摘要
为探究原位覆盖材料对表层沉积物砷(As)的钝化效果,选择可推广应用的锁磷剂(LMB)和增氧剂(CaO_(2)+CaCO_(3)),通过室内培养实验,应用微电极技术和高分辨率平衡式间隙水采集技术(HR-Peeper),研究覆盖材料对沉积物中砷(As)钝化的影响机制。实验设置锁磷剂组、增氧剂组和对照组共3个处理组,分为4个实验阶段(分别以加入覆盖剂后的第4,30,90,150天为节点)。结果表明:锁磷剂与增氧剂可有效去除沉积物中的As。锁磷剂覆盖最高可降低50.86%的溶解态As,影响深度可达到-100 mm,有效期150 d。增氧剂覆盖最高可降低55.52%的溶解态As,影响深度为-100 mm,90 d后效果减弱。锁磷剂与增氧剂覆盖显著降低了溶解态As的释放通量。锁磷剂上的镧离子对砷酸盐有很强的亲和力,可去除溶液中的砷酸盐。此外,锁磷剂和增氧剂增加了沉积物-水界面中的Eh值,使Fe(Ⅱ)被氧化成Fe(Ⅲ),吸附As从而降低As浓度。此外,溶解态As与Fe(Ⅱ)在沉积物剖面上同步变化且显著正相关(P<0.001),证实了Fe和As的耦合释放机制。研究结果可为淡水生态系统中As污染的控制和治理提供支撑。
Laboratory-based incubation experiments were carried out to study the effectiveness of readily available materials on the deactivation of sediment arsenic(As) using micro-electrode technology and micro-interface analysis technology(e.g.HR-Peeper).Group experiments(i.e.lanthanum modified bentonite group(LMB) and oxygenate group(CaO_(2)+CaCO_(3))) were carried out to test the reduction of the dissolved As in sediment interstitial water via adding LMB or CaO_(2)+CaCO_(3) to the sediments after 4,30,90,and 150 day,and compared with control group.The results showed that both LMB and oxygenate could effectively decrease As pollution in sediments.The addition of LMB caused 50.86% reduction in the dissolved As content in sediment interstitial water with the influencing depth of-100 mm and duration of 150 d,while the addition of CaO_(2)+CaCO_(3) caused 55.52% reduction in the dissolved As content in sediment interstitial water with the influencing depth of-100 mm and duration of 90 d.Both additions could dramatically decrease the internal dissolved As release.This could be explained by that the lanthanum ion on LMB had a strong affinity for arsenate and could remove the arsenate from sediment interstitial water.Moreover,the addition of LMB or oxygenate increased the Eh value of the sediments,and further led to the absorption of As by Fe(Ⅲ) oxidized from Fe(Ⅱ).Dissolved As contents along the sediment profile had a positive correlation with Fe(Ⅱ) contents(P<0.001).This study could be helpful for As pollution control in sediment in freshwater ecosystems.
作者
燕文明
蒋超
陈翔
麻林
颜秉龙
何翔宇
李敏娟
田玢
吴挺峰
YAN Wenming;JIANG Chao;CHEN Xiang;MA Lin;YAN Binglong;HE Xiangyu;LI Minjuan;TIAN Fen;WU Tingfeng(State Key Laboratory of Hydrology Water Resources and Hydraulic Engineering,Hohai University,Nanjing 210098,China;Hunan Provincial Water Resources Department,Changsha 410007,China;Lianyungang Water Resources Planning and Design Institute Co.Ltd,Lianyungang 222006,China;Nanjing Institute of Geography and Limnology,Chinese Academy of Sciences,Nanjing 210008,China)
出处
《环境工程》
CAS
CSCD
北大核心
2022年第11期127-133,151,共8页
Environmental Engineering
基金
中科院“西部之光”项目(E129030101)
国家自然科学基金项目(41971047)
湖南省水利基金(XSKJ2019081-42)
水文水资源与水利工程科学国家重点实验室“一带一路”水与可持续发展科技基金(2020491811)
江苏省水利科技项目(2021049)。
作者简介
第一作者:燕文明(1982-),女,高级实验师,主要研究方向为水环境保护与生态修复。ywm0815@163.com;通信作者:吴挺峰,男,副研究员,主要研究方向为环境水文及水环境保护。tfwu@niglas.ac.cn。
