石灰、腐植酸单施及复配对污染土壤铅镉生物有效性的影响

正通过盆栽试验研究在铅(Pb)、镉(Cd)污染土壤中单一及复合添加石灰(w=0.2%)和腐植酸(w=1%、2%和5%)对土壤理化性质、土壤有效态Pb和Cd含量、黑麦草生长及黑麦草吸收Pb和Cd的影响,探讨石灰和腐植酸对土壤Pb、Cd生物有效性的调控效率。结果表明:单施石灰和石灰配施腐植酸处理均能提高土壤pH,显著降低土壤中有效态Pb、Cd含量,     

锌灰中的锌、铅、镉、银元素的检测

对锌灰中可回收利用元素进行定量分析和回收,既减少了环境污染,又补充完善了锌工业流程,提升了经济效益。本文使用电感耦合等离子体原子发射光谱(ICP-AES)方法检测锌灰中的锌、铅、镉、银元素,样品经四酸消解并除硅。在20%的盐酸介质中,于经过优化的仪器条件下测定四种元素。本方法回收率在95.0%~100.5%之间,方法标准偏差小于2.5%,该方法流程简便,检测快速,结果较为准确。     

铅、镉和锌污染对芦苇幼苗氧化胁迫和抗氧化能力的影响

对Pb, Cd和Zn胁迫下芦苇幼苗叶片和根内超氧阴离子自由基(O2-)和过氧化产物丙二醛(MDA)的含量、电解质渗漏以及超氧化物岐化酶(SOD)和过氧化物酶(POD)活性进行了研究. 结果表明，受3种重金属的影响，叶片和根内O2- 积累，MDA含量增加，伴随着电解质渗漏增大，显示发生了膜脂过氧化，细胞膜系统遭到破坏；作为植物抗氧化系统中的关键酶，SOD和POD活性高于对照，说明在重金属胁迫下芦苇幼苗体内的抗氧化能力增强. 可见，在重金属污染下细胞内O2- 浓度升高带来的膜脂过氧化增强是重金属伤害植物的主要原因；而保护酶系统SOD和POD活性的升高则可能是芦苇抗过氧化的机理之一.     

在鼠的肌体中泥炭腐植酸对铅和镉的吸收和分布的效应

可以应用合成的交换作用或络合物形成来阻止或减少肌体内毒性作用的金属结合。但是这种方法部分地有显著的副作用,因而在实践中禁止应用。当前的工作在于检验腐植酸作为天然的交换及络合物质是否没有特有的毒性副作用。     

不同钝化剂对铅镉重金属污染土壤的修复影响研究

为研究不同种类钝化剂对铅、镉重金属污染土壤的修复效果影响,选择某化工厂铅、镉污染比较严重的黄壤作为修复对象,采用单一的无机钝化剂、生物炭类钝化剂、矿物钝化剂和有机-无机混合钝化剂对土壤进行修复。在不同类型钝化剂下,设计三因素三水平正交实验,除了钝化剂类型之外,所有条件都相似,研究上述各个类型钝化剂对土壤中铅、镉含量的钝化效率影响。研究结果表明,实验中所选择的生物炭、石灰、含硫型土壤调理剂、硅藻土按照一定比例混合而成的矿物钝化剂,对受试土壤中重金属铅、镉的钝化效果最好;通过正交实验结果可知,在矿物钝化剂使用量为460kg·hm^-2、土壤水分为50%、土壤粒径>2mm的情况下,能够获得最佳的铅、镉钝化效果,钝化效率分别为79.85%和87.18%。     

腐植酸复混肥对小白菜生长和土壤养分含量的影响

通过小区田间试验,研究了腐植酸对土壤肥力、小白菜产量及其品质的影响。结果表明,施用腐植酸复混肥不仅可以改善土壤肥力,而且可以提高作物的产量和品质。其中,小麦产量提高38．1％、VC含量提高32．4％、水溶性糖含量提高28．7％、N素利用率提高19．3％,土壤有机质含量提高16.1％。     

石墨消解-原子吸收测定土壤中的锌和镉

采用石墨消解的方法进行样品消解,并用原子吸收光谱法测定土壤中锌和镉的含量。实验结果表明:锌在石墨消解结合火焰原子吸收光谱法中锌浓度在1 mg/L以下成线性相关,相关系数R2=0.9995,该方法的最低检出限为0.02 mg/kg。而镉元素在小于10μg/L之间成指数函数相关,相关系数R2=0.99889,该方法的最低检出限为0.02 mg/kg。测定结果精密度、准确度令人满意。     

硝酸-氢氟酸微波消解-ICPMS测定土壤铜、 锌、 镉、 铅

建立了硝酸-氢氟酸体系微波消解-ICPMS同时测定土壤中铜、锌、镉、铅4种元素的分析方法。优化了微波消解所使用的混合酸体系。在建立的实验条件下,土壤中铜、锌、镉、铅的检出限为0. 02～0. 7μg/g,检测土壤标准物质中的铜、锌、镉、铅,结果均在保证值范围内,准确度较好。实际样品分析结果显示,相对标准偏差范围在1. 0%～6. 9%之间,精密度良好。该方法酸用量少,操作简便,快速,检出限低,准确度高,精密度好,适用于土壤中铜、锌、镉、铅的同时分析。     

火焰原子吸收法测定火电厂废水重金属铜、锌、铅、镉的方法验证

本文通过测试全程序空白、标准回归曲线、检出限、相对标准偏差、加标回收率等实验对火焰原子吸收法测定火电厂废水重金属铜、锌、铅、镉进行方法验证。方法验证检出限分别为0.011 mg/L、0.004 mg/L、0.044 mg/L、0.002 mg/L;相对标准偏差分别为0.93%、1.06%、2.46%、1.11%;标准物质的最大相对误差分别为5.4%、6.0%、2.8%、2.3%;三种不同浓度的样品加标回收率分别为97.85%、96.91%、98.17%、96.98%;该方法具有较高的灵敏度和准确度、精密度等特点。火焰原子吸收光谱法对火电厂环保废水中的铜、锌、铅、镉重金属离子的检测是比较有优势的。     

火焰原子吸收法测定地表水铜、铅、锌、镉样品的前处理分析

针对不同河流地表水采用不同的处理方法以及在保存期内重金属的检测进行探讨。     

土壤镉污染的植物修复技术

镉在土壤中有稳定、积累和不易消除的特点,且可通过食物链富集使人体慢性中毒.植物修复技术是一种清除环境污染的绿色技术,具有成本低、不破坏土壤生态环境、不引起二次污染等优点,具有广阔应用前景.土壤镉污染植物修复技术有植物提取、植物挥发、植物稳定和植物促进等修复技术,在镉污染土壤的治理时,应根据土壤条件、污染的程度、预期的修复目标、时间限制、成本等因素加以综合考虑,选择合适的修复技术或组合,达到高效、低耗的双重效果.     

Reclamation of soil polluted by gas condensate using peat compost

An approach to the reclamation (the recovery of fertility) of soil polluted by gas condensate in the territory of a boosting compressor station using peat compost was developed. The efficiency of soil reclamation was evaluated by an analysis of catalase and dehydrogenase enzyme activities and by the sowing and cultivation of perennial grasses in the area.     

草炭土影响下土壤对硒的吸附特性研究

采用吸附解吸批量实验研究了草炭土影响下土壤对Se的吸附行为,为合理利用Se及防止土壤Se污染提供依据。结果表明,土壤对硒的吸附量随着反应时间先快速增加而后趋稳,在6 h内达到平衡,草炭土比例高的土壤吸附平衡时间长。草炭土增加了土壤对硒的吸附,但抑制了硒的解吸,从而降低了硒的可移动性。硒初始浓度越高,吸附量越高,但在添加了草炭土的土壤中,初始硒浓度大于100μg/L后,解吸率保持稳定。     

草炭土影响下土壤对硒的吸附特性研究

采用吸附解吸批量实验研究了草炭土影响下土壤对Se的吸附行为,为合理利用Se及防止土壤Se污染提供依据。结果表明,土壤对硒的吸附量随着反应时间先快速增加而后趋稳,在6 h内达到平衡,草炭土比例高的土壤吸附平衡时间长。草炭土增加了土壤对硒的吸附,但抑制了硒的解吸,从而降低了硒的可移动性。硒初始浓度越高,吸附量越高,但在添加了草炭土的土壤中,初始硒浓度大于100μg/L后,解吸率保持稳定。     

Influence of phosphate on cadmium adsorption by soils

In batch equilibrium experiments, it was found that orthophosphate increased Cd adsorption and decreased its desorption by three representative soils. Ion activity products in the equilibrium solution indicated that cadmium activity was under saturated with respect to Cd₃(PO₄) (s) on the Red earth(Typic Hapludult) and the Yellow-brown earth(Typic Hapludalf). With the calcareous Yellow fluvo-aquic soil(Typic Haplaquent), phosphate enhanced Cd adsorption at lower Cd concentration but it decreased the adsorption at high Cd level. Ion activity products and solubility diagrams suggested that at high Cd level Cd₃(PO₄)₂ had formed and the activity of Cd in solution was controlled by this precipitate. This implies that the formation of Cd₃(PO₄)₂ (s) is unable to decrease Cd activity so long as soil adsorption sites are unsaturated by Cd. It is suggested from these results that one could not expect decreasing soil Cd availability by phosphate fertilization unless a simultaneous rise in soil pH also occurs.     

Removal of cadmium or lead from polluted water by biological amphiphiles

Biological amphiphiles were examined for the removal of Cd²⁺ or Pb²⁺ from polluted water within a pH range from 2.5 to 7.5 at a fixed ratio of amphiphilic concentration to heavy metal concentration (C _A /C _M ) on a molar basis of approximately 11. Tannic acid, among eight amphiphiles, was selected for Cd²⁺ or Pb²⁺ removal because it exerted noticeable improvement within limited pH ranges. In the presence of tannic acid, the removal of Cd²⁺ or Pb²⁺ was investigated as a function of pH ranging from 2.5 to 13 at C _A /C _M ratios from 1.2 to 11. The removal capacity (mass of metal/mass of tannic acid) increased with decreasing C _A /C _M for both Cd²⁺ and Pb²⁺. Removal capacities were 0.084 and 0.154 g/g-tannic acid for Cd²⁺ and Pb²⁺ at pH 6.9 and 4.4, respectively. The maximal removals for Cd²⁺ and Pb²⁺ were 99 and 96%, respectively.     

土壤中镉的吸附解吸研究进展

综述了土壤中镉的危害性和赋存形态,分别介绍了土壤中镉的吸附解吸动力学模型和动力学特征,并分析了土壤中的镉吸附解吸过程的影响因素,包括环境因素(温度)、土壤质地(有机质和pH)、外源材料(海泡石、石灰、生物炭、复合材料、柠檬酸、EDTA和表面活性剂)等因素,较系统地探究土壤中镉吸附解吸的本质和特征,介绍了国内外最新的研究进展,为土壤中的镉污染研究及后续修复治理提供理论依据与技术支持。     

土壤对重金属Cu(Ⅱ)、Cd(Ⅱ)的吸附研究

采用等温吸附平衡法研究了土壤对重金属Cu2+和Cd2+的吸附,研究了浓度、搅拌时间、静置时间以及pH对土壤吸附铜和镉影响。结果表明,土壤对铜的吸附量大于镉,土壤对重金属吸附的最佳条件是搅拌15 min,静置20 min,pH为7.0,初步确定土壤对铜和隔的吸附属于Freundlich吸附。     

Treatment of fuel peat by the addition of lime with a freeze-thaw cycle

Dewatering of fuel peat by mechanical pressing can be greatly improved by treating the peat with lime and then running it through a freeze-thaw cycle. Results are presented for different concentrations of lime and different types of treatment.     

Removal of cadmium and lead from soil using aescin as a biosurfactant

Remediation of a soil contaminated with cadmium or lead was performed by a soil washing process using aescin as a biosurfactant. The removal of cadmium and lead from the soil was evaluated as a function of aescin concentration and pH in a batch process. A 30-mM aescin solution was most effective in the removal of cadmium and lead at pH 6.8. Cadmium and lead migrated from the soil to the aescin-containing aqueous phase, depending on the pH value. We found that 41% of cadmium (pH 7.8) and 25% of lead (pH 2.8) in the soil matrix migrated into a 30-mM aescin solution. Also, the complexation of aescin with cadmium and lead ions was confirmed by Fourier transform infrared spectroscopy and electrical conductivity measurements. As a result, the maximal complexation capacity of aescin with metal ions was approximately aescin/cadmium=2∶1 and aescin/lead=3∶1 on a molar basis. It was suggested that aescin may sequester cadmium and lead ions by the carboxylic and saccharide moieties. Then, the complex of aescin with cadmium or lead may migrate to the aqueous phase as the result of dispersion.