化工进展 ›› 2018, Vol. 37 ›› Issue (11): 4509-4521.DOI: 10.16085/j.issn.1000-6613.2018-0357

• 资源与环境化工 • 上一篇    

有机改性磁性碱性钙基膨润土的制备及对Cu(Ⅱ)和Mn(Ⅱ)的吸附

施华珍1, 刘坤2, 汤睿1, 朱颖2, 陈宁华2, 王迎亚1, 张寒冰2, 童张法1,3, 閤明勇2   

  1. 1 广西大学化学化工学院资源化工应用新技术广西高校重点实验室, 广西 南宁 530004;
    2 广西大学资源环境与材料学院, 广西 南宁 530004;
    3 广西碳酸钙产业化工程院, 广西 南宁 530004
  • 收稿日期:2018-02-11 修回日期:2018-04-16 出版日期:2018-11-05 发布日期:2018-11-05
  • 通讯作者: 童张法,教授,博士生导师,主要从事精细化工和环境修复应用研究。E-mail:zhftong@sina.com。
  • 作者简介:施华珍(1991-),女,硕士研究生,主要从事工业废水处理。
  • 基金资助:
    国家自然科学基金(21576055,21766001)、广西碳酸钙产业化工程院开放课题(TSG201501)及广西石化资源加工及过程强化技术重点实验室主任课题(2016Z006)。

Organically modification of magnetic alkaline Ca-bentonite and its adsorption for Cu(Ⅱ) and Mn(Ⅱ)

SHI Huazhen1, LIU Kun2, TANG Rui1, ZHU Ying2, CHEN Ninghua2, WANG Yingya1, ZHANG Hanbing2, TONG Zhangfa1,3, HE Mingyong2   

  1. 1 Guangxi Colleges and Universities Key Laboratory of New Technology and Application in Resource Chemical Engineering, School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, Guangxi, China;
    2 College of Resources, Environment and Materials, Guangxi University, Nanning 530004, Guangxi, China;
    3 Guangxi Engineering Academy of Calcium Carbonate Industrialization, Nanning 530004, Guangxi, China
  • Received:2018-02-11 Revised:2018-04-16 Online:2018-11-05 Published:2018-11-05

摘要: 为提高磁性碱性钙基膨润土(magnetic alkaline Ca-bentonite,MACB)的吸附性能和磁稳定性,以壳聚糖和羧甲基纤维素钠的交联共聚膜(chitosan/sodium carboxymethyl cellulose copolymer film,CC)为改性剂,采用一步共沉淀法制备了CC改性的磁性碱性钙基膨润土MACB/CC(CC-modified magnetic alkaline Ca-bentonite,MACB/CC),对改性前后材料的结构特性进行分析,并进行MACB/CC对Cu(Ⅱ)和Mn(Ⅱ)的吸附性能研究。研究结果表明,有机共聚膜CC已成功负载在MACB表面,有机改性后的MACB/CC具备更好的磁分离性能和磁稳定性;Cu(Ⅱ)和Mn(Ⅱ)在MACB/CC上的吸附是一个先快速而后缓慢的过程,吸附时间为60min时,MACB/CC对Cu(Ⅱ)和Mn(Ⅱ)的吸附率已分别达到97%和85%;溶液的初始pH对MACB/CC吸附的影响明显,随着pH的升高,MACB/CC对Cu(Ⅱ)和Mn(Ⅱ)的吸附率逐渐上升,在pH为7时对两种重金属的吸附率达到99%和92%;当Cu(Ⅱ)和Mn(Ⅱ)共存时,MACB/CC对Cu(Ⅱ)的吸附能力大于Mn(Ⅱ);经5次循环利用后,MACB/CC对Cu(Ⅱ)和Mn(Ⅱ)的吸附率仍分别保持在93%和90%以上;MACB/CC对Cu(Ⅱ)和Mn(Ⅱ)的吸附符合Langmuir模型,Langmuir吸附容量分别为94mg/g和38mg/g,吸附过程可由准二级动力学模型描述,说明控制吸附速率的主要是化学吸附;MACB/CC对Cu(Ⅱ)和Mn(Ⅱ)的吸附机理主要包括阳离子交换、表面沉淀和络合作用。总之,相对于MACB,经有机修饰的MACB/CC具有更好的吸附性能、磁稳定性和磁分离能力,是一种非常有应用前景的重金属废水吸附材料。

关键词: 磁性碱性钙基膨润土, 有机改性, 复合材料, 吸附, 动力学模型

Abstract: To further improve the adsorption performance and magnetic stability, magnetic alkaline Ca-bentonite (MACB) was organically modified by chitosan/sodium carboxymethyl cellulose copolymer film (CC). CC-modified MACB (MACB/CC) was prepared by one-step coprecipitation process. The characterizations of both MACB/CC and MACB and the adsorption properties of Cu(Ⅱ) and Mn(Ⅱ) from aqueous solution were investigated. The characterization results indicated that the surface of MACB was successfully covered with CC. MACB/CC exhibited rapid solid-liquid separation ability and highly magnetic stability. The adsorption rate of Cu(Ⅱ) and Mn(Ⅱ) on MACB/CC was rapid initially but slowed down thereafter. The respective adsorption of Cu(Ⅱ) and Mn(Ⅱ) on MACB/CC were 97% and 85% with 60min adsorption time. Meanwhile, the adsorption was strongly dependent on the initial pH and Cu(Ⅱ) & Mn(Ⅱ) adsorption on MACB/CC increased with the initial pH increase. Cu(Ⅱ) & Mn(Ⅱ) adsorption reached 99% and 92% at pH 7.0, respectively. The results also showed the competition adsorption ability between Cu(Ⅱ) and Mn(Ⅱ) was in the order of Cu(Ⅱ)>Mn(Ⅱ). After five recycles, Cu(Ⅱ) and Mn(Ⅱ) adsorption on MACB/CC still maintained above 93% and 90%, respectively. The adsorption isotherms were well described by Langmuir model with the respective Langmuir adsorption capacities of Cu(Ⅱ) and Mn(Ⅱ) being 94mg/g and 38mg/g. The adsorption kinetics study demonstrated that the adsorption process fitted the pseudo-second order model well, indicating that the rate-determination step for MACB/CC was chemical adsorption. The main mechanisms of Cu(Ⅱ) and Mn(Ⅱ) removal by MACB/CC were cation exchange, precipitation and complexation. Due to the enhanced adsorption performance, better magnetic stability and separation ability, MACB/CC could be deemed as a potential adsorbent for the removal of heavy metals from wastewater.

Key words: magnetic alkaline Ca-bentonite, organically modification, composites, adsorption, kinetic modeling

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