磁性多壁碳纳米管对磺胺类药物的吸附行为

Adsorption of sulfonamides by magnetic multiwall carbon nanotubes

制备磁性多壁碳纳米管,将MWCNTs羧酸化后再进行加磁,并用于磺胺类药物的吸附行为研究,考察吸附剂用量、溶液pH值、吸附时间和溶液浓度对吸附行为的影响。结果表明,50 mg磁性MWCNTs粉末在50 m L pH值为6,浓度为2 mg/L的磺胺混合标准溶液中吸附30 min,各种磺胺药物的去除率达到85%以上。磁性MWCNTs吸附磺胺类药物的过程符合准二级动力学模型(R2>0.99),平衡吸附容量的试验值与理论计算值更为接近。磁性多壁碳纳米管对磺胺类药物的吸附过程符合Langmuir模型,为可逆吸附。对磁性MWCNTs上吸附的磺胺类药物进行脱附试验,发现5%的氨水甲醇的洗脱效果最好。磁性MWCNTs对磺胺类药物进行10次脱附再吸附反复试验,磺胺类药物的回收率在80%以上,表明磁性MWCNTs对磺胺类药物具有很好的吸附性能,且可以反复使用,磁性MWCNTs具有一定的开发前景和应用价值。

Magnetic multiwall carbon nanotubes（MWCNTs） were prepared by soaking purified MWCNTs in a solution containing ammonium ferrous sulfate and ammonium ferric sulfatewith a pH of 11-12 at 50 ℃ for 30 min,and were used as an adsorbent for sulfonamides.Processing parameters affecting the adsorption efficiency were investigated,including the amount of adsorbent,pH value,adsorption time and the concentration of the sulfonamide solution.The removal of sulfonamides reached 85%when the ratio of the magnetic MWCNTs to the solution was 1 mg/mL,the pH value was 6 and the time of adsorption was 30 min.Adsorption kineticsfollowed apseudo-second order model and the Freundlich equation described the adsorption isotherm well.Desorption tests of the magnetic MWCNTs showed that the best elution was in ammonia-methanol（v/v,5：95）.The recovery of sulfonamides was more than 80%after ten desorption and adsorption cycles,indicating that the magnetic MWCNTs can be reused.