粉煤灰漂珠表面碳纳米管的生长及铅离子吸附研究

Growth of Carbon Nanotubes on Fly Ash Floating Beads Surface and Adsorption of Lead Ions

采用化学气相沉积法在粉煤灰漂珠表面进行碳纳米管的催化生长,结合扫描电镜(SEM)、傅里叶红外光谱(FT-IR)的表征,探究其微观结构及表面性质;并将其用于铅离子吸附,考察溶液p H值、吸附时间、初始浓度对吸附铅离子的影响。结果表明,粉煤灰漂珠表面覆盖一层碳纳米管,管径在30~50 nm范围内变化,且碳纳米管表面含有羧基、羟基及内脂基等含氧官能团;在25℃,p H值为7,吸附时间为180 min时,粉煤灰漂珠/碳纳米管对Pb2+的吸附效果最好,吸附容量为38. 23 mg/g。粉煤灰漂珠表面生长碳纳米管对铅离子吸附过程符合准二级动力学模型;等温吸附过程符合Freundlich方程。

The carbon nanotubes were catalytically grown on the surface of fly ash floating beads by chemical vapor deposition. The scanning electron microscopy( SEM) and Fourier transform infrared spectroscopy( FT-IR) were conducted to characterize its microstructure and surface properties. And the effects of solution p H value,adsorption time and initial concentration of lead ions adsorption on carbon nanotubes were also investigated. The results show that the surface of the fly ash floating beads is covered with a layer of carbon nanotubes,whose diameter varies from 30 nm to 50 nm,and the surface of the carbon nanotubes contains oxygen-containing functional groups such as carboxyl groups,hydroxyl groups and lactone groups;at 25 ℃,p H value is 7,and the adsorption time is 180 min,there exists the best adsorption effect,and the adsorption capacity is 38. 23 mg/g. The adsorption process of carbon nanotubes grown on the surface of fly ash floating beads conforms to the quasi-secondary kinetic model;the isothermal adsorption process accords with the Freundlich equation.