Removal of As and Heavy Metals （Cd, Cu and Pb） in Fine Soil from Soil Washing Process Using Chelating Agent

Fine soil generated from the soil washing process can be the second problem, as contaminants are concentrated in the fine soil, and also took the difficult forms to treat because soluble and exchangeable fractions are already removed by soil washing process; therefore, the fine soil is indicated to hazardous waste, and discarded in hazardous waste landfill. Thus, this research would be performed that arsenic and heavy metals formed difficult to remove in the fine soil were converted to more treatable fractions with chelating agents. Moreover, feasibility study to apply the second remediation targeted to the fine soil inquired. As a result, the chelating agent was decided 50 mM Na2EDTA, and it could develop the complex. In addition, the result of sequential extraction showed that Mn/Fe-oxide fraction, comprised about 28% of amount at first, was decreased about 16%, and organic fraction, consisted approximately 20%, was also decreased about 11%, while exchangeable fraction and carbonate fraction were increased. This result means that the difficult fractions removed could change fractions） by chelating agent. This research can provide the possibility hazardous waste because of difficulty to remediate. the more treatable fractions （exchangeable and carbonate to treat the fine soil, although the fine soil was regarded to

Study on Treatment of Heavy Metals in Fly Ash by a Chelating Agent

The fly ash from two municipal solid waste incineration plants in Shanghai was treated by the self-developed organic composite chelating agent. The results indicated that the stabilization effect of Pb in the fly ash by the composite chelating agent was the best,and the proportions of its easily leaching form in the two kinds of fly ash decreased from 29. 60% and 27. 49% to 3. 05% and 0. 29% respectively. The leaching toxicity of stabilized fly ash was lower than the limits of Standard for Pollution Control on the Landfill Site of Municipal Solid Waste（ GB 16889- 2008）,so it can be landfilled separately in the landfill site of municipal solid waste.

Extraction of Heavy Metals from Solid Material by Supercritical CO_2

Extraction of heavy metal ions from solid matrix by means of an incorporation of chelating agents with supercritical carbon dioxide（scCO2） was investigated experimentally. Four commercially available chelating agents, diethylammonium diethyldithiocarbamate（Et2NH2DDC）, trifluoroacetylacetone（TFA）, hexafluoroacetylacetone（HFA） and thenoyltrifluoroacetone（TTA） were tested. The extraction experiments were conducted at 50 °C and 1.39×107― 2.80×107 Pa. According to the experimental results, for the extraction of Cu2＋, all the chelating agents investigated here are effective. For other metal ions, such as Pb2＋, Ni2＋ and Cd2＋, Et2NH2DDC exhibited a better extraction result, while other chelating agents were less effective. This investigation is expected to provide a tentative evaluation on the scCO2-based metal extraction from solid media.

The Improvement of Phytomediation on the Treatment Effectiveness of Heavy Metals with Energy Sunflower Plants with Calcium Peroxide and Phytohormones

Phytomediation is an environmentally friendly green rehabilitation technology that is often incorporated with an application to improve calcium peroxide and phytohormones required for the growth of agricultural plants with the expectation to improve the effectiveness of plant rehabilitation. This study mainly consists of two parts: 1) water culture experiment and 2) pot culture experiment. In the water culture experiment, we attempt to understand the influence of the addition of calcium peroxide, phytohormones (IAA and GA3) and a chelating agent on the growth of sunflower plants. From the growth, we are then able to know the effectiveness of the addition of phytohormones. However, in the pot culture experiment, when hormones and the chelating agent EDTA are introduced to different plant groups at the same time, if the nutrition in the water required by plants is not available, the addition of the hormone cannot negate the toxicity caused by EDTA. In terms of calcium peroxide, due to quick release of oxygen in water, this study fails to apply calcium peroxide to the water culture experiment. When the pot culture experiment is used to examine the influence of hormones at different concentration levels on the growth of sunflowers, GA3 10-8 M is reported to have the optimal effectiveness, followed by IAA 10-8 M;IAA 10-12 M has the lowest effectiveness. According to an accumulation analysis of heavy metals at different levels, GA3 concentrates in leaves to transport nutrition in soil to leaves. This results in an excellent TF value of 2.329 G of GA3 than 1.845 of the control group indicating that the addition of the hormone and chelating agent to GA3 increases the TF value and the chelating agent is beneficial to the sunflower plant. If we examine phytoattenuation ability, the one-month experiment was divided into three stages for ten days each. The concentration level of heavy metals in the soil at each stage dropped continuously while that of the control group decreased from 31.63 mg/kg to 23.96 mg/kg, GA3 from 32.09 mg/kg to 23.04 mg/kg and EDTA from 30.65 mg/kg to 25.93 mg/kg indicating the quickest growth period of the sunflowers from the formation of the bud to blossom. During the stage, the quick upward transportation of nutrition results in quick accumulation of heavy metals;the accumulated speed of heavy metals is found higher than that of directly planted plants. This study shows an improvement in the effectiveness of the addition of hormones on plant extraction and when rehabilitation is incorporated with sunflowers with the beginning bud formation, better treatment effectiveness can be reached.

重金属捕获剂EDTC协同处理EDTA-Cu/RhB的去除特性

以乙二胺(C_(2)H_(8)N_(2))和二硫化碳(CS_(2))为原料,采用共混法合成重金属捕集剂N,N-双(二硫代羧基)乙二胺(EDTC)。考察物料配比、投加顺序、溶液pH、时间和温度等因素对EDTC作为药剂协同处理废水中络合态铜(EDTA-Cu)和染料罗丹明B(Rhodamine B,RhB)双组分体系的去除特性影响,并与单组分EDTA-Cu和RhB体系的去除效果进行对比。结果表明:常温下,于180mg/L的EDTA-Cu和1800mg/L的RhB水体中投加1.3g/L EDTC时,EDTA-Cu和RhB的去除量分别高达150mg/g和850mg/g,水体pH在2~10范围内运行稳定。与EDTC处理水体中单组分EDTA-Cu和RhB的去除效果相比,EDTC可有效同时去除水体中的络合铜和RhB,且具有协同效应。因此,EDTC可作为水处理药剂应用于协同处理带有络合态金属和染料的复杂废水。

改性淀粉对垃圾焚烧飞灰中Pb和Cd稳定化研究

垃圾焚烧飞灰中Pb和Cd对人体及环境危害极大且浸出质量浓度严重超标。为稳定飞灰中的Pb和Cd,合成了一种以玉米淀粉为主体的有机螯合剂,用于处理飞灰中的Pb和Cd。通过改变螯合剂投加质量分数、养护时间、液固比(mL∶g)和pH值来研究螯合剂稳定效果并进行表征。X射线衍射(X-ray Diffraction,XRD)结果显示,改性处理未改变玉米淀粉的结晶结构类型。通过对结晶度计算,表明改性过程发生在淀粉结晶区。扫描电镜(Scanning Electron Microscope,SEM)结果显示,处理前飞灰比表面积较大,飞灰经过改性玉米淀粉处理后粒径明显增大,降低了飞灰比表面积。通过傅里叶变换红外(Fourier Transform Infrared,FT-IR)光谱表征,显示飞灰处理前后主要存在碳酸盐、硫酸盐和硅铝酸盐。采用单因素试验确定改性淀粉螯合飞灰Pb和Cd的最佳条件为:改性淀粉投加质量分数为3%、养护时间为24 h、液固比(mL∶g)为2∶5、pH值为7~9。该条件下,Pb和Cd浸出质量浓度最低分别为0.162 mg/L、0.087 mg/L,对Pb和Cd稳定化率均大于93%,浸出质量浓度远低于《生活垃圾填埋场控制标准》限值。淋溶试验显示,淋溶速率较慢及酸雨条件下,螯合体中Pb和Cd的溶解程度较高。

油料作物联合外源添加物强化重金属污染农田修复效果的研究进展

本文综述了螯合剂、氯化物、微生物与油料作物联合的相关研究进展。发现不同联合应用的修复效果和修复机理有所差异,同一油料作物联合三种修复手段产生的修复效果不同,从而修复不同污染类型和污染程度土壤时有更适宜的搭配,为提高油料作物修复效率提供更多新的思路和参考。

亚氨基二琥珀酸功能化改性活性炭的制备以及对水中二价铜离子吸附行为研究

随着现代工业的迅速发展,水中重金属污染日趋严重。活性炭在重金属治理方面应用广阔,为提高其吸附能力,分别用亚氨基二琥珀酸(IDS)和乙二胺四乙酸(EDTA)功能化处理活性炭得到螯合剂IDS-AC和EDTA-AC。比较两种材料对水中铜离子吸附行为,筛选出对铜离子吸附效果最佳的材料。使用红外光谱(FT-IR)和X光电子能谱(XPS)等表征手段对作用铜后的功能化活性炭表征分析,并进行吸附实验。结果表明:IDS-AC对铜离子具有更好的吸附效果,与原始的AC相比,IDS-AC对Cu(Ⅱ)的吸附量提高了249.69%,EDTA-AC仅提高23.23%。在1mmol/L Cu(Ⅱ)水溶液中,IDS-AC最佳吸附pH为4.0,最佳投加量范围为0.4~1.6g/L,吸附平衡时间在4h左右。IDS-AC对于重金属的吸附是化学吸附,对重金属离子作用机理主要包括材料表面的配位原子N与重金属发生配位作用,重金属被固定在环状结构内,形成稳定螯合物。

垃圾焚烧飞灰螯合稳定化处理效果评价

对无锡市某电厂垃圾焚烧飞灰,采用硫化钠及二硫代氨基甲酸盐进行螯合稳定化处置,研究螯合前后飞灰中9种重金属(Cu、Pb、Cd、Zn、Ni、Cr、Ba、As、Hg)的浸出毒性变化。结合物相及微观形貌分析,探究飞灰主要组成及污染成分。结果表明,飞灰中Pb、Cd和Ni浓度远超浸出标准。经螯合剂处理后稳定效果明显,其中Cu去除率最高,可达97.55%。而对于Pb、Cd及Ni,螯合后浸出浓度最低值分别为0.01 mg/L、0.01 mg/L、0.04 mg/L。螯合后所有金属浓度均满足安全填埋要求。同时,经螯合稳定后样品的综合潜在生态风险等级也由很强降为很轻,所有金属元素单因子生态危害保持在较低水平,稳定效果明显。

土壤环境化学及化学修复研究与分析

本研究旨在探究污染土壤中重金属铅的螯合修复效果,采用EDTA作为螯合剂,通过不同浓度的螯合剂对污染土壤进行处理。实验结果表明,螯合剂浓度和处理时间对土壤中的铅浓度有显著影响。本文详细描述了实验设计、操作步骤和数据分析过程,并对修复效果进行评估。通过对比不同浓度螯合剂的实验数据,提出了一种可行的土壤重金属修复方法,并讨论了实验中pH值变化的影响,这项研究对于理解土壤环境污染的化学修复机制具有重要意义并可作为实际应用的参考。

煤矸石螯合改性后对选矿废水中重金属离子吸附研究

选取贵州省某6个矿区煤矸石进行均匀混合,通过700℃煅烧后获得热活化的样品。采用螯合剂次氮基三乙酸(NTA)与羧甲基淀粉(CMS)对热活化的样品进行改性,制备低成本的改性煤矸石吸附剂。通过单因素静态吸附实验分别研究了pH、CMS与NTA固液比、吸附剂投加量、吸附时间等对改性煤矸石吸附废水中Cu^(2+)和Pb^(2+)的影响。结果表明,在焙烧温度为700℃、CMS与NTA最佳固液质量比(简称固液比)为1∶15、溶液pH=9、吸附时间为2 h、投放量为0.8 g/L条件下,改性煤矸石能够吸附选矿废水中大量Cu^(2+)和Pb^(2+),最佳去除率分别为69.34%和79.98%。结合吸附等温模型拟合分析,吸附剂对Pb^(2+)的吸附过程以单层的化学吸附为主。

螯合剂和有机酸对商陆修复镉砷污染农田的影响

基于利用植物提高Cd和As复合污染农田修复效率的目标,通过大田试验方法探究了乙二胺四乙酸(EDTA)、皂素(SAP)、柠檬酸(CA)和苹果酸(MA)对商陆萃取农田土壤Cd和As的影响。结果表明,施用4种不同螯合剂和有机酸对商陆的生长没有产生不利影响,且可以显著影响商陆对土壤Cd和As的吸收积累。与对照组相比,EDTA、SAP、CA和MA处理60 d后导致商陆叶片Cd含量分别提高116.4%、55.0%、81.5%和109.9%,商陆地上部Cd积累量提高40.4%~106.0%,商陆地上部As积累量提高15.8%~55.1%。商陆各器官Cd和As的富集系数和转运系数也受螯合剂和有机酸施用的影响。施用EDTA、SAP、CA和MA均对商陆根际土壤Cd和As含量产生显著影响,SAP处理对降低商陆根际土壤Cd含量的影响最显著,而MA处理对降低商陆根际土壤As含量的影响最显著。研究表明,EDTA、SAP、CA和MA均可提高商陆萃取农田土壤Cd和As的效率,尤其是EDTA和MA的效果更好。

螯合剂对矿山水体底泥中重金属提取效率研究

为实现矿山水体底泥重金属污染的绿色修复,利用EDTA、GLDA和MGDA等3种螯合剂在不同的条件下提取矿山水体底泥中的重金属Cd、Cu和Ni并分析其作用机理。研究采用分批提取、BCR提取等试验方法比较分析了EDTA、GLDA和MGDA等3种螯合剂和不同影响因素对矿山水体底泥中重金属提取效率的影响。研究结果表明,最佳淋洗时间因重金属元素及螯合剂种类而异,pH是螯合剂提取重金属效率的主要影响因素,螯合剂浓度的增加能显著提高重金属去除率,累计循环淋洗对重金属的去除效率提升不足5%。螯合剂去除矿山水体底泥中重金属是通过改变重金属的存在形态。在室温体系下,3种螯合剂最适使用条件为:EDTA与重金属离子摩尔比6∶1(淋洗时间16 h,pH=4),循环淋洗2次;GLDA与重金属离子摩尔比4∶1(淋洗时间8 h,pH=4),循环淋洗3次;MGDA与重金属离子摩尔比6∶1(淋洗时间8 h,pH=4),循环淋洗3次。在最适使用条件下,螯合剂对Cd的去除效果由大到小依次为EDTA、GLDA、MGDA,对Cu的去除效果由大到小依次为MGDA、EDTA、GLDA,对Ni的去除效果由大到小依次为MGDA、GLDA、EDTA。绿色螯合剂GLDA和MGDA可以替代传统螯合剂EDTA,提高成本效益和环境友好性。用Na_2S处理淋洗液后,重金属回收率可达95%以上,处理后淋洗液中重金属含量低于国家排放标准,可直接排放。研究结果可为螯合剂去除矿山水体重金属污染底泥提供理论支撑。

二硫代氨基甲酸盐类螯合剂对飞灰中六种重金属的稳定化研究

该研究合成一种含双二硫代氨基甲酸盐结构的螯合剂(TETA-DTC),用于稳定垃圾电厂飞灰中的6种重金属(Cd、Pb、Cu、Ni、Zn、Cr),通过比较TETA-DTC螯合剂与商用重金属稳定剂H的稳定化效果,探究TETA-DTC螯合剂对飞灰中重金属的稳定机理。结果表明,当TETA-DTC螯合剂添加量为4%时,可以使飞灰中6种重金属的浸出浓度低于GB 16889—2008《生活垃圾填埋场污染控制标准》的限值,其中对Cd、Pb的稳定化率都超过98%,而稳定剂H在4%添加量时,不能使Cd、Pb浸出浓度达标,稳定化率低于90%,对于Zn、Ni,TEAT-DTC的效果也好于H,而对于Cu、Cr,二者的稳定效果相差不大;扫描电镜图显示,药剂稳定化处理后飞灰颗粒间空隙更小,颗粒与颗粒结合得更紧密,说明螯合剂对飞灰中金属有很好的稳定作用;红外光谱图显示,TETA-DTC中的N和S参与了螯合反应。

妊娠期重金属中毒解毒剂治疗的研究进展

随着现代工业的发展,我国重金属污染问题日趋严重,重金属可以持久蓄积于人体,对孕妇及儿童的健康结局产生不利影响,给社会及家庭带来了沉重的负担。临床上常用的螯合剂在重金属的治疗中取得了较大的进展,但妊娠期用药也存在着一定的安全问题与副作用,而抗氧化剂的使用和必需微量元素的补充可弥补螯合剂的不足。本文综述了重金属中毒的治疗进展,从螯合剂、抗氧化剂、必需微量元素及解毒剂联合治疗等方面进行介绍,旨在为妊娠期重金属中毒的临床治疗提供新的思路。

DTC类重捕剂在化学镀镍浓废液深度除镍中的应用研究

以催化氧化还原预处理后的化学镀镍浓废液为对象,通过使用DTC(二硫代氨基甲酸盐)类复合重捕剂对其进行深度除镍,研究了重捕剂用量、反应时间、初始pH、反应温度和初始镍浓度对处理效果的影响。结果表明,在重捕剂用量为600 mg/L、初始pH为7、反应温度为25℃的条件下,反应3 min后即可将镍浓度从24.5 mg/L稳定降低至0.05 mg/L,镍去除率高达99.8%,符合电镀废水中重金属镍的排放要求。

提高植物修复效率的技术途径与强化措施

通过物理、化学或生物学手段,从土壤、植物及其生境3个方面着手来提高植物去除土壤重金属能力是植物修复技术应用研究的重要方向.对国内外植物修复过程中所应用的强化手段与辅助措施进行了一定的研究,分别阐述了施肥、水分管理、耕作栽培、修复剂、生物技术等方法的作用机制及应用效果.今后,植物修复技术需针对有应用前景的超富集植物进行生境特征的系统研究,并着重开发高效、低风险的土壤修复剂,注重植物修复成套技术的工程应用研究.

螯合剂处理重金属污染底泥的实验研究

A new type of heavy metal chelating agent,potassium diisopropyl dithiophosphate was synthesized and the treatment of sediment contaminated by heavy metals by this chelator was investigated.The results indicated that when the dosage of potassium diisopropyl dithiophosphate was 3%(mass),the stabilization rate of heavy metals in sediment,such as Pb,Cu,Cd,could reach more than 85%,and the effect was better than inorganic stabilization chemicals,like Na2S and Na3PO4. After treatment the sediment could meet the US standards for heavy metals waste landfill.Meanwhile,the maximum leaching capacity of the treated sediment was much lower than the case with inorganic stabilization chemicals,and such stabilization effect could be obtained in a wide range of pH. The heavy metals in sediment after treatment could be transformed from exchangeable to organically bound and residue,reducing secondary contamination risk when the environment has changed.

重金属螯合剂处理焚烧飞灰的稳定化技术研究

进行了垃圾焚烧飞灰的新型稳定化药剂——重金属螯合剂的实验室研究，探讨了本螯合剂处理焚烧飞灰的稳定化工艺流程及处理效果．结果表明，本螯合剂对飞灰中重金属的总捕集效率高达９７％以上，其效果显著优于无机稳定化药剂Ｎａ２Ｓ和石灰，且处理后的飞灰能达到重金属废物的填埋控制标准，同时，其处理后的飞灰的最大浸出量远低于无机稳定化药剂处理后的飞灰，且能在较宽的ｐＨ范围内都具有好的稳定化效果。

DTC类重金属捕集剂研究的进展

二硫代氨基甲酸盐 (dithiocarbamate ,DTC)衍生物对重金属有极强的螯合能力 ,在环境治理中主要有螯合剂和螯合树脂两种利用形式。前者主要用于成分复杂污染物中重金属离子的去除 ;后者主要用于环境分析中金属的分离与预富集。今后进一步研究方向应为 :根据物质结构与性能的关系 ,开发更加稳定、高效、低毒的产品 。