复合微胶囊的制备及对重金属镉的吸附性能
发布时间：2018-08-28 16:41
【摘要】：由于重金属的致毒性、来源广、非生物降解性及生物累积性,已经引起人们的广泛关注。我国专门为此制定了《“十三五”生态环境保护规划》,将重金属污染的预防与治理提上议事日程。本研究以壳聚糖为微胶囊囊壁,以纳米四氧化三铁修饰腐殖酸、纳米羟基磷灰石修饰腐殖酸以及介孔分子筛修饰腐殖酸三种复合吸附剂为囊芯,采用复合凝聚法制备复合微胶囊吸附剂,并将其分别用于水溶液中Cd(Ⅱ)的去除。制备的复合微胶囊采用傅里叶红外、X射线衍射、扫描电子显微、比表面积等手段进行表征,并考查实验条件对重金属离子吸附量和去除率的影响,并开展了吸附动力学和吸附等温研究。具体内容如下:(1)复合微胶囊吸附剂Fe_3O_4/HA@CS对Cd(Ⅱ)的吸附实验表明,吸附最佳pH=7,且去除率为97%;平衡吸附时间为60min,复合吸附剂对Cd(Ⅱ)的平衡吸附量为48.5mg/g。吸附动力学研究表明,吸附机理可能既包含化学吸附过程,也包含物理吸附。吸附等温研究表明,Langmuir等温吸附模型可以很好地描述Fe_3O_4/HA/CS吸附Cd(Ⅱ)的过程。(2)复合微胶囊吸附剂HAP/HA/CS在pH=7时对Cd(Ⅱ)吸附效果最佳,去除率达95%,比单一HAP的去除率提升了16.8%;吸附等温研究表明,Freundlich等温吸附模型可以很好地描述HAP/HA/CS吸附Cd(Ⅱ)的过程。(3)复合微胶囊吸附剂CS/HA/MCM在pH=7时对Cd(Ⅱ)的去除率达到84%以上,与单一的MCM-41相比提升了12%;吸附过程在40min达到吸附平衡,吸附容量为92.6mg/g,比单一的MCM-41、HA/MCM分别提升了3.5%和3.1%。吸附过程符合准二级动力学模型,且Langmuir等温吸附模型可以很好地描述CS/HA/MCM吸附Cd(Ⅱ)的过程。
[Abstract]:Due to the toxicity of heavy metals, extensive sources, non-biodegradability and bioaccumulation, people have attracted wide attention. In order to prevent and control heavy metal pollution, China has formulated the "Thirteenth five year Plan for Ecological Environment Protection", which puts the prevention and treatment of heavy metal pollution on the agenda. In this study, chitosan was used as microcapsule wall, nano-ferric oxide as humic acid, nano-hydroxyapatite as humic acid and mesoporous molecular sieve as capsule core. The composite microcapsule adsorbents were prepared by complex coagulation method and were used for the removal of Cd (鈪，
本文编号：2209974
[Abstract]:Due to the toxicity of heavy metals, extensive sources, non-biodegradability and bioaccumulation, people have attracted wide attention. In order to prevent and control heavy metal pollution, China has formulated the "Thirteenth five year Plan for Ecological Environment Protection", which puts the prevention and treatment of heavy metal pollution on the agenda. In this study, chitosan was used as microcapsule wall, nano-ferric oxide as humic acid, nano-hydroxyapatite as humic acid and mesoporous molecular sieve as capsule core. The composite microcapsule adsorbents were prepared by complex coagulation method and were used for the removal of Cd (鈪，
本文编号：2209974
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