三维石墨烯材料的制备及在水处理中的应用研究进展

Progress in Preparation of Three-dimensional Graphene Materials and Their Applications in Water Treatment

随着经济的快速发展,越来越多的污染物质进入水体,污染环境,危害人体健康,污染废水亟待净化处理。在众多污水处理方法中,吸附法因经济、高效而被广泛使用。相较于传统吸附剂,石墨烯材料作为一种新型碳材料,具有比表面积大、化学稳定性好、含氧官能团丰富、可修饰性强等优点,对水体中的污染物具有较强的吸附能力。但二维石墨烯材料因片薄、粒径细小,在吸附污染物后较难实现固液分离,从而产生二次污染。将二维石墨烯组装成三维多孔网状聚集体,不仅能有效阻止石墨烯结构层的堆积,促进污染物的扩散吸附,还有利于吸附污染物后的固液分离。因此,在水污染处理领域,三维石墨烯吸附材料逐渐成为研究的焦点。三维石墨烯材料是以(氧化)石墨烯为主体交联形成的多孔网状宏观体新材料,继承了本征石墨烯良好的理化性能。其多孔网状纳米结构赋予自身较高的孔隙率和较快的溶质传输速度等特性,使其在水污染处理中具有良好应用前景。利用不同的化学物质,采取不同的制备方法对石墨烯材料进行接枝改性、掺杂复合等,可促进石墨烯三维宏观结构和微观孔隙结构的形成。综合国内外研究成果发现,三维石墨烯主要通过静电相互作用、π-π堆叠作用、疏水作用、氢键作用和络合作用等与污染物质结合,实现污染物的去除。对于阳离子污染物质,增加三维石墨烯材料表面的活性基团及吸附位点,可有效提高其对阳离子物质的吸附容量,优化其耐酸碱性,并提高吸附质的脱附率。而疏水亲油的三维石墨烯材料是去除油类污染物质的理想吸附材料,提高其孔隙率、比表面积和机械强度可大幅提高吸附材料的吸附性能,增强其弹性强度及热稳定性可显著提高其循坏再生性能。基于水环境污染治理的迫切需求以及三维石墨烯材料优异的吸附性能,本文从水污染治理角度出发,系统总结了水热自组装法、溶剂热自组装法、化学气相沉积法、有机高分子模板法和冰模板法等制备三维石墨烯材料的机理,综述了三维石墨烯材料在含染料、油污等有机污染物以及重金属离子废水中的吸附应用,并对其研究前景和发展趋势进行了展望。

With the rapid development of economy,more and more pollutants have entered the waters,leading to the environment pollution and endangering human health.Therefore,the purification and treatment of polluted waste water are extremely urgent.In many sewage treatment methods,adsorption method is widely used because it is economical and highly efficient.Compared with the traditional adsorbents,graphene material,as a new type of carbon material,has the advantages of large surface area,excellent chemical stability,rich oxygen functional groups and strong modifiability,and it has strong adsorption capacity for pollutants in water.Nevertheless,the thin film and fine particle size of two-dimensional graphene make its separation from water after the adsorption of pollutants difficult,thus causing secondary pollution.If the two dimensional graphene is assembled to three dimensional porous network aggregates,it can not only prevent the accumulation of graphene structure layer effectively,but also facilitate the diffusion and adsorption of pollutants,and contribute to the solid-liquid separation after adsorption.Therefore,in the field of water pollution treatment,three dimensional graphene adsorbents have gradually become the research focus.The three-dimensional graphene material ia a new kind of porous block material which is mainly formed by the cross-linking ofgraphene or graphene oxidized.It inherits the excellent physical and chemical properties of intrinsic graphene.The nano porous structure endow three-dimensional graphene with high porosity and high solute transmission speed and other favorable characteristics,which decide its vast application prospects in water pollution treatment.Different chemical substances and various preparation methods can be adopted to graft and modify graphene materials,in the purpose of promoting the formation of the three-dimensional macrostructure and micropore structure of graphene.According to the research results at home and abroad,it can be found that the forces of three dimensional graphene adsorbing pollutants mainly include electrostatic interaction,π-πstacking,hydrophobic interaction,hydrogen bonding and complexation.For cationic pollutants,increasing the active groups and adsorption sites on the surface of three dimensional graphene can effectively improve the adsorption capacity,and optimizing their acid and alkaline resistance can effectively improve the desorption rate of adsorbents.The hydrophobic lipophilic three-dimensional graphene material is the ideal material for oil pollution removal.Improving the porosity,specific surface area and mechanical strength can greatly improve the adsorption capacity,and enhancing its elastic strength and thermal stability can significantly improve the performance of the cycle of regeneration.In consideration of the urgent needs of water pollution control and excellent adsorption performance of three-dimensional graphene materials,we systematically summarized the mechanism of three-dimensional graphene materials prepared by hydrothermal self-assembly method,solvothermal self-assembly method,chemical vapor deposition,organic polymer template method and ice template method from the perspective of water pollution control.In addition,the applications of 3 Dgraphene materials in the adsorption of organic pollutants like dye,oil and heavy metal ions in waste water are introduced.Finally,the research prospect and development trend of three-dimensional graphene are proposed.