Remediation of a Sandy Soil Contaminated with Cadmium,Nickel, and Zinc using an Insoluble Polyacrylate Polymer

Abstract

This study was carried out to investigate whether an insoluble polyacrylate polymer could be used to remediate a sandy soil contaminated with cadmium (Cd) (30 and 60 mg Cd kg^?1 of soil), nickel (Ni) (50 and 100 mg Ni kg^?1 of soil), zinc (Zn) (250 and 400 mg Zn kg^?1 of soil), or the three elements together (30 mg Cd, 50 mg Ni, and 250 mg Zn kg^?1 of soil). Growth of perennial ryegrass was stimulated in the polymer‐amended soil contaminated with the greatest amounts of Ni or Zn, and when the three metals were present, compared with the unamended soil with the same levels of contamination. Shoots of plants cultivated in the amended soil had concentrations of the metals that were 24–67% of those in plants from the unamended contaminated soil. After ryegrass had been growing for 87 days, the amounts of water‐extractable metals present in the amended soil varied from 8 to 53% of those in the unamended soil. The results are consistent with soil remediation being achieved through removal of the metals from soil solution.     

4种生物炭对镉污染潮土钝化修复效果研究

以甘蔗叶、木薯秆、水稻秸秆和蚕沙为原材料,采用限氧热解法在500℃下制备生物炭,通过室内培养实验,研究在不同培养时间(0,15,30,45d)条件下,生物炭施入潮土(Cd浓度5mg/kg)后对土壤基本性质及土壤中镉(Cd)化学形态的影响,探讨了生物炭修复镉污染土壤的可行性。结果表明:添加生物炭后,土壤pH值和阳离子交换量(CEC)随着培养时间的增加而逐渐增加,而土壤有机碳(SOC)含量则呈先增加至最大值而后缓慢降低的趋势,但仍高于对照。同时,生物炭的施入显著降低了土壤中弱酸可提取态Cd和可还原态Cd含量,提高了可氧化态Cd和残渣态Cd含量,且随着培养时间的延长这种转化趋势更为明显。4种生物炭对潮土中Cd钝化效果表现为蚕沙生物炭水稻秸秆生物炭木薯秆生物炭甘蔗叶生物炭。培养结束(45d)时,与对照相比,添加蚕沙生物炭的土壤中弱酸可提取态Cd含量降低了42.07%,可还原态Cd含量降低了35.19%,可氧化态Cd和残渣态Cd含量分别增加了292.59%和339.29%,从而大大降低了Cd的生物有效性,由此可见,生物炭对镉污染土壤的修复是切实可行的。     

MgAl-LDHs磁性颗粒对镉污染农田土壤的减量修复研究

本研究以不同巯基改性的镁铝层状双金属氢氧化物(MgAl-LDHs)为原材料制备了四种毫米级磁性颗粒修复材料,并开展了对土壤中镉(Cd)去除效果的对比试验,考察MgAl-LDHs磁性颗粒修复材料的投加量和作用时间对Cd去除效果的影响,探讨了修复材料对三种实际污染农田土壤(Cd总量在0.73~0.86 mg/kg之间)中Cd的去除效果与机制。结果表明,以泰克莱尔MgAl-LDHs为原材料制得磁粒MgAl-LDHs-C对Cd的去除效果最好。确定磁粒MgAl-LDHs-C与土壤的最佳投加质量比为1:10,最适作用时间为3 h,在此条件下,浙江台州土壤DTPA提取态Cd含量由0.56 mg/kg下降至0.30 mg/kg；控制m(土):V(液)为1:2,反应温度为25 ℃,振荡频率为180 r/min,按照最优选投加量和作用时间分别向江苏太仓、甘肃白银和浙江台州污染农田土壤中施用MgAl-LDHs-C,三种土壤中Cd总量去除率分别达到26.0%、23.8%和34.7%。对土壤Cd的形态分析结果表明,MgAl-LDHs-C可以显著降低土壤可交换态、可还原态、可氧化态Cd的含量。本研究所制备的MgAl-LDHs-C材料具有良好的土壤Cd去除能力,可为Cd污染农田土壤的减量修复提供科学依据。     

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。     

青葙修复镉污染土壤的田间试验研究

为探索氯化铵与柠檬酸和青葙(Celosia argentea L.)联合修复重金属Cd污染土壤的方法,通过田间试验,研究了氯化铵与柠檬酸对青葙生长和吸收富集Cd的影响、根际土与非根际土之间的差异,以及对土壤Cd含量和形态的影响。结果表明,种植青葙并施加氯化铵(C+AC)处理能显著促进青葙地上部干重的提高,比只种植青葙(C)处理增产53.03%;种植青葙并施加柠檬酸(C+CA)处理能提高青葙对Cd的吸收富集能力,地上部Cd含量比C处理提高16.64%;而C+AC处理对青葙地上部Cd积累量的促进效果最佳,比C处理提高69.49%;青葙的种植均显著降低根际土Cd的酸溶态含量,C、C+AC和C+CA处理的降低幅度分别为10.31%,15.00%和12.67%,显著大于非根际土;C+CA处理的土壤Cd含量降率最大,为5.33%,而不种植青葙,不施加药剂(CK)处理为1.43%,只有C+CA处理的26.83%。因此,青葙植物提取对Cd的降低仍起关键作用,且施加柠檬酸对表层土壤Cd的修复性能最好。     

施用不同磷肥对海泡石钝化修复镉污染土壤影响的研究

通过油菜盆栽试验研究了添加不同剂量磷肥对重金属Cd污染土壤海泡石钝化修复效应的影响。结果表明:海泡石(S)、海泡石钝化的基础上施钙镁磷肥(S+CMP)和普钙(S+SSP)均显著降低了油菜地上部位和根部中Cd含量(P0.05),其中地上部位中Cd含量的降低率分别为74.73%、8.80%~62.63%和67.58%~70.33%;根部中Cd含量的降低率分别为84.40%、33.67%~79.37%和73.79%~92.16%,S处理和S+CMP处理均能显著的增加油菜的生物量(P0.05),但S+SSP处理对油菜生物量影响不明显。与CK相比,S、S+SSP和S+CMP处理均显著提高了土壤pH值,且显著降低了TCLP(Toxicity characteristic leaching procedure,TCLP)浸提态Cd含量(P0.05),其降低率分别为43.86%、36.84%~52.63%和26.32%~31.58%。S处理和S+CMP处理显著的增加了土壤脲酶活性,且S、S+SSP和S+CMP处理均不同程度的增加了土壤过氧化氢酶活性,在一定程度上改善了土壤环境质量。     

Roles of Bacillus megaterium in Remediation of Boron,Lead, and Cadmium from Contaminated Soil

Phytoremediation is an attractive, economical alternative to soil removal and burial methods to remediate contaminated soil. The objective of this study was to investigate the effects of adding different rates of Bacillus megaterium on the capacity of Brassica napus plants to take up boron (B), lead (Pb), and cadmium (Cd) from polluted soils under field conditions. Field experiments were conducted using a randomized complete block design with control (without pollution and B. megaterium application) and B, Pb, and Cd in two doses (0 and 100 mg kg^?1), B. megaterium with four doses (no application and 10⁸ cfu B. megaterium ml^?1 sprayed at 50 ml plot^?1, 100 ml plot^?1, 150 ml plot^?1). Results indicated that soil pollution treatments significantly decreased seed (SDMY), shoot (SHDMY), root (RDMY), and total dry-matter yield (TDMY) of plants at 42.9, 3.8, 62.6, and 23.4% for B-polluted treatment; 25.8, 8.7, 17.6, and 14.2% for Pb-polluted treatment; and 33.2, 7.0, 14.0, and 16.4% for Cd-treatment without B. megaterium application, respectively. However, the application of B. megaterium ameliorated the negative effects of B, Pb, and Cd at 41.4, 52.7, and 10.9% for B; 24.4, 21.6, and 4.9% for Pb; and 22.8, 22.0, and 3.3% for Cd, respectively. The potentially bioavailable and relatively available fraction of soil B, Pb, and Cd increased with increases in the B. megaterium application but total fraction and stable fraction decreased. It is concluded that the seed and shoot parts of B. napus can be used as hyperaccumulators for plant B, Pb, and Cd remediation according to remediation factors but the shoot is the biggest part of the plant, and thus an important portion of the plant to remove B, Pb, and Cd from the B-, Pb-, and Cd-contaminated soils. To decrease desired concentration for 8 mg B kg^?1, 4 mg Pb kg^?1, and 3 mg Cd kg^?1 in the active rooting zone of soil, approximately 2, 6, and 21 years would be necessary with only 150 ml plot^?1 B. megaterium–sprayed soil cultivated with B. napus, respectively.     

鱼骨粉对土壤Cd污染钝化修复效应及其理化性质的影响

通过1年静态培养试验,研究了鱼骨粉对碱性和酸性Cd污染土壤钝化修复效应、基本理化性质和酶活性的影响。结果表明:随着鱼骨粉施加量的增加,酸性和碱性土壤中pH、有机质和阳离子交换量增加,而含水率则较对照降低了2.90%~6.19%和0.10%~1.81%。土壤中TCLP(toxicity characteristic leaching procedure)提取态Cd含量随鱼骨粉投加量增加而降低,较对照最大分别降低49.7%和17.0%。施加鱼骨粉后,碱性土壤中过氧化氢酶活性显著升高(p<0.05),过氧化物酶则受到抑制,脲酶活性仅在≤1%鱼骨粉处理时有所促进,而在酸性土壤中,过氧化氢酶、过氧化物酶和脲酶活性最大分别可增加90.5%,65.4%,75.8%。施用鱼骨粉改变了土壤有机碳官能团的数量,其中酚类化合物、脂肪C、芳香C官能团含量均有所增加。土壤中有效态Cd与土壤有机质含量、过氧化氢酶活性呈极显著负相关关系(p<0.01),与土壤pH、阳离子交换量呈显著负相关关系(p<0.05)。研究表明利用鱼骨粉钝化修复Cd污染土壤较为有效可行。     

Electrokinetic Remediation of Pentachlorophenol Contaminated Clay Soil

This paper presents a bench-scale experimental study performed to investigate the remediation of low permeable soil contaminated with pentachlorophenol (PCP) using the electrokinetic technique. A total of six electrokinetic tests were performed using kaolin soil spiked with 100 mg/kg of PCP. The first three tests were performed with an applied voltage gradient of 1 VDC/cm, where each test employed one of the three different flushing solutions: deionized water, electrolyte, or buffered electrolyte. The other three tests were performed using the same electrolyte solution, but each employed voltage gradient of 2 VDC/cm under constant and periodic application modes and constant voltage gradient with electrode liquid recirculation. The results of this study showed that PCP can be degraded in an electrokinetic system due to the direct electrochemical reduction process at the electrodes. The degradation of PCP ranged from 52% to about 78% depending on the conditions present. As the applied voltage gradient across the PCP-contaminated soil increased, the electroosmotic flow and PCP migration toward the cathode increased, resulting in higher PCP degradation by the direct reduction process. In the tests with electrolyte flushing solution, PCP degradation was about 58% and 65% under the applied voltage gradients of 1 and 2 VDC/cm, respectively. The mode of application of voltage potential across the PCP-contaminated soil showed noticeable effect on the system pH and electroosmotic flow and hence the PCP degradation. The highest PCP degradation (i.e., 78%) was in the test with constant 2 VDC/cm voltage gradient and recirculation application. Overall, this study demonstrated that electrokinetic technology has the potential to remediate PCP-contaminated clay soils by the direct reductive process. The electroosmatic flow as well as degree of PCP degradation during electrokinetics depend on the applied potential gradient and properties of the aqueous phase such as pH, ionic strength, and presence of carbonates.     

添加螯合剂诱导－栽培红叶菾菜（Beta vulgaris var. cicla L.）修复铅和镉污染土壤效果的研究

以雄安新区安新县重金属污染农田土壤为供试土壤,以Cd超积累植物红叶菾菜（Beta vulgaris var. cicla L.）为供试植物,设置不同浓度EDTA和柠檬酸（0,2.5,5,7.5,10 mmol kg?1）处理进行盆栽试验,探究螯合诱导－红叶菾菜修复Cd、Pb污染土壤的可行性。结果表明:（1）与对照相比,添加EDTA螯合剂使红叶菾菜生长及生物量均受到抑制,一定浓度柠檬酸处理能显著促进植物生长,5 mmol kg?1柠檬酸处理对植物株高、茎粗及生物量与对照相比的上升比例分别为4.52%、44.07%和50%;（2）添加EDTA螯合剂后土壤中Cd、Pb有效态含量相比对照分别提高了108.61% ~ 235.39%、67.98% ~ 224.16%,柠檬酸处理后土壤Cd、Pb有效态含量最大提高了180.07%、186.01%,EDTA对土壤重金属的活化效率显著高于柠檬酸;（3）通过对红叶菾菜地上部Cd、Pb含量及富集系数比较发现,EDTA更能促进红叶菾菜对Pb的吸收,柠檬酸更能促进红叶菾菜对Cd的吸收;（4）螯合剂处理后土壤中铵态氮、有效磷、速效钾含量显著增加。就本文试验条件、供试材料而言,螯合诱导－红叶菾菜修复铅镉复合污染土壤是可行的。     

镉砷复合污染水稻土原位钝化修复技术研究进展

随着工农业的发展,稻田土壤正面临严重的重金属污染问题,水稻作为南亚和东南亚的主要粮食作物,稻米安全问题显得尤为突出。镉和砷两者在生物地球化学循环上有明显差异,因此镉和砷复合污染水稻土的修复一直是一个棘手的问题。综述了镉砷复合污染水稻土原位钝化技术的研究现状,将钝化技术梳理为氧化还原型、微生物转化累积型、材料型和耦合钝化技术四类。氧化还原型钝化技术重点指出稻田水分调控驱动的氧化还原电位Eh和pH变化、不同元素的生物地球化学循环、有机质等对镉和砷的迁移转化机制;微生物转化累积型钝化技术重点阐明功能微生物对砷和镉的吸收、转化、区室化、菌表吸附等作用机制;材料型钝化技术重点分析现有钝化材料的分类及其与镉和砷的固定化机制;耦合型钝化技术重点总结上述三种技术综合体系下,镉和砷的协同钝化应用。同时对未来镉砷复合污染水稻土的原位钝化修复提出展望,进一步探讨了镉砷在稻田土壤生物地球化学循环过程涉及的新型机制研究方向、修复钝化技术的创新延展趋势;期望在稳产、增产的基础上,寻求一种深度融合现代农业生产模式、保障稻田安全利用的土壤钝化改良技术体系或模式。     

正丙醇与羟丙基-β-环糊精复配对高浓度DDT污染土壤的增效洗脱修复研究

以武汉某高浓度滴滴涕(DDT)污染场地土壤为研究对象,采用正丙醇和羟丙基-β-环糊精(HPCD)为洗脱剂进行相关的洗脱试验,并嵌合升温措施,研究了其对DDT污染场地土壤的洗脱修复效果。试验结果表明,20%正丙醇和50 g L-1HPCD复配、50℃水浴连续洗脱5次,可以使土壤中DDT总量的平均去除率达到96.41%。研究为DDT污染场地土壤的异位增效洗脱技术研发提供了一种有效手段。     

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.     

膨润土对轻度镉污染土壤钝化修复效应研究

通过盆栽和大田小区试验,研究了膨润土对Cd污染土壤修复效应。结果表明,盆栽和大田条件下施用膨润土后土壤Cd交换态含量分别较对照降低了41.3%~86.1%和7.9%~24.6%,铁锰氧化物结合态(OX)和残渣态(RES)Cd含量则有所上升。水稻各部分Cd含量总体上随膨润土投加量的增加而降低,与对照相比,盆栽条件下根、茎、叶、糙米中Cd含量最大降幅分别达到46.0%、49.8%、54.2%和71.8%,大田小区条件下水稻各部分Cd含量最大降幅分别达到35.3%、48.8%、36.0%和40.9%。投加不同浓度膨润土后,水稻幼苗叶片SOD酶活性和可溶性蛋白含量在一定程度上有所促进,而POD酶活性和MDA含量则表现为明显的抑制效应(P0.05)。在盆栽和大田实验中,施用膨润土显著提高土壤过氧化氢酶活性(P0.05),与之相反,在盆栽实验中,土壤Cd蔗糖酶活性较对照处理显著降低(P0.05),降幅达44.3%~52.3%,而大田条件下各处理间差异不显著(P0.05);脲酶活性随膨润土施加量的增加呈现出先降低后增加的趋势。     

几种酸和盐对As污染土壤的化学萃取修复

通过实验室浸泡试验,研究了4种酸溶液和2种盐溶液对As污染土壤化学萃取修复的效果及其机理,同时从土壤pH的改变和土壤组分的溶出2个方面研究了化学萃取对土壤的负面影响.结果表明,4种酸溶液中,H3PO4对土壤As的去除效果较好.其次是C6H8O7,HCl和HCIO4则没有明显效果;2种盐溶液中,KH;PO4的效果较好,NH4HCO3的效果不理想.5～200 mmol/L的H2PO4和KH2PO4对土壤As的去除率分别为7.76%～22.85%,6.81%～20.21%.H3PO4对土壤As的去除是风化溶解土壤组分带来As的释放与PO3-4置换土壤As这2种机理共同作用的结果.其中PO3-4发挥了主要的作用;KH2PO4对土壤As的去除则完全归因于PO3-4对土壤As的置换.在去除As的同时,酸溶液不同程度地造成土壤酸化,导致Ca,Mg,Si等土壤组分的溶出,而盐溶液对土壤pH值影响较小,导致土壤组分的溶出也很少.KH2PO4能有效去除土壤As,而且对环境友好,是修复As污染土壤较理想的萃取剂.     

植物–微生物联合修复镍污染土壤研究进展

土壤健康是粮食安全的保障,人类活动给土壤造成的污染亟待治理。镍是人体必需微量元素,但过量的镍具有较大的毒性。目前我国土壤中镍污染比较严峻,应尽快响应《土壤污染防治行动计划》来改善土壤中镍污染状况。本文综述了植物–微生物联合修复技术的基本原理,微生物在镍污染土壤中对植物生长状况、有效态镍含量以及植物吸收镍的影响,对寻找合适的植物和微生物修复镍污染土壤具有重要意义;最后,提出将有机酸运用到植物–微生物联合修复镍污染土壤中、建立PGPB库和寻找我国超富集植物等下一步研究的重点。     

Soil Microbiomes—a Promising Strategy for Contaminated Soil Remediation: A Review

Bioremediation is a process mediated by microorganisms and represents a sustainable and eco-friendly way to degrade and detoxify environmental contaminants. Soil microbiomes clearly become a key component of bioremediation as they are more stable and efficient than pure cultures, being recognized as one of the scientific frontiers of the soil environmental science and technology fields. Recently, many advancements have been made regarding the investigation of remediation mechanisms by soil microbiomes and the interactions inside them. This has greatly expanded our ability to characterize the remediating function of soil microbiomes and identify the factors that influence their efficiency for remediation. Here, we suggest that soil microbiomes are a promising strategy for soil remediation. Research is now needed to identify how we can manipulate and manage soil microbiomes to improve remediation efficiency and increase soil fertility at the same time. Therefore, this review aims to emphasize the importance of soil microbiomes in bioremediation and promote further development of this strategy into a widely accepted technique.     

Remediation of Pesticide Contaminated Soil by Planting and Compost Addition

Pesticide contaminated material was obtained from an agrichemical retail facility in Illinois. In an effort to improve physical properties and increase microbial activity and plant growth in the contaminated matrix, the material was mixed with uncontaminated soil or with mature yard waste compost to determine the impact of compost compared to soil on plant establishment and growth, development of soil microbial activity, and herbicide inactivation. Plant growth, particularly weed growth, was significantly greater in compost containing mixes than it was in soil mixes. Microbial activity, as measured by dehydrogenase activity, was significantly higher in compost-containing mixes than in soil mixes. The combination of planting and compost addition resulted in significant increases in herbicide inactivation in the contaminated materials. The results strongly suggest that remediation of herbicide contamination at agrichemical retail facilities can be achieved quite rapidly and at moderate cost and also demonstrate that the combination of compost addition and planting can accelerate xenobiotic degradation in contaminated soils.     

生物泥浆反应器在污染土壤修复中的应用

近年来生物修复技术因具有处理费用低、不产生二次污染且处理效果可靠有效的特点被认为是最具生命力的一种土壤处理手段.总结了生物泥浆反应器这种高效生物修复技术的原理,工艺流程、运行方式、应用范围和运行费用,并重点介绍了其强化手段.已有的土壤生物修复技术受环境条件限制较大,很难在短时间内达到修复目的,生物泥浆反应器作为一种高效的土壤生物修复技术在高浓度、难降解有机物污染土壤的快速修复处理中具有良好的研究开发价值和广阔的应用前景.     

秸秆还田对镉污染农田土壤中镉生物有效性的影响

通过温室盆栽试验和土壤培养试验,研究了重金属镉污染水稻土和人为模拟镉污染土壤上不同种类和不同量的作物秸秆还田后,土壤中可提取态镉的动态变化规律以及对白菜生长和吸收重金属镉的影响。结果表明,秸秆还田显著提高了2种镉污染土壤的pH值。镉污染水稻土上还田玉米和菜豆秸秆显著提高了土壤中醋酸铵提取态镉和DTPA提取态镉含量,秸秆还田后2周时醋酸铵提取态镉含量增加了17%~33%,随时间延长,土壤中可提取态镉增加变的不明显。模拟镉污染土壤上还田玉米和菜豆秸秆对土壤中醋酸铵提取态镉和DTPA提取态镉含量影响不明显。镉污染水稻土上秸秆还田量2%时显著降低了白菜体内镉含量,还田菜豆秸秆和玉米秸秆白菜体内镉含量分别降低了18%和27%。还田玉米秸秆影响了白菜生长,降低了白菜的产量;模拟镉污染土壤上还田菜豆秸秆对白菜生长和镉含量影响不明显,但还田2%玉米秸秆降低了白菜生物量,增加了白菜镉含量。