CIESC Journal ›› 2020, Vol. 71 ›› Issue (11): 5309-5319.DOI: 10.11949/0438-1157.20200092

• Energy and environmental engineering • Previous Articles     Next Articles

Removal of ammonium ions in wastewater by electrosorption with TiO2 modified graphene electrode

Hailing GAO1,2(),Bin XU1(),Yuexiang GAO1,Yueming ZHU1,Songhe ZHANG2,Yimin ZHANG1   

  1. 1.Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environmental, Nanjing 210042, Jiangsu, China
    2.College of Environment, Hohai University, Nanjing 210098, Jiangsu, China
  • Received:2020-01-20 Revised:2020-06-12 Online:2020-11-05 Published:2020-11-05
  • Contact: Bin XU

TiO2改性石墨烯电极电吸附去除污水中NH4+

皋海岭1,2(),徐斌1(),高月香1,朱月明1,张松贺2,张毅敏1   

  1. 1.生态环境部南京环境科学研究所,江苏 南京 210042
    2.河海大学环境学院,江苏 南京 210098
  • 通讯作者: 徐斌
  • 作者简介:皋海岭(1995—),女,硕士研究生,2195223166@qq.com
  • 基金资助:
    江苏省自然科学基金青年科学基金项目(BK20170111);江苏省科协青年科技人才托举工程;国家自然科学基金青年科学基金项目(51808251);水体污染控制与治理科技重大专项项目(2017ZX07203-004)

Abstract:

In this study, the TiO2 modified graphene composite material (RGO/ TiO2) was prepared by hydrothermal method, and its morphological structure and electrochemical properties were investigated. Then RGO/TiO2 material was assembled into electrode, and NH4+ ions electrosorption efficiencies of unmodified graphene (RGO) electrode and the RGO/TiO2 electrode were compared. The effects of applied voltage, circulating velocity and initial concentration on NH4+ ions electrosorption by RGO/TiO2 electrode were investigated. The characteristics of NH4+ ions electrosorption and the effect of advanced NH4+ ions removal from simulated actual wastewater containing NH4+ ions were also studied. The results showed that the RGO/TiO2 composite material had a three-dimensional pore structure with specific surface area of 382.08 m2·g-1 and specific capacitance of 325.80 F·g-1 at a scan rate of 0.01 V·s-1, which were better than those of the RGO material. The initial adsorption capacity of RGO/TiO2 electrode was 28.3% higher than that of RGO electrode. After 10 cycles of regeneration adsorption, the adsorption capacity of NH4+ ions of RGO/TiO2 electrode only decreased 5.87%, and its cyclic regeneration adsorption property was better than that of RGO electrode. In addition, the applied voltage 2.0 V, circulating velocity 35 ml·min-1 and initial concentration 1.0 mmol·L-1 were the optimal NH4+ ions electrosorption conditions for RGO/TiO2 electrode. The electrosorption process of NH4+ ions by RGO and RGO/TiO2 electrodes was in accordance with the quasi-first-order kinetic model and the Freundlich isothermal adsorption model. The electrosorption of NH4+ ions was a multi-layer adsorption behavior on heterogeneous surface and physical adsorption was the dominant. When the RGO/TiO2 electrode was connected in 4-stage series, the removal efficiency of simulated actual NH4+ refining purified water reached 86.84%.

Key words: graphene, TiO2, composites, electrosorption, NH4+

摘要:

通过水热法制备得到TiO2改性石墨烯复合材料(RGO/TiO2),考察了其形貌结构和电化学性能。将其组装成电极,对比未改性石墨烯(RGO)电极和RGO/TiO2电极的电吸附NH4+性能。重点考察外加电压、循环流速、初始浓度等工艺参数对RGO/TiO2电极电吸附NH4+的影响,并对其电吸附NH4+特性和对模拟实际含NH4+废水深度脱NH4+效果进行研究。结果表明:RGO/TiO2复合材料具有三维孔洞结构,比表面积为382.08 m2·g-1,比电容量在扫速为0.01 V·s-1时达到325.80 F·g-1,优于RGO材料。RGO/TiO2电极的初次电吸附量较RGO电极提升了28.3%,循环再生吸附10次后,RGO/TiO2电极的NH4+吸附量仅降低了5.87%,循环再生吸附性能优于RGO电极。外加电压2.0 V、循环流速35 ml·min-1和NH4+初始浓度1.0 mmol·L-1为RGO/TiO2电极的最佳NH4+电吸附条件。RGO和RGO/TiO2电极电吸附NH4+过程符合准一级动力学模型和Freundlich等温吸附模型,电吸附NH4+为非均匀表面的多层吸附行为,以物理吸附为主。RGO/TiO2电极4级串联时对模拟实际含NH4+炼油净化水的去除率达到86.84%。

关键词: 石墨烯, TiO2, 复合材料, 电吸附, NH4+

CLC Number: