生态环境学报 ›› 2022, Vol. 31 ›› Issue (12): 2422-2430.DOI: 10.16258/j.cnki.1674-5906.2022.12.017

• 研究论文 • 上一篇    下一篇

氢氧化钠改性坡缕石对Cd污染土壤的钝化修复效果

任珺1,2,3,*(), 潘佳璇1,2, 陶玲1,2,3, 仝云龙1,2, 王若安1,2, 孙新妮1,2   

  1. 1.甘肃省黄河水环境重点实验室,兰州交通大学,甘肃 兰州 730070
    2.兰州交通大学环境与市政工程学院/环境生态研究所,甘肃 兰州 730070
    3.甘肃瀚兴环保科技有限公司,甘肃 兰州 730070
  • 收稿日期:2021-07-10 出版日期:2022-12-18 发布日期:2023-02-15
  • 通讯作者: *
  • 作者简介:任珺(1968年生),男,教授,博士,从事污染环境生态修复理论与技术研究。E-mail: renjun@mail.lzjtu.cn
  • 基金资助:
    甘肃省黄河水环境重点实验室项目(20JR2RA002);甘肃省黄河水环境重点实验室项目(21YRWEK007);甘肃省黄河水环境重点实验室项目(21YRWEG003);甘肃省教育厅产业支撑计划项目(2021CYZC-31);兰州市人才创新创业项目(2021-RC-41);甘肃省科技计划项目(22CX3GA076)

Stabilization Remediation of Soil Polluted by Cd Using Palygorskite Modified by NaOH

REN Jun1,2,3,*(), PAN Jiaxuan1,2, TAO Ling1,2,3, TONG Yunlong1,2, WANG Ruo’an1,2, SUN Xinni1,2   

  1. 1. Key Laboratory of Yellow River Water Environment in Gansu Province, Lanzhou Jiaotong University, Lanzhou 730070, P. R. China
    2. School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou 730070, P. R. China
    3. Gansu Hanxing Environmental Protection Co., Ltd., Lanzhou 730070, P. R. China
  • Received:2021-07-10 Online:2022-12-18 Published:2023-02-15

摘要:

土壤重金属污染原位钝化修复技术主要通过钝化剂的溶解沉淀、离子交换吸附、氧化还原、有机络合等反应来降低土壤中重金属的生物有效性,在重金属污染修复中具有重要意义。为研究NaOH改性坡缕石对污染土壤中Cd的钝化作用,以坡缕石为原料,采用浸渍法,将NaOH与坡缕石按照不同质量比进行改性,并在人工配制的Cd污染土壤上进行钝化实验和盆栽实验,研究NaOH改性坡缕石对Cd污染土壤的钝化效果以及对玉米植株生长性状和玉米植株Cd富集的影响。研究结果显示:与对照相比,添加NaOH改性坡缕石能显著降低土壤中DTPA和TCLP提取有效态Cd含量,提高钝化效率,降低生态风险指数,其中添加NaOH与坡缕石质量比为1?2的改性材料,两种有效态Cd含量降幅最大,分别为22.37%和26.60%。添加NaOH改性坡缕石能有效地改善玉米植株的生长性状。与对照相比,添加质量比为1?2的改性材料后,玉米植株的茎长、根长、茎、根鲜质量和茎、根干质量分别增加了71.45%、65.21%、22.06%、44.44%、33.96%和50%,同时玉米植株茎和根对Cd的富集以及Cd在玉米植株体内的转运均有显著降低,其茎部Cd含量最大降幅为32.01%,根部Cd含量最大降幅为15.67%,转运系数最多可降至0.538,一定程度上有助于Cd固定在土壤和玉米植株的根中,减少其对植物和人体的毒害作用。玉米植株的茎生物量、根生物量与Cd的生物有效态均呈极显著负相关,玉米植株体内的富集系数、转运系数与生物有效态Cd均呈极显著正相关。由此可知,NaOH改性坡缕石在Cd污染土壤的修复工作中,具有较为广阔的应用前景。

关键词: 坡缕石, NaOH, Cd, 土壤, 钝化, 生态风险

Abstract:

In situ stabilization remediation of heavy metal in contaminated soils with amendments can reduce the bioavailability of heavy metals in soil through dissolution/precipitation, exchange/adsorption, oxidation/reduction and organic complex. This method has been considered as a non-replaceable and important measure for contaminated soil remediation. In order to study the stabilization effect of NaOH modified palygorskite on Cd in contaminated soil, this study took palygorskite as raw material and adopted impregnation method to modify NaOH and palygorskite according to different mass ratios, and carried out stabilization experiment and pot experiment on manually prepared Cd contaminated soil. The stabilization effect of NaOH modified palygorskite on Cd-contaminated soil and its effect on growth characteristics and Cd enrichment of maize plants were studied. The results showed that compared with the control, NaOH modified palygorskite could significantly reduce the content of available Cd extracted by DTPA and TCLP, improve the stabilization efficiency, and reduce the ecological risk index. The mass ratio of NaOH to palygorskite was 1?2. The content of available Cd extracted by DTPA and TCLP decreased the most, which were 22.37% and 26.60%, respectively. NaOH modified palygorskite could effectively improve the growth characteristics of maize plants. Compared with the control, the weight ratio of adding NaOH was 1?2. The stem length, root length, stem and root fresh weight and stem and root dry weight of maize increased by 71.45%, 65.21%, 22.06%, 44.44%, 33.96% and 50%, respectively, and the enrichment of Cd in maize plants’ stems and roots and the transport of Cd in maize plants were significantly reduced. The maximum reduction of Cd content in maize stems and roots were 32.01% and 15.67%, respectively. The transfer factor can be reduced to 0.538 at most, which helps Cd to be fixed in soil and roots of maize plants to a certain extent, reducing its toxic effect on plants and human body. The stem biomass and root biomass of maize plants were negatively correlated with the bioavailable Cd, and the bioconcentration factor and transfer factor in maize plants were positively correlated with the bioavailable Cd. In conclusion, NaOH modified palygorskite has a broad application prospect in the remediation of Cd contaminated soil.

Key words: palygorskite, NaOH, Cd, soil, stabilization, ecological risk.

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