日本遗弃化学武器销毁残渣中元素分析及砷形态分析

采用X射线荧光光谱法对日本遗弃在华化学武器销毁残渣元素分布进行了分析,同时用土壤连续提取法对残渣样品的砷形态进行了提取。结果表明,黄剂及红剂销毁残渣样品中主要元素均为铁、铜、砷、钛、铅等,其中砷元素占比大且危害最深。进一步对样品进行分析结果显示,残渣中砷形态主要为Fe-结合态、Ca-结合态、残渣态等。分析结果对销毁残渣的二次处理提供了必要的技术支撑,在敦促日方改进销毁技术方面具有重要的现实意义。

Determination of Competitive Adsorption and Desorption of Heavy Metals by Isotherm and Sequential Extraction Methods in Different Soil Orders in Erzurum Plain

The objective of this study was to DTPA （complexion agent） and a sequential extraction procedure, and adsorption-desorption isotherm （competitive） evaluate the mobility and distribution of Fe, Zn, Mn, Cu, Cd, Ni, and Pb using the in surface samples of five soil great groups differing in their physicochemical properties. For determining heavy metal adsorption and desorption capacities of soil samples, six different concentrations （0, 2.5, 5, 10, 15 and 20 mg Lt） were used in a laboratory experiment with tree replications. An analytical procedure involving sequential chemical extractions has been used for partitioning of heavy metals into five fractions. Sorption isotherms were characterized using linear, Frendlich and Langmuir equations. The results indicated that the selective sequences of the metal adsorption based on the distribution coefficient was Pb〉Cu〉Ni〉Cd〉Zn〉Mn〉Fe and Pb, Cu, and Ni are the most strongly sorbed metals by these soils, whereas Cd, Zn and Mn are the least sorbed ones. The total adsorbed amount of these metals on the studied soils was well described by Langmuir equation. Calciorthid had the highset Pb, Cu, Ni, Cd, Zn, Mn, and Fe adsorption, and the sequences followed order Fluvaquent〉Argiustoll〉Pellustert〉Haplustept of the studied soil.

Application of Kinetic Models in Describing Soil Potassium Release Characteristics and Their Correlations with Potassium Extracted by Chemical Methods

Potassium （K） release characteristics in soil play a significant role in supplying available K. Information on K-release characteristics in soils of central Iran is limited. The objectives of this study were to determine K release characteristics and correlations of K release rate constants with K extracted by different chemical methods in surface soils of ten calcareous soils of central Iran. The kinetics of K release in the soils was determined by successive extraction with 0.01 mol L-1 CaC12 in a period of 2-2017 h at 25±1℃. Soil K was extracted by distilled water, 0.5 mol L-1 MgNO3, 0.002 mol L-1 SrC12, 0.1 mol L-1 BaC12, 0.01 mol L-1 CaC12, 1 mol L-1 NaC1, 1 mol L-1 boiling HNO3, 1 mol L-1 NH4OAC, Mehlich 1, 0.002 mol L-1 SrC12 ＋ 0.05 mol L-1 citric acid, and ammonium bicarbonate-diethylenetriamine pentaacetic acid （AB-DTPA）. A plot of cumulative amounts of K released showed a discontinuity in slope at 168 h. Thus, two equations were applied to two segments of the total reaction time （2-168 and 168-2 017 h）. Cumulative amounts of K released ranged from 55 to 299 mg kg-1 in 2-168 h and from 44 to 119 mg kg-1 in 168-2 017 h. Release kinetics of K in the two time segments conformed fairly well to parabolic diffusion, simplified Elovich, and power function models. There was a wide variation in the K release rate constants. Increasingly higher average concentrations of soil K were extracted by distilled water, Mehlich 1, SrC12, CaC12, SrC12 ＋ citric acid, AB-DTPA, MgNO3, NaCI, NH4OAc, BaCI2, and HNO3. Potassium release rate constants were significantly correlated with K extracted. The results of this study showed that information obtained from mathematical modeling in two reaction time segments can help to estimate the K-supplying power of soils.