Reactions Between Fulvic Acid,A Soil Humic Compound,and Montmorillonite

The magnitudes of d001 spacings of fulvic acid-Na-montmorillonite complexes were not affected by temperatures between 25 and 60°C. Slightly more than one half of the total amount of fulvic acid adsorbed by Na-montmorillonite was in the interlamellar spaces, with the remainder on external surfaces. The d001 spacings and amounts of fulvic acid adsorbed in the interlamellar spaces of Pb⁺⁺?, Mg⁺⁺?, Co⁺⁺? and Ni⁺⁺? saturated montmorillonite decreased with increase in pH. The capacities of cation saturated clays to adsorb fulvic acid in interlamellar spaces decreased in the following order: Pb⁺⁺ > Mg⁺⁺ > Co⁺⁺ > Ni⁺⁺. The exotherm near 670°C in the DTA curve of the fulvic acid-Na-montmorillonite complex signalized the formation of an interlayer complex.     

统一腐殖酸与黄腐酸概念的再探讨

根据国家标准化工作导则中概念术语的无歧义及统一性和内容唯一性原则要求,提出了将腐殖酸和黄腐酸划分为2种有机酸的理论依据和农业生产应用的实践依据;指出了将黄腐酸包括在腐殖酸中的概念导致产品名称不规范、检测方法不统一,不利于资源合理开发应用。应以科学发展观为指导,以国家标准化工作导则为依据,实现腐殖酸与黄腐酸概念的统一,促进腐殖酸肥料标准化工作的开展和腐殖酸产业的健康发展。     

Flocculation of Clay Suspensions in the Presence of Humic and Fulvic Acids

Surface waters which contain suspended clay and organic matter, differ strongly in response to flocculation from suspensions of “pure” reference clays in controlled systems. The mechanism of interference was investigated by means of a synthetic system, consisting of suspensions of reference clay with humic and fulvic acid added. These organic soil acids increase the colloidal stability of the suspension. Due to chemical reaction taking place between the organic acids and the cationic flocculant, higher flocculant doses were required in systems where interaction of clay and organic matter occurred.     

Structural Determination and Occurrence in Ahiflower Oil of Stearidonic Acid Trans Fatty Acids

Several marine oils and seed oils on the market contain relevant quantities of stearidonic acid (18:4n‐3, SDA). The formation of 18:4n‐3 trans fatty acids (tFA) during the refining of these oils necessitates the development of a method for their quantification. In this study, 18:4n‐3 was isolated from Ahiflower and isomerized to obtain its 16 geometric isomers. The geometric isomers of 18:4n‐3 were isolated by silver ion HPLC (Ag⁺‐HPLC) and characterized by partial reduction with hydrazine followed by gas chromatography analysis. The elution order of all 16 isomers was established using a 100 m × 0.25 mm 100% poly(biscyanopropyl siloxane) capillary column and at the elution temperature of 180 °C. The 4 mono‐trans‐18:4n‐3 isomers produced during the refining of oils rich in 18:4n‐3 were chromatographically resolved from each other, but c6,t9,c12,c15‐18:4 coeluted with the tetra‐cis isomer. These 2 fatty acids (FA) were resolved by reducing the separation temperature to 150 °C, but this change caused tetra‐cis‐18:4n‐3 to coelute with t6,c9,c12,c15–18:4. Combining the results from 2 isothermal separations (180 and 150 °C) was necessary to quantify the 4 mono‐trans 18:4n‐3 FA in Ahiflower oil.     

腐植酸微生物菌剂在滨海盐渍化土壤上的应用效果

通过筛选能够在高渗透压条件下生长繁殖的巨大芽孢杆菌和枯草芽孢杆菌,将它们作为功能微生物接种到腐植酸中,应用于滨海盐碱地改良,同化学改良法比较,盐碱地土壤理化性状显著改善,土壤微生物数量明显增多,生物量碳、土壤的呼吸作用和酶活性也有一定增加;枣长势良好,植株健壮,叶色浓绿,未出现盐碱化症状。3年生枣和7年生枣,平均株产达1.8 kg和28.6 kg,增产幅度明显。试验表明利用腐植酸微生物菌剂进行滨海盐碱地改良是一种经济有效的办法。     

城市污泥中胡敏酸和富里酸测定方法研究

城市污水处理过程排放大量的剩余污泥,剩余污泥成分复杂,如何将其有效利用一直是影响城市发展的重要问题。腐殖质是污泥颗粒结构的重要组成部分,在污泥堆肥等污泥资源化利用过程中发挥着重要作用。腐殖质中可提取检测的成分为胡敏酸和富里酸,我国目前还没有关于城市污泥中胡敏酸和富里酸含量测定的标准方法。本文提供一种用于测定城市污泥中胡敏酸和富里酸含量的方法,该方法安全简单,条件温和,数据可靠。     

Influence of Ozonation of Humic and Fulvic Acids on Diuron Adsorption on Activated Carbon

The effect of ozonation on the competitor effect of humic and fulvic acids against diuron in adsorption on activated carbon in drinking water process has been studied. Ozonation treatment allows the removal of herbicides from drinking waters by modification of humic and fulvic acids structures. These latest are responsible for their adsorption variation on activated carbon. An ozone dose similar to that used in industrial pre-ozonation (1.3?mg ozone/l) does not cause significant transformations of humic and fulvic acids which could decrease their competitor effect and increase significantly the adsorption capacity of the activated carbon for a well-adsorbed pesticide like diuron.     

尿素中添加腐植酸、黄腐酸、重过磷酸钙和氯化钾能抑制氨的挥发

该试验比较了不同混合物,尿素-重过磷酸钙-氯化钾、尿素-重过磷酸钙-氯化钾-腐植酸、尿素-重过磷酸钙-氯化钾-黄腐酸、尿素-重过磷酸钙-氯化钾-酸性混合物(黄腐酸+腐植酸)在对氨损失,土壤pH值,铵态氮和可利用硝态氮积累等方面的影响,以尿素单独施用作为对照。方法:在实验室条件下,利用一个封闭式动态空气流量系统来评估是否混有重过磷酸钙、氯化钾、腐植酸、黄腐酸的情况下尿素的有效性。氨损失、土壤pH值、土壤中铵态氮以及可利用硝态氮是由标准程序测定的。结果:与对照组(单独施用尿素)相比,处理尿素-重过磷酸钙-氯化钾,尿素-重过磷酸钙-氯化钾-腐植酸,尿素-重过磷酸钙-氯化钾-黄腐酸,尿素-重过磷酸钙-氯化钾-酸性混合物(黄腐酸+腐植酸)中氨损失明显地减少,减少率由12.92%、20.12%、25.94%达到100%,土壤中的铵态氮也有类似的变化。从所有的处理来看,只有尿素-重过磷酸钙-氯化钾-黄腐酸,尿素-重过磷酸钙-氯化钾-酸性混合物(腐植酸+黄腐酸)明显地积累了土壤中可利用硝态氮,这一结果与本研究中pH值的结果一致。结论:尿素、重过磷酸钙、氯化钾中混合腐植酸或者酸性的腐植酸和黄腐酸混合物能够显著减少氨损失。这项研究结果有助于提高尿素中N,P,K使用的有效性,同时减少环境污染。     

土壤腐殖酸的提取及表征

从土壤中提取腐殖酸样品,并用物理和化学等方法对其进行了表征。同时,对提取过程中的一些问题如氮气保护、纯化也做了探索。结果表明有无氮气保护对最终产物无明显影响;ＨＦ－ＨＣｌ混酸能降低样品灰份;本腐殖酸含有的芳香结构较多,属大分子量低腐殖化的腐殖质级分     

褐煤粒度对碱法制备胡敏酸和富里酸的影响

以不同粒度的白音华褐煤碱性煤浆为原料,5%(质量分数,下同)NaOH溶液和1 mol/L H2SO4溶液为pH值调节剂,制备胡敏酸和富里酸。通过容量法和紫外可见分光光度法分析胡敏酸和富里酸的含量、提取率、E4/E6值和DPPH(1,1-二苯基-2-三硝基苯肼)抗氧化活性,探讨褐煤粒度对胡敏酸和富里酸的影响规律。结果表明:当褐煤粒度减小到13.28μm时,胡敏酸和富里酸的总提取率为86.34%,胡敏酸与富里酸的分子量和芳香缩合度最为相似。该粒度条件下,富里酸的提取率可达62.28%,游离腐植酸质量分数为47.4%,DPPH自由基清除率为41.3%,富里酸的抗氧化活性显著。     

腐植酸在土壤修复中的作用

目前,腐植酸对污染土壤的修复作用已经引起了人们的广泛关注。本文在介绍了腐植酸来源及其结构特点的基础上,论述了腐植酸在土壤改良、重金属污染及有毒有机污染物污染土壤修复等方面的作用。其中,腐植酸对土壤的改良作用主要包括改良土壤结构、改良盐碱地以及提高土壤肥力等;腐植酸对重金属和有毒有机污染物污染土壤的修复作用主要包括腐植酸对重金属和有机物的吸附沉淀作用、氧化还原作用以及腐植酸能够促进土壤微生物对有机污染物的降解等。最后,讨论了腐植酸在土壤修复中需要进一步加强研究的方面,为腐植酸在土壤修复中的应用提供重要参考。     

Heats of Combustion of Fatty Acids and Fatty Acid Esters

The military uses JP-8, a kerosene type hydrocarbon, to fuel most of its vehicles and is seeking a renewable alternative fuel that meets strict JP-8 specifications. Biodiesel is typically a mixture of different alkyl esters produced from the transesterification of triglycerides readily available in plant oils and used cooking oil. To date, no traditional biodiesel meets the requirements for heat of combustion, freezing point, viscosity and oxidative stability to be a stand-alone replacement for JP-8. This work is a fundamental survey of the heat of combustion of single fatty acid esters and a predictive model for estimating the heat of combustion given a known molecular structure. The gross heat of combustion of various C6–C18 fatty acids and the methyl, propyl and isopropyl esters of these fatty acids was measured. This study sought to relate the effect of chain length, degree of unsaturation and branching to the critical fuel property of the gross heat of combustion (H _c). It was found that H _c (kJ/g) increased with chain length. A nearly linear relationship was found between wt% carbon and hydrogen, and H _c. Group contribution models previously published for hydrocarbons and polymers were modified to more accurately predict the heat of combustion of the fatty acids and esters. Modification of the molar heat values of carboxylic acid, methyl, and methylene groups improved correlation of the model with the experimental results.     

Influence of Fatty Acid Moieties of Sorbitan Esters on Polymorphic Occurrence of the Palm Mid‐Fraction

The influence of chain length and subcell packing of fatty‐acid moieties in sorbitan esters (SE) on the polymorphism of the palm midfraction (PMF) was examined. SE with different fatty‐acid moieties (sorbitan tripalmitate; sorbitan tristearate [STS]; and sorbitan tribehenate [STB]) were blended with PMF and PMF polymorph formation was examined using synchrotron radiation X‐ray diffraction and differential interference contrast microscopy. PMF without additives was crystallized in the β′ form under the isothermal condition at 22 °C; however, the addition of STS, which forms an α subcell structure, promoted the crystallization of PMF in the α form. In contrast, crystallization of PMF in the β′ form was accelerated by the addition of STB. These results showed that when the chain length of the fatty‐acid moiety between fat and emulsifiers was similar, the crystallization of PMF in the α form was promoted by the α subcell packing in STS crystals that were nucleated prior to PMF crystallization. In contrast, STB crystals, which have an α subcell packing, accelerated the crystallization of PMF in the β′ form because of the large difference between the chain lengths of STB and PMF. Therefore, structural similarities in both the chain length and the subcell packing are essential features that regulate the template effect, and the promotion of the crystallization of PMF in the β′ form by the addition of STB was caused by heterogeneous nucleation.     

Curupira tefeensis II: Occurrence of Acetylenic Fatty Acids

Four acetylenic fatty acids [11-octadecen-9-ynoic acid (E) (ximenynic acid), 11-octadecen-9-ynoic acid (Z), 9,11-octadecadiynoic acid and 13-octadecen-9,11-diynoic acid (E) (exocarpic acid)] were found in the seed oil of Curupira tefeensis (Olacaceae) as minor compounds. The mass spectra of the methyl esters (EI and CI mode), picolinyl esters and 4,4-dimethyloxazoline derivatives of these acids are discussed in detail. Furthermore the NMR data of 9,11-octadecadiynoic acid and 13-octadecen-9,11-diynoic acid are presented.     

生化黄腐酸与其他来源黄腐酸组成性质的初步比较

通过引用有关文献数据,对生化黄腐酸（BFA）与其他来源黄腐酸的化学组成、结构和性质进行了对比研究,推断BFA是一种富含糖苷配键、羟基、甲氧基和氨基的低芳香度水溶性脂肪酸,似属新生态腐植酸类范畴。建议对BFA进行系统的分析检测,以期推动BFA的基础研究、标准制定和推广应用。     

活性腐植酸在保护地连作土壤上的应用研究

采用田间试验的方法,对于连作5年的温室黄瓜和连作4年的温室番茄,进行活性腐植酸不同组合的施肥试验研究。结果表明:活性腐植酸能够降低土壤容重,提高田间持水量;增加土壤有机质和有效养分含量,提高保护地土壤pH值,减缓土壤酸化,降低土壤含盐量;还能够提高土壤微生物数量,提高土壤酶活性、土壤温度和土壤呼吸速率。     

腐植酸在土壤改良中的研究与应用

腐植酸是一种天然的有机高分子混合物,在农业生产中具有改良土壤、提高化肥利用率、刺激作物生长、增强作物抗逆能力和改善农产品品质等五大作用。此外,腐植酸对降低土壤重金属生物有效性也有明显效应。藉此,本文结合近年来腐植酸的实际应用,总结分析了腐植酸在土壤改良方面的研发与应用进展,包括土壤保水和作物抗旱、重金属污染治理和盐碱化改良等。此外,针对腐植酸产业发展中存在的问题,提出了相应的建议。     

Diffusion Coefficients and Molecular Weight Distributions of Humic and Fulvic Acids Determined by Flow Field-Flow Fractionation

Abstract

The ability to characterize molecules whose physical and chemical properties are intimately linked to their diffusion coefficients and molecular weight is important to further understanding of chemical transport in the environment. Flow field-flow fractionation (flow FFF) was used to obtain separations of water-soluble macromolecules of varying molecular weight, including polystyrene sulfonates and humic substances. The separation occurs due to differing diffusion rates for chemical species of differing molecular weight in aqueous solution. Flow FFF uses fluid flow as the mechanism of separation. A model that yields liquid phase diffusion coefficients as a function of molecular weight was utilized to determine molecular weights from degree of separation. Separations of polystyrene sulfonates, a humic acid, and two fulvic acids of known molecular weight were accomplished using flow FFF. The separations obtained were used to develop a relationship between flow FFF separation and species molecular weight. Separations were obtained for humic and fulvic acids of unknown molecular weight.     

腐植酸、腐植酸肥料在构筑“土肥和谐”关系中的重要作用和地位

土生万物,予肥优生。土离不开肥,肥离不开土,土肥一家亲,构筑"土肥和谐"新关系是历史的选择。长期以来,在农业上"就土说土,就肥说肥"的单元模式,使得土肥之间互相脱节。腐植酸是土壤的,腐植酸是肥料的,腐植酸是生态环境的。新时期,让腐植酸充分发挥联土联肥的亲和作用,既可为构筑"土肥和谐"新关系发挥重要作用,又可为农业生产可持续发展贡献力量。     

pH值、腐植酸类型以及铝对亚砷酸盐和砷酸盐与溶解腐植酸络合的影响

溶解的天然有机质(DOM)会影响水环境中砷(As)的存在形式。在环境相关的砷/溶解有机质(DOC)比率和p H条件下,使用平衡透析法研究了As(Ⅲ)和As(Ⅴ)络合到两种商业腐植酸的条件分布系数(Dom)。在所有p H值范围内,As(Ⅴ)比As(Ⅲ)能更好地络合到腐植酸上,p H值为7左右时腐植酸的络合能力最强,因为在低p H值时,H+会与As竞争络合位点;而在高p H值时,OH-会与腐植酸竞争As。对于这两种氧化态,Dom的值会随着As/DOC比率减少而增加。对As(Ⅲ)和As(Ⅴ)来说,Dom值可以和As/DOC比值拟合为一个函数。在相同的条件下,陆生的腐植酸与As的络合能力比水生的腐植酸高1.5~3倍。在As/DOC比值较低时,Al3+也可以与As竞争络合位点。在正常环境条件下,约10%的As(Ⅴ)可以与天然有机质络合,而只有在As/DOC比值较低时,才会有10%的As(Ⅲ)被络合到腐植酸上。在将As络合到自然有机物上时,应考虑到自然环境。