固定化黄孢原毛平革菌生产乙二醛氧化酶的研究

聚氨酯泡沫固定化黄孢原毛平革菌限碳培养能有效地生产乙二醛氧化酶,乙二醛氧化酶的底物丙酮醛、乙二醛等不能诱导乙二醛氧化酶的合成,藜芦醇、苯甲醇能诱导乙二醛氧化酶的合成。Mn2+浓度为2.96×10-5mol/L时活力最高,Fe2+、Cu2+对产量影响不大,空气中能合成乙二醛氧化酶,但效果不如通氧。在较优的培养条件下,乙二醛氧化酶活力为29.1U/L。     

Effect of ozone pre‐treatment of colored upland water on some biological parameters of sand filters

A pilot treatment plant for potable water, consisting of an ozonating unit followed by slow sand filters, was built in order to determine the relationship between filter biomass and performance following ozonation of colored feed water of upland origin. The color is due largely to the presence of humic substances, being most prevalent after heavy rainfall in the catchment. Ozone improves color by breaking down large humic molecules to smaller organic species, thus providing more bioavailable material in the water. Slow sand filtration, applied after ozonation, removes some of this material at the expense of more rapid clogging of the filters. This study on the schmutzdecke showed that the overall biomass of ozonated filters after clogging was significantly greater compared to non‐ozonated filters. Results revealed an increase in the heterotrophic biomass, but no significant change in the autotrophic community biomass, in slow sand filters receiving pre‐ozonated water.     

以乙二醛为交联剂的壳聚糖纤维交联机理探索

采用乙二醛为交联剂对壳聚糖纤维进行交联处理以改善纤维强度。基于对红外光谱和核磁共振图谱的分析,探索了乙二醛与壳聚糖纤维交联反应的机理。研究结果表明,乙二醛特殊的化学结构使其利于亲核试剂的攻击,而壳聚糖的氨基和羟基具有亲核性,因此乙二醛可以与壳聚糖发生交联反应。交联反应主要有两类:一类是发生在壳聚糖C2氨基与乙二醛羰基之间的Schiff碱反应,占据主导地位;另一类是发生在壳聚糖C6羟基与乙二醛羰基之间的缩醛化反应,处于次要地位。     

乙醛硝酸氧化制备乙二醛的工艺研究

乙二醛作为精细化工中的一种重要的中间体,广泛应用于化工的诸多领域中。但由于其在开发应用方面存在局限性,不能大量生产,使乙二醛供不应求。通过分析乙醛硝酸氧化生成乙二醛的工艺路线,对不同催化剂的催化效果进行相关阐述。     

高效液相色谱法测定化妆品中乙二醛的方法研究

建立了柱前衍生化,高效液相色谱法（HPLC）测定化妆品中乙二醛的方法。样品用乙腈-水溶液溶解,与2,4-二硝基苯肼在弱酸条件下衍生化反应,衍生物直接用HPLC测定,用外标法定量。方法的相关性好（γ〉0.9990）,样品测定的相对标准偏差RSD〈5%,加标回收率为91.4%～98.0%,检出限为1.6μg/g。本方法线性范围宽,测定结果准确,适用于化妆品中乙二醛的常规分析。     

我国乙二醛生产技术进展及市场分析

乙二醛是一种重要的精细化工产品,在医药、轻工、纺织印染以及石油化工等方面具有广泛的用途。目前,乙二醛的生产方法主要有乙二醇气相氧化法和乙醛硝酸氧化法2种,我国的乙二醛采用乙二醇气相氧化法进行生产。介绍了乙二醛的生产技术及其进展,分析了我国乙二醛的生产、消费及发展前景,提出了今后的发展建议。     

Evaluation Of Ozone/Biological Treatment For Disinfection Byproducts Control And Biologically Stable Water

Impacts of ozonation followed by biological filtration on the formation of disinfection byproducts and the production of biologically stable water were studied on pilot plant and full-scale at two U.S. locations (Oakland, CA and Tampa, FL). Also evaluated is a method to estimate bacterial regrowth potential by comparing it to assimilable organic carbon (AOC) measurements. At both locations, settled plant water is diverted to the pilot plant where it is split into two parallel trains. One train is ozonated, then Filtered through anthracite/sand dual media followed by GAC or through a GAC/sand dual media filter. The other train (control) is identical except that the water is not ozonated. The full scale plants have sedimentation, ozonation, then GAC/sand filtration.     

Wrinkle resistant properties and antibacterial efficacy of cotton fabrics treated with glyoxal system and with combination of glyoxal and chitosan system

This study examined the possibility of using glyoxal and chitosan in one‐step finishing to impart both durable press performance and antibacterial efficacy on cotton fabrics. Glyoxal treatment provided good wrinkle resistant property and fair antibacterial activity on the finished fabrics, but the loss of breaking strength retention of the finished fabrics was a main problem of this treatment. Chitosan added in the combination of glyoxal and chitosan system also provided comparable results in wrinkle resistant and antibacterial properties on the finished fabrics as the glyoxal did. The advantage of chitosan in the combination of glyoxal and chitosan system was the improvement of the breaking strength retention of the finished fabrics without affecting the durable press property of the finished fabrics. However, the yellowing of the finished fabric was still a problem when the finished fabrics were treated with the combination of glyoxal and chitosan system. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1372–1377, 2006     

Adsorption and Microbiological Mechanisms for Removal of Natural Organics in Granular Activated Carbon Columns

Performance data for GAC columns treating surface water are analyzed to determine the relative importance of physical adsorption and biological activity, with and without pre-ozonation. Kinetic and equilibrium adsorption parameters for the source water are used in the Homogeneous Surface Diffusion model to predict GAC performance over 83 weeks. The model underestimates removal of TOC for ozonated and unozonated streams by 46% and 28%, respectively, which is attributed to omission of biological removal in the model.     

Removal Of Residual Organics From Drinking Water By Ozonation And Activated Carbon Filtration: A Pilot Plant Study

The effects of ozonation, granular (GAC) and biological activated carbon (BAC) in the removal of natural organic matter and precursors of disinfection byproducts from drinking water were studied on pilot scale. Ozonation was determined to be the best method to reduce concentrations of the precursors of AOX, chloroform and mutagenicity, whereas BAC removed organic matter the most effectively. Reductions in TA100 mutagenicity were an average 40%, 4%, 26% in ozonated, GAC and BAC filtered water, respectively. Average reductions of AOX levels were similar at 48%, 7% and 35%, respectively. The chloroform formation potential always increased after GAC filtration.     

离子色谱在乙二醛电氧化过程中的应用

基于离子色谱原理,成功地研发出一种适用于乙二醛电氧化过程主要物种快速检测的新技术。研究表明,该技术不仅具有设备简便,检测快速灵敏和选择性高等优势,而且还能实现同时测定多种组分的目的。检测灵敏度小于0 5mg/L,保留时间、峰高、峰面积的变异系数均小于2%;对各物种回收率的检测结果为97%～103%。离子色谱电导检测技术的成功研发为乙二醛电氧化过程物种的实时、快速检测提供了便捷的分析手段,这对电合成体系的生产指导和过程评价具有重要意义。     

HPLC determination of glyoxal in aldehyde solution with 3-methyl-2-benzothiazolinone hydrazone

Based on the absorption property of a diazine that can be formed by reaction of glyoxal and 3-methyl-2-benzothiazolinone hydrazone (MBTH) in the Ultraviolet-visible (UV-vis) spectral region, a HPLC method was developed for the determination of glyoxal in acetaldehyde solution. Glyoxal was derivatised from MBTH and the derivatives (diazine) were analyzed by HPLC for identification and quantification. The determination was performed on a ZORBAX Eclipse XDB-C18 column (4.6 × 250 mm, 5 mm) at 35°C with an injection volume of 10 mL, using a mixture of acetonitrile-water solvent (99∶5, v∶v) as a mobile phase with a flow rate of 0.8 mL·min^-1. The proper derivative reaction conditions were the temperature of 70°C, MBTH to carbonyl molar ratio of 12, and reaction time of 110 min. The glyoxal diazine was a yellow dye with a maximum molar absorptivity at 401 nm and its retention time was 5.2 min under optimal HPLC conditions. The standard curve for glyoxal had a strong linear relationship with a regression coefficient (R² = 0.999) in the range of 0.002–0.020 g·L^-1. The analysis of glyoxal in an oxidising solution gave accurate results with a relative standard deviation (RSD) value of 0.55%. The average relative recovery was 102%. This efficient HPLC technique is also proposed for detecting other dicarbonyl compounds besides glyoxal.     

Applications of bifunctional aldehydes to improve paper wet strength

Glyoxal and glutaraldehyde behave very differently for improving wet strength of paper. It is found that glyoxal is very efficient for improving temporary wet strength of paper without the presence of a catalyst and exposure to elevated temperatures. When a metal salt, such as Zn(NO₃)₂, is used as a catalyst and the curing temperature is increased, the durable wet strength of glyoxal‐treated paper increases at the expense of its flexibility, as shown by reduced stretch and folding endurance. Glutaraldehyde is not able to provide any improvement in wet strength to paper, even under high curing temperatures, provided no catalyst is used. With the aid of a metal salt catalyst, glutaraldehyde imparts excellent durable wet strength to paper without significantly sacrificing folding endurance, and the wet strength of glutaraldehyde‐treated paper increases steadily as curing temperature increases. The different behavior of glyoxal and glutaraldehyde may be attributed to their different reactivity toward cellulose. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2539–2547, 2002     

Influence of glyoxal on curing of urea-formaldehyde resins

In the present paper, the effect of glyoxal on the gel formation within the adhesive systems based on urea-formaldehyde (UF) resins is shown. A reduction of formaldehyde content in wood-based panels by decreasing the formaldehyde/urea molar ratio in the UF resins leads to increasing of the UF resin gel time, and impairing the qualitative characteristics of the UF-based wood materials. Glyoxal is shown to speed up the crosslinking of the macromolecules as well as significant reduction of gel time of adhesive composition. The first reason is the result of reaction between glyoxal and ammonium ion leading to protons releasing. Another reason is that glyoxal and its interaction products react with macromolecules of the UF resin forming a three-dimension cross-linked structure. The gel time and the pot life of the UF resin are measured by the oscillatory viscometer. Formation of the UF cross-linked resin structure with glyoxal and a curing catalyst (ammonium sulfate) is studied using dispersion Raman scattering spectroscopy. Particleboards (PB) are produced using different amount of glyoxal and formaldehyde/urea molar ratio in the UF resin. The properties are evaluated according to the European Standards and include density, internal bond, thickness swelling moisture content and formaldehyde content.     

The Determination of Carbonyl Compounds in Ozonated Water by the PFBOA Method

PFBOA, O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine, is excellent as a derivatizing agent in the GC determination of carbonyl compounds in ozonated water samples. Surface and waste waters have been ozonated. The carbonyl ozonation by-products were identified as PFBOA derivatives by gas chromatography-mass spectrometry. The main by-products of ozonation identified were formaldehyde, glyoxal, methylglyoxal, and 13 other compounds. The characteristics of the first three compounds with respect to production and decomposition during ozonation are discussed.     

Ozonation/Post-Chlorination of Humic Acid: A Model for Predicting Drinking Water Disinfection By-Products

Experiments were performed to evaluate disinfection by-products in model humic acid solutions which were ozonated at three different ozone to carbon levels and then chlorinated. These experiments were conducted in order to help understand whether the ozone/post-chlorination process alters the amount and type of mutagenic by-products formed, from those produced by chlorination of humic acid alone. Disinfection by-products were identified by gas chromatography/mass spectrometry (GC/MS). Samples of clarified and sand-filtered Mississippi River water at a pilotscale drinking water treatment plant in Jefferson Parish, Louisiana, that were ozonated and post-disinfected with chlorine, also were analyzed by GC/MS. A comparison of the by-products in the pilot plant study versus those in our laboratory study showed that similar compounds were produced. The effect of bromide ion in the pilot plant water on by-product formation also is discussed.     

Ozonation of Humic Substances: Effects on Molecular Weight Distributions of Organic Carbon and Trihalomethane Formation Potential

Four different sources of humic substances were studied to determine the effects of ozonation on molecular weight-distributions, based on dissolved organic carbon (DOC) and trihalomethane formation potential (THMFP). Solutions of two soil-derived fulvic acids and a one soil-derived humic acid, as well as dissolved organic matter (DOM) associated with a natural water source were studied. Both gel permeation chromatography (GPC) and ultrafiltration (UF) were employed to define apparent molecular weight (AMW). Applied ozone doses ranged from 2.0 to 2.5 mg O₃/mg DOC. Overall samples of untreated and ozonated waters, as well as individual molecular weight fractions, were characterized according to DOC, UV absorbance, and THMFP. Ozonation resulted in a significant disappearance of higher AMW material with a corresponding increase in lower AMW material. Although little overall reduction in DOC concentration was observed, significant overall reductions in UV absorbance and THMFP levels were observed.     

Biodergradability and GAC Adsorbability of Micropollutants by Preozonation

In order to evaluate the effect of preozonation on GAC adsorbability and biodegradability and to discuss the performance of BAC, three kinds of batch experiments have been conducted, using humic acid as the test substance. Conclusively, it is recognized that preozonation evidently improves the biodegradability of humic acid, but the equilibrium adsorption constant k, is not changed. However, the adsorption rate is greatly improved. Based on these results and continuous experiments, the characteristics of the removal mechanism of organics by a BAC filter and a GAC filter are compared.     

Impact of Support Media on the Biological Treatment of Ozonated Drinking Water

An extensive review of the technical literature was conducted in order to determine the advantages and disadvantages of the various media used for biological filtration of ozonated drinking water. Granular activated carbon (GAC) filters were found to be significantly more efficient than conventional filters such as sand and anthracite coal. The type of activated carbon also impacted the performance of biofilters; due to their greater adsorption capacity, microporous GACs were found to be better suited than macroporus GACs.     

乙二醇催化氧化制备乙二醛节能工艺比较

乙二醛是一种用途十分广泛的有机化学中间体,市场上销售的产品多是浓度为30~40%的乙二醛水溶液,在纺织印染、建材、皮革、医药、农药、国防、涂料、轻工、粘合剂和环保等方面具有广泛的应用,国内现有生产装置多采用乙二醇催化氧化工艺,对于乙二醇氧化工艺降低生产能耗具有重大意义。