碳热法合成纳米零价铁-活性炭复合材料性质表征和应用

采用碳热法合成纳米零价铁-活性炭复合材料,原材料采用蔗糖和氯化亚铁。蔗糖和氯化亚铁溶液经过高温热解后,蔗糖成为多孔性活性炭,而氯化亚铁则被还原成零价铁。不同合成温度下所制备材料的X射线衍射结果表明:碳热法能成功合成零价铁,且零价铁颗粒为纳米级;合成温度从500℃升至1 100℃时,材料中铁含量逐渐增加;电子扫描电镜图像则进一步显示出纳米零价铁被包裹在活性炭结构中;合成材料的比表面积和微孔容积最高分别达到311 m2·g-1和0.053 m L·g-1,为多孔性材料;合成材料对水中的Cr(VI)有很好的去除能力。     

多种工艺联合处理医药废水的研究

介绍了应用“混凝沉淀-芬顿氧化-微电解-混凝沉淀-UBF-接触氧化-沉淀-活性炭吸附”多种工艺联合处理医药及其中间体生产废水。处理后的废水经监测证明,各项指标均达到国家排放标准,其中COD、BOD、SS及色度的去除率分别为99.5%、98.6%、85.7%和97.2%以上。为医药难降解废水的处理开辟了新途径。     

超低浓度马来酸催化水解纤维素的机理研究

将超低浓度马来酸应用于纤维素水解研究,对间歇条件下最优工况的产物和超低浓度硫酸水解纤维素产物与前人结果进行比较,初步探讨了马来酸水解纤维素的机理。试验在高温高压反应釜中进行,液固比为20∶1,转速为500 r/min,反应压力为4 MPa,改变温度和酸浓度,多点采样,结果发现,超低马来酸催化滤纸纤维素水解产糖效果较好,糠醛类降解产物明显少于硫酸催化。推导整合马来酸催化纤维素水解的基本原理,与常规无机酸催化相比,马来酸水解可同时遵循拟糖苷酶催化与一般酸催化机理,并能通过自身特性有效抑制还原糖的降解,从而获得较高的糖收率。     

三层液电解精炼提纯冶金级硅研究

在氟化物熔盐电解质体系下,把Cu与冶金级多晶硅熔配成合金作为阳极硅源,利用杂质与硅析出电位的差别,通过控制电解工艺条件和参数,对冶金硅进行了电解精炼提纯研究.结果表明:电解过程平稳,且电流效率保持95%以上;阴极电沉积硅呈颗粒状,尺寸约为100μm;随着电解时间的延长,分散的硅的颗粒有聚集成大尺寸硅球的趋势.ICP-AES分析表明,最后得到的产物硅与冶金级硅相比,硼含量由12.7mg/kg降低到2.4mg/kg,磷含量由98.6mg/kg减少到4.3mg/kg.     

生物炭和乙醇对油菜秸秆沼气发酵特性的影响

对生物炭和乙醇提高油菜秸秆厌氧发酵沼气产率进行实验研究,探索不同乙醇浓度对中温和高温厌氧发酵沼气产率、木质纤维素降解和微生物菌群结构的影响。结果表明：生物炭和乙醇可促进沼气产率和纤维素降解。随着乙醇浓度的增大,沼气产率先增大后减小,3 g/L乙醇浓度时中温和高温发酵沼气产率最高,分别为219.3和240.5 mL/g。从木质纤维素降解来看,中温发酵组纤维素含量由预处理秸秆的54.00%降至18.69%～25.03%。测序结果显示乙醇浓度为3 g/L的中温发酵沼渣中厚壁菌门和拟杆菌门相对丰度最高,揭示了生物炭和乙醇促进油菜秸秆厌氧发酵产气的机制。     

木质素磺酸盐在微波/H2O2体系中降解行为研究

通过比较处理前后紫外可见光谱、红外吸收光谱、凝胶过滤色谱(GPC)的变化和对降解产物的气质分析,研究了木质素磺酸钠在微波/H2O2体系中的降解行为。试验发现,微波/H2O2体系能有效促使木质素降解,降解过程中苯丙烷侧链和苯环都遭到了不同程度的破坏。在低浓度双氧水条件下,中间产物中含有大量芳香醛;在高浓度双氧水条件下,芳香醛含量减少,低分子量脂肪酸含量增多。降解后残渣的分子量减小,分布变窄。通过对木质素磺酸钠降解后的产物分析,推测了其在微波/H2O2体系中降解的可能机理,为木质素资源的高效综合利用寻找新的途径。     

芬顿的原理与应用

电芬顿作为一种新型电化学氧化技术,由于它在阴极和阳极都能产生羟基自由基(·OH)氧化降解水体中污染物,引起了学者们广泛的关注。针对含苯酚废水来源广、危害大、成分复杂的特点,采用Fenton技术对苯酚废水的处理效果进行了研究,考察了催化剂、氧化剂、粉煤灰的用量和pH值对芬顿试剂氧化苯酚的影响。     

芬顿的原理与应用

电芬顿作为一种新型电化学氧化技术,由于它在阴极和阳极都能产生羟基自由基(·OH)氧化降解水体中污染物,引起了学者们广泛的关注。针对含苯酚废水来源广、危害大、成分复杂的特点,采用Fenton技术对苯酚废水的处理效果进行了研究,考察了催化剂、氧化剂、粉煤灰的用量和pH值对芬顿试剂氧化苯酚的影响。     

有机钙盐预处理纤维素的热解试验研究

摘要：在管式炉上进行了预处理纤维素（CaFA纤维素）的热解实验，研究了预处理对纤维素热解特性的影响。样品红外压片分析显示预处理影响了纤维素组成单元吡喃环的稳定性，且CaFA纤维素出现了明显的羧酸根官能团振动。热解实验表明：预处理使得纤维素的半焦和气体产率增加，生物油产率下降。CaFA纤维素最大生物油产率为0.496(g/g)，相比未处理纤维素最大生物油产率降低19.1%。CaFA纤维素的气体产物中，CO含量减少，而CO2、CH4和H2含量增加，一定程度上提高了热解气相产物中的氧含量。GC-MS分析表明预处理对纤维素生物油组分具有明显的选择性，CaFA纤维素生物油中，大分子糖类及其衍生物的相对含量显著减少，而小分子酮类物质明显增加。     

电混凝法处理电镀废水中的Cu^2＋和Zn^2＋

利用电混凝法处理含Cu^2＋和Zn^2＋的电镀废水,系统地考察了电解电压、进水pH值、极板间距、电解时间等因素对废水处理效果的影响,确定了最佳的电解条件。实验结果表明,电混凝法处理的电镀废水出水水质较好。当电压为80 V,pH值为5,电解时间30 min,极板间距为10 mm时,处理后的废水中Zn2＋浓度为0.36mg/L,去除率达到97.9%,Cu^2＋浓度为0.0049 mg/L,去除率达到99.9%,均可达到国家规定的排放标准,且该法运行方便,处理时间短,是较理想的电镀废水处理工艺。     

Bio-hydrogen production based on catalytic reforming of volatiles generated by cellulose pyrolysis: An integrated process for ZnO reduction and zinc nanostructures fabrication

The paper presents a process of cellulose thermal degradation with bio-hydrogen generation and zinc nanostructures synthesis. Production of zinc nanowires and zinc nanoflowers was performed by a novel processes based on cellulose pyrolysis, volatiles reforming and direct reduction of ZnO. The bio-hydrogen generated in situ promoted the ZnO reduction with Zn nanostructures formation by vapor-solid (VS) route. The cellulose and cellulose/ZnO samples were characterized by thermal analyses (TG/DTG/DTA) and the gases evolved were analyzed by FTIR spectroscopy (TG/FTIR). The hydrogen was detected by TPR (Temperature Programmed Reaction) tests. The results showed that in the presence of ZnO the cellulose thermal degradation produced larger amounts of H₂ when compared to pure cellulose. The process was also carried out in a tubular furnace with N₂ atmosphere, at temperatures up to 900 °C, and different heating rates. The nanostructures growth was catalyst-free, without pressure reduction, at temperatures lower than those required in the carbothermal reduction of ZnO with fossil carbon. The nanostructures were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and transmission electron microscopy (TEM). The optical properties were investigated by photoluminescence (PL). One mechanism was presented in an attempt to explain the synthesis of zinc nanostructures that are crystalline, were obtained without significant re-oxidation and whose morphologies are dependent on the heating rates of the process. This route presents a potential use as an industrial process taking into account the simple operational conditions, the low costs of cellulose and the importance of bio-hydrogen and nanostructured zinc.     

一株纤维素降解新菌种发酵玉米秸秆的生物产氢特性研究

试验从连续流发酵产氢反应器（ZL92114474．1）中分离筛选出一株高效纤维素降解产氢细菌Clostridilan sp．X9。X9利用微晶纤维素（MC）作为发酵产氢底物,得到最大单位体积产氢量（YH2）、比产氢率（YH2／s）和纤维素降解率分别为780mL H2／L-culture、5．1mmol H2／g-cellulose和69．6％。采用酸、碱、氨水和酸化汽爆方式预处理玉米秸秆,结果表明,酸化汽爆方式可以获得最佳的预处理效果。x9利用酸化汽爆玉米秸秆（cSES）发酵产氢的YH2、YH2／s和纤维索降解率分别达到730mL H2／L-culture、4．3mmol H2／g-cellulose和64％。这说明新菌种X9在利用玉米秸秆类生物质纤维素发酵产氢方面具有很好的应用潜力。     

热纤梭菌转化木质纤维素产乙醇的研究进展

热纤梭菌是一种高效的、能直接分解纤维素的嗜热厌氧菌,其转化纤维素的主要产物有乙醇、乙酸、乳酸、CO₂和H₂等,是目前最有希望实现纤维素转化工业化的菌株之一。本文综述了热纤梭菌转化木质纤维素产乙醇的相关研究,涉及热纤梭菌的代谢途径、纤维素降解机制及其在合成乙醇方面的最新进展。     

拟康氏木霉和白腐菌混菌发酵处理稻草秸秆的研究

以拟康氏木霉3.3002(Trichoderma pseudokoningii)和白腐菌5.776(Phanerochaete chrysosporium)的混合菌发酵处理稻草秸秆,并对处理结果进行了试验研究.研究结果表明,当接人拟康氏木霉与白腐菌时间间隔为3 d.接种液体积比为2 ml:2 ml,氮源为0.3%(质量分数)的(NH4)2SO4,发酵时间为8 d时,稻草秸秆纤维索降解率和木质素降解率分别为40.38%和31.52%,比单独使用拟康氏木霉(纤维素和木质素降解率分别为24.62%,13.78%)或白腐菌(纤维素和木质素降解率分别为6.96%,20.06%)处理稻草秸秆的效果有显著提高.     

Fermentative bio-hydrogen production from cellulose by cow dung compost enriched cultures

The performance of hydrogen production from cellulose by the cow dung compost enriched continuously in defined medium containing cellulose was investigated. In the initial experiments, batch-fermentation was carried out to observe the effects of different substrate concentration conditions on the rate of cellulose-degrading, growth of bacteria and the capability of hydrogen-producing from cellulose. The result showed that the cellulose degradation decreased from 55% at 5 g/l to 22% at 30 g/l. The maximum cumulative hydrogen production and the rate of hydrogen production first increased from 828 ml/l at 5 g/l to 1251 ml/l at 10 g/l then remained constant beyond 10 g/l. The maximum hydrogen production potential, the rate of hydrogen production and the yield of hydrogen was 1525 ml/l, 33 ml/l.h, and 272 ml/g-cellulose (2.09 mol/mol-hexose) was obtained at substrate concentration 10 g/l, the hydrogen concentration in biogas was 47–50%(v/v) and there was no methane observed. During the conversion of cellulose into hydrogen, acetate and butyrate were main liquid end-products in the metabolism of hydrogen fermentation. These results proposed that cow dung compost enriched cultures were ideal microflora for hydrogen production from cellulose.     

Microbial diversity of hydrogen-producing bacteria in batch reactors fed with cellulose using leachate as inoculum

Hydrogen production using cellulosic residues offers the possibility of waste minimization with renewable energy recovery. In the present study, heat-treated biomass purified from leachate was used as inoculum in batch reactors for hydrogen production fed with different concentrations of cellulose (2.5, 5.0 and 10 g/L), in the presence and absence of exogenous cellulase. The heat-treated biomass did not degrade cellulose and hydrogen production was not detected in the absence of cellulase. In reactors with cellulase, the hydrogen yields were 1.2, 0.6 and 2.3 mol H₂/mol of hydrolyzed cellulose with substrate degradation of 41.4, 28.4 and 44.7% for 2.5, 5.0 and 10 g/L cellulose, respectively. Hydrogen production potentials (P) varied from 19.9 to 125.9 mmol H₂ and maximum hydrogen production rates (R_m) were among 0.8–2.3 mmol H₂/h. The reactor containing 10 g/L of cellulose presented the highest P and R_m among the conditions tested. The main acid produced in reactors were butyric acid, followed by acetic, isobutyric and propionic acids. Bacteria similar to Clostridium sp. (98–99%) were identified in the reactors with cellulase. The heat-treated leachate can be used as an inoculum source for hydrogen production from hydrolyzed cellulose.     

一株纤维素降解菌的筛选及其在沼气应用中的研究

利用实验室保存的细菌、真菌和从牛粪、猪粪中分离出来的多株菌株,对秸秆纤维素进行降解试验,从而筛选出了能够降解秸秆纤维素(降解率为43.75%)的优势菌株.用几株降解效果较理想的菌株处理秸秆,对处理后的秸秆进行沼气发酵,通过高效气相色谱仪对沼气成分进行分析,发现从牛粪中筛选出的N2菌株效果较好,发酵2周后,其产气中甲烷含量为62.48%(体积分数,下同),二氧化碳含量为31.83%,氮气含量为2.11%.通过生理生化鉴定,初步鉴定N2菌株为枯草杆菌(Bacillus subtilis).     

Co-fermentation of glucose,starch, and cellulose for mesophilic biohydrogen production

The aim of this study was to assess the synergistic effects of co-fermentation of glucose, starch, and cellulose using anaerobic digester sludge (ADS) on the biohydrogen (H₂) production and the associated microbial communities. Yields of H₂ were 1.22, 1.00, and 0.15 mol H₂/mol hexose-added in fermentation reactions containing glucose, starch, and cellulose as mono-substrates. The H₂ yields were greater by an average of 27 ± 4% than expected in all the different co-substrate conditions, which affirmed that co-fermentation of different substrates improved the H₂ potential. Glucose addition to starch and/or cellulose favored acetate synthesis, while cellulose degradation was associated with the propionate synthesis pathway. Illumina sequencing technology and bioinformatics analyses revealed operational taxonomic units (OTUs) in the Phyla Bacteroides, Chloroflexi, Firmicutes, Proteobacteria, Spirochaetes, Synergistes, and Thermotogae were common in mono- and co-substrate batches. However, OTUs in the Phyla Acidobacteria, Actinobacteria, and Bacteroidetesee were unique to only the co-substrate conditions.     

Anaerobic digestion of maize and cellulose under thermophilic and mesophilic conditions – A comparative study

The aim of this study was to advance in understanding of digestion process of energy crops. Cellulose and maize silage were fermented in batch mode at mesophilic (38 °C) and thermophilic (55 °C) conditions and corresponding organic loads of 5.5 ± 0.2 kgVS/m³, 11.2 ± 0.3 kgVS/m³ and 16.7 ± 0.4 kgVS/m³.For both substrates more stable and faster digestion took place at 38 °C. Due to complex structure maize degradation was characterized by varying digestion rate and longer total digestion time resulting form breakdown of hard-degradable fractions. The digestion retard at increased OLRs of cellulose and lower degradation level obtained for all cellulose series confirm a higher overloading potential for systems dealing with single-component-substrates but also the enhanced sensitivity of such systems to any inconvenient digestion conditions.Based on observed patterns of volatile fatty acids and oxidation-reduction potential, different fermentation mechanisms can be concluded for cellulose and maize, but also for different temperature modes. Conversion of maize at highly reductive conditions with increased concentrations of butyric acid was accompanied by much higher activity of hydrogenotrophic methanogens than for cellulose digestion.Two factors showed a strong potential to influence test results: an insufficient VS content of inoculum, which caused reduced biogas yields, and a high natural biodiversity of maize silage, resulting in higher biogas yields than calculated based on the maize composition.     

Saccharification of paper products by cellulase from Penicillium funiculosum and Trichoderma reesei

Used paper products contribute largely towards organic-based waste produced and dumped by the world population. Cellulose, a structural component of paper materials, can be hydrolysed into glucose by a multi-component enzyme system called cellulase. Cellulase from Penicillium funiculosum and Trichoderma reesei were applied in the saccharification of paper products such as foolscap paper, filter paper, newspaper and office paper as well as microcrystalline cellulose. Foolscap paper showed the strongest susceptibility towards enzymatic hydrolysis with both enzymes. With an enzyme concentration of 10.0 mg/mL for each cellulase system the strongest synergistic action was observed at a combination of 1:1 (m/m) during saccharification of all cellulose materials. The individual enzyme performance as well as their synergistic actions showed different rates of hydrolysis during degradation of the investigated cellulose substrates.