高庙子钠基膨润土纳米孔隙结构的同步辐射小角散射

Nano-Pore Structure of Gaomiaozi Na-Bentonite by Synchrotron Radiation Small Angle X-ray Scattering

针对内蒙古地区2种钠基膨润土(GMZ001,GMZ07),采用同步辐射小角X射线散射(SAXS)技术进行纳米孔隙结构表征,通过FIT2D软件数据处理和背底散射扣除,校准并基于Porod校准后的曲线,利用最大熵统计方法得到孔径分布,分析了Guinier曲线并通过小角区域近似和外推方法,得到回转半径和孔径尺寸。同时,基于双对数曲线求斜率测定了分形维数。结果表明:GMZ07的散射强度大于GMZ001散射强度;Porod正偏离效应表明造成微密度起伏的不均匀区可能是膨润土中存在无定形成分。GMZ001分选性较GMZ07好,孔径集中;与GMZ001平均孔径和最可几孔径相比,GMZ07尺寸更小。最大熵理论估算的平均孔径相比于Guinier曲线估算的偏高,但差值不大。二者分形类型及维数差别不大,表明2种膨润土复杂程度类似。上述研究为膨润土SAXS制样、数据处理、孔结构参数获取提供参考。

The nanopore structure of sodium-bentonites(from Inner Mongolia,China)was characterized by a synchrotron radiation small-angle X-ray scattering(SAXS)technique.The FIT2 D data processing and background subtraction were used to calibrate based on the Porod calibration.The pore size distribution and the Guinier curve were determined,and the radius of gyration and aperture size were obtained via approximating and extrapolating the small angle region.Also,the fractal dimension was determined based on the slope of double logarithmic curve.The results show that the scattering intensity of GMZ07 is greater than that of GMZ001.The Porod positive deviation effect indicates that uneven zone causing microdensity fluctuation could be due to the presence of amorphous component in bentonite.GMZ001 is better than GMZ07,and the pore size is concentrated.The average pore size and the most probable pore size of GMZ07 are smaller than those of GMZ001.The average pore size estimated based on the maximum entropy theory is greater than that estimated by the Guinier curve,but the difference is small.The fractal types and dimensions are similar,indicating the similar complexities of two bentonites.