TREATMENT OF SWEET GUM LIGNIN BY LACCASE AND LMS

INTRODUCTIONLaccaseisakindofcopper-containingoxidase熏whichwidelydistributesinplantsandmostfungi.Laccasecancatalyzetheoxidationofphenolicsubstances熏soitiswidelyusedinmanyfieldssuchaschemical熏environmental熏biologicalandpapermakingetc.laccaseInpapermakin…     

白腐菌降解氯代酚类化合物的特性研究

研究了Mn^2＋对白腐菌（Phanerochanete chrysosporium）产生的过氧化物酶（MnP和LiP）活力的影响及胞内外酶在氯代酚化合物降解过程中的作用。结果表明：Mn^2＋对MnP和LiP的活力有显著影响；白腐菌对相对分子质量低的有机化合物的降解主要在细胞内依靠胞内酶的作用进行，而胞外酶加快了降解速率；两种胞外酶MnP和LiP在降解过程中所起的作用不同，MnP起主要作用，LiP起次要作用。白腐茵对酚类化合物的基质亲和性较活性污泥低，适宜于高浓有机废水的预处理；白腐茵对毒性的忍受能力与活性污泥微生物相似，但处理方式和条件的改变可以提高其毒性忍受能力。     

木素生物降解酶活力的表面活性剂头基效应研究

用分光光度技术研究了木素生物降解关键酶木素过氧化物酶(LiP)和锰过氧化物酶(MnP)在不同类型表面活性剂存在下,催化氧化木素模型化合物藜芦醇(VA)、2,6-二甲氧基苯酚(DMP)和丁香醛连氮的活力.表面活性剂选择了非离子型、阴离子型和阳离子型中具有代表性的曲拉通-100(TX-100)、十二烷基硫酸钠(SDS)、琥珀酸二辛酯磺酸钠(AOT)、十六烷基三甲基溴化铵(CTAB).结果表明非离子型表面活性剂TX-100对MnP和LiP有激活作用,而离子型表面活性剂对两种酶均有抑制作用,且阴离子表面活性剂的抑制作用远大于阳离子表面活性剂.此外,就MnP而言,表面活性剂对酶促反应的影响大小还与底物性质有关.TX-100对高疏水性底物丁香醛连氮的激活作用要比低疏水性底物DMP大.     

氧脱木素过程中羟基自由基的控制

氧脱木素的主要问题是提高其脱木素选择性,而氧脱木素过程中产生的含氧自由基是影响其脱木素选择性的主要因素.而本文用改进的Fenton反应Co2 -H2O2体系产生羟基自由基(HO.),用茜素紫3B的氧化来显色测定HO..将Co2 -H2O2体系与深度脱木素竹浆进行反应,并通过添加HO.捕获剂来控制HO.的数量,研究HO.与竹浆中木素和碳水化合物的反应情况.把HO.捕获剂作为助剂用于深度脱木素竹浆氧脱木素过程,研究HO.的量对氧脱木素过程的影响.研究结果表明,HO.能与木素和碳水化合物发生反应,具有脱木素作用,但对碳水化合物的降解也较严重.HO.捕获剂具有清除HO.的作用,在氧脱木素过程中加入HO.捕获剂能减少碳水化合物的降解,提高氧脱木素选择性.     

Catalytic oxidation of phenol in wastewater-A new application of the amorphous Fe78Si9B13 alloy

The amorphous Fe78Si9B13 alloy was used as a heterogeneous Fenton catalyst in the process of phenol degradation.The influences of main operating parameters such as reaction temperature,catalyst amount,hydrogen peroxide dosage and initial pH of solution on phenol degradation rate were investigated.The maximum mineralization of phenol was achieved at 60°C,6 g/L Fe78Si9B13, 0.31 mol/L hydrogen peroxide,with an initial pH of 2.5.More than 99%of phenol was completely removed under the optimum conditions within 10 min for a solution containing 1000 mg/L of phenol.Batch experiments for solutions containing phenol con- centrations ranging from 50 to 2000 mg/L were investigated under the above conditions and the same excellent degradation rate was obtained.The Fe78Si9B13 showed better catalytic activity than iron powder and Fe 2+ .Addition of n-butannol(hydroxyl radical scavenger)decreased the degradation rate of phenol,which demonstrates that hydroxyl radicals were mainly responsible for the removal of phenol.We demonstrated that phenol may be degraded by hydroxyl radicals decomposed by hydrogen peroxide on the surface of Fe78Si9B13 and illustrated the reaction mechanism for this process.This amorphous alloy exhibited high stability in recycling experiments and showed excellent reuse performance even after continuous operations of 8 cycles.     

Hydroxyl radicals induced by quartz particles in lung alveolar macrophages： the role of surface iron

Previous studies have shown that hydroxyl radical generation is a key step in the mechanism of pathogenic process caused by airborne particles to the lung. However, there is no direct evidence for dose-response relationship between airborne particles and hydroxyl radical generation. In this study, hydroxyl radicals generated in lung alveolar macrophages exposed to quartz particles were measured using a highly sensitive capillary electrophoresis-fluorescence detection method. The results demonstrated that quartz particles induced the generation of hydroxyl radical in a dose-dependent manner, and the amount of the hydroxyl radicals was 10^-10 mol/10⁶ cells. The viability of alveolar macrophages exposed to quartz particles decreased with the increase of quartz concentration, showing a clear dose-response relationship. Hydroxyl radical scavenger mannitol could increase the viability of quartz-treated cells, suggesting that hydroxyl radical contributed directly to cell death. In this study this contribution accounted for about 5%?20% of cell death. The hydroxyl radical generating potential was found to be related to surface iron content of the quartz particles.     

Formation of hydroxyl radicals and oxidation of toluene under corona discharge with water vapor as radical source

With water vapor as the radical source, hydroxyl radicals （. OH） of strong oxidation property were formed by corona discharge, which was directly detected by electron spin resonance （ESR） technology. These · OH could efficiently degrade gaseous organic pollutants so as to reduce the toxicity of waste gas. The experimental result of toluene degradation under DC corona discharge showed that the degradation efficiency of toluene was nearly 100% in the medium of air containing saturated water vapor under the condition that interelectrode voltage was 20 kV, discharge current was 0.1 mA, reaction time was 120 s and initial concentration of toluene was 168 mg/m^3, respeUvely. Seven intermediate products of toluene oxidation dissolving in liquid phase were also determined. The empolyment of environmental friendly - OH provides a new approach for the removal of gas pollutants.     

酰化剂对木质素羟值测定的影响

参照聚醚多元醇羟值测定方法，比较了邻苯二甲酸酐(PA)和对甲基苯磺酰异氰酸酯(TSI)作为酰化剂进行木质素羟值的测定结果，发现TSI可以与木质素分子中的部分酚羟基发生酰化反应，而PA只能与醇羟基反应，故TSI的测定结果远高于PA的测定结果。提出以酰化能力与多异氰酸酯接近的异氰酸苯酯(PI)为酰化剂测定木质素样品羟值，PI法测试结果介于PA-吡啶法和TSI-乙腈法之间。     

白腐菌对秸秆中木质素生物降解的研究

研究了白腐菌及其产生的木质素降解酶系对秸秆的木质素生物降解方法，探讨了黄孢原毛平革菌和杂色云芝单一菌株生物降解及双菌株联合降解木质纤维素的规律，白腐菌双菌联合固态培养可使木质素降解率达到47．64％，脱木素选择性为4．74．采用模拟大规模白腐菌堆积培养（厚度30cm）的方法降解秸秆木质素，培养30d，木素降解率为32．54％，表明此方法是一种可行的大规模生物顸处理方法．     

高效木质素降解菌的筛选及降解性能研究

【目的】筛选纯化及鉴定木质素降解菌,对其降解性能进行初步研究。【方法】从某制浆造纸厂的造纸废水污泥中,筛选获得2株具有木质素降解能力的细菌LD-1和LD-2。通过形态观察和16SrRNA序列分析对菌株进行鉴定;采用苯胺蓝平板脱色法及以TC为指标分别定性定量测定2株细菌的木质素降解能力。【结果】LD-1和LD-2分别被鉴定为Sphingobacterium属和Bacillus属的菌株,命名为Sphingobacterium sp.LD-1和Bacillus sp.LD-2。通过苯胺蓝平板脱色实验,发现LD-1和LD-2均具有良好的木质素降解能力。经测定,两株菌种发酵7d对木质素的降解率分别达到52.23%和50.36%。【结论】成功筛选到2株能高效降解木质素的菌株LD-1和LD-2。     

一种新的羟自由基生成方法及其在亚甲基蓝降解中的应用

对苯二甲酸是一种羟自由基捕获剂,它与羟自由基作用后生成有荧光的羟基对苯二甲酸,通过测定超声前后对苯二甲酸荧光强度的变化间接测定超声所产生的羟自由基的量.对时间、功率、pH等因素进行初步的研究,考察它们对超声产生羟基自由基的影响,发现超声时间越长、超声功率越大,产生的羟自由基的量越多,在超声时间为10min、超声功率为100W时250mL对苯二甲酸溶液中产生羟自由基浓度31.14μmol/L,且羟自由基产生量与时间呈现出一定的量化关系;此外,pH值对羟自由基的产生量影响不大.本方法可检测到超声产生的羟自由基最短时间为2min,最低检出限达到0.063μmol/L,稳定性好、操作简便,测定快速.采用超声处理亚甲基蓝溶液,亚甲基蓝逐渐被降解,进一步证实羟自由基的产生,为超声降解提供理论依据.     

添加因子对Fhhh菌株降解废水性能影响的研究

在精对苯二甲酸(PTA)石油化工废水中，添加氮、磷、Mn^ 2 3种因子，测定该3种添加因子对Fhhh菌株降解废水效率的影响．结果表明，在6组试验中，TA3组降解CODcr的效率最高．是TA1组的25倍；MnP酶的活性水平最高，是TA1组的1.4倍研究结果为现场试验调控Fhhh菌株降解废水的潜力，提供了重要依据。     

Degradation of organic pollutants by a Co3O4-graphite composite electrode in an electro-Fenton-like system

A novel composite electrode was constructed by pressing together Co3O4 and graphite and it was used as the cathode in an electro-Fenton-like (EFL) system. The poor electron transport characteristic of Co3O4 was overcome by incorporating graphite. In situ electro-catalytic generation of hydroxyl radicals (·OH) occurred at high current efficiencies from pH 2-10, extending the traditional Fenton reaction pH range. Cyclic voltammetry and AC impedance spectrometry were used to characterize the composite electrode. The ability of the EFL system to degrade organic compounds was investigated using sulforhodamine B (SRB) and 2,4-dichlorophenol (2,4-DCP) as probes. Decoloration of SRB (1.0×10-5 mol/L) was complete (100%) in 150 min and SRB was effectively degraded from pH 2-10. The decomposition of SRB was studied using Fourier transform infrared spectroscopy (FT-IR) and total organic carbon (TOC) analysis and results indicated that the final degradation products were carbon dioxide, carboxylic acids and amines. The EFL system also decomposed 2,4-DCP and the degradation was 98.6% in 240 min. Electro-catalytic degradation of SRB occurs by a ·OH mechanism. After 5 times reused, the degradation rate of SRB did not significantly slow down. The electrode shows excellent potential for use in advanced oxidation processes (AOPs) used to treat persistent organic pollutants (POPs) in wastewater.     

娄彻氏链霉菌发酵改善水稻秸秆加工性能的研究

【目的】应用正交试验,研究了娄彻氏链霉菌发酵对水稻秸秆加工性能的影响。【方法】在30℃、含水率为65%的条件下,探究了发酵时间、接种量、碳氮比3因素对水稻秸秆质量损失率,纤维素、半纤维素和木质素的降解率,以及最大压应力和黏度(加工性能)的影响,并利用SPSS 19.0软件分析了降解条件与水稻秸秆理化性能的相关性。【结果】娄彻氏链霉菌发酵条件对水稻秸秆的降解性与加工性能的影响顺序为:发酵时间碳氮比接种量;通过相关性分析可得,发酵时间与纤维素、半纤维素和木质素的降解率以及质量损失率极显著正相关,与秸秆的最大压应力和黏度显著负相关。发酵的最优条件为:碳氮比为25,接种量为0.8%,发酵时间为20 d。此时水稻秸秆的最大压应力为5.62 MPa,较原秸秆降低了10.74%;黏度为415.8 m Pa"s,较原秸秆提高了29.7%;平衡扭矩则降低了18.2%。微观结构(SEM)显示发酵后水稻秸秆表面粗糙、凹凸不平,内部结构发生了变化。【结论】娄彻氏链霉菌发酵改变了水稻秸秆的物理化学结构,改善了水稻秸秆的加工性能。     

NREL法测定大米草原料组分的含量

采用美国国家可再生能源实验室(NREL)方法定量大米草原料中纤维素、半纤维素及木质素。72%浓硫酸水解1 h、4%稀硫酸水解1 h可将大米草的纤维素、半纤维素降解为可用HPLC定量的单糖,适宜的样品添加量为0.3 g。同时,NREL法测定大米草纤维素、半纤维素及木质素的含量分别为32.92%、27.65%和24.2%。这三个组分的含量是评价大米草预处理、酶解及发酵工艺条件的重要依据。     

粉丹竹磺化化学机械浆木素结构的31P-NMR和13C-NMR波谱分析

粉丹竹磺化化学机械浆（SCMP）的木素结构在漂白和老化过程中发生变化，使用纤维素酶酶解-弱酸水解的两步法对SCMP及其漂白浆、漂后老化浆中木素进行分离提纯，利用31P-NMR和13C-NMR波谱对木素样品中的结构及其比例进行研究。结果表明：SCMP木素样品中三种结构单元—对-羟苯基（H）、愈疮木基（G）和紫丁香基（S）的比例为G:S:H=30:42:28。在其漂白和漂白浆老化过程中，总酚羟基分别减少了30.7%和38.4%，而羧基的含量分别增加了53.2%和55.3%，木素结构中烷基芳基醚键和α-烷基醚键发生了断裂，γ-烷基醚键则比较稳定，同时木素侧链发生断裂，形成香草醛、Ar-COOH和Ar-CH2-COOR等结构。     

Photodegradation of <Emphasis Type="Italic">N</Emphasis>-nitrosodiethylamine in water with UV irradiation

The direct photolysis of N-nitrosodiethylamine （NDEA） in water with ultraviolet （UV） irradiation was investigated. Results showed that NDEA could be completely degraded under the direct UV irradiation. The effects of the experimental conditions, including the initial concentration of NDEA, humic acid and solution pH, were studied. The degradation products of NDEA were identified and quantified with gas chromatography-mass spectrometry （GC-MS） and high performance liquid chromatography （HPLC）. It was confirmed that methylamine （MA）, dimethylamine （DMA）, ethylamine （EA）, diethylamine （DEA）, NO2^- and NO3^- were the main degradation products. The photolysis degradation mechanism of NDEA was also discussed. As a result of N-N bond fission, NDEA was degraded by direct UV irradiation.     

稻草木质素的硫酸法提取与表征

用硫酸法提取农作物废弃物稻草中的木质素,采用质量分数72%的硫酸,以15(mg)∶1(L)的液固单位比,室温下反应2 h,得到产率9.23%的木质素.利用扫描电镜(SEM)、综合热分析、傅里叶红外光谱(FTIR)和氢核磁共振波谱(¹H-NMR)分析手段表征木质素的物理性质和化学结构,结果表明:木质素呈表面粗糙且有大量孔隙的不规则块状结构,在175~700 ℃内发生热解,分子结构中存在着大量羟基、羰基和醚键等活性官能团,属于对羟基苯基-愈创木基-紫丁香基型木质素.     

稀土氧化物掺杂对TiO2/沸石光催化性能的影响

以钛酸丁酯和稀土氧化物为原料, 采用溶胶 凝胶法制备了镧、 钕和镱稀土离子掺杂TiO₂/沸石光催化剂. 通过XRD和IR方法对样品进行表征, 研究了不同沸石粒径及不同稀土氧化物掺杂量(质量分数)对农药敌敌畏光催化降解性能的影响. 结果表明, 当沸石最佳粒径为0.15 mm, La³⁺掺杂量质量分数为3.0%时（以TiO₂质量计）, 稀土离子的掺杂可显著提高TiO₂//沸石的光催化降解性能.     

Surface modification of γ-Al2O3 by sodium ions

¹H/²³Na double resonance NMR techniques were employed to study the modification of surface hydroxyls on γ-Al₂O₃ by sodium ions. ¹H→²³Na cross polarization (CP) experiment can resolve three kinds of sodium cations that are closely associated with surface hydroxyl groups, while the signal of deposited salt-Na₂CO₃, which is not connected to surface hydroxyl groups, is completely suppressed. ¹H{²³Na} spin echo double resonance experiments reveal the surface modification in more detail. At low Na⁺ coverage (5%, 10%), the acidic hydroxyl groups are preferentially coordinated with sodium ions, while both the acidic and the basic hydroxyl groups are accessible for sodium ions at high coordination that causes proton of the OH groups to be easily dissolved, which is evidenced by the fact that with calcination temperature of the catalysts increasing, the acidic hydroxyl groups are preferentially removed and only the basic hydroxyl groups remain when the calcination temperature is raised to 600℃.