煤的吸附特性与表面能关系的实验研究

Experimental Research on Relationship Between Adsorption Characteristics and Surface Energy of Coal

为建立煤的吸附特性与表面能的定量关系,利用悬滴法恒温27℃测试不同浓度下的APG(烷基糖苷)溶液表面张力,以及利用躺滴法测试临界胶束浓度下APG溶液在煤表面的平衡接触角,进而计算出煤的表面能。研究结果表明:APG溶液在煤表面形成的接触角远小于水在煤表面形成的接触角,同时随着煤变质程度的提高呈现先增大后减小的趋势,这是APG分子与煤之间分子间作用力及煤表面疏水官能团联合控制的结果;随着煤样变质程度的提高,煤的表面能与吸附常数a皆呈现先减小后增大的趋势;表面能随吸附常数a的增大较好的服从指数函数变化规律,根据回归模型,煤的表面能最后趋近于35.63 m N/m。

To establish a quantitative relationship between adsorption characteristics and surface energy of coal,the pendant drop method is used to test the surface tension of different concentrations of APG（ alkyl glucoside） solution at a constant temperature of 27 ℃.The sessile drop method is used to test the equilibrium contact angle of APG dropping on the surface of different kinds of coal samples.The results show that the equilibrium contact angles of APG on coal surface are much smaller than those of water on the coal surface.With coal metamorphic grade increasing,the contact angles of APG on coal surface increase first and then decrease,which is controlled by the coupled effect of intermolecular force between the APG and coal molecules,and the decreasing of hydrophilic functional groups.With coal metamorphic grades increasing,the surface energy and adsorption constants of coal samples decrease first and then increase.Surface energy increases with the adsorption constants a and the change law between the two parameters obeys exponential function better. According to the regression model,the surface energy of coal can finally approach 35. 63 m N / m.