名山河流域黄壤组分对微团聚体吸附解吸镉的影响

选取名山河流域4种土地利用方式（林地、水田、茶园、旱地）的黄壤为研究对象,采用平衡液等温吸附法和NH4OAC、EDTA溶液解吸法,研究土壤组分（有机质、游离氧化铁）对微团聚体吸附解吸Cd2＋的影响。结果表明：去除土壤组分前后,原土及各粒径微团聚体对Cd2＋的吸附量均随Cd2＋初始浓度增大而增大,吸附量均按以下次序递减：（〈0.002mm）〉2～0.25mm〉原土〉0.053～0.002mm〉0.25～0.053mm,与有机质、游离氧化铁、CEC呈极显著正相关。吸附减少量大小关系为：去除有机质〉去除游离氧化铁,有机质的贡献率大于游离氧化铁。Freundlich方程拟合效果最佳,达到极显著水平,分布系数Kd值与Cd2＋初始浓度呈曲线负相关。NH4OAC解吸率随原吸附Cd2＋初始浓度增大而增大,以最大解吸率计,递减规律为：0.25～0.053mm〉0.053～0.002mm〉原土〉2～0.25mm〉（〈0.002mm）;EDTA解吸率随原吸附Cd2＋初始浓度增大而减小,递减规律与NH4OAC解吸率相反。去除土壤组分后,NH4OAC解吸率上升,EDTA解吸率下降,茶园与旱地黄壤非解吸率减小,林地与水田黄壤非解吸率增大。去除土壤组分后,非专性吸附与吸附总量呈极显著正相关,专性吸附与吸附总量呈极显著负相关。     

Effects of Organic Acids,o-Phenylenediamine and Pyrocatechol on Cadmium Adsorption and Desorption in Soil

This article studied the interaction of cadmium (Cd) and lowmolecular weight organics in Indicotic black (IB) soil.Cadmium adsorption isotherm in this soil was satisfactorilysimulated using Freundlich equation as Q = 905.6C^0.49 with high correlation (r² = 0.984), and its adsorption quantity increased with increasing pH. The presence of citricacid and EDTA significantly reduced Cd adsorption in soil,which was due to the formation of soluble Cd-organic complex. Concentration of cadmium ions in equilibrium solution was determined and percentages of [CdH₂Cit⁺]/[Cd-complex_Total],[CdHCit]/[Cd-complex_Total] and [CdCit^-]/[Cd-complex_Total] vs. pH were successfully calculated. Desorption percentage ofCd, adsorbed in the presence of citric acid and EDTA decreased, compared with that adsorbed in NaNO₃ media. It suggeststhat free sites for Cd adsorption in soil increased in thepresence of organic acid. When o-phenylenediamine, pyrocatechol and aminoethonic acid appeared in Cd equilibrium media, Cd adsorption quantity increased by increasing cation exchange ofpositively charged cadmium complex with soil at low pH. Compared with that performed in the absence of these organics, the exchangeable Cd, desorbed by 0.1 mol L^-1 NaNO₃, reduced obviously, which suggests that Cd-complex was moredifficult to be desorbed than Cd²⁺. Moreover, % Cd desorbedwas linearly correlated with the reverse of the total Cd adsorptionunder unsaturated adsorption.     

Effect of Calcium on the Soil Adsorption of Cadmium and Zinc in Some Spanish Sandy Soils

Castellón Plain is a natural area with an extension of 464 km², situated in Castellón (eastern coast of Spain), with an important number of ceramic industries which generate waste waters containing cadmium and zinc. In this paper, equilibrium adsorption isotherms have been obtained to examine the behaviour of cadmium and zinc in three selected soils of Castellón Plain (Spain) by means of batch experiments. Both metals exhibit non-linear adsorption isotherms with adsorption maximum beyond the dissolved concentration range considered in this study. Statistical analysis showed that data fit slighty better to Freundlich linearization than that of Langmuir. Adsorption coefficients obtained from Freundlich approximation were calculated to evaluate the relative cadmium and zinc distribution between solution and studied soils obtaining coefficients ranging from 5200 to 5900 μg kg^-1μg l^{-1 -n} for cadmium and from 3500 to 43200 μg kg^-1μg l^{-1 -n} for zinc. The effects of salt concentration and calcium competition for adsorption sites were investigated providing different concentrations of CaCl₂ in background solutions. Adsorption capacities of cadmium and zinc in the studied soils decreased when the salt concentration increased. A tenfold increase in calcium concentration reduced the cadmium adsorption capacity approximately by one third whereas the Ca²⁺ ion does not seem a significant competitor with Zn²⁺ for adsorption sites in soils with high organic matter content, where precipitation of zinc can be expected.     

江西省典型水稻土对镉的吸附解吸特性研究

以江西省2种典型水稻土(潜育型、潴育型)为试材,采用振荡平衡法研究了镉在水稻土中的吸附-解吸行为,并利用保留因子对镉在水稻土中的环境风险进行了评估。结果表明:潴育型水稻土的吸附能力较强,明显大于潜育型水稻土,但潴育型水稻土的解吸能力小于潜育型水稻土;2种水稻土对镉的吸附均可用Freundlich方程较好的拟合;镉的环境风险随镉含量的升高先减小后增大,且潜育型水稻土大于潴育型水稻土,但镉在2种水稻土中潜在环境风险均较大。     

Effect of pH on Zinc Adsorption and Solubility in Suspensions of Different Clays and Soils

Zinc solubility in clay and soil suspensions was controlled by chemisorption at pH 4.5 – 7.0. The solubility in clay mineral suspensions was in the order palygorskite < montmorillonite « kaolinite and reflected the high affinity of zinc to palygorskite and the high CEC of montmorillonite. The solubility in soil suspensions was in the order Haplustoll < Torrifluvents and reflected the effect of high CEC and organic matter content of the first. The slopes of the pH-pZn curves, calculated zinc potential and sequential desorption data suggested that Zn⁺⁺ ? Zn(OH)₂ aqueous controlled the solubility of zinc in soil and clay mineral suspensions at pH 7.5 – 9.0. The slopes of the pH–pZn curves of two soils were, however, modified by the possible peptization of organic matter and Zn(OH)₂.     

聚丙烯酰胺对磷素在土壤中吸附-解吸的影响

聚丙烯酰胺（PAM）在农业上作为扰侵蚀剂、保水剂被广泛应用，但施用后对土壤养分保持和释放的影响研究较少。本文采用向土壤（塿土）中添加不同比例（0．1％，0．2％，0．4％占土壤的比例）的PAM溶液，通过磷素等温吸附解吸试验，探讨了PAM对磷素在土壤中吸附和解吸的影响。结果表明。和原土样相比．土壤经PAM处理后抑制了土壤对磷的物理吸附，导致吸附量减小．最大吸附量（Xm）降低，而对磷素在土壤中的化学吸附影响较小．被吸附磷尤其是物理吸附磷的解吸率升高。     

阿特拉津对绿麦隆吸附-解吸作用的影响

采用批平衡实验,研究绿麦隆在单一及复合污染体系中的吸附-解吸行为。结果表明,无论是单一体系还是复合体系,吸附等温线均可用Freundlich模型进行良好的拟合。随着阿特拉津浓度的增加,土壤对绿麦隆的吸附作用降低,表明绿麦隆和阿特拉津之间存在竞争吸附,这可能与土壤的有机质类型和绿麦隆、阿特拉津的性质、结构有关。解吸实验表明,随着阿特拉津的浓度增加,绿麦隆的解吸作用增加。吸附过程的拟合指数n值大于解吸过程的对应值,即绿麦隆在不同体系中的解吸作用均存在一定的滞后性。应用Freundlich解吸等温线参数对吸附-解吸等温线的滞后作用进行量化,CT、（CT＋0.5AT）、（CT＋1AT）和（CT＋2AT）处理解吸等温线的滞后系数ω分别为165.200,146.132,94.534和85.945,即随阿特拉津浓度增加,绿麦隆解吸等温线的滞后性降低。     

磷含量和秸秆添加量对褐土锌吸附—解吸的影响

采用室内培养的方法,通过人为添加不同量的玉米秸秆和磷,研究不同含量磷和作物秸秆对土壤锌吸附—解吸的影响,以探讨磷—锌在土壤中的交互作用机制。结果表明:低锌(Zn10:添加Zn2+浓度为10 mg L-1)条件下,土壤对Zn2+的吸附量随土壤速效磷含量的增加而逐渐降低,表明在石灰性土壤中,随磷含量的增加提高了土壤锌的有效性;而Zn2+的解吸量随土壤中磷含量的增加先升高后降低,添加Zn2+浓度为80 mg L-1(Zn80)条件下,土壤对Zn2+的吸附量明显大于Zn10条件下。土壤中添加不同秸秆量对不同浓度Zn2+吸附时,低锌(Zn10)处理下,在相同磷含量情况下,土壤对Zn2+的吸附量随秸秆添加量的增加而减少,而土壤对Zn2+的解吸量随秸秆量的增加而增加。在不同磷水平下,不同秸秆添加量对Zn2+的吸附趋势差异较大。高锌(Zn80)处理下,土壤对Zn2+的吸附量在不同秸秆量处理下趋势大致相同,且Zn2+吸附量随磷含量的提高先升高后降低;在同一磷水平下,土壤对Zn2+的吸附趋势和Zn10时相似。利用KNO3进行解吸Zn2+时,不添加秸秆和低量秸秆处理变化趋势相同,均在添加磷量为360 mg kg-1时解吸量达到最大,分别为363.5 mg kg-1、424 mg kg-1,而高量秸秆处理下,Zn2+解吸量随磷含量的增加先升高后降低。     

Evaluation of Cadmium,Copper, Lead,and Zinc Levels in Soil Samples near Locust Pods

The genus Prosopis is a tree or shrub in the leguminosae family, subfamily fabaceae (mimosaceae). Many plants of the genus Prosopis are known to have medicinal properties. Only one species of Prosopis is found in Jordan, Prosopis farcta (Banks & Sol.) J.F. Macbr. The local name is Yanbout, and the English name is locust pods.

The aim of this study was to investigate some selected heavy metals including cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn) in Prosopis farcta, an unexplored Jordanian species of the Prosopis genus, because no data are available about these levels in this medicinal plant. These metals were tested in different parts of Prosopis farcta including root, aerial, and fruit as ethanolic extract plant and dry plant. Moreover, these metals were investigated in soil samples collected from the same area in which Prosopis farcta was grown. Results revealed that there was a significant difference between root and fruit for all test elements (P < 0.05). Roots were found to contain high average concentrations of Pb (2.14 µg g^?1), Cu (18.56 µg g^?1), and Zn (13.74 µg g^?1). Copper and Zn concentrations in Prosopis farcta were within the permissible limits, whereas Pb concentration exceeded the permissible limit. Moreover, soil samples were analyzed for the metals. Results revealed that there was a positive correlation between the levels of Cu and Zn in medicinal plants and soils, whereas there was a negative correlation for Pb.

Two certified reference materials (tea leaves, NCSDC 73351; soil, GBW 07406) were analyzed to authenticate the accuracy of the method, and the precision was expressed by relative standard deviation.     

Adsorption of Lead,Cadmium, and Nickel on Benchmark Soils of Pakistan

Eurasian Soil Science - Adsorption and desorption reactions at the solid phase–solution interface, play a significant role in controlling metal concentrations in soil solution and metal...     

Cadmium,Copper and Zinc Biosorption Study by Non-Living Egeria densa Biomass

Water, Air, & Soil Pollution - The processes impacting arsenic toxicity are a function of molecular speciation, where risk from chronic exposure to the reduced arsenic species is estimated to...     

Adsorption and Desorption of Copper in Pasture Soils

Abstract

Copper (Cu) is bound strongly to organic matter, oxides of iron (Fe) and manganese (Mn), and clay minerals in soils. To investigate the relative contribution of different soil components in the sorption of Cu, sorption was measured after the removal of various other soil components; organic matter and aluminum (Al) and Fe oxides are important in Cu adsorption. Both adsorption and desorption of Cu at various pH values were also measured by using diverse pasture soils. The differences in the sorption of Cu between the soils are attributed to the differences in the chemical characteristics of the soils. Copper sorption, as measured by the Freundlich equation sorption constants [potassium (K) and nitrogen (N)], was strongly correlated with soil properties, such as silt content, organic carbon, and soil pH. The relative importance of organic matter and oxides on Cu adsorption decreased and increased, respectively, with increasing solution Cu concentrations. In all soils, Cu sorption increased with increasing pH, but the solution Cu concentration decreased with increasing soil pH. The cumulative amounts of native and added soil Cu desorbed from two contrasting soils (Manawatu and Ngamoka) during desorption periods showed that the differences in the desorbability of Cu were a result of differences in the physico‐chemical properties of the soil matrix. This finding suggests that soil organic matter complexes of Cu added through fertilizer, resulted in decreased desorption. The proportions of added Cu desorbed during 10 desorption periods were low, ranging from 2.5% in the 24‐h to 6% in the 2‐h desorption periods. The desorption of Cu decreased with increasing soil pH. The irreversible retention of Cu might be the result of complex formation with Cu at high pH.     

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.     

Estimation of Reference Values for Cadmium,Cobalt, Chromium,Copper, Nickel,Lead, and Zinc in Brazilian Soils

Abstract

The objectives of this study were 1) to recommend reference values (RVs) and tolerance limits (TLs) for representative Brazilian soils and 2) to propose a model to calculate natural contents of cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) in a soil from the silt, clay, manganese (Mn), iron (Fe), and cation exchange capacity (CEC) values. A set of 256 soil samples was classified by similarity in seven groups, and the concentrations corresponding to the upper quarter of data collected were then calculated. These concentrations are proposed as RVs for Brazilian soils. Additionally, TLs were obtained for each group from the antilog expression (m+2s), where m=mean value and s=standard deviation of data transformed in log₁₀. The classification functions of discriminant analysis proved to be suitable to allocate new samples in the established groups. Thus, it is possible to evaluate soils under anthropic activity and, by comparison with reference values, to be aware of pollution risks in a given area.     

老冲积黄壤微团聚体对As(Ⅴ)与P竞争吸附—解吸特性

土壤微团聚体是土壤的最基本结构单元,不同粒径微团聚体的理化性质的差异不同使得重金属离子在各粒径微团聚体中的吸附—解吸能力大小不同。以名山河流域老冲积黄壤为研究对象,将其划分为4个粒径(2~0.25mm,0.25~0.053mm,0.053~0.002mm,0.002mm)。采用批培养法研究原土及不同粒径微团聚体对As(Ⅴ)与P的竞争吸附—解吸特性。结果表明:原土及不同粒径微团聚体对As(Ⅴ)、P的吸附—解吸特性相似,等温吸附均符合Langmuir和Freundlich方程,但Langmuir方程拟合效果最佳;动力学吸附均符合伪一级方程和伪二级方程,但伪二级方程拟合效果更好。原土及各粒径微团聚体对As(Ⅴ)、P的吸附均以专性吸附为主,非专性吸附为辅。原土及不同粒径微团聚体对As(Ⅴ)、P的最大吸附量不仅与粒径大小有关,与土壤有机质、CEC、游离氧化铁含量呈正相关。由于0.002mm粒径的土壤比表面积大,有机质、CEC、游离氧化铁含量高,故其对As(Ⅴ)、P有最大吸附能力和最高初始吸附速率。As(Ⅴ)、P在各粒径微团聚体上解吸量与其吸附量呈指数关系。当As(Ⅴ)与P共存时,明显互相抑制对方的吸附,促进对方的解吸。As(Ⅴ)与P在0.002mm粒径土壤中存在的竞争吸附—解吸能力最小。     

石灰性褐土中磷锌镉相互作用对其有效性的影响

采用室内培养的方法,研究了石灰性褐土中磷、锌、镉相互作用对土壤中磷、锌、镉有效性的影响。结果表明：（1）磷锌共同培养时,施锌提高了土壤速效磷含量,且随培养时间的延长而降低。在相同锌浓度处理下,土壤中的有效锌含量随施磷量的增加而增加,不同锌浓度处理下,有效锌含量随土壤培养时间的延长而显著降低。（2）磷镉共同培养时,施镉对土壤速效磷含量影响不明显;施磷降低了有效镉含量,但效果不显著;且都随时间的延长而降低。（3）锌镉共同培养时,在培养的前30d,土壤中有效锌含量随施镉浓度增加而降低,但在30d后,有效锌含量有增加的趋势。土壤中有效镉含量在不同锌-镉处理下随培养时间变化有较大差异：在Cd3处理下,加入高浓度锌后显著降低土壤有效镉含量;Cd30处理下,在培养前30d,锌的施入对土壤中有效镉含量影响不明显,但30d以后,土壤有效镉含量随施入锌浓度的增加而显著降低。说明两者的竞争机制随时间的延长发生变化,且施锌能明显降低镉的毒性。     

不同来源生物炭对土壤磷吸附解吸的影响

主要研究了水稻秸秆、小麦秸秆、玉米秸秆、花生壳四种来源的生物炭对土壤磷吸附解吸的影响。研究结果表明:生物炭对土壤磷吸附的影响取决于土壤溶液中磷的浓度,与对照相比,在中低磷浓度(0~90 mg L-1)时,四种生物炭对土壤磷的吸附影响较小,而在较高磷浓度时,小麦秸秆生物炭和花生壳生物炭均抑制了土壤磷的吸附,而水稻秸秆生物炭和玉米秸秆生物炭均能促进土壤磷的吸附。吸附动力学试验表明,在反应开始的4小时内,土壤对磷的吸附较快,吸附量基本达到平衡吸附量的50%;到达吸附平衡时,添加生物炭能够降低土壤对磷的吸附量,四种生物炭对土壤磷的吸附量依次为:小麦秸秆玉米秸秆花生壳水稻秸秆。此外四种生物炭都能促进土壤中磷的解吸,其中玉米秸秆的促进效果最为显著,解吸量比对照高1.76倍。Langmuir方程和Freundlich方程都能很好地拟合生物炭存在下土壤磷的吸附等温线(P0.01),Freundlich拟合程度要比Langmuir方程的高。准一级动力学方程和准二级动力学方程都能很好地描述生物炭存在下土壤磷的吸附动力学(P0.01)。     

6种固化剂对土壤Pb Cd Cu Zn的固化效果

通过在重金属污染土壤中分别施加沸石、石灰石、硅藻土、羟基磷灰石、膨润土和海泡石6种固化剂,研究了这6种固化剂对土壤中Pb、Cd、Cu、Zn的固化效果,筛选出几种效果较好的固化剂。实验结果表明：沸石、石灰石和羟基磷灰石均能够有效地降低土壤中交换态Pb、Cd的含量,并且明显减少了土壤中Pb、Cd的毒性浸出量,其中沸石最多降低土壤中交换态Pb、Cd含量分别达到48.7%和56.2%,减少土壤中Pb、Cd的毒性浸出量达到37.1%和30.1%;沸石、石灰石均能够有效降低土壤中交换态Cu的含量,降低量分别高达68.1%和85.2%,膨润土能有效减少土壤中Cu的毒性浸出量,减少量最高达到66.51%;石灰石对土壤中Zn有着良好的固化效果。     

Distribution of the Metals Lead,Cadmium, Copper,and Zinc in the Top Soil of Cartagena,Spain

This article presents the results of the analysis of the metals lead, cadmium, copper, zinc and aluminum, conducted on a total of 112 soil samples arising from 57 sampling points, distributedthroughout the Cartagena area in southeastern Spain. Both, totalmetal content and soluble fraction (1 M nitric acid medium, exchangeable fraction) were analyzed. Soil samples were taken on the surface of the terrain and at a depth of 35 cm from eachsampling point. For the purposes of this study, sampling points were classified in three groups based on the results of previous research on air pollution in the region: clean areas,contaminated areas and vacant industrial areas. The statisticalanalyses of the results show no significant differences betweenthe surface samples and the 35 cm deep samples from all three areas. Lead, zinc and copper (soluble and total fractions) aresignificantly higher, and pH significantly lower, in the samples coming from the contaminated and vacant industrial areasthan in samples coming from the clean area. Total lead and cadmium are significantly higher in the vacant industrial areas(150 g kg^-1 Pb and 9.3 g kg^-1 Cd) than in the contaminated areas (5.2 g kg^-1 Pb and 2.1 g kg^-1 Cd).Iso-concentration maps have been prepared in order to correlatethe presence of metals with the industrial and mining activities in the region under study. These maps show a clear relationship between human activities and metal concentrationgradients, with peaks corresponding to both active and abandoned industrial and mining facilities.     

四环素在土壤中的吸附与解吸以及镉在其中的影响

采用批平衡实验方法,研究了四环素（TC）在褐土和红壤中的吸附和解吸,以及Cd2＋对四环素在两种土壤上吸附和解吸的影响。结果表明,四环素在褐土和红壤中的吸附可以用Freundlich等温吸附方程拟合,所得lgKf分别为3.039和3.169,这表明四环素在红壤中的吸附能力较强。此外,四环素在两种土壤上的解吸过程都存在滞后现象,所得lgKf,des分别为3.292和3.877,这将可能威胁到土壤环境和人体健康。常见重金属Cd2＋的存在会促进四环素在两种土壤上的吸附,在红壤中表现显著（P〈0.05）;同时红壤中四环素的lgKf,des有所增加,而在褐土中的变化不大。