The closed pores of tectonically deformed coal studied by small-angle X-ray scattering and liquid nitrogen adsorption

IF 4.7 3区材料科学 Q1 CHEMISTRY, APPLIED

Microporous and Mesoporous Materials Pub Date : 2016-04-01 DOI:10.1016/j.micromeso.2015.11.057

Jienan Pan , Qinghe Niu , Kai Wang , Xinghua Shi , Meng Li

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引用次数: 108

Abstract

To study the variation in the characteristics of closed pores in coal under tectonic deformation, three coal samples are selected that differ only slightly in metamorphic degree but differ sharply in deformation degree, with vitrinite reflectance range from 0.88% to 0.96% and deformation degrees corresponding to weak brittle, strong brittle and strong ductile deformations. The experimental methods used are small-angle X-ray scattering and liquid nitrogen adsorption, and the pore diameters obtained by combining the two methods are within the mesopore (2–50 nm) size range. The deformation of coal narrows the distribution of pore diameters. Changes in pore shape are described according to fractal theory: the pore fractal dimension is larger in coal with a greater pore size, and tectonic movement promotes irregularity and fracturing of the original pores. The specific surface area of pores is calculated in this paper. We conclude that the proportion of closed pore specific surface area reaches the peak with the increase of the deformation degree, and then falls gradually. Pore diameters greater than 3.2 nm and less than 3.2 nm correspond to the two parts in the liquid nitrogen adsorption data, with the fractal dimension of the former being larger than that of the latter. The results also show that the closed pore volume increases but the proportion of the total pore decreases with increasing deformation degrees.

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用小角x射线散射和液氮吸附研究了构造变形煤的闭孔

为研究构造变形作用下煤中闭孔特征的变化，选取了3个变质程度差异较小、变形程度差异较大的煤样，镜质组反射率范围为0.88% ~ 0.96%，变形程度分别对应弱脆性、强脆性和强韧性变形。实验采用的方法是小角度x射线散射和液氮吸附，两种方法结合得到的孔径在中孔(2-50 nm)尺寸范围内。煤的变形使孔径分布变窄。根据分形理论对孔隙形态的变化进行了描述:煤中孔隙分形维数越大，孔隙尺寸越大，构造运动促进了原始孔隙的不规则性和破裂性。本文计算了孔隙的比表面积。闭合孔比表面积的比例随着变形程度的增加达到峰值，然后逐渐下降。液氮吸附数据中孔径大于3.2 nm和小于3.2 nm的两部分对应，前者的分形维数大于后者。随着变形程度的增加，封闭孔隙体积增大，但占总孔隙的比例减小。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Microporous and Mesoporous Materials 化学-材料科学：综合

CiteScore

10.70

自引率

5.80%

发文量

649

审稿时长

26 days

期刊介绍： Microporous and Mesoporous Materials covers novel and significant aspects of porous solids classified as either microporous (pore size up to 2 nm) or mesoporous (pore size 2 to 50 nm). The porosity should have a specific impact on the material properties or application. Typical examples are zeolites and zeolite-like materials, pillared materials, clathrasils and clathrates, carbon molecular sieves, ordered mesoporous materials, organic/inorganic porous hybrid materials, or porous metal oxides. Both natural and synthetic porous materials are within the scope of the journal. Topics which are particularly of interest include: All aspects of natural microporous and mesoporous solids The synthesis of crystalline or amorphous porous materials The physico-chemical characterization of microporous and mesoporous solids, especially spectroscopic and microscopic The modification of microporous and mesoporous solids, for example by ion exchange or solid-state reactions All topics related to diffusion of mobile species in the pores of microporous and mesoporous materials Adsorption (and other separation techniques) using microporous or mesoporous adsorbents Catalysis by microporous and mesoporous materials Host/guest interactions Theoretical chemistry and modelling of host/guest interactions All topics related to the application of microporous and mesoporous materials in industrial catalysis, separation technology, environmental protection, electrochemistry, membranes, sensors, optical devices, etc.