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%。     

褐煤中腐植酸活化实验研究

对5种不同组成的褐煤分别用NaOH、Na_2CO_3和KOH 3种固体碱进行腐植酸活化实验,并对比不同pH时的活化率。实验结果表明:用NaOH作活化剂时活化效果较好;控制反应pH10时,褐煤中腐植酸活化率95%;在此条件下,当褐煤中钙镁总质量分数小于2.5%时,腐植酸活化率不受原料影响。     

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。     

Molecular weights of solubilized lignite macromolecules

The determination of molecular weights and molecular weight distributions in humic acids derived from lignite by base extraction has been successfully carried out by low-angle laser light scattering (LALLS) photometry and by coupling size exclusion chromatography (SEC) with LALLS photometry. Since light scattering techniques give absolute molecular weight values, no error-prone calibrations of the size exclusion column were necessary. Reduction of soluble derivatives of the humic acids with zinc in acetic anhydride was required to reduce the optical absorbance so that a linear scattering response was observable. Weight average molecular weights of ≈ 1.3 × 10⁶ and low polydispersity ratios were obtained for humic acid derivatives of Beulah, ND, lignite. Extension of this technique to the study of the more highly crosslinked humin which comprises the major portion of the lignite was investigated by treatment of the lignite with sodium hydroxide solution in a blender. This treatment converted up to 90% of the lignite into humic acids, which could be derivatized and studied by the LALLS techniques. The molecular weights of the products from lowtemperature solubilization of the lignite are inversely proportional to the per cent conversion.     

Evaluation of lignin and cellulose contributions to low-rank coal formation by alkaline cupric oxide oxidation

Oxidation with alkaline cupric oxide has been combined with solid-state ¹³C-n.m.r. spectroscopy to evaluate the cellulose and lignin input to the formation of low rank coals. Model studies carried out on lignin-cellulose mixtures, carbonified cellulose, synthetic coals and synthetic humic acids (melanoidins) have established m-hydroxybenzoic acid as a source indicator for cellulose. This product has been found specifically in the oxidation of bio- and geo-macromolecules containing cellulose and/or thermally altered cellulosic material and is chemically distinct from the characteristic oxidation products of lignin-derived materials. Systematic changes in the distribution of the major oxidation products from lignin provide a chemical fingerprint which, in general, can be utilized to trace the thermal history of the sample. Analysis of two lignite coals from the northern hemisphere has demonstrated their predominantly lignitic origin. On the other hand, a Victorian brown coal (pale lithotype) sample is shown to contain a significant amount of highly transformed carbohydrate materials which are presumably incorporated into the macromolecular structure as humic acid derivatives.     

Aspects of structural features in lignite and lignite humic acids

Structural features of a South Moravian lignite and its humic acid (HA) fraction were studied by means of UV–vis, ¹H and solid-state ¹³C NMR, and FT-IR spectroscopy in addition to basic elemental analyses. The structural differences between the original lignite and its HA-type fraction were relatively minor, and their unambiguous differentiation into distinct categories was possible only by statistical methods. The tested model functions speak strongly for the importance of choosing enough sensitive and meaningful structural parameters which most likely reflect the character or type-rank of the coal-like carbon in question. The results verified that certain aliphatic compounds have their special tasks in the complicated structural network of lignite HA material, and powerful aprotic solvents are needed to obtain a fully dissolved HA solution. Despite some organic material was lost during different effective washing purification operations, the purified lignite HA was typified without significant loss of structural information on the original HA fraction. FT-IR experiments correlated well with those obtained by ¹³C NMR. From environmental points' of view, some water soluble organic trace components released from the original lignite material may be potential troublemakers within the area surrounding the deposit.     

不同溶剂提取宝清褐煤腐植酸的工艺优化及其特性研究

以褐煤的高效利用为出发点,以提高宝清褐煤腐植酸提取率为目标,探索了三种不同溶剂(KOH,NaOH,Na4 P2 O7)提取褐煤腐植酸的最优工艺条件.实验采用响应曲面法考察了反应温度、反应时间、溶剂浓度及其交互作用对腐植酸提取率的影响.结果表明:反应温度对目标值影响最大,且不同影响因素之间的交互作用对目标值有一定的影响,...     

Water-soluble acrylamide copolymers: V. Dispersion properties of poly(acrylamide-co-p-maleimidobenzoic acid) and poly(acrylamide-co-sodium N,N-diallylsulfanilate)

Eight new poly(acrylamide-co-p-maleimidobenzoic acid) (PAMMBA) water-soluble copolymers, 3 , have been prepared in a synthetic study with the objective to determine the influence of ring incorporation on the surface activity of these materials.¹ Sufficient sample was obtained from three of these experiments to enable measurement of the dispersion properties of these polymers using aqueous kaolinite suspensions. PAMMBA-1, -2, and -3 copolymers containing 7, 13, and 23 mole percent p-maleimidobenzoic acid (MBA) were tested. Their effectiveness as dispersants increased with increasing MBA content. But the copolymer containing 23% MBA required a dose rate four to eight times that of DISPEX N-40, a commercial dispersant, to obtain equivalent dispersion properties from a standard kaolinite suspension. In similar copolymer synthesis experiments, ten new poly(acrylamide-co-sodium N,N-diallylsulfanilate) (PAMDAS) copolymers were also prepared and fully characterized.² Sufficient material was isolated from three of these preparations to enable testing of the dispersant activity. PAMDAS-1, -2, -3 copolymers contained 3·0, 8·4, and 19·2 mole percent sodium N,N-diallysulfanilate (DAS) and were tested as dispersants in experiments conducted so as to produce results comparable to those of both the PAMMBA copolymers and a commercial dispersant. Dispersant effectiveness increased with increasing DAS content. PAMDAS-1 (3·0% DAS) was about the same effectiveness as PAMMBA-1 (7% MBA), PAMDAS-2 (8·4% DAS) was more effective than PAMMBA-2 (13% MBA), and PAMDAS-3 (19·2% DAS) was about equivalent in effectiveness to PAMBA-3 (23% MBA). Relative to DISPEX N-40, however, PAMDAS-2, at a dose rate of 2000 ppm by weight was about half as effective as DISPEX N-40 at a 250 ppm dose rate.     

Fe(III)-humate complexes from Megalopolis peaty lignite: A novel eco-friendly fertilizer

Fe(III)-humate complexes were synthesized from Greek peaty lignite of the Megalopolis Basin. The preparation was carried out under mild and low-energy conditions producing a biodegradable, eco-friendly and effective material to substitute the synthetic chelates Fe-EDDHA, Fe-EDTA and Fe-DTPA. Due to both the existing expanded configuration of the humic substances (that make binding sites accessible to the metal ions) and the ionization of functional groups, alkaline environment facilitates the association between Fe(III) ions and the lignite-derived humic substances. UV-vis and IR spectra revealed coordination of the metal ions with the carboxylic and phenolic groups of the oxygen-rich humic substances. Fe(III)-humate complexes were proved stable in a wide pH range similar to Fe-EDDHA synthetic chelates. Furthermore, the presence of K⁺ and humic matter increases the agronomic value of this material establishing alternative applications for Megalopolis peaty lignite.     

Structural elucidation of humic acids extracted from Pakistani lignite using spectroscopic and thermal degradative techniques

The present paper describes the characterization of Pakistan lignite coal, derived humic acids (HAL) and nitrohumic acids (NHA) along with the standard leonardite humic acids (LHA). The study utilized chromatographic and spectroscopic techniques to characterize the structure of coal and derived materials. Pyrolysis coupled to gc/ms was conducted with and without methylating agent (tetramethyl ammonium hydroxide). The pyrolysis study resulted in releasing mainly fatty acid methyl esters, different series of hydrocarbons and α, ω-dicarboxylic acid methyl esters. Triterpenoids, syringic and ρ-coumaric compounds and aromatic compounds derived from lignin moieties were also detected. Fourier transform infrared (FT-IR) and NMR data helped to evaluate the influence of coal rank on regeneration and nitration processes with respect to chemical structural composition of coal and derived materials. FT-IR spectra of four materials were similar except that NHA showed an absorption band at 1532 cm⁻¹, thus confirming the presence of -NO₂ groups. ¹³C NMR indicated higher aromaticity and less hydroxylalkyl material in HAL than NHA. The elemental composition and acid functional group content of four materials were also reported.The combination of results from different analytical techniques gives an improved understanding of the Pakistan coal nature and helpful for its future utilization.     

活化条件对褐煤中水溶性腐植酸含量的影响

为提高褐煤中水溶性腐植酸含量,提高褐煤在农业中的应用效果,研究了温度,活化剂浓度、时间对褐煤中水溶性腐植酸含量的影响.结果表明,随着温度的提高、活化剂浓度的增加、活化时间的延长,褐煤中水溶性腐植酸含量均有提高的趋势;对褐煤中水溶性腐植酸含量影响的重要程度为活化剂浓度>活化剂温度>时间,活化褐煤的优化条件为温度60℃,时...     

Humic Acid,Kerogen, and Black Carbon Isolated from Atmospheric Total Suspended Particulate from Guangzhou,China

The organic macromolecules in total suspended particulate (TSP) are complex and have not been thoroughly investigated. In this article, six composite TSP samples were collected from urban, suburban, and forest sites of Guangzhou. Organic macromolecules in the TSP were separated into humic acids (HA), kerogen and black carbon (KB), and black carbon (BC) by chemical treatment with sodium hydroxide, hydrochloric acid/hydrofluoric acid, and potassium dichromate/sulfuric acid. Note that the BC isolated is part of KB. To obtain sufficient amounts of HA, KB, and BC for subsequent analyses, 1.5 g TSP were used for each sample. The isolated fractions were characterized by elemental analysis, solid-state ¹³C crosspolarization and magic angle spinning nuclear magnetic resonance spectroscopy, Fourier transformed infrared spectroscopy, stable carbon isotopic ratio, and radiocarbon ratio mass spectrometry. Total carbon content in TSP ranged from 12.8 to 19.0%, and HA, KB, and BC were accounted for 2.39–14.8, 37.4–53.5, and 16.0–32.1% of total carbon, respectively. Isolated HAs were characterized by high H/C and N/C atomic ratios; KB showed high H/C but low N/C atomic ratios; BC was low in H/C, indicating a predominance of aromatic units in its carbon skeleton. The δ¹³C and radiocarbon data showed that all macromolecular fractions were mixtures of components having biogenic and fossil-fuel origins. The contribution of biogenic material to HA, KB, and BC, estimated by radiocarbon ratios, are 44.2–61.5%, 17.5–24.8%, and 3.3–17.2%, respectively. The atmospheric optical properties and hygroscopicity of kerogen are not known at present and warrant investigation because of the high content of kerogen in TSP.

Copyright 2013 American Association for Aerosol Research     

Assignment of the i.r. absorption band at 1050 cm in lignite humic acid

An important absorption band in the spectrum of lignite humic acid has been extensively studied. Modification of the humic acid was carried out by oxidation and decarboxylation and the resulting samples were studied by chemical, X-ray, optical density and i.r. methods. The lignite humic acid was compared with humic acids extracted from soils and from river sediment. It is suggested that the i.r. absorption at ≈ 1050cm⁻¹ for lignite humic acid can be predominantly attributed to the C---O stretch of polysaccharides.     

复合碱型腐植酸型煤粘结剂的特性研究

研究了从云南褐煤提取型煤腐植酸粘结剂的过程,主要考察了煤碱质量比和不同碱性添加物包括NaOH,Na4P2O7,Na2CO3和K2CO3等对腐植酸提取率的影响,并进行了成本估算。结果表明,在利用NaOH的条件下,煤碱质量比在10∶1与12∶1之间获得较好提取效果;与利用单一NaOH添加剂相比,在总碱量略有减少的前提下,用Na4P2O7和Na2CO3替代部分NaOH使腐植酸的提取率增加18.4%,粘结剂的粘度提高30%,经济成本下降2.6%。腐植酸钾型型煤的气化效果好于钠型,跌落强度基本相同。     

脲基活化与超声波活化对腐植酸的影响

分别对3种不同含量的腐植酸进行脲基活化和水超声波处理,统计分析2种方法对腐植酸总量、水溶性腐植酸含量和游离腐植酸含量的影响。试验结果表明,脲基活化处理能显著提高腐植酸总量、水溶性腐植酸含量和游离腐植酸含量,水超声效果不显著。     

Ammonia sorption by peat and N fractionation in some peat-ammonia systems

Ammonia sorption is an important peat property for making composts and peat-mineral fertilizers. In this study, we investigated the influence of moisture content of fibric, hemic and sapric peat materials on ammonia sorption capacity, and we determined the N forms and the amount of solubilized humic substances following peat ammoniation. Ammonia sorption capacity increased curvilinearly with degree of decomposition from the fibric to the sapric peats, and increased with peat moisture content up to 600 g H₂O [kg wet peat]^–1 in the range of 400 to 700 g H₂O [kg wet peat]^–1. The amount of chemically sorbed ammonia was highest in the sapric peat containing [600 g H₂O] [kg wet peat]^–1. On a dry weight basis, maximum sorption capacity was 24 g NH₃-N kg^–1 for the fibric peat, 29 g NH₃-N kg^–1 for the hemic peat and 49 g NH₃-N kg^–1 for the sapric peat. Ammonia loss of physically retained ammonia was greatest at the highest moisture content and for the least decomposed peat. At ammoniation rates exceeding 30 g NH₃ [kg dry peat]^–1, exchangeable ammonium and acid-hydrolyzable N were the dominant N fractions in ammoniated peats. Peat ammoniation increased significantly (p < 0.001) the amounts of water-soluble carbon in all peat materials, of fulvic acid in the fibric peat and of both humic and fulvic acids in the hemic and the sapric peats. At maximum ammonia sorption capacity, the total amount of water-soluble and alkali-extractable organic matter reached 338 g kg^–1 in fibric peat, 683 g kg^–1 in the hemic peat and 848 g kg^–1 in the sapric peat. The hemic and sapric peats appeared more appropriate than the fibric peat for making peat-base fertilizers.     

Oxy-ammoniation of Elbistan lignite to produce a nitrogenous fertilizer

Elbistan lignite has been found to contain 50.1 wt% (daf) humic acid. The i.r. spectrum of this lignite, however, indicates the absence of free carboxyl groups. Treatment with mineral acids, however, regenerates the carboxyl groups. A product containing 18.8 wt% N (daf) has been obtained by treatment of HN0₃-treated Elbistan lignite in aqueous ammonia for 4 h at 165 °C and under oxygen pressure. Water-soluble and active nitrogen tests indicate that such products may have the properties of slowrelease nitrogenous fertilizers.     

Identification of straight-chain fatty acids associated with metallic cations in coals

Straight-chain fatty acids and associated cations, such as Ca²⁺, Mg²⁺ and Fe³⁺, in the solvent extracts from the humic substances of Joban lignite and Taiheiyo coal were analysed after treatment with hydrochloric acid. Gas chromatographic analyses showed the most abundant presence of C₁₆ in the C₁₄ to C₃₂ straight-chain fatty acids. The amount of Ca²⁺ bonded to the fatty acids was calculated to be about 20 ppm of the humic substances.     

铁合金用褐煤半焦成型研究

利用云南丰富的褐煤资源制备了腐植酸钠作黏结剂,并用来成型铁合金厂应用的褐煤半焦.研究了黏结剂腐植酸钠的制备方法及褐煤半焦成型工艺,并对不同配比的型焦作了各种强度指标测试.结果表明,腐植酸钠作为半焦成型的黏结剂具有良好的综合指标.实验研究表明:当黏结剂腐植酸钠的配入量大于8%时,褐煤型焦的各项指标达到了铁合金厂的使用要求.     

褐煤腐植酸磺化改性工艺及表征

为提高腐植酸的亲水性能,对褐煤腐植酸进行磺化改性。以Na2SO3为磺化剂,以磺化度为考察指标,通过单因素实验和正交实验研究了磺化温度、磺化剂固液比、磺化时间对褐煤磺化腐植酸磺化度的影响,得到褐煤磺化腐植酸最佳制备条件,并通过红外光谱分析和热重分析对褐煤磺化腐植酸性能进行表征。结果表明:磺化温度对褐煤磺化腐植酸磺化度的影响最大,其次为磺化时间,磺化剂固液比影响较小。在磺化温度50℃,磺化剂固液比2∶20,磺化时间90 min条件下制备的褐煤磺化腐植酸磺化度为17.72%。红外光谱表明:褐煤磺化腐植酸含有苯环、羧基、羟基、酚羟基,磺酸基团明显增多,褐煤腐植酸磺化改性成功。热重分析表明:褐煤磺化腐植酸低于200℃时稳定,大于200℃时发生裂解反应;小于330℃裂解反应为吸热过程,大于330℃为放热过程。