI：
10.1021/ie504265z
复制
发表时间：
2015
影响因子：
4.2
通讯作者：
Chen Jian-Feng
中科院分区：
文献类型：
--
作者：
Sun Qian;Chen Bo;Wu Xi;Wang Miao;Zhang Cong;Zeng Xiao-Fei;Wang Jie-Xin;Chen Jian-Feng
透明纳米晶体悬浮液具有许多独特的性能，因此在许多应用中都是有吸引力的材料。然而，制备具有广泛应用前景的透明纳米氢氧化镁悬浮液尚未实现。本文提出了一种利用高重力反应沉淀法结合连续表面改性合成层状MH纳米晶透明悬浮液的新方法。将MgCl2·6H2O和NaOH乙醇溶液引入旋转填充床（RPB）反应器，转速为2500 rpm，温度为30℃，在乙醇相中代替水相进行反应沉淀，形成MH纳米晶悬浮液，然后用KH570 （KH570/MH = 10 wt %）对其进行改性，最佳时间为3 h，温度为70℃，得到厚度约为1 nm的层状MH纳米晶透明悬浮液。采用透射电子显微镜（TEM）、原子力显微镜（AFM）、紫外-可见光谱（UV-vis）、x射线衍射（XRD）和傅里叶变换红外光谱（FTIR）对制备的透明MH纳米悬浮液进行了表征，并与传统搅拌釜式反应器（STR）合成的纳米悬浮液进行了比较。结果表明，在RPB中制备的产物具有较好的透明度，平均粒径较小，为32 nm。与STR相比，RPB的反应时间从20 min大大缩短到1 s。事实证明，该方法相对于STR具有明显的优势，可以预见，高重力反应沉淀结合表面改性在大规模制备MH纳米晶透明悬浮液中是有前景的。
Transparent nanocrystal suspension exhibits many unique properties, and are thus attractive materials for numerous applications. However, the synthesis of transparent nanocrystal suspension of magnesium hydroxide (MH) with wide applications is yet to be realized. This paper presents a novel route of synthesizing transparent suspension of lamellar MH nanocrystals by using high-gravity reactive precipitation combined with successive surface modification. Reactive precipitation in ethanol phase instead of aqueous phase is conducted by introducing MgCl2·6H2O and NaOH ethanol solutions into a rotating packed bed (RPB) reactor with a rotating speed of 2500 rpm at 30 °C to form MH nanocrystal suspension, which is subsequently modified with KH570 (KH570/MH = 10 wt %) for an optimum time of 3 h and temperature of 70 °C to yield transparent suspension of lamellar MH nanocrystals with about 1 nm in thickness. The as-prepared transparent MH nanocrystal suspension is characterized by transmission electron microscopy (TEM), atomic force microscopy (AFM), UV–vis, X-ray diffraction (XRD), and Fourier transform infrared (FTIR) and compared with those synthesized by conventional stirred tank reactor (STR). The results indicated that the product prepared in RPB had a better transparency, and a smaller average particle size of 32 nm. As compared to STR, RPB had a greatly shortened reaction time from 20 min to 1 s. It is proven that this route has obvious advantages over STR. It could be envisioned that high-gravity reactive precipitation combined with surface modification would be promising in the large-scale preparation of transparent suspension of MH nanocrystals.