常规金属离子对Fe_3O_4磁性纳米颗粒悬浮和沉降的影响  

Effect of normal metal cations on sedimentation of Fe_3O_4 magnetic particles in aquatic environment

作　　者：汪浩[1,2] 朱元荣[2] 赵晓丽[2] 郄玉 郭文景[1,2] 刘沙沙[1,2] 韩雪娇[2] 

机构地区：[1]北京师范大学水科学研究院,北京100875 [2]中国环境科学研究院环境基准与风险评估国家重点实验室,北京100012

出　　处：《环境科学学报》2017年第4期1367-1373,共7页Acta Scientiae Circumstantiae

基　　金：国家自然科学基金(No.41222026;41630645)~~

摘　　要：水体中的有机质、无机盐及酸碱度是影响纳米材料迁移转化的主要因素.考察了Na^+、Mg^(2+)、Ca^(2+)、Sr^(2+)和Ba^(2+)对Fe_3O_4磁性纳米材料(Magnetic Nanoparticles,MNPs)的沉降作用.结果表明,Fe_3O_4MNPs的沉降作用是水体pH、金属离子化合价、离子强度共同影响的结果.整体上,碱土金属离子较Na^+更能加速Fe_3O_4MNPs的沉降.当pH为5.0时,浓度低于1.0 mmol·L^(-1)的Na^+、Mg^(2+)和Ca^(2+)有助于Fe_3O_4MNPs的悬浮;当浓度大于1.0 mmol·L^(-1)时,较强的离子强度促使Fe_3O_4MNPs团聚,发生沉降.当pH为9.0时,碱土金属离子较Na^+更能促使Fe_3O_4MNPs聚沉.因此,纳米颗粒在水体中的扩散和聚沉需要综合考虑金属离子种类和浓度.Inorganic ion,organic matter and pH,are key factors for aggregation of nanoparticles in aquatic environment. In this study,effects of metal ions including Na＋,Mg（2＋）,Ca（2＋）,Sr（2＋）and Ba（2＋）on sedimentation of Fe3O4 MNPs were investigated. Results show that the sedimentation of Fe3O4 MNPs were affected jointly by pH of aquatic environment,valence state and ionic strength of metal cations. Generally,the alkaline-earth metal cations could accelerate the sedimentation of Fe3O4 MNPs more than Na＋. At pH 5.0,when concentrations of Na＋,Mg（2＋）and Ca（2＋）were below 1.0 mmol·L（-1）,these metal cations could slow the sedimentation process of Fe3O4MNPs; however,the sedimentation of Fe3O4 MNPs would be accelerated when concentrations of metal cations were greater than 1.0 mmol·L（-1）. At pH 9.0,alkaline-earth metal ions significantly facilitated the sedimentation of Fe3O4 MNPs more than Na＋,as a result of effect of valence state of metal cations. Therefore,diffusion and sedimentation of nanoparticles should be assessed considering the species and concentrations of metal cations in aquatic environment.

关 键 词：碱土金属 碱金属 磁性纳米颗粒 沉降作用 

分 类 号：X703[环境科学与工程—环境工程]