摘要
为评估不同环境条件对场地土壤砷(As)稳定化效果的影响,采用不同添加量的FeCl_(3)(Fe/As物质的量比分别为2:1、3:1、4:1、5:1、6:1、7:1、8:1)对辽宁省某冶炼厂As污染场地土壤进行修复,通过测定As的浸出浓度和赋存形态筛选稳定化效果最佳的FeCl_(3)添加量;采用不同pH和不同液固比浸提稳定化后的土壤,通过测定As的浸出浓度研究不同环境条件下FeCl_(3)对As稳定化效果的影响。结果表明:与未加FeCl_(3)相比,各添加处理As浸出浓度降低了84.9%~92.8%(P<0.05),Fe/As物质的量比为6:1时As的浸出浓度最小,稳定效果最好。FeCl_(3)添加促进了As由活性较高的非专性吸附态和专性吸附态向活性较低的残渣态转化,有效态As含量降低了6.9%~8.4%。与酸性浸提相比,中性及碱性浸提条件下As的浸出浓度明显升高;浸提溶液pH为4时As的浸出浓度最低,pH为13时As的浸出浓度最高,二者相比As的浸出浓度增加了584.4%。与较高液固比浸提相比,较低的液固比浸提增加了As的浸出浓度(P<0.05);液固比为20:1时As的浸出浓度最低,浸出率最大,液固比为1:1时As的浸出浓度最高,浸出率最低。研究表明,FeCl_(3)可通过改变场地土壤中As的赋存形态有效降低As的浸出浓度,碱性和低液固比浸提增大了稳定化后土壤中As的环境风险。建议根据修复后场地土壤面临的实际环境选择相应的pH和液固比进行浸提,以安全评价As污染场地的稳定化效果及环境风险。
To evaluate the effects of various environmental conditions on the stabilization of As in soil of development land,FeCl_(3) with different additions(Fe/As molar ratio 2∶1,3∶1,4∶1,5∶1,6∶1,7∶1,and 8∶1,respectively)was added to stabilize As in contaminated soil at a smelting plant in Liaoning Province.The suitable amount of FeCl_(3) for stabilization was selected by measuring the leaching concentrations and fractions of As.The effects of FeCl_(3) addition on As stabilization under the various environmental conditions were assessed by measuring the leaching concentration of As in stabilized soil with different pH levels and different liquid-solid ratios.The results showed that compared with no FeCl_(3) addition,the leaching concentration of As decreased by 84.9%-92.8%among FeCl_(3) addition treatments(P<0.05),and the minimum leaching concentration of As occurred under the treatment of Fe/As at a molar ratio of 6∶1,and the stabilization effect was the best.The addition of FeCl_(3) promoted the transformation of As from the nonspecific adsorption state and specific adsorption state with high activity to the residual state with low activity,and the available As content decreased by 6.9%-8.4%.The leaching concentration of As under neutral and alkaline extraction conditions increased significantly,compared to those under the acidic extraction conditions.The leaching concentration of As was the lowest when the pH of the extraction solution was 4,and it was the highest at a pH of 13;the leaching concentration of As increased by 584.4%,comparing the two conditions.The leaching concentration of As increased significantly(P<0.05)under the lower liquid-solid ratio of the extraction system,compared to the higher liquid-solid ratio of the extraction system.The leaching concentration of As was the lowest and the leaching rate was the largest when the liquid-solid ratio of the extraction system was 20∶1,while the leaching concentration of As was the highest and the leaching rate was the lowest when the liquid-solid ratio of the extraction system was 1∶1.The results showed that FeCl_(3) addition can effectively reduce the leaching concentration of As by changing the As fractions in soil of development land,and the alkaline and the lower liquid-solid ratio of extraction system increase the environmental risk of As in stabilized soil.It is thus recommended to select the corresponding pH and liquid-solid ratio for an extraction system according to the actual soil environment so as to safely evaluate the stabilization effect and the environmental risk of As in soil of development land.
作者
欧成浩
苏燕
田楚琪
管秀静
姜绍元
王坚
党秀丽
OU Chenghao;SU Yan;TIAN Chuqi;GUAN Xiujing;JIANG Shaoyuan;WANG Jian;DANG Xiui(College of Land and Environment,Shenyang Agricultural University,National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources,Key Laboratory of Arable Land Conservation in Northeast China,Ministry of Agriculture and Rural Affairs,Shenyang 110866,China;Shenyang Institute of Environmental Sciences,Shenyang 110167,China)
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2023年第11期2464-2471,共8页
Journal of Agro-Environment Science
基金
国家重点研发计划项目(2020YFC1806400,2017YFD0801103)。
关键词
砷
浸出浓度
赋存形态
稳定化
场地土壤
arsenic
leaching concentration
fraction
stabilization
site soil
