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71.
针对红壤、棕壤、褐土、黑土4种中国典型的Cd污染土壤,应用Ca(OH)2、Ca(H2PO4)2以及层状双金属氢氧化物(Layered Double Hydroxides,LDHs)、水化氯铝酸钙(CaAl-Cl LDH)开展钝化修复,并从土壤Cd的生态风险和健康风险角度进行修复效果对比研究。分析钝化剂对土壤pH值、土壤Cd的赋存形态以及土壤Cd直接经口摄入的生物可给性的影响,并对修复机理进行深入探究。结果表明,在Ca(OH)2、Ca(H2PO4)2和CaAl-Cl LDH各自相对最优施用量下,3种钝化剂均可显著降低土壤Cd的活性系数(P<0.05),平均降幅分别为16.1%、56.9%和29.2%,可降低土壤Cd的作物吸收量及Cd对周边生态环境的风险。此外,施用CaAl-Cl LDH能显著且更为有效地降低土壤Cd的生物可给性(P<0.05)及Cd对人体的健康风险,在胃和小肠阶段的平均降幅为19.2%和33.0%,其中胃阶段分别达到施用Ca(OH)2和Ca(H2PO4)2的3.11和1.99倍,小肠阶段为5.99和2.72倍。该研究为Cd污染土壤钝化修复剂的开发、改进和选择提供了科学依据和参考。 相似文献
72.
土壤污染已经成为全球性问题,也是中国环境危害最为严重的问题之一。本文数据来源于中国知网(CNKI)和Web of Science (WOS)数据库,利用CiteSpace软件对2011—2020年土壤修复研究领域的文献进行可视化分析,探讨了土壤修复相关研究的现状及未来发展趋势。研究表明:土壤修复领域的研究(1)发文量总体呈上升趋势,中国、美国、西班牙、印度、澳大利亚是英文发文量位居前5的国家;中国以科学院为主要发文机构;(2)从关键词的中心性和文献被引频次分析得到重金属污染土壤及修复是目前主要的研究内容,而生物修复及生物炭是土壤修复领域的研究热点(3)农药污染土壤修复、生态修复、修复材料及修复技术的研发是未来土壤修复研究领域的重要方向。 相似文献
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Recently in Japan, like in other industrialized countries, treatment of contaminated soil or ground has become an important issue in redeveloping such areas as old factories, mining sites, and other polluted sites. In these cases, measures such as a construction of cut-off walls and disposal to controlled waste disposal sites have been so far taken. But, the treatment of contaminated soils has become more difficult nowadays. Therefore, remediation of contaminated soil by removal or extraction of contaminants is necessary and various methods have been developed and applied in many countries. Authors have tried to develop an electrokinetic remediation method for soil contaminated with heavy metals and some basic and pilot scale experiments have been carried out. In this paper, the results of a model experiment using an artificial soil contaminated with Cu or Ph or Cr are presented as follows. i) In the electrokinetic process, migration of water to the cathode by electroosmosis, migration of ions to the cathode or anode by electrophoresis and electrolysis of water occur spontaneously. ii) Upon DC loading, Cu and Pb migrate to the cathode and accumulate as oxides or hydroxides near the cathode but are not removed from contaminated soil. However, in the case of Cr contaminated soil, Cr in the form of Cr(VI) migrates to the anode and is removed from soil through the drainage water. iii) After DC loading for 2 weeks, the concentration of exchangeable cations and composition of soil changed drastically while the CEC and clay mineralogy did not change appreciably. 相似文献
77.
Abstract The adsorption of Cr(VI) ion on synthetic hydrated oxides of iron (goethite (α-FeOOH) and lepidocrocite (γ-FeOOH)) with different crystallinities was studied in order to remove the Cr(VI) ion from polluted water. At pH 4.5, the amounts of the adsorbed Cr(V1) ion on goethite and lepidocrocite were 51.9 and 62.2 mmol g?, respectively. Probably, this is due to the fact that the structure of lepidocrocite is more open than that of goethite. Lepidocrocite, therefore, is more effective for the removal of Cr( V1) ion from Cr(Vl)-contaminated and acidic groundwater and sewage. 相似文献
78.
利用生物活性污染物剥离技术修复Hg污染的工业土壤 总被引:1,自引:0,他引:1
The method to remove bioavailable amounts of heavy metals from a contaminated soil by using plants is defined as bioavailable contaminant stripping (BCS) and could safely be applied if the soil’s long-term ability to replenish the bioavailable pool is known. The aim of this study was to evaluate the ability of three common plant species selected, Brassica juncea, Poa annua, and Helianthus annus, to remove bioavailable amounts of mercury (Hg) from a contaminated industrial soil containing 15.1 mg kg-1 Hg. Trials were carried out under greenhouse conditions using pots (mesocosms). According to the precautionary principle, we modified the BCS remediation approach by adding a new step, in which mercury bioavailability was increased by the addition of a strong mobilizing agent, ammonium thiosulphate, (NH 4 ) 2 S 2 O 3 , to obtain an estimate of the likely long-term bioavailable Hg pool. The modified BCS remediation approach was called enhanced bioavailable contaminant stripping (EBCS). After one growth cycle, nearly all the bioavailable mercury (95.7%) was removed and the metal remaining in the soil was considered inert since it was neither extractable by (NH 4 ) 2 S 2 O 3 nor taken up by plants during a second growth cycle. The results demonstrated that EBCS appeared promising since it removed the most dangerous metal forms while substantially shortening the cleanup time. 相似文献
79.
采用盆栽试验方法研究了聚丙烯酸盐对SDomingos金矿区重金属污染土壤的修复作用。在《聚丙烯酸盐对长期重金属污染土壤的修复研究(I)》^[30](以下简称研究I)中聚丙烯酸盐的应用显著提高了土壤持水能力和土壤的pH,同时土壤中水溶性重金属的含量也比对照显著降低,从而使果园草Orchardgrass(Dactylis glomerata L.cv.Amba)的生物量得到显著增加。为更全面地说明聚丙烯酸盐在该重金属污染土壤修复上的作用,进一步探讨了聚丙烯酸盐对重金属污染土壤微生物属性的影响。结果表明,土壤细菌数量随聚丙烯酸盐水平的增加而增加,不同处理之间差异显著(P≤0.05);与对照相比,聚丙烯酸盐处理的真菌数量显著增加(P≤0.05),但随着聚丙烯酸盐水平的增加而显著降低(P≤0.05),这可能是由于0.4%和0.6%的聚丙烯酸盐处理土壤pH显著提高所导致的。因此使用微生物数量评价土壤质量时,细菌比真菌表现更突出。使用聚丙烯酸盐修复的土壤脱氢酶、磷酸酶、蔗糖酶、蛋白酶和纤维素酶的活性均比对照显著增加(P≤0.05),而脲酶活性的下降则可能是由于聚丙烯酸盐带来大量的铵态氮产生的抑制作用所致。综合研究I中的结果,聚丙烯酸盐不仅可以改善重金属污染土壤的理化性状而且对于土壤微生物属性也有显著的改善作用。从果园草生物量来看,0.4%聚丙烯酸盐的用量对该污染土壤的修复具有实践应用价值。 相似文献
80.
通过细菌计数和Biolog方法,研究了在3.0V·cm^-1的电压梯度下,不同电场切换周期(24h、5h、10min和1min)对土壤微生物群落的影响。结果表明,电压梯度为3.0V·cm^-1的电场作用能够促进土壤微生物的活性,但会轻微地降低土壤微生物功能多样性,电场切换不能改变这种电场对微生物群落的影响;长时间的电场处理下,电极反应对微生物数量和功能多样性损害严重,切换电场电极能有效消除电极效应,电场电极切换周期≤5h时,可保护电极附近土壤微生物多样性,当切换周期≤10min时,不仅可保护土壤微生物多样性,而且可以保护微生物数量。研究结果说明了电场电极切换能有效降低电极反应对微生物群落的影响,揭示了电场电极切换对土壤微生物群落影响的规律,为电场电极切换方法在污染土壤电动强化生物修复技术中的深化和应用提供理论依据。 相似文献