摘要
Cr在环境中释放易导致重金属污染,其所造成的环境危害与Cr存在形态紧密相关。Cr(Ⅵ)多以Cr_(O)_(4)^(2–)或Cr_(2)O_(7)^(2−)形式存在,在水体中具有较高溶解度和迁移性,且具有较大的毒性。水铁矿具有大比表面积和高反应活性,是环境中Cr(Ⅵ)的重要吸附剂;同时,水铁矿也是一种天然半导体矿物,在光照诱导作用下可产生光电子并转移电子。然而,水铁矿表面的光化学反应对Cr(Ⅵ)地球化学行为的影响尚不清楚。因此,本研究探讨了光照对水铁矿去除Cr(Ⅵ)的影响。结果表明:在黑暗条件下,水铁矿通过吸附作用去除了57%的Cr(Ⅵ);在光照有氧条件下,水铁矿对Cr(Ⅵ)的去除率上升到67%;在厌氧条件下,光照效应的增强作用更加明显,水溶液中Cr(Ⅵ)几乎完全被去除。结合傅里叶变换衰减全反射红外光谱(ATR-FTIR)和X射线光电子能谱(XPS)分析发现,水铁矿能够快速吸附Cr(Ⅵ),其中有62%的Cr在水铁矿表面被还原,占总去除率的41.5%。因此,光照能够通过还原作用增强水铁矿对Cr(Ⅵ)的去除,从而降低Cr(Ⅵ)的迁移性和环境毒性。本研究为深入认识地表环境中铁(氢)氧化物对氧化还原敏感元素地球化学行为的制约机理提供了新信息。
The release of chromium in the environment can easily lead to heavy metal pollution,and its environmental hazards are closely related to the existing forms of Cr.Cr(Ⅵ)commonly exists in the form of Cr_(O)_(4)^(2–)or Cr_(2)O_(7)^(2−)ions,which have high solubility and mobility in water and high toxicity.Ferrihydrite has a large specific surface area and high reactivity and is a vital adsorbent for Cr(Ⅵ)in the environment.At the same time,ferrihydrite is also a natural semiconductor mineral that can produce photoelectrons and transfer electrons under light irradiation.However,the effect of photochemical reactions on the surface of ferrihydrite on the geochemical behavior of Cr(Ⅵ)is still unclear.Therefore,this study investigated the effect of light irradiation on Cr(Ⅵ)removal by ferrihydrite.The results showed that 57%of Cr(Ⅵ)was removed by ferrihydrite through adsorption under dark and aerobic conditions.Under light and aerobic conditions,the removal efficiency of Cr(Ⅵ)by ferrihydrite increased to 67%,whereas under anaerobic conditions,the enhancement effect of light irradiation was more obvious,and Cr(Ⅵ)was almost completely removed from the aqueous solution.Combined with in situ attenuated total reflection Fourier transform infrared(ATR-FTIR)spectroscopy and X-ray photoelectron spectroscopy(XPS),ferrihydrite was found to rapidly adsorb Cr(Ⅵ),and 62%of the Cr was reduced on the surface of ferrihydrite,accounting for 41.5%of the total removal efficiency.Therefore,light irradiation can enhance the removal of Cr(Ⅵ)by ferrihydrite through reduction,thereby reducing the mobility and environmental toxicity of Cr(Ⅵ).This study provides new information for understanding the constraints of iron(hydr)oxides on the geochemical behavior of redox-sensitive elements in the surface environment.
作者
吕瑛
陈情泽
朱润良
朱建喜
何宏平
LV Ying;CHEN Qingze;ZHU Runliang;ZHU Jianxi;HE Hongping(CAS Key Laboratory of Mineralogy and Metallogeny/Guangdong Provincial Key Laboratory of Mineral Physics and Materials,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,Guangdong,China;CAS Center for Excellence in Deep Earth Science,Guangzhou 510640,Guangdong,China;University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《地球化学》
CAS
CSCD
北大核心
2024年第1期153-162,共10页
Geochimica
基金
国家自然科学基金项目(41902040、41872044)
中国科学院青年创新促进会专项项目(2020347)联合资助。
关键词
光照
水铁矿
六价铬
吸附
氧化还原反应
light irradiation
ferrihydrite
hexavalent chromium
adsorption
redox reaction