State Key Laboratory of Hydraulic Engineering Simulation and Safety, Tianjin University, Tianjin 300072, PR China.
Tianjin Key Laboratory of Composite and Functional Materials, School of Materials Science and Engineering, Tianjin University, Tianjin 300072, PR China.
J Nanosci Nanotechnol. 2019 Nov 1;19(11):7178-7184. doi: 10.1166/jnn.2019.16616.
Halloysite nanotubes (HNTs) are natural clay minerals with a tubular structure. They have attracted considerable attention as a potential nanocontainer due to their abundance, biocompatibility and nontoxicity. In this study, HNTs were handled with H₂SO₄ at 70 °C. The morphology and structure of these acid-treated and original HNTs were investigated by scanning electron microscopy (SEM), energy dispersion spectrum (EDS), transmission electron microscope (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR), and their specific surface area was determined by automatic gas adsorption analyzer. The loading efficiency and release behavior of acid-treated HNTs for 2-Mercaptobenzothiazole (MBT) were investigated by UV-vis spectrophotometer. Results show that acid-treated HNTs retained their tubular structure, but their internal diameter expanded by 35-37 nm after 32 h of acid treatment. After 72 h of acid treatment, HNTs can be transferred into amorphous silica nanotubes. Moreover, the specific surface area of these HNTs samples initially increased with the increase in acid treatment time but then started to decrease after 32 h. The specific surface area of acid-treated HNTs at 32 h can reach 251.6 m₂/g, which was much higher than that for untreated HNTs (55.3 m₂/g). In addition, the loading capacity of acid-treated HNTs can reach 32.1% for HNTs-32, which is about three times higher than that of original HNTs. The acid treatment has slight effect on the release behavior.
埃洛石纳米管（HNTs）是一种具有管状结构的天然粘土矿物。由于其丰富的储量、良好的生物相容性和低毒性，它们作为潜在的纳米容器引起了人们的极大关注。在本研究中，HNTs 在 70°C 下用 H₂SO₄ 处理。通过扫描电子显微镜（SEM）、能谱（EDS）、透射电子显微镜（TEM）、X 射线衍射（XRD）和傅里叶变换红外光谱（FTIR）对这些酸处理前后的 HNTs 的形貌和结构进行了研究，并通过自动气体吸附分析仪测定了其比表面积。通过紫外可见分光光度计研究了酸处理 HNTs 对 2-巯基苯并噻唑（MBT）的负载效率和释放行为。结果表明，酸处理后的 HNTs 保留了其管状结构，但在 32 h 的酸处理后其内径扩大了 35-37nm。酸处理 72 h 后，HNTs 可转化为无定形硅纳米管。此外，这些 HNTs 样品的比表面积最初随酸处理时间的增加而增加，但在 32 h 后开始下降。32 h 酸处理的 HNTs 的比表面积可达 251.6 m²/g，远高于未处理的 HNTs（55.3 m²/g）。此外，酸处理 HNTs 的负载能力可达 32.1%，对于 HNTs-32，约为原始 HNTs 的三倍。酸处理对释放行为影响较小。
