水铁矿结晶转化过程中钨的再分配研究  

Redistribution of Tungsten During the Crystalline Phase Transformation of Ferrihydrite

作　　者：黄瑞 卢磊 李伟峻 杜辉辉 HUANG Rui;LU Lei;LI Weijun;DU Huihui(College of Environment&Ecology,Hunan Agricultural University,Changsha 410128,P.R.China)

机构地区：[1]湖南农业大学环境与生态学院,湖南长沙410128

出　　处：《生态环境学报》2024年第10期1563-1569,共7页Ecology and Environmental Sciences

基　　金：湖南省重点研发计划项目(2023NK2027);国家重点研发计划青年科学家项目(2023YFD1702700)。

摘　　要：钨是一种受关注较少的污染物,目前对其环境行为的认识还十分有限。在表生环境中,铁矿物-水界面是调控钨等含氧阴离子固液分配和形态的关键界面,对预测钨的迁移和归趋有重要意义。探究水铁矿结晶转化过程中钨的形态转化和再分配,旨在为钨在表生环境中的迁移转化和归宿提供科学依据。参考2-line水铁矿的制备方法合成水铁矿-钨吸附(FhW_Ads)和共沉淀(FhW_Cor)复合体,在60℃好氧条件下进行为期60 d的老化试验,结合X射线衍射和化学形态提取,研究水铁矿转化及钨的形态特征。结果显示:在无钨存在,60 d后最终有82%的水铁矿转化为针铁矿或赤铁矿;而在FhW_Ads和FhW_Cor体系中,针铁矿或赤铁矿特征衍射峰出现时间较晚且强度更弱,最终FhW_Ads体系中水铁矿转化了73%,FhW_Cor体系中转化了57%,意味着钨抑制水铁矿的结晶转化,且共沉淀方式抑制效果更显著。在水铁矿结晶转化过程中,钨逐渐被释放到溶液中,且FhW_Ads体系中钨的释放量(154 mg·L^(-1))高于FhW_Cor体系(110 mg·L^(-1));被释放的钨随后被转化产物再吸附。在矿相转化过程中,钨除了被释放到溶液中,还部分插入矿物晶格内,部分可能转化为结晶态钨铁矿(FeWO4)。该研究结果证实,铁矿物是钨的重要“库”,且铁-钨的复合方式和矿相转化显著改变钨的结合形态和再分配,进一步影响其迁移和归趋。这对理解钨在富铁环境中的环境行为提供了支撑。Tungsten is a contaminant that has received relatively little attention,and our understanding of its environmental behavior remains limited.In surficial environments,the Fe mineral-water interface plays a crucial role in regulating the solid-liquid distribution and speciation of tungsten and other oxyanions,making it significant for predicting the migration and fate of tungsten.This study investigates the speciation,transformation,and redistribution of tungsten during the crystallization of ferrihydrite,aiming to provide scientific evidence for tungsten's migration,transformation,and fate in surficial environments.Using the 2-line ferrihydrite synthesis method,we prepared ferrihydrite-tungsten adsorption(FhW_Ads)and co-precipitation(FhW_Cor)complexes.Aging experiments were conducted for 60 days under aerobic conditions at 60℃.The transformation of ferrihydrite and the speciation of tungsten were analyzed using X-ray diffraction and chemical speciation extraction.Results indicated that in the absence of tungsten,82%of ferrihydrite transformed into goethite or hematite after 60 days.In the FhW_Ads and FhW_Cor systems,the characteristic diffraction peaks of goethite or hematite appeared later and were weaker in intensity.Ultimately,73%of ferrihydrite transformed in the FhW_Ads system,and 57%in the FhW_Cor system,suggesting that tungsten inhibits ferrihydrite crystallization,with the co-precipitation showing a more pronounced inhibitory effect.During the crystallization of ferrihydrite,tungsten was gradually released into the solution,with the amount of tungsten released in the FhW_Ads system(154 mg·L^(-1))being higher than in the FhW_Cor system(110 mg·L^(-1)).The released tungsten was subsequently re-adsorbed by the transformation products.In addition to being released into the solution,tungsten may partially incorporate into the mineral lattice or transform into crystalline tungsten-iron compounds during the mineral phase transformation.The results of this study confirm that iron minerals serve as an important�

关 键 词：水铁矿 矿相转化 钨 吸附 共沉淀 

分 类 号：X13[环境科学与工程—环境科学]