硅胶负载杂多酸吸附脱除模拟柴油中的苯胺及其动力学研究

利用等体积浸渍法在硅胶上负载w=5%的杂多酸磷钼酸或硅钨酸,采用XRD、FT-IR和低温N_2吸附-脱附等方法对硅胶及负载杂多酸硅胶进行了表征。XRD结果表明,硅胶及负载杂多酸硅胶都具有无定形非晶态结构,FT-IR结果未出现明显的磷钼酸或硅钨酸特征峰,硅胶和负载杂多酸硅胶的比表面积、平均孔径和孔容几乎相同。负载杂多酸硅胶对模拟柴油中苯胺的吸附脱除效果研究表明,两种负载杂多酸硅胶的吸附效果均明显优于硅胶。303、323和343 K下吸附脱除模拟柴油中苯胺的动力学研究结果表明,苯胺在两种负载杂多酸硅胶上的吸附符合准一级动力学方程。颗粒内扩散模型分析表明,颗粒内扩散过程不是吸附过程的唯一影响因素。采用焙烧和醇洗的方法对吸附后的负载杂多酸硅胶进行再生处理,两种样品的焙烧再生效果均明显优于醇洗,再生率可达89%以上。

ADSORPTION REMOVAL AND DYNAMICS OF ANILINE FROM MODEL DIESEL WITH SILICA GEL-SUPPORTED HETEROPOLY ACID

5% Phosphomolybdic acid or silicotungsitc acid were loaded on the silica gel by using impregnationmethod.The silica gel and silica gel-supported heteropoly acid were confirmed by characterization with X-ray diffraction(XRD),Fourier transform infrared spectrum(FT-IR)and N2 adsorption-desorption.The XRD results indicated that the three samples are of amorphous structure.No characteristic peaks of heteropoly acid were found in FT-IR results.The average pore diameter,Brunauer-Emmett-Teller(BET)surface area and pore volume of silica gel and silica gel-supported heteropoly acid were almost identical.The adsorption removal of aniline in model diesel over silica gel and silica gelsupported heteropoly acid was investigated.The experiment results indicated that the adsorption denitrification performance of silica gel-supported heteropoly acid was more superior to that of silica gel.The kinetics on adsorption denitrification of silica gel-supported heteropoly acid was studied at 303,323 and 343 K.The results indicated that the R2 of pseudo first-order equation for two silica gel-supported heteropoly acid samples was obviously higher than that of pseudo second-order equation,implying that the adsorption of aniline was belong to pseudo first-order equation.The fitting results by using intraparticle diffusion model indicated that the adsorption process was not only influenced by intraparticle diffusion.Furthermore,two samples could be easily regenerated its adsorption denitrification performance by using calcination method which is significantly better than ethanol regeneration method and the regeneration rate is more than 89%.