Adsorption Performance of Multi-walled Carbon Nanotubes to Trace Benzodiazepines
The adsorption performance of MWCNTs to four benzodiazepines including diazepam,estazolam,alprazolam and triazolam was examined.Four drugs can be adsorbed rapidly and quantitatively on MWCNTs in the static adsorption experiment,and the adsorption equilibrium was obtained within 10 min.The adsorptive capacities of MWCNTs increase with increasing concentration of these drugs.In original drugs concentration,the adsorptive capacities of MWCNTs to four drugs were greater.The adsorptive capacity was 7.95,7.88,7.99 and 7.73 mg/g,respectively.The effects of experimental temperature were studied at 295 K,303 K and 313 K.The adsorptive capacities of MWCNTs increased while temperature dropped.The data were simulated by Freundlich and Langmuir equations.The Langmuir equation accorded with the static adsorption characteristic of the compounds.The data from the dynamic adsorption experiment showed that the adsorption capacity and the extraction recoveries of four drugs on MWCNTs were satisfactory.The extraction recoveries of four drugs were more than 90%.The results indicated that MWCNTs could be used as a solid phase sorbents for the determination of benzodiazepines residues.