| 地下水曝气-砂滤处理产生的废弃石英砂中铁砷含量与形态分布 |
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| 引用本文： | 张耀强,胡冰冰,谢世伟,袁松虎.地下水曝气-砂滤处理产生的废弃石英砂中铁砷含量与形态分布[J].地学前缘,2021,28(5):208-214. |
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| 作者姓名： | 张耀强 胡冰冰 谢世伟 袁松虎 |
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| 作者单位： | 中国地质大学(武汉)生物地质与环境地质国家重点实验室,湖北武汉430074;武汉科技大学城市建设学院,湖北武汉430065 |
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| 基金项目： | 国家自然科学基金创新群体项目(41521001);湖北省自然科学基金创新群体项目(2018CFA028) |
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| 摘 要： | 高铁高砷地下水严重威胁饮水质量,曝气-砂滤法因处理效果好且成本低在农村地区得到广泛应用。砂滤过程石英砂表面富集铁和砷后需定期更换,然而废弃石英砂堆置具有砷释放风险。本文以江汉平原某水厂砂滤池废弃石英砂为研究对象,采用激光剥蚀-等离子体质谱(LA-ICP-MS)、拉曼光谱(Raman)、X射线衍射(XRD)和分步化学提取等手段,研究了砂样中的Fe和As含量及形态分布。结果表明,砂粒表面形成了一层厚度为20100 μm的高铁砷薄层,薄层内部Fe和As含量显著高于两侧,Fe和As分布高度相关(R2=0.985)。砂样表面铁矿物以无定型/弱结晶型为主,同时检出赤铁矿和臭葱石等矿物。砂样中Fe和As总含量分别为20.1 mg/g和53.4 μg/g。砂样表面铁主要以易溶解态、碳酸盐结合态和易还原态为主,As主要吸附在铁矿物上。研究区降雨充沛,当废弃石英砂遭遇雨水冲刷或淹没时,可能导致铁砷薄层中As解吸或随Fe矿物还原溶解而释放。
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| 关 键 词： | 废弃石英砂 高砷地下水 砷释放 砂滤 饮用水处理 |
| 收稿时间： | 2020-05-12 |
Content and speciation distributions of Fe and As in disposed quartz sand from groundwater treatment by sequential aeration and sand filtration |
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| ZHANG Yaoqiang,HU Bingbing,XIE Shiwei,YUAN Songhu.Content and speciation distributions of Fe and As in disposed quartz sand from groundwater treatment by sequential aeration and sand filtration[J].Earth Science Frontiers,2021,28(5):208-214. |
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| Authors: | ZHANG Yaoqiang HU Bingbing XIE Shiwei YUAN Songhu |
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| Institution: | 1. State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Wuhan), Wuhan 430074, China2. School of Urban Construction, Wuhan University of Science and Technology, Wuhan 430065, China |
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| Abstract: | Drinking water security is threatened by elevated iron (Fe) and arsenic (As) concentrations in groundwater. Sequential aeration and sand filtration has been widely used for the high-performance, low-cost groundwater treatment in rural areas. During filtration, Fe, As-enriched quartz sand needs periodic replacement. The disposed sand frequently piles up on land, risking As release. In this research, the content and speciation distributions of Fe and As in disposed quartz sand collected from a drinking water treatment plant in the Jianghan plain, were investigated by LA-ICP-MS, Raman spectroscopy, X-ray diffraction and sequential chemical extraction. The results show that the sand surface was coated with a 20-100 μm thick Fe, As-rich layer, with Fe and As significantly concentrated in the central layer than on the outer layers; the As and Fe spatial distributions in the coating were highly correlated (R2> 0.985). The Fe phases were mainly amorphous and weakly crystalline, and the presence of hematite and scorodite was detected. The total contents of Fe and As in the quartz were 20.1 mg/g and 53.4 μg/g, respectively. The highly dissolvable Fe (oxy)hydroxides and carbonate-bound, reducible Fe species predominated in the coatings, whereas As was mainly adsorbed on the surface of Fe phases. Due to the abundant rainfall in the study area, As release from the disposed quartz sand could occur as a consequence of rain washing or anaerobic Fe bio-reduction. |
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| Keywords: | disposed quartz sand high-arsenic groundwater arsenic release sand filtration drinking water treatment |
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