典型石英族矿物表面差异性对其吸附重金属的影响  

Effects of surface differences in typical quartz minerals on the absorption of heavy metals

作　　者：唐翠华[1,2,3] TANG Cuihua(Hubei Key Laboratory of Petroleum Geochemistry and Environment(Yangtze University),Wuhan 430100,Hubei,China;College of Resources and Environment,Yangtze University,Wuhan 430100,Hubei,China;Key Laboratory of Exploration Technologies for Oil and Gas Resources,Ministry of Education,Wuhan 430100,Hubei,China)

机构地区：[1]油气地球化学与环境湖北省重点实验室(长江大学),湖北武汉430100 [2]长江大学资源与环境学院,湖北武汉430100 [3]油气资源勘探技术教育部重点实验室,湖北武汉430100

出　　处：《地球化学》2023年第6期707-714,共8页Geochimica

基　　金：国家自然科学基金项目(41703108)资助。

摘　　要：矿物表面微结构及其性质是矿物表界面作用的关键制约因素,控制着重金属元素在表生地球化学环境中迁移和归趋。本文对比了典型石英族矿物(α-石英、α-方石英)对Cu^(2+)、Pb^(2+)、Zn^(2+)、Co^(2+)等重金属离子的吸附特征和规律,通过等温滴定量热技术分析了2种矿物吸附这4种离子的热力学特征,并结合EPR谱初步分析了Cu^(2+)和Co^(2+)在2种不同矿物表面上的吸附机制和差异。结果表明:(1)α-石英、α-方石英对4种重金属离子有明显的选择性吸附,且对Cu^(2+)和Pb^(2+)的吸附能力明显大于Zn^(2+)和Co^(2+)。离子吸附量与矿物表面羟基位密度呈正相关关系,因此,α-石英的单位面积吸附量均大于α-方石英;(2)α-石英、α-方石英吸附Cu^(2+)、Pb^(2+)、Zn^(2+)为吸热反应,且α-石英的反应焓变值大于α-方石英。α-石英、α-方石英吸附Co^(2+)为放热反应,可能与重金属离子在其表面形成产物的结构不同有关;(3)α-石英、α-方石英与Cu^(2+)发生配位,主要生成了内层配合物(g=2.08)。α-石英吸附Co^(2+)产物中存在属于Co(Ⅱ)的产物信号峰,而在α-方石英中无较明显此峰,表明Co^(2+)在α-方石英表面可能形成了其他局部微观结构,并不以简单的配位吸附Co(Ⅱ)的形式存在,但需进一步验证。本研究进一步明确了石英族矿物表面微结构和性质差异对其吸附重金属的影响。The surface microstructure and properties of minerals play crucial roles in governing their surface/interface interactions,as well as the migration and fate of heavy metal elements in supergene geochemical environments.This paper presents a comparative study on the adsorption characteristics and behaviors ofα-quartz andα-cristobalite concerning Cu^(2+),Pb^(2+),Zn^(2+),and Co^(2+)ions.The thermodynamic features of the adsorption of these ions by the two minerals were investigated using isothermal titration calorimetry.When combined with the EPR spectra,the adsorption mechanisms of Cu^(2+)and Co^(2+)on the surfaces of the two minerals were elucidated.The research results demonstrate that:(1)α-quartz andα-cristobalite exhibit clear adsorption selectivity for the four heavy metal ions,with their adsorption capacity for Cu^(2+)and Pb^(2+)significantly greater than that for Zn^(2+)and Co^(2+).The adsorption amount was positively correlated with the density of hydroxyl sites on the mineral surface,resulting in a greater adsorption amount per unit area forα-quartz compared to that ofα-cristobalite.(2)The adsorption of Cu^(2+),Pb^(2+),and Zn^(2+)byα-quartz andα-cristobalite is endothermic,and the enthalpy of the former is greater than that of the latter.The thermal effect of the adsorption of Co^(2+)byα-quartz andα-cristobalite is distinctly different from that of Cu^(2+),Pb^(2+),and Zn^(2+),as it is an exothermic reaction.This divergence may be attributed to the different structures of heavy metal ions formed on the surface.(3)Cu^(2+)predominantly coordinates on the surface ofα-quartz andα-cristobalite to form an inner complex(g=2.08).A signal peak belonging to Co(Ⅱ)appears in theα-quartz adsorption product,but no obvious peak is observed inα-cristobalite.This indicates that Co^(2+)may have formed other local microstructures on the surface ofα-cristobalite,rather than a simple coordinated adsorption Co(Ⅱ)form,although further investigation is needed to confirm this.

关 键 词：α-石英 Α-方石英 表面差异性 吸附 重金属 

分 类 号：P574[天文地球—矿物学]