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1.
木质素的高值转化对于生物质的全组分利用具有重要意义,直接关乎生物炼制产业链的经济可行性。离子液体作为一种新型催化剂,具有较高的可设计性、结构稳定性和热稳定性,可用于木质素催化转化制备具有高附加值的小分子产物以提高木质素的利用效率。以乙醇胺类和胍类离子液体为催化剂,考察了木质素种类与用量、催化剂种类与浓度、反应温度和pH值等因素对丁香醛收率的影响。结果表明:当催化剂为乙醇胺四氟硼酸盐[MEA]BF4,木质素与催化剂用量比为2∶1,固液比1∶150,温度160 ℃,pH=4.35,反应6 h后丁香醛收率最高,为9.20%。 相似文献
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对比了酸析法和碱析法对碱法草浆造纸黑液中木质素的去除效果,并分析了聚合氯化铝(PAC)絮凝剂对酸析和碱析后木质素的絮凝效果。实验结果表明:酸析法和碱析法都能有效析出造纸黑液中的木质素,酸析法对色度的去除效果要优于碱析法;当造纸黑液pH为3时,COD去除率达到72.0%,色度去除率为97.7%;当造纸黑液pH为13时,COD去除率达到55.0%,色度去除率为22.3%;PAC对于酸析后木质素有较好的絮凝效果,当废水温度为55℃、PAC加入量为45mL/L时,COD去除率可以达到79.5%,色度去除率为98.5%;PAC絮凝剂对于碱析后的造纸黑液色度的去除效果较差。 相似文献
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文章用比值—导数光谱法测定香草醛的含量。实验结果表明,香草醛木素溶液在pH≤7时香草醛在230 nm处有吸收,在pH>7时在248 nm处有吸收。根据不同pH值和不同浓度条件下香草醛木素溶液的比值-导数光谱,说明在230 nm处的光谱信号在pH≤7不受pH值影响,248 nm处的光谱信号在pH>7不受pH值影响。在230 nm和248 nm处的光谱信号对浓度的变化较为敏感,在此两处吸收值可用于香草醛的测定。 相似文献
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在自制的圆柱型双层玻璃反应器中,以木素类模型物紫丁香醇(SL)为目标化合物,考察Fenton试剂对紫丁香醇的降解效果,研究溶液的pH值、H2O2的用量、Fe2+的用量、紫丁香醇溶液初始浓度、反应时间、紫外光照射等因素对紫丁香醇降解的影响。实验结果表明:在室温条件下,当体系pH值为3.0时,加入两倍理论用量的H2O2,Fe2+与H2 O2的物质的量之比为1︰50,反应60 min后,50 mg/L的紫丁香醇的去除率可达87.5%;当体系中引入紫外光后,Fenton试剂的氧化性明显增加,反应速度显著加快,30 min后紫丁香醇可完全矿化。 相似文献
6.
Two different kinds of black liquor from the papermaking industry were treated by acidification and reuse. The experimental parameters and conditions were discussed in detail. The experimental results indicated that the treatment process mentioned in this article is an effective process for the treatment of black liquor from the papermaking industry. By the treatment, the solid materials in black liquor are transferred into two by-products and the other components are reused or evaporated. Thus, no wastewater except some condensation water would be discharged in pulping process and the problem of oollution of black liauor would be effectively solved. 相似文献
7.
Wilkins K Larsen K Simkus M 《Environmental science and pollution research international》2003,10(4):206-208
Since volatile mold metabolites are used for the detection of mold growth in buildings, it was interesting to determine whether different indoor mold species show different affinity for the major components of wood, a common building material. Growth and volatile metabolites were studied when Aspergillus versicolor, Penicillium chrysogenum, and P. palitans were grown on laboratory substrates containing the major wood constituents cellulose, xylan and lignin. Microbial volatile organic compounds (MVOCs) were characterized by thermal desorption/gas chromatography/mass spectroscopy. Growth and volatile metabolites varied considerably and there appeared to be complementary substrate specificities for P. chrysogenum, and P. palitans grown on cellulose and xylan. The failure of A. versicolor to produce characteristic MVOCs when grown on media containing wood constituents suggests that systems using volatile metabolites to detect microbial growth in buildings may be fundamentally unreliable for the detection of this species. 相似文献
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Since the ability to degrade lignin with one kind of white-rot fungi or bacteria was very limited, superior mixed flora‘s ability to degrade lignin was investigated by an orthogonal experiment in this paper. The results showed that superior mixed flora reinforced the ability to degrade lignin, the degradation rates of both sample 9 and 10 were beyond 80% on the day 9. The cooperation between lignin peroxidase(LiP), Mn-dependent peroxidase(MnP) and laccase (Lac) for lignin degradation was also studied. By examining the activities of three enzymes produced by superior mixed flora, it was found that Lac was a key enzyme in the process of biological degradation of lignin but Lip was not; the enzyme activity ratios of Lac/MnP and Lac/LiP were significantly correlative with the degradation rate of lignin at the 0.01 level; and the ratio of MnP/LiP was an important factor affecting the degradation rate of lignin. 相似文献