土壤淋洗是一种有效修复重金属污染土壤的方法,而淋洗剂的选择是淋洗过程的关键因素,直接影响淋洗效率。研究了4种淋洗剂(乙酸、柠檬酸、CaCl2、FeCl3)对Cd轻度污染的农田土壤淋洗性能及影响因素。结果表明:淋洗效果依次为FeCl3＞柠檬酸＞乙酸＞CaCl2;FeCl3的淋洗机理是Fe3+与土壤中的Cd2+离子交换,其水解出的H+可促进碳酸盐结合态Cd溶出,Cl-还可与Cd2+形成稳定的螯合物;经优化后的最佳的淋洗条件是固液比为1∶5,浸提时间为4 h,此时乙酸、柠檬酸、CaCl2和FeCl3的最大土壤Cd去除率分别为30.24%,24.62%,24.82%,81.90%;pH值对淋洗效果的影响较大,除CaCl2外,3种淋洗剂的淋洗效果都随pH值的升高而降低(pH值在2.5～5.0范围内),FeCl3的淋洗效果降低最为显著。研究成果可为Cd污染农田土壤修复提供技术支撑。
Abstract
Soil washing is an effective approach for the remediation of heavy metal contaminated soil. Soil washing agent is a crucial factor which directly affects the efficiency of washing. We examined the performances of four washing agents, inclusive of acetic acid, citric acid, CaCl2, and FeCl3, in purifying farmland soil slightly contaminated by Cadmium (Cd) and the influential factors. We found that the effect of FeCl3 is the optimum, followed by citric acid, acetic acid, and CaCl2 in sequence.The H+ hydrolyzed from the exchange between Fe3+ from FeCl3 solution and Cd2+ from the soil stimulated the dissolution of carbonate bounded form of Cd; Cl- together with Cd2+ could also form a stable chelate. In optimized operation condition (solid-liquid ratio at 1∶5, and washing for 4 hours), the maximum removal rate of Cd was 30.24%, 24.62%,24.82%, and 81.90% by acetic acid, citric acid, CaCl2, and FeCl3, respectively. The pH value of soil had large impact on the washing effect. Apart from CaCl2,the washing effects of the other three washing agents all declined with the rising of pH value within 2.5-5.0, among which the washing effect of FeCl3 underwent the most severe decline.
关键词
农田土壤 /
重金属镉污染 /
土壤淋洗 /
FeCl3 /
有机酸
Key words
farmland soil /
cadmium contamination /
soil washing /
FeCl3 /
organic acids
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
参考文献
[1] 孙庆瑚,汪再娟,金 锋,等.环境镉污染对人体健康影响的研究.医学研究通讯,2003(11) :20-21.
[2] LI Xiao-yu, LIU Li-juan, WANG Yu-gang,et al. Heavy Metal Contamination of Urban Soil in an Old Industrial City (Shenyang) in Northeast China. Geoderma, 2013, 192(1): 50-58.
[3] WANG Shuai-long, XU Xiang-rong, SUN Yu-xin,et al. Heavy Metal Pollutionin Coastal Areas of South China: A Review.Marine Pollution Bulletin, 2013, 76(1/2): 7-15.
[4] 陈怀满. 土壤-植物系统中的重金属污染.北京: 北京出版社,1996.
[5] 曾咏梅,毛昆明,李永梅.土壤中镉的危害及其防治对策.云南农业大学学报,2005,20(3):360-365.
[6] ABUMAIZAR R J, SMITH E H. Heavy Metal Contaminants Removal by Soil Washing. Journal of Hazardous Materials, 1999, 70(1/2): 71-86.
[7] VAN BENSCHOTEN J E, MATSUMOTO M R, YOUNG W H. Evaluation and Analysis of Soil Washing for Seven Lead-contaminated Soils. Journal of Environmental Engineering, 1997, 123(3): 217-224.
[8] REED B E, CARRIERE P C, MOORE R. Flushing of a Pb(Ⅱ) Contaminated Soil Using HCl, EDTA, and CaCl2. Journal of Environmental Engineering, 1996, 122(1): 48-50.
[9] 曾 敏,廖柏寒,曾清如,等. 3种萃取剂对土壤重金属的去除及其对重金属有效性的影响. 农业环境科学学报,2006,25(4):979-982.
[10] 孙 涛,毛霞丽,陆扣萍,等. 柠檬酸对重金属复合污染土壤的浸提效果研究.环境科学学报, 2015,35(8):2573-2581.
[11] 陈春乐,王 果,王珺玮. 3 种中性盐与HCl复合淋洗剂对Cd污染土壤淋洗效果研究.安全与环境学报, 2014,14(5) : 205-210.
[12] 陈海凤,莫良玉,范稚莲. 有机酸对重金属污染耕地土壤的修复研究. 现代农业科学,2009,16(3):141-143.
[13] MAKINO T, SUGAHARA K, SAKURAI Y,et al. Restoration of Cadmium Contamination in Paddy Soils by Washing with Chemicals: Selection of Washing Chemicals. Environmental Pollution, 2006, 144(1):2-10.
[14] MAKINO T, KAMIYA T, TAKANO H, et al. Restoration of Cadmium Contaminated Paddy Soils by Washing with Calcium Chloride: Verification of On-site Washing. Environmental Pollution, 2007, 147 (1):112-119.
[15] MAKINO T, KAMIYA T, TAKANO H,et al. Restoration of Cadmium Contaminated Paddy Soils by Washing with Chemicals: Effect of Soil Washing on Cadmium Uptake by Soybean. Chemosphere, 2007, 67(4):748-754.
[16] ISOYAMA M,WADA S I.Remediation of Pb-contaminated Soils by Washing with Hydrochloric Acid and Subsequent Immobilization with Calcite and Allophonic Soil. Journal of Hazardous Materials, 2007,143: 636-642.
[17] 史志鹏.低分子量有机酸对两种污染土壤铅释放的影响.武汉:华中农业大学,2012.
[18] 罗 冰,张清东. 柠檬酸浸出土壤中铜、锌的优化设计.环境工程学报,2013,7(9):3629-3634
[19] MOON D H,LEE J R, WAZNE M,et al.Assessment of Soil Washing for Zn Contaminated Soils Using Various Washing Solutions. Journal of Industrial and Engineering Chemistry, 2012, 18(2): 822-825 .
[20] 易龙生,王文燕,刘 阳,等.柠檬酸、EDTA 和茶皂素对重金属污染土壤的淋洗效果[J].安全与环境学报,2014,14(1): 225-228.
[21] 李丹丹,郝秀珍,周东美.柠檬酸土柱淋洗法去除污染土壤中Cr的研究. 农业环境科学学报, 2013,32(10): 1999-2004.
[22] 梁金利,蔡焕兴,段雪梅,等. 有机酸土柱淋洗法修复重金属污染土壤. 环境工程学报, 2012, 6(9):3339-3343.
[23] GB/T 17141—1997,土壤质量铅、镉的测定石墨炉原子吸收分光光度法.北京:中国环境出版社,1997.
[24] HJ 700—2014,水质 65种元素的测定电感耦合等离子体质谱法.北京:中国环境出版社,2014.
[25] 鲁如坤. 土壤农业化学分析方法. 北京:中国农业出版社, 1999.
[26] MAKINO T, TAKANO H, KAMIYA T, et al. Restoration of Cadmium Contaminated Paddy Soils by Washing with Ferric Chloride: Cd Extraction Mechanism and Bench-scale Verification. Chemosphere, 2008, 70(6):1035-1043.
[27] YANG Z, ZHANG S, LIAO Y,et al. Remediation ofHeavy Metal Contamination in Calcareous Soil by Washing with Reagents: A Column Washing. Procedia Environmental Sciences, 2012, 16(4): 778-785.
[28] TOKUNAGA S, HAKUTA T. Acid Washing and Stabilization of an Artificial Arsenic Contaminated Soil. Chemosphere, 2002, 46(1): 31-38.
[29] 罗 希,林 莉,李青云.镉污染稻田土壤土柱淋洗修复研究.长江科学院院报,2017,34(6):24-28,34.
[30] 严世红. 酸化土壤中镉化学形态特征与钝化研究.淮南:安徽理工大学,2014.
[31] 李玉姣,温 雅,郭倩楠,等. 有机酸和FeCl3复合浸提修复 Cd、Pb污染农田土壤的研究.农业环境科报,2014,33(12):2335-2342.
[32] 杨忠芳,陈岳龙,钱 鑂,等. 土壤 pH 对镉存在形态影响的模拟实验研究.地学前缘, 2005,12(1):252-260.
[33] 王 叶.柠檬酸废水作为淋洗剂对土壤重金属镉的协同去除研究.青岛:中国石油大学,2014.
基金
水利部公益性行业科研专项(201501019)
PDF(1536 KB)
