The Study On Adsorption Of Phenolic Compounds On Carbon Nanotubes

As a new member of Fullerene family,Carbon nanotubes(CNTs) have been extensively concerned from their discovery by Iijima in 1991. Because of their unique physical and chemical properties,carbon nanotubes have been one of the hotspots in the nanomaterial field.In recent years,with their preparation in batches carbon nanotubes have been applied in many fields,such as hydrogen storage,quantum nanowires,superior adsorbent,catalyst suports and chemical sensors,etc. This paper mainly includes three parts as follows: Part one: Adsorption of different substituted phenol on carbon nanotubesThe thermodynamics properties and mechanism of sorption process were studied for adsorbing phenol,p-cresol,p-methoxyphenol and p-nitrophenol in aqueous solution with carbon nanotubes(CNTs).The effects of original concentration and temperature were reviewed and the adsorption isotherms at different temperature were determined.The data have been evaluated with Freundlich and Langmuir equation and thermodynamic function(ΔH~0, ΔG~0 and ΔS~0 ) have been calculated.The results showed that the adsorptive capacity of these phenolic compounds were p-nitrophenol>p-methoxyphenol>p-cresol>phenol.Their adsorptive capacity increased with the increase of original concentration and the effect of temperature on adsorption was unobvious.The adsorption process for these phenolic compounds on CNTs proved to be driven with physical adsorption characteristic.Finally,the possible theory was discussed. Part two: Adsorption of phenol and a -naphthol on carbon nanotubesThe adsorption of phenol and a -naphthol from aqueous solution onto carbon-nanotubes has been studied at 20℃ in this experiment. The adsorption isotherms were measured and their amount adsorbed were compared respectively.According to the evaluation of Langmuir equation ,1~H-NMR and TG the results of adsorption werediscussed.It was found that a -naphthol was adsorbed much more than phenol.And there is stronger π - π stacking interaction between carbon nanotubes and a -naphthol than it between carbon nanotubes and phenol. Part three: Competetive adsorption of phenolic compoundsPartial Least-squares(PLS) method together with UV-Vis spectrophotometry is applied to simultaneous determination of phenol, p-methoxyphenol and a -naphthol in aqueous solution. And the competitive adsorption of these compounds on carbon nanotubes is studied by this method. The results show that the recovery is 96%~ 107.6% and is satisfying. The concentration and adsorptive amount of phenol, p-methoxyphenol and a -naphthol computed by PLS method are closely consistent with them computed by Langmuir Competitive Adsorption(LCA) model.