As(Ⅴ)和P(Ⅴ)在针铁矿{110}晶面上的竞争吸附机理研究  

Competitive Adsorption Mechanisms of As(Ⅴ)and P(Ⅴ)on the{110}Facet of Goethite

作　　者：冉跃 周少奇[1,2] 曹效鑫 李占彬 马凯 RAN Yue;ZHOU Shaoqi;CAO Xiaoxin;LI Zhanbin;MA Kai(School of Resources and Environmental Engineering,Guizhou University,Guiyang 550025,China;Guizhou Academy of Sciences,Guiyang 550001,China;China Water Environment Group Co.,Ltd,Beijing 101101,China;Guizhou Provincial Institute of Analysis and Testing,Guiyang 550000,China)

机构地区：[1]贵州大学资源与环境工程学院,贵州贵阳550025 [2]贵州省科学院,贵州贵阳550001 [3]中国水环境集团有限公司,北京101101 [4]贵州省分析测试研究院,贵州贵阳550000

出　　处：《环境科学与技术》2024年第10期37-45,共9页Environmental Science & Technology

基　　金：国家重点研发计划项目:“水资源高效开发利用”重点专项中2016年第一批申报项目“综合节水技术”下设置的“典型地区农村供排水一体化技术及应用示范”(2016YFC0400700)。

摘　　要：为了研究As(Ⅴ)和P(Ⅴ)在针铁矿{110}晶面上的竞争吸附行为,该研究制备了高{110}晶面暴露度的针铁矿(Goe),并利用XRD、SEM和TEM等技术对材料的晶体结构、表面形貌及暴露晶面进行了表征。通过吸附试验结合CD-MUSIC(电荷分配-多位点络合)模型和DFT(密度泛函理论)计算,系统探讨了As(Ⅴ)和P(Ⅴ)的吸附行为及其竞争机制。结果表明,制备的针铁矿材料具有较高的{110}晶面暴露度,对As(Ⅴ)和P(Ⅴ)的吸附容量分别达到0.206和0.190 mmol/g(pH=7),吸附行为更符合Freundlich模型。通过CDMUSIC模型分析,发现As(Ⅴ)和P(Ⅴ)主要通过双齿配位吸附于Goe表面,其中As(Ⅴ)表现出较P(Ⅴ)更强的双齿配位竞争力。FTIR和XPS分析进一步证实,As(Ⅴ)和P(Ⅴ)主要竞争表面Fe—OH位点,通过与Fe—OH配体交换形成新的络合物(Fe-O-As/P)吸附。DFT计算结果表明,As(Ⅴ)和P(Ⅴ)在{110}晶面上双齿构型的吸附能分别为-2.67和-2.23 eV,证实了As(Ⅴ)对双齿位点更强的吸附亲和力。此外,DFT计算显示,O—As—O的角度低于O—P—O的角度,且As(Ⅴ)络合物的Fe—O键长更小,利于As(Ⅴ)通过双齿配位吸附的稳定。该研究深入探讨了分子尺度下As(Ⅴ)和P(Ⅴ)在环境中竞争吸附的行为,为理解有毒金属的环境地球化学迁移提供了新见解,并为污染控制和修复提供了理论依据和技术支持。To investigate the competitive adsorption behavior of As(Ⅴ)and P(Ⅴ)on the{110}crystal face of goethite(Goe),we prepared goethite with a high exposure of{110}crystal faces.The crystal structure,surface morphology,and exposed crystal faces of the materials were characterized using XRD,SEM,and TEM.Through adsorption experiments combined with the CD-MUSIC(charge distribution-multisite complexation)model and DFT(density functional theory)calculations,we systematically explored the adsorption behavior and competitive mechanisms of As(Ⅴ)and P(Ⅴ).The results showed that the prepared goethite material exhibited a high{110}crystal face exposure,with adsorption capacities for As(Ⅴ)and P(Ⅴ)of 0.206 and 0.190 mmol/g(pH=7),respectively.The adsorption behavior conformed more to the Freundlich model.CDMUSIC model analysis revealed that As(Ⅴ)and P(Ⅴ) were primarily adsorbed on the Goe surface through bidentate coordination,with As(Ⅴ)exhibiting stronger bidentate coordination competitiveness compared to P(Ⅴ).FTIR and XPS analyses further confirmed that As(Ⅴ)and P(Ⅴ)mainly competed for the surface Fe-OH sites,forming new complexes(Fe-O-As/P)through ligand exchange with Fe-OH.DFT calculations showed that the adsorption energies of bidentate configurations for As(Ⅴ)and P(Ⅴ)on the{110}crystal face were-2.67 and-2.23 eV,respectively,confirming the stronger adsorption affinity of As(Ⅴ)for bidentate sites.Additionally,DFT calculations indicated that the O-As-O angle was smaller than the O-P-O angle,and the Fe-O bond length in the As(Ⅴ)complex was shorter,facilitating the stability of As(Ⅴ)adsorp⁃tion through bidentate coordination.This study provides an in-depth exploration of the competitive adsorption behavior of As(Ⅴ) and P(Ⅴ) at the molecular scale in the environment,offering new insights into the geochemical migration of toxic metals and providing theoretical support and technical guidance for pollution control and remediation.

关 键 词：针铁矿 晶面 竞争吸附 CD-MUSIC模型 DFT计算 

分 类 号：X131[环境科学与工程—环境科学]