甲基纤维素在重量法测土壤硅中的应用研究

在重量法测定土壤全硅中，用甲基纤维素作凝聚剂，试验结果表明，用该凝聚剂与动物胶作凝聚剂测定土壤全硅的结果基本一致。甲基纤维素法的回收率为９３．８％—１０８．３％，标准差为０．３０％，变异系数最大为０．８８％；动物胶法的回收率为９２．３％—１０５．３％．用两种方法测定同一样品，两者间的绝对相差最大只有０．５％；ｔ检验表明，ｔ＝０．３６１＜ｔ（０．０５）＝２．２０，差异极不显著．因此，甲基纤维素可作为重量法测土壤硅的凝聚剂．     

Biodegradability of blends of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) with cellulose acetate esters in activated sludge

Blends of the bacterially produced polyester poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) with cellulose acetate esters (CAE) further substituted with propionyl or butyryl groups (degree of substitution: 2.60 propionyl and 0.36 acetyl or 2.59 butyryl and 0.36 acetyl, respectively) were exposed for 4 months to activated sludge to determine their biodegradability. Samples of such blends made by solution-mixing and solvent-casting had complex morphologies in which both individual components as well as a miscible blend phase were present. Additionally, the two opposite surfaces of solvent-cast films showed both physical and chemical differences. After 2 months, samples of pure PHBV had degraded by more than 98% (15 mg/cm² of surface area), whereas a pure CAE sample had degraded less than 1% (<0.2 mg/cm²). Samples containing 25% CAE lost less than 40% of their initial weights (6 mg/cm²) over the total 4-month period. Samples with 50% CAE lost up to 16% weight (2 mg/cm²), whereas those containing 75% CAE lost only slightly more weight than corresponding sterile control samples (1 mg/cm²). NMR results confirm that weight loss from samples containing 25% CAE resulted only from degradation of PHBV and that the surface of samples became enriched in CAE. Solvent-cast film samples containing equal amounts of PHBV and CAE degraded preferentially on the surface which formed at the polymer-air interface. Scanning electron microscopy and attenuated total reflectance infrared spectroscopy revealed this surface to have a rougher texture and a greater PHBV content.     

有机碳源物对淹水土壤中氮素转化的影响

八周淹水培养试验表明：木质素对土壤矿质氮影响不大，纤维素则影响强烈，而淀粉的影响比纤维素更为强烈持久．硫铵与纤维素或淀粉配施时，氮的固持作用大于矿化作用，在培养期间均没有释放出氮素．在八周时间内．氨基酸态氮趋向增加，表明是微生物对氮素的固持作用；氨基糖态氮占全氮比例很低而且变化不大；其它有机组分氮在短期内的变化没有明显的规律性．     

CMC/NI复合材料净化水中的As(Ⅲ)

采用羧甲基纤维素钠(CMC)为包覆材料,通过原位修饰技术改性纳米铁(NI),制得羧甲基纤维素包覆型纳米铁复合材料(CMC/NI)。利用场发射扫描电镜、傅立叶红外光谱仪和X射线衍射仪对CMC/NI复合材料进行表征;以水溶液中As(Ⅲ) 的有效去除率为目标,探索了制备条件(铁源种类、包覆质量比CMC/(CMC+Fe)和制备温度等)和反应条件(砷溶液初始pH值、反应温度和复合材料投加量等)对复合材料净化水中As(Ⅲ)的影响。结果表明,改性后的CMC/NI复合材料分散性和抗氧化性得到提高,具有良好的As(Ⅲ)净化能力。以FeSO4为铁源,包覆比为37%,20℃条件下制备的复合材料,以1.5 g/L加入到温度为30℃,pH为7,初始浓度为2 mg/L的砷溶液中,反应24 h,其As(Ⅲ)去除率可达98%。     

离子液体预处理纤维素及木质纤维素的研究进展

稳定性好、溶解能力强的离子液体,能够快速瓦解木质纤维素网络结构,提高纤维素酶的可及度和酶解效率,可大幅度降低预处理成本。本文综述了常见离子液体的组成、离子液体对木质纤维素的溶解分离等预处理方法及其原理。     

Ion-exchange polymers modified bacterial cellulose electrodes for the selective removal of nitrite ions from tail water of dyeing wastewater

Ion-exchange polymer and modified carbonization bacterial cellulose(CBC) electrodes were fabricated using varying amounts of cation-exchange polymers(glutaric acid(GA) and sulfosuccinic acid(SSA)) and assembled within an asymmetric capacitive deionization unit(p-CDI).The performance of selective NO₂^-electro-adsorption was studied.The AC/CBCSSA group showed a better salt adsorption capacity(14.56 mg/g) and nitrite removal efficiency(71.01%) than the AC/CBC-GA(10.72 mg/g,47.8...     

膜生物膜工艺处理含盐工业废水

采用了膜生物膜工艺处理含盐羧甲基纤维素生产废水。接种污泥为普通污泥,经驯化使其适应含盐废水,在污泥驯化阶段,生物膜表现出极佳的盐度冲击后恢复能力。通过较长的水力停留时间(5～15 d)和较低的COD有机负荷(平均1.6 kg/(m3·d)左右),生物膜COD去除率基本达90%。膜池内,悬浮固体浓度基本保持在5 000 mg/L以内;通过聚偏氟乙烯中空纤维膜过滤,出水悬浮固体浓度保持在5 mg/L以内。膜污染可通过重复的气水反洗和定期的化学清洗得以缓解。     

微生物固体发酵转化水生植物的研究

采用黑曲霉、绿色木霉和耐热克鲁维酵母发酵芦苇叶和浮萍原料,研究植物原料中粗蛋白含量的变化以及纤维素酶活的变化。研究结果表明,在水生植物原料中接种7%的黑曲霉和3%的热克鲁维酵母进行共发酵的效果最佳,发酵后芦苇叶原料和浮萍原料中粗蛋白含量分别提高了8.58倍和3.64倍;黑曲霉与耐热克鲁维酵母共发酵时其降解纤维素的能力显著提高。有望利用该工艺发酵这两种水生植物生产蛋白饲料。     

分解纤维素的高温真菌筛选及其对烟杆的降解效果

为研制促进烟杆堆肥的微生物菌剂,进行了分解纤维素的高温真菌筛选.结果表明,从不同原料腐熟堆肥中筛选到4株降解纤维素的高温真菌,它们均能在以羧甲基纤维素钠(CMC-Na)或烟杆粉末为唯一碳源的培养基上生长.菌株在2～5d内可长满CMC-Na-刚果红平板和烟杆粉末培养基.菌株摇瓶培养时2d可达到产酶高峰,酶活(CMCase)超过10U.菌株对烟杆的降解效果较好,7d内的降解率最高可达42.2%,对烟杆中的纤维素、半纤维素和木质素的分解率分别可达52.7%、47.9%和37.6%.     

水解酸化处理黄麻生物脱胶废水试验

针对黄麻生物脱胶废水浓度高、处理难度大的问题,采用水解酸化与膜生物反应器组合工艺对黄麻生物脱胶废水进行了处理试验。考察水解酸化池对COD、氨氮、木质素等的去除效果;并通过调节试验条件,考察水力停留时间、pH值、温度等因素对水解酸化效果的影响,得出处理黄麻生物脱胶废水的最佳实验条件。结果表明,水解酸化预处理工艺提高了废水的可生化性,对COD、氨氮均有较高的去处效率,对于降低纤维素的聚合度、促成纤维素的水解起到了关键的作用,为后续的好氧处理创造了有利条件。试验在水力停留时间10 h下,COD与氨氮去处率最高分别达35%,40%;影响水解酸化的因素主要为pH值和水力停留时间。