CTAB吸附对褐煤亲水性抑制作用机理的研究  

Mechanism of the decrease in hydrophilicity of lignite by adsorption of CTAB

作　　者：刘晓阳[1] 张雷[1] 刘生玉[1] 樊民强[1] Liu Xiaoyang Zhang Lei Liu Shengyu Fan Minqiang(College of Mining Engineering, Taiyuan University of Technology, Taiyuan, Shanxi 030024, Chin)

机构地区：[1]太原理工大学矿业工程学院,山西省太原市030024

出　　处：《中国煤炭》2017年第5期99-104,共6页China Coal

基　　金：国家自然科学基金资助项目(21376161)

摘　　要：表面活性剂在褐煤表面的吸附特性对其亲水性抑制具有重要影响,在研究了阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)在褐煤表面的吸附特性,并分析吸附等温线、吸附热力学和吸附动力学,通过润湿热测定考察了CTAB吸附量与褐煤表面亲水性抑制效率的相关性后,进一步探讨了褐煤吸附CTAB后表面含氧量和孔结构的变化对其亲水性抑制的影响。研究结果表明,CTAB在褐煤表面的吸附是放热过程,吸附量随着温度的升高而增大;吸附等温线较符合Freundlich模型,吸附速率可以用二级动力学方程描述;褐煤吸附CTAB后,其表面有序度增加,亲水性降低;在褐煤表面吸附的CTAB覆盖了其亲水含氧官能团,并且在褐煤的大孔中发生聚集,还可能引起小孔结构的堵塞;吸附表面活性剂对褐煤亲水性的抑制是表面含氧官能团含量和孔结构变化共同作用的结果。Adsorption characteristics of surfactant exert important effect on decrease in the hydrophilicity of lignite. This research studies on the adsorption of eetyltrimethylammonium bromide （CTAB） on lignite surface. The adsorption isotherm, thermodynamics and kinetics were analyzed. The relationship between adsorption amount of CTAB and inhibiting efficiency was discussed by the measurement of wetting heat. The change of surficial oxygen content and pore structure of lignite after adsorption of CTAB was also studied. It is found that adsorption of CTAB on lignite was exothermic, and the adsorption amount increased with the increasing temperature. Adsorption isotherm fitted well with the Freundlich model, and the second-order kinetic model could be used to decrease the adsorption process. The degree of surface order of lignite was enhanced after adsorption CTAB, and the wetting heat also decreased. The functional oxygen groups were covered by adsorbed CTAB on lignite surface. Moreover the aggregation of surfactant was also occurred in big pores, and fractional of small pores were probably blocked. The decrease in hydrophilicity for lignite by adsorption surfactant was attributed to the comprehensive effect of the content of oxygen functional groups and pore structure.

关 键 词：褐煤 亲水性 CTAB 吸附 

分 类 号：TQ531[化学工程—煤化学工程]