腐植酸类物质的性质和应用

在伟大领袖毛主席关于“农业学大寨”的伟大号召下,全国各地为夺取农业丰收掀起了广开肥源的群众运动,制出了许多新化肥、土化肥。腐植酸类肥料就是其中一种。腐植酸类物质存在于土壤、泥炭、褐煤中,风化烟煤中有再生腐植酸,也可以用人工氧化煤的方法(如用空气、氧气、硝酸等作为氧化剂)制得再生腐植酸。用硝酸氧化制得的称硝基腐植酸。一般人们把从土壤、泥炭、褐煤中用碱(通常用氢氧化钠)抽提出的一部分,称为腐植酸。     

泥炭降解的新加工方法

泥炭降解的新加工方法柳丽芬，赵树昌（大连理工大学化工学院大连１１６０１２）关键词泥炭，降解，棕腐酸泥炭是含多种有价值化合物的复杂混合物，如果加工温度过高会产生较多ＣＯ＿２和Ｈ＿２Ｏ，并破坏其中有潜在应用价值的产物，最终产生大量的炭。如何保持泥炭的化学...     

硝酸氧解法提高泥炭中黄腐酸的产率

硝酸氧解法提高泥炭中黄腐酸的产率;腐植酸;硝酸氧化降解     

低阶矿物制备腐植酸盐的开发及应用研究

腐植酸盐(HA)主要存在于低阶矿物(硅酸盐类、泥炭、褐煤和风化煤等矿物)中,本文作者介绍了从低阶矿物中提取HA盐的新工艺及在各行业的应用,并对我国未来低阶矿物和腐植酸盐领域的发展前景进行了展望.     

唾液酸类化合物的合成研究进展

综述了近年来在唾液酸及其衍生物、类似物的设计、合成，以及它们作为唾液 酸酶抑制剂等相关的生物学应用方面的研究进展。     

人参属中药腐解化感作用研究进展

人参、西洋参和三七为人参属近缘物种,形态和化学成分相似,均具有连作障碍的特性。人参属中药连作后,土壤环境逐渐变得不适宜其生长,植株长势变弱易患病,导致生长发育受到抑制,出现严重的根腐病、须根脱落,甚至植株死亡现象。而造成人参属连作障碍的主要原因之一是化感物质的自毒作用,人参残体降解物作为人参化感物质主要来源之一,会导致种子发芽率下降,种苗死亡率升高、根腐病等病害加重,最终造成连作障碍。在人参属中药连作过程中,通过化感物质与土壤交流,也会直接或间接影响土壤理化性质的变化。对人参属中药腐解化感作用的研究进展以及腐解对土壤成分的影响进行综述,以期为人参属中药腐解化感作用及土壤利用的相关研究提供借鉴。     

生物样品中大田软海绵酸类毒素代谢规律及检测方法的研究进展

近年来,中国赤潮污染日趋严重,因此引发多起贝类毒素中毒事件,威胁消费者的食用安全。大田软海绵酸（okadaic acid,OA）及其衍生物鳍藻毒素（dinophysistoxins,DTXs）是分布最广、危害最大的一类腹泻性贝类毒,具有急性腹泻毒性及多种慢性毒性。建立生物体液样品中OA类毒素残留的检测方法对辅助诊断患者的中毒情况极为必要。文章简要介绍了OA类毒素的理化性质、中毒事件、毒理作用,并详细总结了生物样品中OA类毒素代谢规律及检测方法的研究进展。     

塑料制品中高关注物质测定方法的研究进展

综述了塑料制品中高关注物质测定方法的研究进展。介绍了邻苯二甲酸酯、有机锡、阻燃剂和全氟化合物等4类高关注物质的化合物信息,总结了气相色谱法、液相色谱法及质谱法测定塑料制品中上述高关注物质,并展望了高关注物质测定方法的发展趋势(引用文献40篇)。     

枇杷叶中活性物质提取方法研究进展

综述枇杷叶中活性物质提取方法。枇杷叶中常见活性物质主要有黄酮类、多糖类、三萜酸以及苷类化合物等。提取方法有微波辅助提取法、超声波辅助酶法、水提醇沉提取法以及超临界二氧化碳萃取法等。微波辅助提取法提取效率高,选择性好,可用于热不稳定物质。超声波辅助酶法节约萃取时间,低毒环保,提高酶解得率。水提醇沉提取法应用范围广,操作简单,成本低。超临界二氧化碳萃取法可用于热稳定性较差的物质,灵敏度高,相对成本高。这些方法在药用植物提取中得到了广泛的应用。在保证较好的选择性和重复性前提下,使用绿色、环保、经济的溶剂减少环境污染,提高活性物质提取得率是现代提取方法的发展方向。     

类二十烷酸分析方法及应用的研究进展

类二十烷酸是一大类由二十碳多不饱和脂肪酸氧化产生的具有生物活性的不饱和脂肪酸,是重要的炎症因子,广泛存在于体液和组织中,调节体内众多生理和病理过程。类二十烷酸在生物体内种类众多,含量较低,并且存在大量同分异构体,因此生物体内类二十烷酸的分离和分析具有较大的挑战。本文对近5年来类二十烷酸的分析方法和其在生物样品分析中的应用进行归纳总结,重点介绍了不同分析方法的特点及其在生物样品分析中的最新进展,旨在为类二十烷酸的体内药物分析及应用研究提供参考。     

土壤腐殖质的分析化学研究进展

对土壤腐殖质的分析化学研究进展作了综述。具体包含如下几个方面的内容；土壤腐殖质的组成和结构的研究，土壤腐殖质的起源和形成的研究，土壤腐殖质与土壤中有机，无机物质的相互作用的研究以及有机物料的分解，转化及其对腐殖质影响的研究，同时，对土壤腐殖质的研究中有待进一步用分析化学方法解决的几个问题进行了探讨。     

Automated Fluorometric Determination of Humic Substances in Natural Water

Abstract

A procedure for automating the analysis of humic substances in natural fresh water samples is described. Thirty samples are analysed per hour in a working range of 0.5 mg/l to 20 mg/l. Significant interferences observed in other methods are eliminated.     

BINOL衍生的手性磷酸催化的不对称反应研究进展

综述了近年来BINOL衍生的手性磷酸作为一类强酸性Brφnsted酸催化剂,在不对称氢转移反应、Friedel-Crafts, Mannich, Aza Diels-Alder, Aza-ene-type, Pictet-Spengler等反应中的研究进展.参考文献37篇.     

泥炭土连续碱抽提腐殖酸的分子结构特征

从Pahokee泥炭土中连续碱抽提分离出8个不同的腐殖酸级分，并对每一级分进行了元素分析、傅里叶变换红外光谱（FTIR）、固态^13C核磁共振（^13CNMR)、高效排阻色谱（HPSEC）等一系列定性、定量研究。结果表明：所分离出的8个腐殖酸级分存在明显的结构性质差异，随提取和蔼的增加，O／C原子比由0．52减少到0．36，H／C原子比由1．05增加到1．52，相应于结构中含氧基团的减少和脂族基的增加，表观分子量也由7．7K增加到22．1K。同时，^13C NMR显示长链脂肪碳结构由无定型向晶型转变。此工作表明在所研究的腐殖酸中可能存在分别具有芳香或脂肪特性的两类腐殖酸结构，每种类型都有不同的分子量分布、元素组成、基团结构和母质来源。在特定的环境因素下，不同类型的腐殖酸会共存于同一体系中，增加了腐殖物质的非均匀性和复杂性。     

The Study of Influence of Metal Ions on Thermal Decomposition of Humic Acids

Investigations of the influence of the following metal ions: Ca, Mg, Ba, Cr, Mn,Co, Ni, Fe(II), Fe(III), Cu, Zn, Cd, Pb, Hg, Al and Ag on thermal decomposition of humic acids were carried out. Metal-humic compounds were obtained by ion exchange method and by complexing of metal cations on humic acids. For the investigations of thermal decomposition TG and DTA were used. Presence of metal ions in structure of humic acids mostly increases intensity of their thermal decomposition particularly the Hg and Cu ions.They shift this process to lower temperatures 100–300°C. Mass loss of organic matter in this temperature range in humic-mercury compounds are higher by more than 35%, and in humic-copper compounds are higher by more than 20% compared with the mass loss of humic acids itself. Ni and Co ions also increase the intensity of thermal decomposition of humic acids, but Ca, Ba and Mg ions inhibit that process. This revised version was published online in July 2006 with corrections to the Cover Date.     

Complexation Properties of Typical Soil and Peat Humic Acids with Copper(II) and Cadmium(II)

Abstract

Potentiometric titration with ion-selective electrodes was applied to determine characteristic parameters like the degree of complexation and the approximate molecular weight of humic acids from theoretical considerations and conditional stability constants for the complexes of Cu(II) and Cd(II) with humic acids obtained from sources such as garden soil, peat prepared by decomposing water hyacinth in soil and humified water hyacinth. Double-reciprocal and Scatchard plots were constructed to determine the conditional stability constants of the complexes formed. Cu(II) was found to have more affinity for the humic acids than Cd(II) and the stability of the metal complexes in aqueous medium was found to increase with increasing pH. The order of stability of the complexes was M-HA (soil)>M-HA (peat)>M-HA (humified water hyacinth), where M and HA represent metal and humic acids, respectively.     

Characterization of Composts and Humic Acids from Pulp and Paper Mill Biosludges by DSC in Association with FT-IR Spectroscopy

Samples of pulp and paper mill biosludges with different maturation ages (fresh biosludge and composts collected after 3 weeks, 1 year and 2 years of composting) and their corresponding humic acids were analyzed by thermal analysis with DSC in association with FT-IR spectroscopy. The DSC curves obtained exhibited endotherms in the low-temperature region, assigned to dehydration processes, exotherms at around 370°C, attributed to the loss of peptidic structures, and high-temperature exotherms, assigned to the loss of functional groups; the lignins were thermostable, regardless of the maturation age of the compost. The results obtained provided evidence that, during composting, the organic matter evolved in the direction of higher molecular complexity and stability, leading to a more homogeneous product closely resembling humic-like substances. This revised version was published online in July 2006 with corrections to the Cover Date.     

The Effect of Supramolecular Humic Acids on the Diffusivity of Metal Ions in Agarose Hydrogel

Humic acids are known as natural substances of a supramolecular nature. Their self-assembly ability can affect the migration of heavy metals and other pollutants in nature. The formation of metal-humic complexes can decrease their mobility and bioavailability. This study focuses on metal ions diffusion and immobilization in humic hydrogels. Humic acids were purchased from International Humic Substances Society (isolated from different matrices—peat, soil, leonardite, water) and extracted from lignite mined in Czech Republic. Copper(II) ions were chosen as a model example of reactive metals for the diffusion experiments. The model of instantaneous planar source was used for experimental data obtained from monitoring the time development of copper(II) ions distribution in hydrogel. The effective diffusion coefficients of copper(II) ions showed the significant dependence on reaction ability of humic hydrogels. Lower amounts of the acidic functional groups caused an increase in the effective diffusion coefficient. In general, diffusion experiments seem to act as a valuable method for reactivity mapping studies on humic substances.     

The Singular Molecular Conformation of Humic Acids in Solution Influences Their Ability to Enhance Root Hydraulic Conductivity and Plant Growth

Some studies have reported that the capacity of humic substances to improve plant growth is dependent on their ability to increase root hydraulic conductivity. It was proposed that this effect is directly related to the structural conformation in solution of these substances. To study this hypothesis, the effects on root hydraulic conductivity and growth of cucumber plants of a sedimentary humic acid and two polymers—polyacrylic acid and polyethylene glycol—presenting a molecular conformation in water solution different from that of the humic acid have been studied. The results show that whereas the humic acid caused an increase in root hydraulic conductivity and plant growth, both the polyacrylic acid and the polyethylene glycol did not modify plant growth and caused a decrease in root hydraulic conductivity. These results can be explained by the different molecular conformation in water solution of the three molecular systems. The relationships between these biological effects and the molecular conformation of the three molecular systems in water solution are discussed.     

溶剂气浮法去除水中腐殖酸的动力学和热力学初步研究

研究了溶剂气浮法去除水中的腐殖酸,该技术可以作为生物处理后的填埋渗出液的后处理方法。腐殖酸通过与表面活性剂十六烷基三甲基溴化铵生成离子缔合物气浮进入有机溶剂异戊醇而从水中去除。大于计量比的表面活性剂的量在10 m in之内可达92%的去除率。气浮速率在一定程序上随着气流速率的增加而增加,基本上与有机溶剂的体积无关。同时,还考察了电解质、乙醇及溶液的pH值对水中腐殖酸的溶剂气浮过程的影响。研究表明,该溶剂气浮过程遵从一级动力学。气浮过程的表观活化能作为一个特征参数被提出来,其值为2.87 kJ/mol。