摘要
To increase the adsorption capacity of the Corylus heterophylla Fisch（HS） for Pb2＋, HS was chemically modified using NaOH aqueous solution and 95% ethanol and was labeled as SHS; then SHS was chemically modified using mercaptoacetic acid. The SHS modified with mercaptoacetic acid（MHS） was characterized using FTIR, SEM, and XPS. The results indicated that the --SH group was present on MHS, and after Pb2＋ adsorption, the absorption value of the characteristic peak of the --SH group decreased. The adsorption and desorption properties of this func- tionalized material were investigated as well as the influences of parameters, such as pH value, type of desorption reagent, dosage, flow rate and maximum sample volume. The Pb2~ adsorption of MI-IS reached a maximum with pH〉5. The experimental data of Pb2＋ adsorption using MHS were fitted using the Langmuir isothermal adsorption model, and a maximum adsorption capacity of 61.54 mg/g was obtained. This was much higher than the adsorption capacity of SHS before modification with the thiol group. After adsorption, MHS was desorbed using a 0.2 mol/L HC1 solution, and the percent of desorption was higher than 99%. MHS was used as a solid-phase extractant in the analysis and determination of Pb2＋ content in food and water samples, and the enrichment times achieved 150-fold.
To increase the adsorption capacity of the Corylus heterophylla Fisch（HS） for Pb2＋, HS was chemically modified using NaOH aqueous solution and 95% ethanol and was labeled as SHS; then SHS was chemically modified using mercaptoacetic acid. The SHS modified with mercaptoacetic acid（MHS） was characterized using FTIR, SEM, and XPS. The results indicated that the --SH group was present on MHS, and after Pb2＋ adsorption, the absorption value of the characteristic peak of the --SH group decreased. The adsorption and desorption properties of this func- tionalized material were investigated as well as the influences of parameters, such as pH value, type of desorption reagent, dosage, flow rate and maximum sample volume. The Pb2~ adsorption of MI-IS reached a maximum with pH〉5. The experimental data of Pb2＋ adsorption using MHS were fitted using the Langmuir isothermal adsorption model, and a maximum adsorption capacity of 61.54 mg/g was obtained. This was much higher than the adsorption capacity of SHS before modification with the thiol group. After adsorption, MHS was desorbed using a 0.2 mol/L HC1 solution, and the percent of desorption was higher than 99%. MHS was used as a solid-phase extractant in the analysis and determination of Pb2＋ content in food and water samples, and the enrichment times achieved 150-fold.
