泥炭的化学降解

用ＨＮＯ_３－Ｈ_２ＳＯ_４混合体系研究了七台河及桦川泥炭的化学降解过程。较为详细地考察了Ａ／Ｐ（ＨＮＯ_３－Ｈ_２ＳＯ_４（１００％）／泥炭）比，温度及时间对降解产物收率及组成性质的影响。通过ＩＲ、紫外、可见光谱、功能团、元素分析等对降解产物进行了表征。得出了七台河及桦川泥炭最佳降解条件及水溶酸（ＦＡ）、水不溶酸（ＮＦＡ）、棕腐酸（ＮＨｙＡ）等的收率。     

Carboxymethylation of peat in 2-propanol

The effects of the time and temperature of alkaline pretreatment and the time and temperature of the carboxymethylation of peat in 2-propanol on the concentration of carboxymethyl groups and the solubility of the resulting products in water and an aqueous alkali solution were studied. The viscosity characteristics of the aqueous and aqueous alkaline solutions of peat carboxymethylation products were studied.     

Study on the acid hydrolysis of Peat: 1. extraction of carbohydrates

Peat and its derived products such as peat extracts or hydrolysates offer a variety of possibilities as raw materials for the development of chemical and biochemical processes. Acid hydrolysis of peat yields soluble carbohydrates which can be utilised as fermentation media. In this work, Sphagnum peat moss was hydrolysed under various conditions of H₂SO₄ concentration, retention time, temperature, peat concentration, peat particle size distribution and original moisture content in the peat. The results suggest that mild conditions of hydrolysis, which will minimise possible negative effects on other nutrients available in peat, are adequate for the release of the carbohydrates present in peat. It was found that peat particle size distribution and original moisture content as well as peat concentration will also affect the yield of carbohydrates obtained.     

Impact of the presence of solids on peroxidase‐catalyzed treatment of aqueous phenol

The impact of the presence of solids on the treatment of aqueous solutions of phenol using horseradish peroxidase (HRP) and hydrogen peroxide was investigated. The solids studied were silica gel, kaolin, bentonite, cellulose and peat moss. Kaolin, bentonite, cellulose and peat moss enhanced phenol transformation at pH 5.0 and 7.0 starting at concentrations of 100, 1000 or 10 000 mg dm^?3. At pH 9.0, bentonite and kaolin had negative impacts when present at 10 000 mg dm^?3 and peat moss when present at 1000 mg dm^?3 and 10 000 mg dm^?3. In the case of bentonite and peat moss, the enhancing effects at pH 7.0 were associated with the dissolved or colloidal constituents, while in the case of kaolin, the enhancing effects were due to the solid material. Freshly made bentonite suspensions inactivated the peroxidase enzyme; however aged bentonite suspensions and their supernatants did not affect enzyme stability. H₂O₂ was unstable in solutions containing peat moss constituents. Phenolic solutions treated in the presence of bentonite, kaolin and peat moss were significantly less toxic than the controls, indicating that these materials were able to interact with and partially neutralize precursors of toxic reaction products. Copyright © 2003 Society of Chemical Industry     

超高含水率水泥固化泥炭土压缩模量和固结系数研究

泥炭土具有高含水率、高有机质含量、大孔隙比和低剪切强度等特点。化学固化常用于提升泥炭土地基承载力和抵抗变形能力。通过开展单向固结试验,研究了含水率、有机质含量、pH值、水泥掺量和掺料粒径对水泥固化泥炭土压缩模量和固结系数的影响。研究表明,随着水泥掺量和养护龄期增加,水泥水化反应生成的凝胶不断增长,固化土压缩模量随之增长。泥炭土初始含水率从600%降至300%后,固化土压缩模量增加了3.5倍。有机质含量从40%增至80%(质量分数)时,固化土压缩模量降低了50%。pH值从7.0降至3.5时,固化土压缩模量降低了15.8%。固化泥炭土的压缩模量和固结系数受含水率、水泥掺量影响最大,有机质含量次之,pH值影响最小。掺石英砂能提升固化泥炭土的压缩模量,且石英砂粒径越小,固化土压缩模量增幅越大。     

Fouling tendency of ash resulting from burning mixtures of biofuels. Part 3. Influence of probe surface temperature

Mixtures of peat with bark and peat with straw were burned in a large lab-scale entrained flow reactor under controlled conditions, and deposits were collected on an air-cooled probe controlled at four to six different probe surface temperatures between 475 and 625 °C. The results show that the probe surface temperature has no effect on the deposition rate when peat is burned. When burning bark, either alone or in mixtures with peat, the deposition rate decreases with increasing probe surface temperature. When burning straw, either alone or in mixtures with peat, the deposition rate increases with increasing probe surface temperature up to 550 °C and remains constant at higher temperatures. The Cl content in the deposits decreases with increasing probe surface temperature, regardless of the mixture composition. In deposits obtained from burning peat–bark mixtures, K appears as K₂SO₄ when the deposition rate is low and as KCl when the deposition rate is high. In deposits obtained from burning peat–straw mixtures, no clear relationship is found between the deposition rate and the contents of Cl, S and K in the deposits.     

pH值对泥煤吸附Ni~(2+)动力学的影响

以泥煤作为研究对象,考察了N i2+在泥煤上的吸附规律。元素分析、红外光谱与热重分析表明,泥煤上起吸附作用的主要基团是分子侧链上的各种含氧官能团:—COOH,—OH,—C O等。采用批次法研究了溶液pH值对N i2+在泥煤上吸附动力学的影响。实验表明:泥煤吸附N i2+的过程可大致分为2个阶段;pH值是影响泥煤吸附的重要因素,随pH值增加N i2+吸附量增大,吸附反应速率也增大。N i2+在泥煤上的吸附动力学过程很好地符合假二级反应模型,为泥煤处理N i2+废水过程提供一定的理论指导。     

Peat hydrogenolysis using H2/CO mixtures: Micropetrological and chemical studies of original material and reaction residues

The transformation of crude peat (peat in its natural aqueous medium) has been studied under hydrogenolysis conditions using CO and H₂ mixtures as reducing agent. Batch autoclave experiments were conducted with a moderately humified peat at reaction temperatures up to 400°C.Micropetrological and chemical studies on untreated and treated peat as well as on THF extracted residues show that the different organic components present in peat undergo changes very similar to those observed during coal liquefaction. Liptinitic components are rapidly converted and do not appear in the unconverted residues above 275°C. The huminitic components regularly increase their reflectivity and appear to have been coalified to the stage of subbituminous coal A, from that point on being the major contributors to the newly formed vitroplast. The latter is observed for the first time following the hydrogenolysis treatment at 300°C. Beyond this temperature the vitroplast undergoes severe alterations becoming a bitumen-like material.In the presence of anthracene oil as organic carrier solvent, the hydrogenolysis reactions using CO and H₂ result in the formation of mesophase at temperatures as low as 380°C. Coke-like structures can thus be formed from peat.     

Acetylation of alkali-treated peat

The effects of time, temperature, and the amount of an acetylating reagent in the esterification of peat with acetic anhydride in the presence of sodium hydroxide after mechanochemical activation on the concentration of bound acetyl groups and the solubility of the resulting products in acetone were studied.     

Fouling tendency of ash resulting from burning mixtures of biofuels. Part 2: Deposit chemistry

Mixtures of peat with bark and peat with straw were burned in a lab-scale entrained flow reactor under controlled conditions, and deposits were collected on an air-cooled probe at a temperature of 550 °C. The fuel and deposit compositions were compared using chemical fractionation analysis and SEM/EDX. Chemical fractionation analysis was capable of explaining the relative fouling tendency of peat, bark, and straw. The composition of deposits obtained from firing peat, bark, and straw individually resembled the composition of their ashes. When firing peat–bark and peat–straw mixtures, it was found that the deposition rate only started to increase when the Cl/S molar ratio in the feed ash exceeded 0.15. The composition of the ensuing deposits resembled the deposits obtained from burning either bark or straw individually. For peat–bark mixtures it was concluded that the presence of S in the feed suppresses deposition by sulfating chloride compounds, leading to deposits that contain less Cl and have less molten phase. For peat–straw mixtures it was concluded that the deposition behaviour is governed by other mechanisms than the interaction of Cl and S.     

Composition of bitumens from alkylated peat

The composition of bitumen compounds from alkylated peat was determined. An increase in the yield of bitumen from alkylated peat is based on the esterification reaction. Various compounds from peat can serve as alternative raw materials for chemical industry.     

Composite Molded Products Based on Recycled Thermoplastics and Waste Cellulosics. I. Peat Moss-Recycled Pe Composites

Effects of three different modified (i.e., chlorinated, chlorosulfonated, and maleated) polyethylenes (PEs) on the mechanical properties and dimensional stability of recycled PE composites filled with biomass (peat moss) have been investigated at room temperature and after exposure to boiling water for 24 h. From the experimental results, it is suggested that differently modified PEs play an important role in improving the physicomechanical properties of the peat moss-filled recycled PE composites, even after exposure to boiling water. However, maleated PE is by far the best coupling agent as far as mechanical properties and dimensional stability of the peat moss-filled recycled PE is concerned. The effects of concentrations of peat moss and coupling agent (i.e., chlorinated PE) on the properties of the composites have been statistically analyzed based on an experimental design and on an empirical quadratic model.     

化学接枝法制备腻子型吸水膨胀橡胶研究

吸水膨胀橡胶是一种新型的功能高分子材料,过去多用机械共混的方法制备,但是这种方法存在着反复使用性能差的缺点,针对这个问题,本实验采用过硫酸铵/硫代硫酸钠氧化还原引发体系,有效地使丙烯酸钠单体与天然胶乳接枝共聚,制备出吸水倍率相当高的腻子型吸水膨胀天然橡胶。实验结果表明:反应温度、引发剂用量对吸水倍率和接枝率有明显的影响,单体用量对吸水倍率影响较大;反复吸水能力基本保持不变。     

Comparisons of the yields and properties of the oil products from direct thermochemical biomass liquefaction processes

Several different direct thermochemical biomass conversion processes are compared based on the results of an experimental program using standard wood and peat feedstocks. The program was part of the International Energy Agency, Biomass Liquefaction Test Facility project. The operating conditions of the processes compared differed greatly. General correlations of the properties of the oils produced from these processes are made based on the severity of the operating conditions. Important parameters in considering process severity are temperature, pressure, time at reaction conditions and added reactants or catalysts.     

The effect of surfactants on peat dewatering

The effect of cationic, anionic and neutral surfactants on the mechanical dewatering of a highly decomposed fuelgrade peat has been examined. Surfactant adsorption and zeta potential of the peat particles correlated with dewatering of peat samples. The cationic surfactants had large positive effects on dewatering, the anionic surfactants had a negative effect while the neutral surfactant had no effect. The effects of the surfactants could be explained by charge neutralization and double layer suppression. The cationic surfactants were superior to analogous organic salts because of enhanced interaction by the hydrophobic effect.     

Enhanced reactivity of metal-impregnated peat char and semi-coke during gas phase hydrogenolysis

Methane formation in the reaction between peat-derived chars and hydrogen was studied using peat semi-coke and doped chars. The latter were prepared by ion exchange of the initial material prior to pyrolysis. Impregnation with relatively large amounts of finely dispersed transition metals (up to ≈15 wt%) results in significant enhancement of methane production. Devolatilization prior to hydrogenolysis exerts a marked influence on the behaviour of the char due to its effect on the concentration of surface oxygen species. The lower the devolatilization temperature, the higher the methane yield. Two distinct peaks are present during the methane formation: a low-temperature peak involving the presence of CO and a high-temperature peak related to the direct reaction between H₂ and the char. The conversion profiles could be well approximated by a two-parameter model.     

Bromination of humic acids of different origin

Data on the introduction of bromine atoms into the structure of humic acids isolated from the peat of Tver oblast and the brown coal of the Moscow Basin were generalized, and a comparative analysis of relevant methods was performed. It was shown that the test humic acids are similar in terms of structural parameters and demonstrate similar behaviors in the processes of bromination and hydrobromination. The dependences of the structural parameters of bromine-containing humic preparations on the mass fraction of bromine in them were obtained; correlations between the yields of humic preparations from the peat and the brown coal in the course of modifications were found; and the possible reaction paths of the bromination and hydrobromination processes were discussed. The biological activity of the bromine-containing humic preparations was tested, and its direct dependence on the mass fractions of bromine and phenolic hydroxyls in the humic preparations was found. It was shown that the modification of peat humic acids by hydrobromination is preferable for the production of biologically active humic preparations.     

The effect of hydrothermal dewatering of Pontianak tropical peat on organics in wastewater and gaseous products

This paper describes a study of the effects of hydrothermal dewatering of raw tropical peat from Pontianak, West Kalimantan-Indonesia, on the amounts of organic compounds released into wastewater and gaseous products. Hydrothermal upgrading and dewatering of the peat was carried out in a batch-type autoclave reactor at temperatures between 150 and 380 °C at a maximum pressure of 25.1 MPa for 30 min. It was found that the extent of decomposition of organics during hydrothermal dewatering depended on temperature increase.Wastewater from hydrothermal dewatering was found to contain organic carbon (TOC) ranging from 800 ppm at low temperatures, to 7504 ppm at high temperatures. A number of sugars and furans were detected in the wastewater at 250 °C, and organic acids and alcohols at all temperatures. Phenol and phenolic derivatives were observed at 250 °C, and significant amounts of CO₂, CO and H₂ were detected at all temperatures studied; CH₄ was detected only at 380 °C, but at this temperature CO₂ was no longer detected.A simplified schematic diagram of the decomposition behavior of tropical peat in the hydrothermal dewatering process is discussed with respect to the change in the concentration of organics in wastewater and gaseous products as determined by TOC, GC, GC–MS and ¹³C NMR analyses of the solids produced.     

2G/n-BuLi体系丁二烯一苯乙烯溶液共聚体系的偶联反应

以ｎＢｕＬｉ为引发剂,二乙二醇二甲醚（２Ｇ）作为结构调节剂,在丁二烯－苯乙烯负离子共聚体系中加入ＳｎＣｌ４或己二酸二乙酯（ＤＥＡＰ）进行偶联反应,研究了２Ｇ用量、不同聚合反应温度、偶联反应温度、偶联反应时间及共聚物不同链末端结构对偶联反应的影响。结果表明,随着２Ｇ添加量的增加、聚合反应温度及偶联反应温度的提高,存在偶联反应效率下降的趋势。在相同条件下ＳｎＣｌ４的偶联效率高于ＤＥＡＰ,且体系共聚物末端结构对偶联效率无明显影响     

Effect of structuring on the density of the liquid in colloidal capillary porous bodies

A method has been developed for calculating the density of the liquid in peat being dried, and liquid density data have been obtained for the first time for peat specimens differing in dispersity and for different drying temperatures. These data are at variance with the tabulated data for the corresponding structuring periods. Unprocessed and slightly processed peat specimens are characterized by smaller density values. High densities are observed for profoundly processed peat. The liquid density as a function of temperature passes through a maximum. At temperatures above the hydrogen bonding manifestation limit, the interaction between elements of the wet peat body is mainly due to the molecular van der Waals forces. The porosity of peat varies with temperature in both structuring periods. There is a discrepancy between the density data obtained using the conventional approach and those obtained by the method suggested here. The data coincide only for the first structuring period, when the moisture content is fairly high, because of the insignificant structuring effect of the solid phase.