磁性纤维素/Fe_3O_4/活性炭复合材料吸附刚果红性能研究

Study on Adsorption of Congo Red by the Composite Material of Magnetic Cellulose/Fe_3O_4/Activated Carbon

采用NaOH/硫脲/尿素混合水溶液低温溶解的绿色工艺快速溶解纤维素,并以纤维素、Fe3O4、活性炭为原料制得磁性纤维素/Fe3O4/活性炭复合吸附剂,运用XRD、SEM、TGA等技术手段对其进行了全面表征。将刚果红溶液作为目标污染物,考察了吸附剂投加量、溶液初始浓度等对吸附效果的影响,并对吸附动力学、热力学进行了探讨。结果表明,增大溶液初始浓度能有效提高吸附量;去除率随着吸附剂投加量的增加而提高。磁性纤维素/Fe3O4/活性炭复合吸附剂对刚果红偶氮染料的吸附等温线符合Freundlich模型,吸附过程符合拟二级动力学方程,内扩散为主要控速步骤。吸附是熵推动的自发放热过程,低温有利于反应的进行。

Cellulose was dissolved rapidly in NaOH/thiourea/urea aqueous solution at low environment temperatures,which was a ＂green＂ process.By blending cellulose solution with Fe3O4 and activated carbon,the magnetic cellulose/Fe3O4 /activated carbon composite was prepared.Its structure was examined by XRD、SEM and TGA.With the congo red solution as the target pollutants,the effects of the adsorption dosage and the initial concentration of congo red on the adsorption of congo red was inspected,and then discussed with adsorption kinetics and thermodynamics.The results indicated that the effect of initial concentration on adsorption capacity was remarkable,the rate of decolorization enhanced with the increasing adsorbent dosage.The absorption of congo red by the composite followed the Freundlich isotherm,the kinetic data met pseudo-secondorder equation and the intraparticle diffusion was the rate-controlling step.Lower temperature was favorable to adsorption due to the spontaneous and exothermic nature of the adsorption process.