赤铁矿{001}和{012}晶面对Cr(Ⅵ)吸附差异性研究  

Study on the difference of Cr(Ⅵ)adsorption on{001}and{012}facets of hematite

作　　者：廖荣 罗才贵[1,2] 高琦 钟丽娴 罗仙平[1] LIAO Rong;LUO Caigui;GAO Qi;ZHONG Lixian;LUO Xianping(Jiangxi Key Laboratory of Mining and Metallurgy Environmental Pollution Control,Ministry of Education,Jiangxi University of Science and Technology,Ganzhou 341000,Jiangxi,China;Engineering Research Center for Efficient Development and Application of Tungsten Resources,Ministry of Education,Jiangxi University of Science and Technology,Ganzhou 341000,Jiangxi,China)

机构地区：[1]江西理工大学江西省矿冶环境污染控制重点实验室,江西赣州341000 [2]江西理工大学钨资源高效开发及应用教育部工程研究中心,江西赣州341000

出　　处：《有色金属科学与工程》2023年第6期862-870,共9页Nonferrous Metals Science and Engineering

基　　金：国家自然科学基金资助项目(41902038);江西理工大学钨资源高效开发及应用教育部工程研究中心开放课题资助项目(W-2021YB002);中国博士后科学基金面上资助项目(2018M6432);江西省研究生创新专项资金资助项目(YC2021-S550)。

摘　　要：赤铁矿是热稳定性最高的铁氧化物,其与环境污染物相互作用(吸附)对污染物的迁移、转化甚至环境归趋均具有重要影响。前人采用粗制赤铁矿研究其对污染物的吸附作用,所得结果难以准确说明其矿物表面的反应性质。基于此,采用水热法成功合成了主暴露{001}晶面、{012}晶面的赤铁矿纳米颗粒(HNPs和HNCs)。在此基础上,研究了赤铁矿不同晶面对Cr(Ⅵ)的吸附动力学和热力学特征,并考察了pH、离子强度等对赤铁矿不同晶面吸附Cr(Ⅵ)的影响。结果表明,HNPs与HNCs对Cr(Ⅵ)的吸附过程均遵循准二级动力学模型,且分别符合Langmuir和Freundlich等温吸附模型。随着温度升高,KL与KF均减小,△H^(ɵ)<0,说明吸附过程为放热过程。HNPs与HNCs对Cr(Ⅵ)的吸附量随溶液pH增大均减小。结合离子强度实验结果与DFT计算得出,HNPs对Cr(Ⅵ)的吸附主要以表面络合为主,推测吸附构型为单齿单核;而HNCs对Cr(Ⅵ)的吸附主要由表面络合与静电吸附共同主导,推测吸附构型为双齿双核。上述结果为赤铁矿应用于环境治理提供参考。Hematite is the most thermally stable iron oxide,and its interaction(adsorption)with environmental pollutants has an important influence on the migration,transformation,and even environmental fate of pollutants.However,crude hematite was used to study its adsorption effect on pollutants,and the results obtained did not accurately indicate its mineral surface reactivity.In this study,hematite nanoparticles(HNPs and HNCs)with{001}and{012}facets were successfully synthesized by employing a hydrothermal method.On this basis,the kinetic and thermodynamic characteristics of Cr(Ⅵ)adsorption on different facets of hematite were investigated,and the influence of pH and ion strength on the adsorption of Cr(Ⅵ)on different facets of hematite was studied.The results showed that the adsorption processes of Cr(Ⅵ)on HNPs and HNCs were both described by the quasi-second-order kinetic model,which follows the Langmuir and Freundlich isothermal adsorption models,respectively.With the increase in temperature,the decrease in KL and KF as well as△Hɵ<0 indicated that the adsorption processes were exothermic.The adsorption amounts of HNPs and HNCs to Cr(Ⅵ)decreased with increasing solution pH.Combined the results of the ionic strength experiments with the DFT calculations,the adsorption of Cr(Ⅵ)on HNPs was mainly dominated by surface complexation,and the adsorption configuration was monodentate mononuclear,while the adsorption of Cr(Ⅵ)on HNCs was mainly dominated by surface complexation and electrostatic adsorption,and the adsorption configuration was bidentate binuclear.The above results can be expected to provide a reference for the application of hematite in environmental governance.

关 键 词：赤铁矿 不同晶面 Cr(Ⅵ) 吸附构型 

分 类 号：TF111.31[冶金工程—冶金物理化学] TD989[矿业工程—选矿]