The stable isotope 56Fe was used to simulate the radioactive 55Fe,59Fe,and 52 Fe ions existing in the wastewater generated by nuclear medicine and then the removal efficiency of 56Fe2+ in water was studied using chitosan functionalized multi-walled carbon nanotubes (CS-MWNTs) as adsorbent.The influences of pH,temperature,time,and equilibrium ion concentration on the adsorption capacity were studied.The results show that in the same conditions,the adsorption capacity of CS-MWNTs is significantly increased compared to the pristine multi-walled carbon nanotubes (MWNTs).Both CS-MWNTs and MWNTs exhibit a better removal efficiency of Fe2+ in neutral solutions than in acidic solutions,while in basic solutions,the Fe2+ will precipitate and the removal of Fe2+ is no longer due to the adsorption effect.The adsorption equilibrium will be reached in about 3 h and the adsorption of Fe2+ to either CS-MWNTs or MWNTs is endothermic.At room temperature of 25 ℃ and pH=5,the saturate adsorption capacity of CS-MWNTs for Fe2+ is 51 mg/g,and that of pristine MWNTs is 27 mg/g.The Freundlich adsorption model can well represent the adsorption of Fe2+ to both of two kinds of adsorbent materials.%采用稳定性同位素56Fe的硫酸亚铁溶液模拟核医学放射性废水中的55Fe、59Fe、52 Fe,研究经壳聚糖修饰的多壁碳纳米管CS-MWNTs对亚铁离子的吸附效果.并研究不同pH值、温度、时间、平衡离子浓度对吸附量的影响.结果表明,在相同条件下,CS-MWNTs相比原始多壁碳纳米管MWNTs吸附量有较大提升.CS-MWNTs与MWNTs在中性条件下的吸附效果均较酸性条件下的好,而在偏碱性条件下,溶液会发生沉淀,吸附不再是主要作用.CS-MWNTs与MWNTs对亚铁离子的吸附作用约在3h达到平衡,且均为吸热反应.在室温25℃、pH=5条件下,CS-MWNTs和MWNTs对亚铁离子的饱和吸附量分别为51 mg/g和27 mg/g.两种吸附材料的吸附过程均符合Freundlich方程.
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