硝酸处理对褐煤中可提取性腐殖酸含量及其吸附特性的影响

采用硝酸氧化及一次平衡法,研究了硝酸处理对褐煤中的可提取性腐殖酸含量、CEC（阳离子交换量）、E₄/E₆及其对各种养分离子吸附规律变化的影响。结果表明:一定强度的HNO₃能使褐煤中可提取性腐殖酸含量增加45.8%以上,使其阳离子交换能力提高;随硝酸处理时间的不断延长,褐煤中可提取性腐殖酸含量和CEC均呈先增加后减小的趋势,但CEC达到最大值所需时间相对较长;硝酸处理后的褐煤腐殖酸光学性质也发生了很大的变化。经硝酸处理褐煤腐殖酸样品对铵、钾吸附能力分别可提高58.73%和41.53%,其等温吸附式分别符合Freundlich和Langmuir方程。而对磷的吸附能力降低,一定条件下其吸附量仅为处理前的5.33%,其等温吸附式用Langmuir方程描述最佳。上述结果表明,经硝酸处理后,褐煤腐殖酸更适宜作为缓效肥料基质使用。     

褐煤腐植酸对钾的吸附特性研究

为给褐煤的有效利用和腐植酸缓效肥的研制提供理论依据,本试验采用吸附等温线的试验方法,探讨了K⁺平衡溶液浓度、平衡时间、pH值及固液比对褐煤腐植酸钾吸附的影响。结果表明：介质pH值升高有利于腐植酸样品对钾的吸附,且能加快吸附反应的速度;当pH<4.4时,K_d1>K_d2,此时以物理吸附为主。当7.12K_d1<K_d2,化学交换占主导地位。其等温吸附曲线符合Langmuir吸附形式,动力学吸附用Elovich方程描速最佳。经硝酸处理后的褐煤腐植酸样品对钾的吸附能力有了一定程度的提高。适宜的固液比能提高2种样品对钾的单位吸附量,分别在固液比为0.06和0.04时达最大,其单位吸附量分别为0.079 g/g和0.094 g/g。     

Adsorption and desorption of cadmium by synthetic and natural organo-clay complexes

Tracer levels of ¹⁰⁹Cd were used to study the adsorption and desorption of Cd by synthetic and natural organo—clay complexes. Synthetic organo—clay complexes were made by adsorbing humic acid extracted from soil to various forms of < 2 μm diameter montmorillonite (Na, Ca, Al, and Fe saturated and Ca-montmorillonite coated with Al or Fe hydroxide). Natural organo—clay complexes were fractionated from the clay fraction of a Captina silt loam by density-gradient centrifugation in a large-scale zonal rotor.To evaluate the influence of humic acid on adsorption of Cd, Cd was adsorbed to the various forms of montmorillonite before and after humic acid adsorption. No appreciable difference in Cd adsorption was noted except in the case where montmorillonite was coated with Al or Fe hydroxides. Cadmium was found to be strongly bonded to clays coated with Al or Fe hydroxides; however, Cd adsorption to these clays after humic acid adsorption was considerably less. Data indicated Cd and humic acid adsorption sites on Al or Fe coated clays were either identical or prior adsorption of humic acid simply covered available Cd sites.Cadmium adsorption to clay density fractions showed that greatest adsorption was to fractions containing high quantities of organic matter or sesquioxides. Desorption of Cd with 0.01 M Ca (NO₃)₂ showed that Cd was adsorbed more tenaciously to the sesquioxides than organo—clay fractions.     

Mechanisms of humic material adsorption on kaolin clay and activated carbon

Gel permeation chromatography was used for monitoring the changes in humic molecular weight distribution after contact with kaolin clay and activated carbon. The high molecular weight fractions excluded from Sephadex G-50 were less removed by carbon indicating the exclusion effect of pores, but were preferentially adsorbed by clay. The aliphatic portion of humic acids is effectively removed by carbon as suggested by the decrease in E₄: E₆ ratio. The Freundlich and the Langmuir isotherms showed curvilinearity which was resolved into two straight lines. The sorption effect in humic molecular weight distribution suggests the necessity of batch adsorption test with respect to the treated humic material.     

FRACTIONATION OF HUMIC ACID BY GEL PERMEATION CHROMATOGRAPHY

Humic acids from the L layer and B_2hhorizons of a humus-iron podzol were fractionated by gel permeation chromatography. Elution of the gel column with distilled water adjusted to pH 7.5 gave a fractionation based on both gel permeation and adsorption chromatography. This procedure gave filtered products containing most of the organic nitrogen, and an absorbed fraction. The latter contained most of the components which gave benzene carboxylic acids on oxidation of the humic acid with dilute nitric acid.     

Sephadex-Gelfiltration von Huminsäuren und deren Gehalt an Aminosäuren

Gel filtration on Sephadex of humic acids and their content of amino acids

• 1 Brown humic substances from the A_h of an iron-humus podzol were separated on Sephadex G 25 into three fractions. The first fraction (Ve/Vo = 1.0–1.5) has the lowest value of Q 4/6 (5.0–8.0), the second the highest Q 4/6 (10.0–12.0) and the third a middle one (8.0–10.5). The adsorption effect may take place during separation.
• 2 The asymmetric form of the integral elution curves of the first fraction indicated that the humic substances are a set of particles with different size. The separation is influenced by diffusion into the pores of gel matrix.
• 3 In the first fraction were determined 16, in the second 13 and in the third 10 amino acids.
• 4 The titration curves of the first fraction (after separation on G 25) indicated that the rate of pH change with alkali added becomes its maximum at pH 6.5–7.5 at different ionic strengths.
• 5 Dialysed humic acids (H⁺ form) were fractionated on G 75. The alkali consumption up to pH 7.5 in the eluate shows that small amounts of mineral acids increase the conductivity of the solution. Their V_e is lower than that of the second fraction of humic acids. Therefore it is impossible to determine the alkali consumption by the second fraction and by the humic acids as a whole without their total desalting.

     

Chromatographic Separation of Green Humic Acid from Podzol Humus

One of the authors, Kumada ¹⁾ has found that absorption spectra of podzol humic acids, remarkably different from the other soil humic acids, have fairly distinct absorption bands near 620, 570 and 450 mµ, and he tentatively named them. P type humic acid. P type humic acid seems specific not only in its visible absorption spectra, but also in infra. red absorption spectra, in susceptible to electrolytes, etc. The authors are now engaged in the study of the nature and properties of P type humic acid, and recently they have found that it is composed of at least two main fractions, the one is reddish brown, and the other green, in alkaline solution. The experimental results are briefly presented.     

PHENOLIC HYDROLYSIS PRODUCTS FROM GEL CHROMATOGRAPHIC FRACTIONS OF SOIL HUMIC ACIDS

Humic acids extracted from the Bh horizon of a kauri (Agathis australis) podzol and the A horizon of a yellow-brown earth under hard beech (Nothofagus truncata), both New Zealand soils, were fractionated by a ‘salt boundary’ technique using a dextran gel, and the fractions hydrolysed with 6 M hydrochloric acid. Lignin-derived phenolic acids were analysed by gas chromatography of the ether-soluble hydrolysis products of the humic acids. The lignin derivatives from the kauri podzol humic acid are probably modern products derived from the present-day scrub vegetation, whereas those from the yellow-brown earth humic acid are derived from the deciduous vegetation.     

蒙脱石对不同施肥处理土壤胡敏酸及其级分的吸附特征Ⅰ.蒙脱石对胡敏酸的吸附特征

以17年不同施肥处理土壤胡敏酸为材料,研究了不同性质胡敏酸与钙饱和蒙脱石的 吸附特征。结果表明,钙饱和蒙脱石对土不同施肥处理胡敏酸的吸附曲线可用单表面Langmuir方程、双表面Langmuir方程以及Freundlich方程来描述。由单表面Langmuir方程计算的有机肥处理（厩肥、秸秆）胡敏酸的吸附量和吸附强度大于无肥、化肥处理。温度升高各处理胡敏酸吸附量增加,但吸附强度下降。双表面Langmuir揭示,蒙脱石对胡敏酸的吸附呈现高低两种能位的吸附。高能点位的吸附以化学吸附为主,是吸热反应,低能点位的吸附以物理吸附为主,是放热反应。有机肥处理和无肥、化肥处理相比,高能点位吸附相对减弱,低能点位吸附相对增强。     

Cyanidadsorption an Sesquioxiden,Tonmineralen und Huminstoffen

Cyanide adsorption on sesquioxides, clay-minerals and humic substances The adsorption of cyanide (KCN) on sesquioxides, clay minerals, and humic substances at different pH-values was studied. Moreover we looked for the CN-adsorption on L-layers of the humus forms mull, moder and mor. Cyanide was only adsorbed by humic acid. The amount of CN adsorbed increased with increasing pH of the reaction solution. IR-spectroscopic investigations of CN treated humic acids revealed that the cyanide was adsorbed at low pH (<7) as HCN-molecules by formation of hydrogen bonds with COOH-, COH-, OH- and NH₂-groups of the humic acid. At pH > 7 the cyanide was mainly adsorbed as CN^? by charge transfer with acceptor-molecules such as chinones. The cyanide adsorption of L-layers of humus forms decreased in the order mor > mull > moder. It is surmised that the HCN-molecules were not only adsorbed by humic acids in these layers but also by oxidation products of lignin, pectin, protein, cellulose, and carbon-hydrates of fulvic acids. Solutions of K₂HPO₄ did not desorb cyanides from humic acids to any great extent.     

柠檬酸存在下施硅对土壤磷吸附和解吸特性影响

以棕壤为研究对象,采用室内培养的方法,通过加硅酸钙处理、硅酸钙+1 mmol/L柠檬酸处理和硅酸钙+2 mmol/L柠檬酸处理,研究了柠檬酸存在下施硅对棕壤中磷素吸附和解吸特性的影响,并用Langmuir方程、Freundlieh方程与Temkin方程对其进行拟合分析,其中磷吸附解吸试验采用恒温批处理平衡法.结果表明,Langmuir与Temkin模型对处理后棕壤磷的吸附拟合效果最好.硅酸钙+1 mmol/L柠檬酸处理的棕壤对磷的吸附量最大,为500mg/kg;硅酸钙+2 mmol/L柠檬酸处理的棕壤对磷的解吸量及解吸率最大,最大解吸率可达45.2％.因此,硅酸钙+1 mmol/L柠檬酸处理的棕壤对磷肥的储存能力最强,硅酸钙+2 mmol/L柠檬酸处理的棕壤对磷活化能力最强,即供磷能力最强.     

Association of cadmium,zinc, copper,and nickel with components in naturally heavy metal‐rich soils studied by parallel and sequential extractions

Abstract

In this study, a new parallel and sequential extraction procedure was proposed to investigate the solubility of metals [cadmium (Cd), zinc (Zn), copper (Cu), and nickel (Ni)] and their association with soil components in naturally metal‐rich soils of Norway. Two different soils, alum shale (clay loam) and moraine (loam), developed on alum shale minerals were used. Each soil had two pH levels. For parallel and successive extractions, H₂O, 0.1M NH₄OAc (soil pH), 0.3M NH₄OAc (soil pH), 1M NH₄OAc (soil pH), and 1M NH₄OAc (pH 5.0) were used. A significant amount of Cd was extracted by NH₄O Ac related to concentration of NH₄OAc in the extracting solution. The amounts of Zn, Cu, and Ni extracted by these reagents were almost negligible except with 1M NH₄OAc (pH 5.0). Thus these metals were strongly bound to soil components. A seven step sequential extraction procedure was applied to evaluate the association of metals with soil constituents. The extractions were performed sequentially by extracting the soil with reagents having an increasing dissolution strength: 1M NH₄OAc (soil pH), 1M NH₄OAc (pH 5.0), 1M NH₂OH.HCl (in 25% HOAc), 1M NH₂OH.HCl (in 0.1M HNO₃), 30% H₂O₂ (in 0.1M HNO₃), 30% H₂O₂ (1M HNO₃), and aqua regia. In both soils at both pH levels investigated, appreciable percentages of total Cd (20–50%) were found associated with the NH₄OAc extractable fraction (mobile fraction). For Zn, Cu, and Ni, the percentage of total metal extracted with NH₄OAc was low (<4%), but it increased significantly by introducing a reducing agent (NH₂OH.HCl). The NH₂OH.HCl‐extractable fraction was the greatest fraction (>60%) for all four metals examined. These results suggest that among the metals studied, only Cd was easily desorbed from soil and should be considered mobile and potentially bioavailable. Other metals (Zn, Cu, and Ni) were strongly associated with the soil components and should be considered less available to plants. Using the sequential fractionation technique as a measure of availability, mobility and potential bioavailability of these four metals in the alum shale soils were: Cd>Zn>Ni>Cu.     

Efficiency of GAC for Treatment of Leachate from Soil Washing Process

Granular activated carbon (GAC), granular activated alumina (GAA) and a ferric chloride solution (FCS) were tested for the treatment of leachate contaminated by heavy metals. The leachate was collected following the remedation of soils using weak organic acids and/or their salts, EDTA and DTPA. Only GAC was found to effectively remove heavy metals (Cd, Cu, Cr, Hg, Mn, Pb and Zn as chelates) from the leachate. At optimum pH ranging from 5.4 to 6.9, 97% of Hg was removed while at optimum pH ranging from 6.9 to 7.7, 78 to 96% of Cd, Cu, Mn, Pb and Zn were removed. Some 77% of the Cr was removed at optimum pH of 5.4. Adsorption rate constant and Langmuir adsorption capacity of GAC were found to be 0.01 min^?1 and 19 mg metal chelate g^?1 of GAC, respectively. Freundlich constants, k and n were found to be 21 mg g^?1 and 2.778, respectively. The brown color of the leachate turned colorless after GAC treatment.

     

我国几种主要土壤胶体的NH4+吸附特征

本文讨论我国几种主要土壤胶体的NH₄⁺吸附特征。土壤胶体对NH₄⁺的吸附符合两种表面Langmuir方程。土壤胶体对NH₄⁺的结合能力强弱顺序是:黄棕壤>黑土、(土娄)土>红壤>砖红壤,而NH₄⁺的解吸率大小顺序与此相反。Langmuir吸附方程参数K₁与土壤胶体的粘粒矿物组成有关,并与土壤胶体对NH₄⁺的相对偏好性(A值)呈正相关。Langmuir参数(M₁+M₂)与土壤胶体的CEC呈正相关,去有机质(OM.)前后△K₁与△OM.呈反相关。去有机质可增加土壤胶体对NH₄⁺的偏好性。土壤胶体的NH₄⁺吸附和解吸特征决定于其组成和表面性质,并受有机无机复合作用的影响。永久电荷吸附位对NH₄⁺的偏好性较强,而可变电荷吸附位则较弱。     

Analysis of the variable charge of two organic soils by means of the NICA-Donnan model

We have tested to see if the generic set of NICA‐Donnan model parameters, used to describe isolated humic substances, can also describe soil humic substances in situ. A potentiometric back‐titration technique was used to determine the variable surface charge of two organic peat soils at three different ionic strengths. The non‐ideal, competitive‐adsorption NICA‐Donnan model was used to simulate the surface charge, by assuming a bimodal distribution of H⁺ affinity on the soil solid phase. The model provided an excellent fit to the experimental data. The Donnan volume, V_D, varied slightly with ionic strength, although the variation was less than for humic substances in solution. The values obtained for the parameters that define the affinity distributions, the intrinsic proton binding constant (log K_i^int) and the heterogeneity of the site (m_i), were similar to those observed for isolated soil humic acids. The abundance of carboxylic groups in the whole soil represented 30% of the typical value for isolated soil humic acids. The composition of the organic matter of the whole soils, obtained by ¹³C CPMAS NMR, was comparable to the characteristic composition of soil humic acids.     

石灰石和海泡石组配对水稻糙米重金属积累的影响

为了研究组配改良剂(石灰石+海泡石,LS)对于重金属Pb、Cd、Cu和Zn复合污染稻田的修复效果,在湘南某矿区附近稻田中进行了组配改良剂的田间试验。结果表明:施用0~1.8 kg m-2的组配改良剂LS使土壤pH和CEC显著增加,使土壤中Pb、Cd、Cu和Zn交换态含量显著降低。土壤Pb、Cd、Cu和Zn交换态含量的降低是pH升高,土壤胶体的CEC增加及土壤吸附能力增强的共同作用。施用组配改良剂LS显著降低了3个水稻品种(黄华占、丰优9号、Ⅱ优93)糙米中Pb、Cd和Cu的累积量,最大降幅分别为55.8%、66.9%、37.4%,而对糙米中Zn的含量没有明显影响。当LS施用量为1.8 kg m-2时,能使丰优9号糙米中Cd含量(0.195 mg kg-1)达到国家食品中污染物限量标准(0.20 mg kg-1)以下。土壤中交换态Pb、Cd和Cu含量的降低是糙米中重金属累积量减少的原因。土壤交换态Pb、Cd和Cu含量的对数值(lnC交换态)与其糙米中含量(lnC糙米)的对数值之间存在显著的线性相关关系。     

镉在胡敏酸上的吸附动力学和热力学研究

采用镉离子选择电极研究了镉在胡敏酸上的吸附特征。实验结果表明 ,胡敏酸对镉的等温吸附规律与介质pH有关。当pH为 3 0 0和 3 50时符合Freundlich方程 ,当pH在 4 0 0～ 6 50之间更好地符合Langmuir方程 ;在pH为 3 0 0～ 6 50之间 ,吸附量与pH成显著正相关。温度升高吸附量降低 ,吸附热与反应介质的pH有关 ,pH升高 ,吸附反应放热增加 ;胡敏酸对镉的吸附作用力随介质pH改变发生较大变化 ,当pH为6 50时主要为配位基交换作用。胡敏酸对镉的吸附含有部分不释放氢的静电吸附 ,其吸附反应动力学用Elovich方程拟合效果较好     

Effects of humic and fulvic acids on release of fixed potassium

Release of potassium fixed by expanding silicate clays is considered of practical importance in soil fertility. Humic and fulvic acids are expected to play a definite role in liberating this fixed K, because of their chelating power, but not much is known in this respect. The following investigation was conducted to study release of fixed K by montmorillonite and illite, using humic and fulvic acids isolated from the surface horizon of a Cecil soil (Typic Hapludult, Red Yellow Podzolic soil) as extractants. For comparison, extraction was also done with 1 N neutral NH₄ -acetate, a mixture of 0.05 N HCl and 0.025 N H₂SO₄ or H₂ O. Supporting analyses of clays were carried out with X-ray diffraction to establish changes, if any, in crystal structure due to fixation, release of K, or adsorption of humic compounds. The results indicated that humic and fulvic acids released some of the K fixed by montmorillonite or illite. In terms of percentage of the total K fixed, 9 to 28% were released by the various extractants. The percentages K released by humic and fulvic acids were similar from both montmorillonite and illite, but based on absolute values, humic and fulvic acids extracted less K (mg/100 g) from illite than montmorillonite. Although statistically significant at the 5% level of probability, the capacity of humic compounds to liberate fixed K was not different markedly from those of NH₄ -acetate and the double acid mixture. Differences in pH of humic solutions had no influence on extraction of fixed K. X-ray diffraction analysis yielded curves showing an increase in spacing from 10.4 Å for K-montmorillonite to 13.2 Å as a result of extraction with the double acid mixture.     

不同处理褐煤腐殖酸对磷吸附特性的研究

采用吸附等温线的试验方法,研究了平衡溶液中磷浓度、反应时间及介质pH对不同处理的2种褐煤腐殖酸吸附磷的影响及其规律性。结果表明:在试验pH范围内,pH的升高减缓了吸附反应进行的速度,对于未经硝酸处理的样品S1,在pH为4.7时,吸附量和分配系数有一最大值,而样品S2,随着pH的升高,吸附量和分配系数一直减小;经硝酸处理后,样品对磷的吸附能力降低,一定条件下其单位吸附量仅为处理前的5.33%。适宜的固液比例可提高2个不同处理供试样品对磷的单位吸附量,其等温吸附规律可用Langmuir方程来加以描述;其吸附动力学用Elovich方程描述最佳。     

Wechselwirkungen zwischen Boden-Huminstoffen und Metall-Ionen I. Isolierung und Charakterisierung der Boden-Huminstoffe

Interactions between soil humic substances and metal ions I. Isolation and characterization of the soil humic substances From two horizons of a podzol humic acids and fulvic acids were isolated by two different methods. The obtained samples were characterized by elemental analysis, the determination of the ash and moisture content, functional group analysis as well as FTIR-, ¹H-NMR-, and ¹³C-NMR-spectroscopic examinations. In spite of the different isolation methods humic and fulvic acids show great similarities. A higher oxidized state and a lower content of aromatic structural features are clearly observed in the fulvic acids in contrast to humic acids. Besides aromatic structural elements, distinct aliphatic sections were detected in the investigated samples, which showed a lower concentration in the less transformed fractions of the Ahe-horizon.