乙酸铅对PC12细胞形态的影响

为了从形态学角度研究铅诱导细胞凋亡的机制,用100 μmol·L-1乙酸铅对PC12细胞进行染毒24 h,检测细胞整体形态、细胞骨架和细胞超微结构的改变.实验结果显示:乙酸铅染毒24 h后.细胞整体形态和细胞骨架无明显改变.但电子显微镜下已出现细胞核固缩;线粒体肿胀、正常结构消失并伴有空泡化;胞内出现鼓泡等现象.结合前期研究结果,推测线粒体在铅诱导细胞凋亡中起了重要作用.而细胞骨架不参与此过程.     

生物滴滤塔处理模拟印刷有机废气

选取甲苯、乙酸乙酯为目标污染物模拟印刷有机废气,采用生物滴滤塔对其进行处理。从某污水处理厂曝气池活性污泥中筛选出3株能够高效降解甲苯、乙酸乙酯的优势菌种,经鉴定分别为枯草芽孢杆菌（Bacillus subtilis）、蜡状芽胞杆菌（Bacillus cereus）和嗜麦芽寡养单胞菌（Stenotrophomonas maltophilia）。实验结果表明：增大乙酸乙酯配比对VOCs去除率影响不大,而增大甲苯配比导致VOCs去除率下降明显;在进气VOCs质量浓度为约800 mg/m³（甲苯与乙酸乙酯的体积比1∶1）、气体空床接触时间为300 s、菌液喷淋量为800 L/h、菌液温度为25 ℃的条件下,VOCs去除率可达约99%。生物滴滤塔运行一段时间后,对菌种进行再鉴定,结果与处理前一致。     

Partial dissolution of ACQ-treated wood in lithium chloride/N-methyl-2-pyrrolidinone: separation of copper from potential lignocellulosic feedstocks

A cellulose solvent system based on lithium chloride (LiCl) in N-methyl-2-pyrrolidinone (NMP) was used to assess the merits of partial dissolutions of coarsely ground wood samples. Alkaline Copper Quaternary (ACQ)-treated pine wood was of particular interest for treatment given the potential to generate a copper-rich stream apart from solid and/or liquid lignocellulosic feedstocks. Treatment with NMP alone gave yields of soluble materials that were higher than typical extractives contents thereby suggesting a limited degree of wood dissolution. Inclusion of LiCl, which disrupts hydrogen bonding, gave lower wood residue recoveries (i.e., higher dissolution) with higher LiCl concentration. Lower wood residue recoveries coincided with lower Klason lignin and hemicellulose-derived sugar contents in the wood residues. After treatment with 8% LiCl in NMP, subsequent filtration afforded 34% of the ACQ-treated sapwood as a wood residue retaining only 2% of the original copper. Pouring the filtrate over an excess of water resulted in the recovery of 30% of the solids and 50% of the copper together as a copper-enriched lignocellulosic precipitate. Results demonstrate a solvent system showing potential as a means to separate heavy metals from preservative-treated wood and to recover lignocellulosic feedstocks that may be suitable for use in a biorefinery.     

Low toxicant concentrations decrease the frequency of fast-growing seedlings at high densities of annual baby's breath (Gypsophila elegans)

Very low toxicant concentrations reduce the frequency of most vital seedlings in dense stands in vitro.     

纤维素改性技术及其在环境保护中的应用

以天然纤维素为基体进行改性可以得到活性更强的改性纤维素。文章简述了物理、化学、生物等纤维素常用预处理方法,按不同的反应方式对纤维素改性技术作了介绍。本文还对改性纤维素在水处理和空气净化领域应用作了介绍,并对改性纤维素的发展前景作了展望。     

Effects of phosphorus and nitrogen limitation on PHA production in activated sludge

The e ects of phosphorus and nitrogen limitation on polyhydroxyalkanoate (PHA) production and accumulation by activated sludge biomass with acetate as a carbon source were investigated. Pre-selected influent carbon-phosphorus (C:P, W/W) of 100, 160, 250, 500 and 750, and carbon-nitrogen (C:N, W/W) of 20, 60, 100, 125 and 180 were applied in the phosphorus limitation experiments and the nitrogen limitation experiments, respectively. The maximum PHA accumulation up to 59% of the cell dry weight with a PHA productivity of 1.61 mg PHA/mg COD consumed was observed at the C:N 125 in the nitrogen limitation experiment. This value was much higher than that obtained in previous studies with a normal substrate feeding. The study showed that activated sludge biomass would produce more polyhydroxybutyrate than polyhydroxyvalerate under the stress of nutrient limitation, especially under phosphorus limitation conditions. The experimental result also indicated that both phosphorus and nitrogen limitation may cause sludge bulking.     

应用POMS复合膜分离去除废气中挥发性有机污染物

依靠POMS平板单层膜或POMS卷式膜上选择性分离层的选择性溶解和渗透作用,常温负压分离回收废气中乙酸乙酯等挥发性有机污染物(VOC)组分.结果表明,膜两侧操作压差和原料气流量对乙酸乙酯分离效率影响较大;当原料气处理量为1.770 0～2.810 0 m3/(m2·h)、膜两侧操作压差为0.08 MPa,POMS卷式膜乙酸乙酯渗透速率可达7.86 × 10-7 mol/(s·m2·Pa);乙酸乙酯为1 500～4 500 mg/m3时,其去除率可达80%.测得几种VOC组分在POMS复合膜中的溶解吸附量都比较可观,由此预测该膜处理废气中VOC可取得很好的净化效果.甲苯在POMS复合膜中的溶解吸附量低于乙酸乙酯,其实验测得渗透速率也小于乙酸乙酯.甲苯去除率也能达到80%.     

菌株EA41对醋酸酯类化合物的生物降解

利用醋酸乙酯为能源和碳源从土壤中分离到一株菌。在生理生化试验的基础上,利用16S rDNA的方法鉴定这株菌为假单胞菌属细菌。底物特异性试验表明,假单胞菌EA41菌株可代谢多种醋酸酯类化合物。休眠细胞反应试验表明,这株菌的水解酶能水解口香糖的主要成分聚醋酸乙烯酯产生醋酸。     

厨余发酵液与乙酸钠、葡萄糖脱氮性能的比较

通过与乙酸钠、葡萄糖对比,利用批式实验方法对厨余发酵液作为反硝化碳源的脱氮性能进行了研究.在不同COD/N条件下,对3种碳源的反硝化NOx--N去除率进行了比较,研究发现,当COD/N =6.5时,厨余发酵液可以满足反硝化对电子供体的要求,其反硝化潜能PD=0.146 g NOx--N /g COD.然后,在COD/N =5.0条件下,利用动力学方程对反硝化过程进行分段模拟,发现厨余发酵液组在Ss降解阶段的比反硝化速率为7.44 mg NOx--N/(g VSS·h),其整个反硝化阶段的比反硝化速率是乙酸钠组的0.77倍,是葡萄糖组的2.1倍,结果表明,厨余发酵液可以作为快速降解碳源用于反硝化脱氮.     

沉积物和土壤中磷的生物有效性评估新方法

利用自制的氧化铁/醋酸纤维素复合膜(FeO/CAM)发展了一种沉积物和土壤磷的生物有效性评估的新方法. 结果表明:从沉积物和土壤中解吸的生物有效磷(FeO-P)含量随时间增加而增加,至16～20h左右,解吸过程接近平衡;随着土/水比增大而减小,至20～30g/L左右逐渐趋于平缓,且相对标准偏差较小;膜面积为20～30cm²时FeO-P含量差别较小,且相对标准偏差也较小;适当提高振荡频率(一般200r/min左右),有利于促进FeO-P的提取动力学过程.在用于评估水体沉积物和土壤解吸磷的生物有效性方面,FeO/CAM膜克服了氧化铁浸渍滤纸的缺点,易于商品化,具有更好的应用前景.