摘要
工业废水对环境的污染和人体的危害日趋严重,该问题亟待处理。在众多污水处理方法中,膜分离因选择性强、分离性能高而受到广泛应用。膜分离主要利用尺寸筛分和静电排斥原理进行超滤、纳滤、反渗透和正渗透等,但传统的膜材料如偏聚氟乙烯、聚砜、聚酰胺等存在污染物截留率低、机械强度差、耐氯性差等缺点,使膜技术面临巨大的难题与挑战。近年来,石墨烯的研究热潮推动了高分子膜材料的高速发展,氧化石墨烯(GO)优越的性能使GO分离膜成为备受关注的研究热点之一,利用GO纳米片组装的多层结构在增强膜分离性能方面显示出巨大的潜力。与GO改性的常规分离膜不同,多层GO膜物理力学性能和化学稳定性更高,并可通过结构设计如层数、氧化程度、改性状况、层间距等来改善分离效果。多层膜的渗透性与分离层的层数有关,膜层数增加可以提高膜的抗穿透性和选择性;石墨烯的氧化程度决定了GO的层数、亲水性和电荷性质,还原程度的增加有利于膜渗透性的提升,氧化程度则有利于分离性能的提升;可以通过改变电荷性质对GO膜进行改性,从而增强GO与目标分子或离子的相互作用。GO纳米通道的结构则影响着水分子的形态和运输,利用分子动力学可模拟和预测多层GO膜的分离性能。本文简要介绍了多层GO膜的制备方法,探讨了结构控制与GO膜分离性能的关系,详细介绍了GO膜的层数、氧化程度、改性、层间距对分离性能的影响,并通过分子动力学对多层GO膜分离进行模拟分析;展望了其在水处理领域面临的机遇与挑战。
The pollution of industrial wastewater to the environment and the harm to human body are becoming more and more serious,and this problem needs to be dealt with urgently.Among many industrial wastewater treatment methods,membrane treatment is widely used because of its good selectivity and separation efficiency.Membrane treatment,including ultrafiltration,nanofiltration,reverse osmosis and positive osmosis,is mainly based on the principles of size screening and electrostatic exclusion.However,traditional membrane materials,such as polyvinylidene fluoride,polysulfone and polyamide,have some defects,for instance,low rejection rate of pollutants,poor mechanical strength and poor chlorine resistance,which make membrane treatment face enormous difficulties and pressures.In recent years,the research and application of graphene materials have promoted the development of membrane materials.Graphene oxide separation membranes have become one of the research hotspots due to their excellent comprehensive properties.The multilayer structure assembled by graphene oxide nanosheets has shown great potential in enhancing the separation performance of membrane.Unlike graphene oxide modified conventional separation membranes,multilayer graphene oxide membranes exhibit superior physical and mechanical properties and chemical stability,and can be improved by structural design such as layer number,oxidation degree,modification status and interlayer spacing.The permeability of multilayer graphene oxide membrane is related to the number of separated layers,and increasing the number of membrane layers can improve their penetration resistance and selectivity.The number of layers,hydrophilicity and charge characteristic of GO are determined by the oxidation degree of graphene,plus,the increase of reduction degree is beneficial to the improvement of membrane permeability,while the oxidation degree is beneficial to the improvement of separation performance.The modification of GO membrane can change the charge characteristic,thus enhancing the interaction between GO and target molecules or ions.The structure of GO nanochannels affect the morphology and transport of water molecules,and the molecular dynamics can simulate and predict the separation performance of multilayer GO membrane.Here the preparation methods of multi-layer graphene oxide membranes are briefly introduced,and the relationship between structure control and separation performance of graphene oxide membranes is discussed.The effects of layer number,oxidation degree,modification and interla-yer spacing of graphene oxide membranes on separation performance are introduced in detail.The separation performance of multilayer graphene oxide membranes is simulated and analyzed by molecular dynamics.The application progress of multilayer graphene oxide membrane in removing heavy metal ions,desalination and organic matter is reviewed,and the opportunities and challenges in water treatment are prospected.
作者
姚庆达
温会涛
杨长凯
梁永贤
王小卓
但卫华
YAO Qingda;WEN Huitao;YANG Changkai;LIANG Yongxian;WANG Xiaozhuo;DAN Weihua(Fujian Key Laboratory of Green Design and Manufacture of Leather,Jinjiang 362271,China;Xingye Leather Technology Co.,Ltd.,Jinjiang 362261,China;National Engineering Laboratory for Clean Technology of Leather Manufacture,Sichuan University,Chengdu 610065,China)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2020年第15期15047-15058,共12页
Materials Reports
基金
泉州市科技计划项目(2018G001)。
关键词
水处理
膜分离
多层氧化石墨烯膜
性能控制
water treatment
membrane separation
multilayer graphene oxide membrane
performance control
