几种纤维矿物粉尘的真空有机吸附及表面基团变化

Vacuum Organic Adsorption of Several Kinds of Fibrous Mineral Dust and Change of Surface Groups

利用真空有机吸附和红外光谱分析法 ,研究了几种纤维矿物粉尘对不同偶极矩的正己烷 (偶极矩为 0 )、乙醚 (偶极矩为 1 .1 6)和吡啶 (偶极矩为 2 .1 9)的吸附特征及这些有机试剂对表面基团的影响。研究发现 :纤维矿物粉尘对有机试剂的吸附能力并不完全与有机试剂的偶极矩大小成正比 ;部分纤维矿物粉尘对正己烷的吸附为化学吸附 ,吸附解吸后出现了 1 2 62～ 1 2 67cm-1 、1 31 1cm-1 的新的IR谱带 ,它们应是部分纤维矿物粉尘与正己烷发生化学吸附后形成的-SiCH3 键的IR谱带。通过分析红外光谱各吸收带的变化特点 ,论证了部分纤维矿物粉尘吸附有机试剂后表面基团所发生的变化 ,特别是表面OH、表面Si-O

By use of vacuum organic adsorption and infrared spectrometry, the authors studied the characters of vacuum organic adsorption of hexane, ether and pyridine (their dipole moments are very different: hexane is 0, ether is 1.16 and pyridine is 2.19) by several kinds of fibrous mineral dust and changes of surface groups. The study found that the adsorbability of fibrous mineral dusts to organic reagents are not completely directly proportional to the dipole moments of organic reagents. Clay mineral dust has stronger adsorbability to organic reagents (such as hexane) with a smaller dipole monent, and fibrous mineral dusts have stronger adsorbability to organic reagents (such as pyridine) with a bigger dipole moment. Most of fibrous mineral dusts do not possess the ability of detaining the adsorbed molecules. But the adsorption of some fibrous mineral dusts to hexane is chemical adsorption, and there appear 1262～1267 cm -1 and 1311 cm -1 new IR bands after desorption. These bands should be IR bands of -SiCH 3 bonds which were formed after chemical adsorption took place between several kinds of mineral dust and hexane. This paper discusses the changes of surface groups of fibrous mineral dusts after adsorbing organic reagents, especially those of surface OH and surface Si-O-Si.