污染土壤的固化/稳定化处理技术研究进展

固化/稳定化技术具有快速、有效、经济等特点,广泛应用于各类危险废物的处理,但土壤方面的应用还比较匮乏.本文介绍了近年来污染土壤固化/稳定化研究和应用的现状,概括了从实验室研究、现场试验到处理工程的流程,重点对常见固化系统、主要影响因素、处理效果评价、固化机理研究和修复工程的实施等方面的研究进展加以总结,并对其发展趋势加以展望.     

壳聚糖修复重金属污染土壤的研究进展

壳聚糖是一种来源广泛、具有良好的生物相容性、生物降解性的高分子材料,其含有大量氨基、羟基等活性基团,能与重金属离子进行螯合,发生吸附作用。壳聚糖还具有改良土壤、促进植物生长,诱导植物抗逆的作用,在重金属污染农田土壤修复中具有独特的应用优势。综述了近年来国内外有关壳聚糖修复重金属污染土壤的研究进展,探讨了壳聚糖对土壤重金属污染修复的潜力,阐述了壳聚糖在重金属原位钝化修复、土壤淋洗修复、强化植物提取修复三个方面的应用,并指出壳聚糖在重金属污染土壤修复中存在的问题以及对其在未来修复重金属污染土壤的发展进行了展望,以期为壳聚糖重金属修复技术的推广和应用提供参考。     

巯基膨润土钝化修复镉污染水稻土的研究

通过田间种植水稻试验,探究了巯基膨润土(Bent-SH)对镉污染土壤的修复效果及钝化机理.结果表明:添加Bent-SH对土壤理化性质的影响很小,土壤有效态镉含量随Bent-SH添加量的增加逐渐降低,与对照相比,其最大下降率为48.57％.添加Bent-SH降低了土壤镉的迁移能力,降低了大米、秸秆对土壤镉的吸收,其最大下...     

固定/稳定化土壤修复技术的应用与优化分析

固定/稳定化技术是污染土壤修复的常用方法之一,具有费用低、无毒、综合效益好等优点,非常适合我国典型土壤污染区的修复。本文介绍了固定/稳定化方法的作用原理与修复材料,分析了此技术的适用范围及优缺点。文章归纳了近年来固定/稳定化技术在污染土壤修复中的应用成功案例,并结合我国土壤污染的实际状况和修复需求,从加强工程技术与装备研发、优化费用结构和发展环境友好型固定/稳定化技术等角度,提出了固定/稳定化技术应用的优化建议。     

Zn/Cd污染土壤的化学钝化修复

本文研究了天然凹凸棒石和改性凹凸棒石(凹 Fe、凹 Mn、凹 P)对Zn/Cd模拟污染土壤的修复效果.在土壤中添加改良剂20 g/kg土,进行黑麦草盆栽试验.采用植物吸收和化学提取来评价修复效果.植物吸收结果表明凹 P处理效果最好,其原因可能是形成氢氧化物或磷酸盐沉淀;化学提取实验结果表明凹凸棒石可在一定程度上降低弱交换态Zn的含量.     

Removal of Lead from Contaminated Soils by Typha Angustifolia

A greenhouse study was demonstrated for removal of lead (Pb) from contaminated soil by the narrow — leaved cattail, Typha angustifolia. The plants were grown in sandy loam soil containing various concentrations of Pb(NO₃)₂ (53.3, 106.7, 160, 213.3, and 266.7 mg Pb kg^-1 soil). Most lead was accumulated in roots and then transported to leaves. In soil contaminated with 266.7 mg kg^-1 of lead, the plants accumulated 7492.6 mg Pb kg^-1 dry weight in the roots and 167 mg Pb kg^-1 dry weight in the leaves. Yet, no growth retardation from lead was detected. T. angustifolia has high potential as a plant to clean up lead contaminated soil due to its vigorous growth, high biomass productivity, and because it is a perennial in nature. Further work is required to study on the iron plaque formation and its role in metal immobilization.     

土壤重金属复合污染的化学固定修复研究

本文研究糠醛渣、磷矿粉、风化煤3 种修复剂对重金属复合污染土壤的化学固定修复效果.结果表明:糠醛渣、磷矿粉、风化煤3 种修复剂都可一定程度地降低复合污染土壤中的Cu、Zn、Pb、Cd含量,其中以风化煤降低土壤有效态Zn、Cu的效果较好,在风化煤添加量为80 g/kg时土壤有效态Zn的含量降低了37.22%,土壤有效态Cu的含量降低了31.22%;磷矿粉处理修复Pb的效果比糠醛渣、风化煤好,在磷矿粉添加量为80 g/kg时,土壤有效态Pb的含量降低了23.79%;3 种修复剂都能显著降低土壤有效态Cd,在磷矿粉添加量为40 g/kg时,土壤有效态Cd的含量降低最显著,较对照降低了83.09%.在本试验条件下,3 种修复剂对4 种重金属复合污染土壤的修复效果,以Cd 较好,其次是Zn,对Pb的修复效果较差.     

固化/稳定化修复后土壤重金属稳定性及再活化研究进展

固化/稳定化技术是一种经济、有效、快捷的重金属污染主流修复技术,随着我国以风险管控为主导策略的土壤污染防治工作的推进,该技术正发挥着极其重要的作用。固化/稳定化技术处置后土壤中的重金属并未移除,存在再活化的风险。本文对固化/稳定化技术特点、修复效果评估方法、评价标准等进行了系统总结,概述了修复后重金属赋存形态、生物有效性、微观形态等特征,着重阐述了冻融、水环境和酸雨淋溶3类环境胁迫下重金属的再活化行为和影响因素。在此基础上,讨论了当前固化/稳定化修复后土壤和场地环境监管体系构建的现状、不足和发展需求,提出需注重修复后重金属环境行为、再活化定量化等研究方向。     

污染土壤修复技术研究进展

土壤是人类生产活动的重要物质基础,随着社会经济的高速发展和高强度的人类活动,土壤受污染面积不断扩大,土壤质量持续恶化,影响到实现可持续发展的战略目标。由土壤污染导致的农产品的生态安全问题已不容忽视。因此,开展污染土壤修复活动,完善土壤修复技术体系,对阻断污染物进入食物链,防止对人体健康造成危害,实现社会经济可持续发展是非常重要的。该文系统介绍了目前国内外污染场地修复中广泛使用的物理修复技术、化学修复技术、生物修复技术(包括植物修复、微生物修复和动物修复技术)以及相关技术结合使用的联合修复技术,并对各种方法的研究进展进行了较全面的综述,最后也对未来土壤污染修复技术的发展方向进行了展望。     

重金属-有机复合污染土壤的电动强化修复研究

许多污染场地都呈现重金属和有机污染物叠加的趋势,给修复带来了困难和挑战。以红壤为供试土壤,以铜和芘为代表性污染物,研究了添加表面活性剂羟丙基-β-环糊精（HPCD）和氧化剂H2O2对电动修复该复合污染土壤的影响,其目的是实现重金属和有机污染物的同时去除。结果表明,在所有的处理中,芘和铜都有向阴极迁移的趋势;当提高土柱的pH时降低了芘的氧化和降解,同时也阻碍了土壤中铜的迁移和去除;阳极加10%HPCD,阴极控制酸性条件pH3.5有助于土壤中污染物的解吸和迁移,芘和铜的去除率分别可达到51.3%和80.5%;由于H2O2的不稳定性,添加6%H2O2并未明显提高芘和铜的去除率。     

Remediation of Soils Contaminated with Molybdenum using Soil Amendments and Phytoremediation

For ruminants, there is a narrow span betweennutritional deficiency of Molybdenum and its potential toxicity. Molybdenosis occurs among cattlefeeding on forage with Mo concentrations above10 μg g^-1 or a Cu:Mo ratio <2. In the areaunder investigation forage Mo contents in the valleyare as high as 180 μg g^-1 due to industrialpollution, while the alpine pastures, where cattlegraze during summer, are nutrient (e.g. Cu) deficient.When driven to the valley pastures in fall, animalsoften fell ill with molybdenosis, and several died.The aim of the study was to remediate this 300 ha area. Two approaches were attempted: (1) to reduce theMo contents of the forage by immobilizing soil Mo, and(2) to increase plant Mo contents by mobilizing soilMo to increase plant Mo which may then be removed fromthe system (phytoremediation).In a soil extraction experiment we demonstrated thatphosphate fertilization, ammonium sulfate amendment,vermiculite, humic acid and sewage sludge increased Moleaching by 30 to 110%. Fe-humate and Mn-humateapplication decreased Mo in the leachate from96 μg L^-1 to 55 and 7 μg L^-1,respectively. Plant Mo contents were increased up to170% by P-fertilizer and up to 150% by vermiculite.Conversely, sewage sludge, Fe- and Mn-humate decreasedplant Mo contents by 60, 40 and 75% in thegreenhouse. In the field study, the effects weresmaller, but Mo export through plant harvest increasedby 88% after P-fertilization and 84% aftervermiculite amendment. Mn-humate and sewage sludgedecreased plant Mo content by 25 and 40%,respectively, rendering the forage suitable forfeeding of ruminants. P-fertilization and vermiculitemay thus be recommended for the severely contaminatedsites to enhance phytoremediation through Mo export,and Mn-humate and sewage sludge application appearsuited to remediate the less severely contaminated sites.     

Remediation of Lead Contaminated Soil by Column Extraction with EDTA: II. Modeling

Lead contamination of soils is a common problem throughout the world. Laboratory batch test and bench scale experiments have shown that EDTA can be used to remove lead from contaminated soils. However, due to the high cost and laborious task associated with actual environmental remediation of a lead contaminated soil, there is a need to be able to predict the outcome of a remediation process in advance in order to optimize the process and minimize the cost. This paper describes the development and validation of a computer model which can be used to simulate the removal of lead from a contaminated soil column using EDTA as the chelating agent. The model is able to simulate the lead removal from soil based on equilibrium as well as kinetic dissolution of Pb. The comparison of the simulated results with actual lead concentrations both in effluent and soil shows that the model can predict the lead removal process with reasonable accuracy.     

Remediation of Lead Contaminated Soil by EDTA. I. Batch and Column Studies

Extraction using ethylenediaminetetraacetic acid (EDTA), and other chelates has been demonstrated to be an effective method of removal of Pb from many contaminated soils. However, column leaching of Pb from alkaline soils with EDTA has been problematic due to extremely low soil permeability. The first purpose of this study was to develop batch extraction procedures and methods of analysis of batch extraction data to provide Pb solubility information which can be used to model the column extraction of Pb from soils. The second purpose was to determine the effect of the addition of KOH and CaCl₂ to K₂H₂EDTA extract solution on both hydraulic conductivity and Pb removal. A Pb-contaminated soil sample was collected from an abandoned battery recycling facility. Both batch shaker extractions and column leaching experiments were completed using 5 different EDTA extract solutions. When only CaCl₂ was added to EDTA no change in the amount of Pb removed by batch extraction was observed. As expected, lead solubility was observed to decrease as pH was increased by the addition of KOH. However, Pb solubility was only slightly decreased by the addition of both CaCl₂ and KOH. The amount of time required to leach 6.0 L of extraction solution through the soil columns varied from 2 to 33 days. The addition of CaCl₂ and/or KOH resulted in increased soil hydraulic conductivity relative to the EDTA-only solution. The hydraulic conductivity was related to residual calcium carbonate content, suggesting that dissolution of CaCO₃ and subsequent production of CO₂ gas in the soil pores was partially responsible for the observed reductions in soil permeability. However, Pb removal was diminished with the addition of CaCl₂ and KOH because of the decreased Pb solubility and also kinetic limitations associated with the shorter residence time of the extract solution in the column.     

In-Situ Immobilization of Cadmium and Lead by Different Amendments in Two Contaminated Soils

Different soil amendments, including 1% zeolite, 1% bentonite,5% Penghu soil (PHS), 5% Penghu soil + 1% manganese oxide (PHS + MO), 1% MO, and 1.5% silicate slag (SS), were used to immobilize Cd and Pb in two contaminated soils evaluated by single and sequential extractions and by uptake of Chinese cabbage (Brassica Chinensis L.). Results indicated that the PHS and MO significantly (p < 0.05) reduced the 0.1 M HCl extractable Cd and Pb in the two contaminated soils. Allamendment treatments did not change the organic and residual amounts of Cd and Pb in soils A and B, but the PHS andPHS + MOtreatments significantly reduced the exchangeable amounts of Cdand Pb in the two soils as measured by sequential extraction. Thecombination of PHS and MO amendments was associated with ahigh pH value and negative soil surface charge showed the best immobilizing efficiency of Cd and Pb in this study. All soil amendments investigated did not increase the dry matter weight of the plant, and most of them decreased the uptake of Cd and Pb, especially for the PHS and MO. The PHS and MO treatments reduced the extractability of Cd and Pb in two soils and theiruptake by the plant, but only the Pb content in Chinese cabbagefrom the amended soils was less than the background levels of heavy metals in leaf vegetables of Taiwan.     

Accumulation of Lead and Arsenic by Carrots Grown on Lead-Arsenate Contaminated Orchard Soils

Concerns have been raised of possible human food chain transfer of lead and arsenic from crops grown on orchard soils with histories of lead arsenate use. The objective of this study was to determine arsenic and lead uptake by three cultivars of carrots grown on four orchard soils with histories of lead arsenate use. Total concentrations of arsenic and lead in these soils ranged from 93 to 291 and from 350 to 961 mg kg^?1 for arsenic and lead, respectively. Arsenic in peeled carrot ranged from 0.38 to 1.64 mg kg^?1, while lead ranged from 2.67 to 7.3 mg kg^?1 dry weight. This study demonstrated that carrots will accumulate arsenic and lead in the root, which may become a human health risk when consumed. However, further studies are needed to determine what fraction of arsenic and lead in these carrots are bioavailable to humans when consumed.     

土壤有机污染物电化学修复技术研究进展

综述了有机污染土壤的电动力修复和微生物电化学修复的最新研究进展.分析了电动力修复中电极材料、运行条件等因素对污染物去除效果的影响,总结了添加表面活性剂、引入具有降解能力的基质、与化学或生物联合等方式对土壤修复效果的强化作用,阐述了微生物电化学修复的效果、影响因素和微生物群落演变的规律.电化学技术能够有效去除土壤中的有机...     

蚕沙和赤泥用于铅镉污染土壤改良的研究

研究了蚕沙和赤泥对铅镉污染土壤的理化性质和重金属形态分布的影响,并考察了蚕沙和赤泥对小白菜生长情况及吸收重金属的影响。结果表明,蚕沙能大幅提高土壤有机质含量,赤泥使土壤p H值升高,两者都能明显改善土壤理化性质。蚕沙和赤泥不仅能促进土壤中的Pb、Cd由高植物有效性的弱酸提取态向低植物有效性的残渣态转化,还能增加小白菜的植株高度和干生物量并减少小白菜对Pb、Cd的吸收。土壤p H值、有机质含量都与土壤弱酸提取态重金属、小白菜生长情况及重金属的含量具有良好的相关关系。对重金属的钝化修复效率由高到低依次为蚕沙+赤泥复合处理单施蚕沙单施赤泥,最佳钝化处理为3%蚕沙+1%赤泥。     

石灰和海泡石对镉污染土壤的修复效应与机理研究

研究了稻作和旱作两种种植制度下,施用石灰、海泡石及两种改良剂配施对镉污染土壤pH值、土壤镉形态变化及作物对镉的吸收等的影响.结果表明,施用改良剂使稻作条件下的土壤pH提高0.3～1.8个单位,旱作条件下土壤pH提高幅度为0.3～2.0个单位:两种种植制度下,作物有效性较高的酸提取态镉含量显著减少,而作物有效性较低的可还原态和残渣态镉含量显著增加,进而引起了水稻和萝卜对镉的吸收量降低.其中以石灰和海泡石配施的效果最好,单施海泡石次之,单施石灰效果最差,且各处理均随改良剂用量的增加效果增强,虽然,施用改良剂可以有效降低土壤中镉的作物有效性,但对水稻产量和生物量及镉在水稻和萝卜两种作物地上部分的分配规律均没有明显的影响.     

应用灰色关联度法评价砷污染土壤修复效果

采用盆栽试验进行砷污染土壤修复研究,根据4种不同改良剂对土壤修复的效果来评价改良剂的优劣,确定土壤修复最优模式.并采用灰色关联分析和聚类分析评价方法,以生菜生物量、农艺性状和生菜砷吸收量等为指标,对污染土壤修复贡献值进行定量分析和聚类评价.结果表明,磷石膏(20 g/kg)处理关联度值r=0.824最大,聚类分析为最优,是修复砷污染土壤的最优改良剂处理.     

有机黏土矿物修复有机污染研究进展

本文综述了有机黏土矿物对环境中有机污染物吸附的研究进展.具体介绍了黏土类型,改性剂种类,改性条件以及有机污染物性质对吸附性能的影响,有机黏土矿物对有机污染物的吸附机理,并就溶液pH和温度的影响机制进行了分析.文章最后对有机黏土在环境污染治理方面的作用研究作了展望.