中空碳纳米球的制备及VOCs吸附性能

Synthesis and VOCs Adsorption Properties of Hollow Carbon Nanospheres

首先,在碱性条件下,不使用表面活性剂,采用St?ber小球法以正硅酸四乙酯(TEOS)和正硅酸四丙酯(TPOS)为硅源,生成初级氧化硅球形颗粒;然后,使酚醛树脂(间苯二酚和甲醛)与球形氧化硅的羟基共缩合形成酚醛树脂-氧化硅复合材料;最后,经高温碳化和酸蚀获得了空心碳纳米球(HCNSs).通过调节TEOS/TPOS的摩尔比获得了一系列具有良好的单分散性且粒径、壁厚可调节的HCNSs,其粒径和壁厚分别在280-430 nm和15-63 nm的范围内.仅以TPOS为硅源时合成的HCNS-0/4具有较大的粒径(426 nm)和壁厚(63 nm)、较高的比表面积(1216 m^(2)/g)和孔容(0.508 cm^(3)/g),并且具有较大的挥发性有机化合物(VOCs)吸附性能,其正己烷、甲苯和油气的静态吸附容量分别为2.02,1.42和0.926 g/g,正己烷和甲苯的动态吸附容量分别为2.01 g/g和1.37 g/g,均远高于商业化活性炭.

Under alkaline conditions and without using surfactants,primary spherical siliceous particles were produced through St?ber method with tetraethyl orthosilicate(TEOS)and tetrapropyl orthosilicate(TPOS)as silica sources,then phenolic resin-silica composites were obtained by co-condensation of phenolic resin(isobenzene diphenol and formaldehyde)and the hydroxyl groups of silica. Hollow carbon nanospheres(HCNSs)were obtained after high temperature carbonization and acid etching of the phenolic resin-silica composites. By adjusting the molar ratio of TEOS/TPOS,a series of HCNSs with good monodispersity and adjustable particle sizes and wall thicknesses was obtained. The particle sizes and wall thicknesses are in the range of 280—430 nm and 15—63 nm,respectively. HCNS synthesized only with TPOS as silica source(HCNS-0/4)has a larger particle size(426 nm),wall thickness(63 nm),higher specific surface area(1216 m^(2)/g)and pore volume(0.508 cm^(3)/g),and the best VOCs adsorption performance. For HCNS-0/4,the static n-hexane,toluene and oil vapor adsorption capacities are 2.02,1.42 and 0.926 g/g,respectively,and the dynamic n-hexane and toluene adsorption capacities are 2.01 and 1.37 g/g,respectively,which are much higher than those of commercial activated carbon.