混酸预处理多壁碳纳米管吸附Cr~(3+)性能的影响

采用混酸对多壁碳纳米管(MWCNTs)进行处理,并考察了溶液浓度、pH值、时间、共存离子、不同洗脱剂等因素对混酸处理前后多壁碳纳米管吸附Cr3+离子性能的影响。实验结果显示:吸附量随时间和pH值增加而增大,且混酸处理后增加效果更加明显;吸附过程符合Freundlich等温吸附模型;0.5 mol/L HCl和0.1mol/L EDTA对吸附后MWCNTs解吸率均>80%。对混酸处理前后的多壁碳纳米管进行TEM、Zeta电位I、R、分散性测试表征。结果显示:混酸处理MWCNTs后,使其孔容、比表面积、表面基团数量及水溶性均有所增加,这可能是处理后MWCNTs吸附能力提高的主要原因。

Effect of Mixed Acid Pretreatment on Cr3+Adsorption by Multi-walled Carbon Nanotubes

Multi-walled carbon nanotubes were processed by mixed acid and the raw carbon nanotubes and acid pretreated carbon nanotubes were utilized as adsorbent to adsorb Cr3+ in artificial wastewater.Some of the effect factors,such as the initial concentration of Cr3+,pH value,contact time,and coexistence ions in solution,elution agents,etc,were investigated in the study.The results show that adsorption capacity of the two adsorbents increased with the increase in contact time and pH value.In addition,the adsorption capacity of the carbon nanotubes pretreated by mixed acid increase more compared with initial carbon nanotubes.The two adsorption processes fit well to Freundlich isotherm model.Both of the desorption efficiency with 0.5 mol/L HCl and 0.1 mol/L EDTA is over 80%.The two carbon nanotubes were characterized and analyzed by TEM,IR and Zeta potential,etc.The results indicated that mixed acid pretreatment resulted in the pore volume,specific surface area,and amount of functional groups and water solubility of carbon nanotubes increase.Thus,the mixed acid pretreatment possibly improved the adsorption capacity of carbon nanotubes for Cr3+ in solution.