Comparison of five humic acids

The ultimate analyses, u.v-visible absorption spectra, fluorescence spectra and i.r. spectra of five humic acids have been studied. One was obtained commercially from peat, two from organic-rich soils, one from an estuary and one from a marine sediment. The u.v. spectra were used to compare average molecular weights which varied from 800 to 7000 and increased with the atomic $\text{H}\text{C}$ ratio. Fluorescence appeared to be due to poly-nuclear aromatic structures. All the humic acids showed maximum excitation at 360 nm and developed maximum emission in the range 430–455 nm but the humic acids from sediments showed an additional emission maximum at ~410 nm. Fluorescence from the peat humic acid was broad and secondary emission was observed with a maximum at 520 nm which was attributed to the formation of excimers. Fluorescence has been used to monitor the interaction of cations with humic acids in solutions of different ionic strengths which shows promise for distinguishing between metat—humate complex formation and the coagulation of a colloid. The structures of the humic acids are discussed in terms of the structures possessed by lignites.     

腐植酸的分级提纯方法研究进展

综述了近年来国内外腐植酸的分级提纯方法的研究进展。介绍了电泳、凝胶过滤、超滤等现代分离技术在腐植酸分级过程中的应用,归纳了腐植酸提纯方法,最后对腐植酸的分级提纯技术发展趋势进行了展望。     

硫酸铝去除给水中腐植酸机理研究

研究了不同条件下,硫酸铝对给水腐植酸的不同混凝处理作用,探讨了pH值、投药量影响混凝过程的机理.     

原煤中腐植酸的活化处理研究

实验研究原煤中腐植酸各种活化处理方法并进行分析比较,提出可应用于肥料领域的腐植酸活化处理优化方案是碳铵+氨水处理,处理后水溶性腐植酸占游离腐植酸比例达～70%,处理成本仅为260元/t.     

Effects of five variables in phosphorus fixation by humic acids from lignite

A statistically designed experiment was carried out to determine the influence of ionic strength (μ), calcium concentration [Ca], humic acid concentration [HA], phosphorus concentration [P]and pH in fixation of phosphorus by humic acids from a Spanish lignite. The results obtained indicate that fixation increases with increases of pH and [P]and decreases with increases in μ, [Ca]and [HA].     

Separation and identification of amino acids from lignite humic acids by thin layer chromatography

Thin layer chromatography with and without temperature gradient was used to identify ten amino acids in the humic acid hydrolysate of Rovinari lignite, using cellulose and volcanic tuff as stationary phases. The acids found were L-leucine, isoleucine, phenylalanine, L-valine, tyrosine, proline, L-alanine, glutamic acid, threonine and L-lysine.     

Comparative behaviour of coal and maceral concentrates during artificial coalification

A series of experiments were performed in cold-seal autoclaves (confined-pyrolysis) to characterize the behaviour of individual macerais (vitrinite, inertinite, exinite) extracted from the same Lorraine Basin coal during artificial coalification. Rock-Eval pyrolysis, elemental analysis and weight loss determination provided the simple maturation indexes required. Emphasis was laid on the timing of hydrocarbon generation and on the possible similarities existing between inertinite and vitrinite of higher rank. Hydrocarbon potential and hydrocarbon yield were found to increase from inertinite to vitrinite and exinite, but similar mechanisms were involved during the thermal degradation of both inertinite and vitrinite.     

Isolation and characterization of humic acids from Alberta oil sands and related materials

Thirteen humic acid samples were isolated from a number of oil sand feedstocks using 0.5 N NaOH or a mixture of 0.1 N NaOH + 0.1 M Na₄P₂O₇. The feedstocks included three different grades of Athabasca oil sand, two samples of overburden, a sample of centrifuge tailings from the Syncrude Canada Ltd plant in Alberta and a heavy minerals fraction from oil sand tailings containing adsorbed organic matter. Based on the extraction efficiency of the two solvents it appears that the humic acids from oil sand and overburden feedstocks are strongly associated with calcium, while the humic acids from other feedstocks could be bound to non-silicate aluminum and/or iron. Comparison of analytical data for the various humic acid samples with corresponding data for humic acids from subbituminous coal, peat, soil and asphaltenes from bituminous feedstock, shows the similarity of these humic acids to those from subbituminous coal. Examination of the elemental analyses in terms of a van Krevelen diagram shows that most of the data either overlap or fall directly in the region of the recent and shallow kerogens. This kind of organic matter has very little potential for oil production, suggesting that the origin of this organic matter could be different from that of the greater part of the bitumen of the Athabasca oil sands.     

褐煤和柴煤中腐植酸的测定

本国际标准介绍了褐煤和柴煤中腐植酸的测定方法。第二版（ISO5073：1999）是在对第一版（ISO5073：1985）进行技术修改后形成的。本版鹰植酸的测定咀相对比较简单酌容量法取代了重量法（ISO5073：1985）同时附录A还介绍了预先测定腐植酸含碳比的方法。     

Changes of chemical properties of humic acids from crude and fungal transformed lignite

The development of biological processes for fossil energy utilization has received increasing attention in recent years. There are abundance of lignite resources in China and the lignite, a low-grade coal, can be transformed by a Penicillium sp. After fungal transformation, the contents of humic acid and water-soluble humic material increased from 38.6% to 55.1%, and from less than 4.0% to 28.2%, respectively. The differences in chemical properties of crude lignite humic acid (aHA), fungal transformed lignite humic acid (bHA) and water-soluble humic material from fungal transformed lignite (WS) were studied. Elemental analysis and size exclusion chromatography showed that the N content of bHA increased by 47.36% compared with aHA, and the molecular mass of bHA was smaller than aHA. And the WS with the smallest molecular mass contained most content of N. The ¹³C NMR and FT-IR spectra of aHA and bHA showed that aHA contained more aromatic structure than bHA.     

Electrolytic reduction improves treatability of humic acids containing water streams

BACKGROUND: An understanding of the structure of humic acids is essential for their degradation or physical removal from wastewaters. This work aims at targeting the reactivity of these molecules by modifying their properties. Structural alterations were carried out by electrolytically reducing the solution containing humic acid in an electrolytic cell to convert them into less polar structures. RESULTS: Overall it was observed that electrolytic reduction of humic acids strongly facilitated their further treatability. First, the reduced forms of humic acids exhibited improved adsorption on activated carbon. For 1 kW h of electrical energy consumed during electrolytic reduction, the additional chemical oxygen demand (COD) adsorbed was 60 g for a synthetic humic acid solution. Similarly, the additional COD adsorbed (kW h)^?1 was found to be 35 g and 112 g for humic acid‐rich effluent and landfill leachate, respectively. In comparison with non‐reduced control samples, a 200‐fold decrease in the chloroform formation was observed when electrolytically reduced drinking water samples were supplemented with a chlorine dosage of 150 mg L^?1. Moreover, an enhanced membrane flux was obtained with electrically reduced samples, indicating their improved membrane filterability. CONCLUSION: The electrolyzed humus species were characterized by analyzing their surface tension and particle size. This work addresses an alternative technology for the treatment of water streams containing humic acids. Copyright © 2007 Society of Chemical Industry     

农业土壤中土壤有机质和腐殖酸不同粒级的结构表征

摘要：农业土壤中的有机质主要来源于植物残体的部分分解、微生物生物量以及腐殖物质。130核磁共振、羟化四甲铵气相色谱／质谱法和热解气相色谱/质谱法等先进的分析技术被用来研究地中海的深褐色土壤中土壤有机质及相应的腐殖酸的化学结构。羟化四甲铵法对大多数土壤和腐植酸样品的热化学分析的主要产物是木质素提取复合物和非木质素芳香化合物、杂环氮、脂肪酸甲酯和二羧酸二酯。在〉250μm的羟化四甲铵色谱分馏所得的木质素提取复合物要明显多于〈2μm时的。脂肪酸甲酯和二羧酸二酯团长链峰值的相对强度在团聚体大小上有所降低,但是他们却对土壤有机物质的结构表现出明显的贡献。热解气相色谱／质谱法和羟化四甲铵气相色谱／质谱法数据表明在腐植酸的结构中含有大量的木质素和表皮材料。在氧化过程的最后阶段随着颗粒大小的降低腐植酸样品中含有木质素提取物单元,而来源于微生物的活动多种脂肪酸以及高含量的非木质素芳香结构。我们的数据表明：新鲜的有机物质被分解和腐化成腐植酸时存在一个类似于结构的稳定阶段,但这部分产物进一步分解（主要是通过氧芳香碳取代氧烷基）转化为腐化产物。     

氧化及其联用技术去除水中腐殖酸研究进展

水体中的腐殖酸类天然有机物是影响水质重要因素之一,仅靠常规工艺难以去除水中腐殖质。氧化及其联用技术因效率高、能耗低、适用范围广,逐步成为去除此类污染物的预处理技术,臭氧、高锰酸钾等氧化剂具有较强氧化性的特点,已取代传统氧化剂-氯气,能有效将水中天然有机物（natural organic matter,NOM）分解为无毒小分子物质,且降低了饮用水水质致突变风险,其中,臭氧在安全性和副作用方面更具优势,但单一氧化技术存在不同程度的局限性。针对国内外不同水体状况,本文详细比较了氧化-混凝等联用技术去除水中腐殖酸的氧化机理、协同作用、去除效果和应用状况,探讨了不同的氧化及其联用技术去除水中NOM的研究进展情况,分析表明氧化技术组合工艺已成为去除水中腐殖酸的主流工艺,并指出预氧化-膜联用技术因其良好的协同性而具有广泛的应用前景。     

Unexpected enrichment of nitrogen during the diagenetic evolution of sedimentary organic matter

This study examines the behaviour of nitrogen during coalification in two coal series: the sedimentologically homogeneous coal series of the Mahakam delta, Indonesia and a reference coal series composed of samplesfrom several sources. The variations in the total nitrogen contents, in hydrolysable nitrogen, and in the natural isotopic abundance of ¹⁵N are reported. The behaviour of nitrogen during coalification presents three main stages: 1. a first stage where microbial and/or chemical degradations produce a loss of nitrogen; 2. a second stage of preservation, where organic nitrogen does not take part in the reactions involved and consequently remains unchanged in the residual organic matter; and 3. a third stage of thermal alteration, where nitrogen is mainly released with methane.     

Eightfold increased membrane flux of NF 270 by O3 oxidation of natural humic acids without deteriorated permeate quality

BACKGROUND: Membrane fouling by humic acids limits the water recovery of nanofiltration in drinking water production. This article investigates if membrane fouling can be reduced by decomposition of humic acids in the concentrate stream by O₃ oxidation. RESULTS: At a specific O₃ dose of 2.11 g O₃ per g COD (17.0 g m^?3 O₃ (g) for 20 min), a COD reduction of 38% and a hydrophobic COD reduction of 69% is achieved. The membrane permeability of the ozonated solution by NF 270 membranes is higher (20.6 × 10^?9 L s^?1 m^?2 Pa^?1) than the permeability if the untreated solution is filtered (2.4 × 10^?9 L s^?1 m^?2 Pa^?1). The COD retention of the ozonated solution was similar to the retention of the untreated samples. The addition of H₂O₂ allows a better mineralization degree, i.e. UVA removal increased from 53% to 66% if H₂O₂ was added as from 10 min oxidation at the same molar flow rate as O₃. CONCLUSION: O₃ oxidation can substantially alleviate membrane fouling by humic acids in nanofiltration systems and the addition of H₂O₂ can slightly improve its decomposition. Copyright © 2010 Society of Chemical Industry     

山西风化煤腐植酸活化研究

风化煤中腐植酸多被钙离子、镁离子固定,具有生物活性的水溶性腐植酸含量甚微。因此,在生产腐植酸肥料时,有必要进行活化处理。以山西某地风化煤为原料,研究活化剂种类、添加量,加水量,活化温度,反应时间对水溶性腐植酸含量的影响。结果表明,最佳活化条件为:以质量比为2的Na_2CO_3和NaOH混合物为活化剂,活化剂占风化煤质量的12%,加水量占风化煤质量的40%,温度75℃,时间2 h,此条件下水溶性腐植酸质量分数可接近40%。     

煤化度对煤层气成藏特性影响规律的研究

综述了煤层气的成因类型和成气过程的研究现状,说明生物成因和热成因是煤层气的2种主要成因类型,且煤层气生成过程以热成因为主,生物成因为辅。通过分析不同煤化度煤层气的生成过程,说明在整个煤化作用过程中煤层气的生成大致经历了4个阶段,即由植物遗体转化为泥炭阶段、褐煤转型阶段、长焰煤～瘦煤转化阶段以及贫煤～无烟煤阶段。从煤化度角度阐述了不同煤化度煤层气的贮藏特性,即不同煤化度煤层气存在较大差异,特别是不同煤层气吸附、解吸特征的差异影响了其吸附成藏、解吸、渗流及产出的整个过程;煤吸附CH4的能力随着煤化度的增加呈现先急剧增加后缓慢减小的趋势。最后分析了不同煤化度煤层气存在成藏差异的原因,说明煤化学结构、煤物理结构以及成煤过程中地质条件的差异是导致不同煤化度煤层气富集成藏差异性的主要原因。     

Behaviour in solution of humic acids from lignite in the presence of calcium ions

Humic acids (HA) extracted from Spanish lignite, were studied to discover their Ca-complexing capacity and their coagulation threshold. It was found that the concentration of Ca^{+ +} ions necessary for the complete flocculation increased with the increase of pH and ionic strength (μ) and it was linearly dependent on the concentration of HA. The calcium-complexing capacity of HA increased with the increase of pH and registered lower values as μ was increased. The i.r. spectra of the Ca-humic acid complexes show that the metal is complexed mainly by carboxylic groups from the HA.     

Improved extraction of humic acids from vermicomposted organic waste by a column-based continuous elution method

A column-based continuous elution (CCE) method was developed for extracting humic acids (HA) from vermicomposted organic waste. Dissolution of HA by passing extractant (0.2 M NaOH) through vermicompost in a column followed by elution under gravity resulted in yields of 47.5% and 74.7% extractable HA in 24 h by International Humic Substance Society (IHSS) method and CCE method, respectively. These results were 63.3% and 97.9% in 48 h, respectively. The extracted HA showed similar FTIR absorption spectra and chemical compositions. Rate of oxidative degradation of HA during extraction by the CCE method was lower as compared with the IHSS method indicating improvement in extraction without altering the quality.