Novel method for in situ visualization of polycyclic aromatic hydrocarbons in mangrove plants

Two-photon laser confocal scanning microscopy (TPLCSM) was first used to visualize the uptake and movement of naphthalene (NAP), phenanthrene (PHE), and pyrene (PYR), from separately contaminated hydroponics solutions into living Kandelia candel (L.) Druce seedlings. With this non-destructive and non-chemical extraction technique, the experimental results revealed that three types of polycyclic aromatic hydrocarbons (PAH) were observed moving into the K. candel and its translocation to radicle, hypocotyl and leaf, and the transmission rates of these PAH in the K. candel were in the order of NAP?>?PHE?>?PYR. Data demonstrate the manner in which PAH enter, transport, and distribute within the K. candel, and provided us some valuable information on uptake and translocation mechanism of PAH. These findings may help to optimize the phytoremediation strategies of PAH in mangrove wetlands.     

Selective photoreduction of acetonitrile to acetaldehyde in dilute aqueous solutions

Acetonitrile is a commonly used solvent in both industry and research. The treatment of acetonitrile wastes in dilute aqueous solutions with visible light offers advantages to chemical treatment and ultraviolet (UV) irradiation. This study presents the degradation of acetonitrile via a photoinduced electron transfer reaction in the presence of a photosensitizer (dye) and a sacrificial reductant under visible light. Acetonitrile photodegradation (photoreduction) was investigated utilizing a variety of sacrificial reductants and photosensitizers. Optimal results were observed in the presence of methylene green and tri-isopropanolamine with a decrease of acetonitrile in solution to 86% in 24 hours. The only photoreaction product observed was acetaldehyde and a plausible mechanism for the photochemical degradation of acetonitrile is proposed.     

再生水紫外线-氯联合消毒工艺特性研究

以二级出水作为消毒对象,比较了紫外线-氯联合消毒与单一紫外线消毒对水中肠道指示菌的灭活效果,考察了联合消毒工艺副产物(三卤甲烷)生成情况.结果表明,单一紫外线消毒对肠道指示菌的灭活曲线在剂量大于10mJ/cm2时存在拖尾现象,剂量为80mJ/cm2时对总大肠菌群最高对数灭活率约为2.5;而在紫外线剂量20mJ/cm2、氯投加量8mg/L(接触时间30min)条件下,紫外线-氯联合消毒对总大肠菌群的对数灭活率达到7.0.20mJ/cm2紫外线与8mg/L氯消毒组合及80mJ/cm2紫外线与3mg/L氯消毒组合均可有效灭活总大肠菌群浓度至3CFU/L以下.经紫外线照射后再氯消毒,二级出水中三卤甲烷生成量仅为10~55mg/L.80mJ/cm2紫外线照射再氯消毒后三卤甲烷生成量略高于20mJ/cm2紫外线照射再氯消毒的情形.紫外线消毒后投加氯消毒,可有效提高再生水消毒效果,控制消毒副产物生成量.     

Kinetics and mechanisms of reactions for hydrated electron with chlorinated benzenes in aqueous solution

The reactions between chlorinated benzenes (CBzs) and hydrated electron (eaq-) were investigated by the electron beam (EB) and laser flash photolysis (LFP) experiments. Under the EB irradiation, the effects of irradiation dose, initial concentration and the number of Cl atoms on the removal efficiencies were further examined. At 10 kGy, the removal efficiencies of mono-CB, 1,3-diCB, 1,2-diCB and 1,4-diCB were 41.2%, 87.2%, 84.0%, and 84.1%, respectively. While irradiation dose was 50 kGy, the removal efficiencies increased to 47.4%, 95.8%, 95.0%, and 95.2%, respectively. Irradiation of CBzs solutions has shown that the higher the initial concentration, the lower the percentage of CBzs removal. In addition to this, the dechlorination efficiencies of 1,2-dichlorobenzene (1,2-diCB), 1,3-dichlorobenzene (1,3-diCB) and 1,4-dichlorobenzene (1,4-diCB) were much higher than that of chlorobenzene (mono-CB). The kinetics of the reactions was achieved with nanosecond LFP. The rate constants of second-order reaction between eaq- with mono-CB, 1,2-diCB, 1,3-diCB and 1,4-diCB were (5.3±0.4) × 10⁸, (4.76±0.1) × 10⁹, (1.01±0.1) × 10¹⁰ and (3.29±0.2) × 10⁹ L·mol^-1·s^-1, respectively. Density functional theory (DFT) calculations were performed to determine the optical properties of unstable CBzs anion radicals, and the main absorption peaks lied in the range of 300–550 nm. The primary reaction pathway of CBzs with eaq- was gradual dechlorination, and the major products were Cl^- and benzene (CBzs(-Cl^-)). Furthermore, biphenyl (or chlorobiphenyl) was observed during the LFP, which was probably formed by recombination of benzene radicals.     

激光点火器耐压密封及其影响

目的促进激光点火技术在安全弹药领域的应用。方法从激光点火器作用后承受高动态压力的需求出发,研究基于玻璃封接技术的激光点火器密封性能及其影响因素。确定采用箱式电阻炉对激光点火器壳体与透镜间进行玻璃密封的温度为430℃,保温时间为13～15min。对不同始发装药、不同密封工艺的激光点火器透镜发火后,其表面光学膜层变化、与激光点火器相连接的光纤端面损伤程度进行分析,研究点火前后承受气压性能变化。结果始发装药为BPN等点火类药剂时,激光点火器具有较高的动态密封性能,可稳定达到30 MPa下2 min不泄露;始发装药为BNCP等起爆类药剂时,随着装药量的增大,密封性能变差。结论改善玻璃封接工艺有利于提高密封性,如封接长度变长,发火后耐压密封性会有所提升。     

微波辐射烟杆氯化锌法制造活性炭工艺

提出了利用烟杆废料制造活性炭的新工艺.采用正交试验法对影响活性炭性能的因素,如微波辐射的功率、辐射时间、氯化锌浓度等进行了系统研究,得到了最佳工艺条件:微波辐射功率750 W,辐射时间7 min,氯化锌浓度为50%,利用该工艺条件所制备活性炭的产率为34.7%,亚甲蓝脱色力为17 mL/0.1 g,碘吸附值为1 093.4 mg/g.对比该活性炭与市售一级活性炭的微观结构,发现其具有更发达的微观孔隙结构.同传统方法相比,微波辐射法缩短了工艺时间,提高了产品性能.     

紫外诱变筛选高效氧化亚铁硫杆菌

为了取得高效氧化亚铁硫杆菌（T.f菌）,采用紫外线诱变处理,对照射1.5 min,3 min,5 min的菌株进行实验测试,结果表明,T.f3将Fe^2＋完全氧化由7 d缩短为5 d,并且在较低SO3^2-浓度范围内,Fe2＋浓度与SO3^2-的氧化速率呈正相关性,但当菌液浓度一定时,增加Fe2＋浓度,SO3^2-的氧化速率不会明显增加。     

酸碱预处理对常压微波辐射剩余活性污泥磷释放的影响

考察了污泥酸、碱预处理在常压微波处理过程中对碳、氮、磷释放的影响.结果表明,NaOH预处理将污泥磷释放率从28.8%提高到59.1%,但同时引起了碳、氮的大量释放.同碱预处理相比,硫酸预处理能够将常压微波辐射作用下污泥磷的释放率提高3倍,达到84.5%,并可达到选择性释放碳、氮、磷的效果（氮和COD释放少,而磷释放显著）,有利于后续的磷回收.优化试验表明,pH为2.1～2.2是常压微波辐射作用下污泥磷释放的最佳硫酸预处理条件.     

供水管网不同管材内壁微生物分布的显微观察

采用扫描电镜、原子力显微镜以及激光共聚焦显微镜对不锈钢插片表面和供水管网末端PPR管内壁微生物的分布和生物膜结构进行了观察和分析.结果表明,在供水管网中,不锈钢材质表面不利于微生物附着生长,在短时间内(3个月)只有很少的微生物附着.在管网末端PPR管表面有明显的微生物附着生长,细菌容易附着在基底表面的凹穴中,细菌与基底是紧密黏附在一起的.扫描电镜和原子力显微镜结合是观察管壁非连续生长生物膜表面结构的有效手段.采用激光扫描共聚焦显微镜可同时实现管壁生物膜内部和三维结构观察.     

有机胺插层四钛酸对直接湖蓝5B的吸附性能研究

在微波辅助下对四钛酸进行了有机胺插层,获得了正辛胺﹑正十二胺﹑正十六胺插层四钛酸材料,研究了3种层状物质作为吸附剂,pH﹑震荡时间﹑吸附剂用量等因素对直接湖蓝5B偶氮染料吸附的影响,确定了3种材料吸附的最佳条件。研究表明:微波有机胺插层四钛酸材料具有优良的吸附性能,pH=1.0时,正辛胺插层四钛酸用量为0.8 g/L﹑振荡时间40 min,正十二胺插层材料和正十六插层材料用量为0.4 g/L﹑振荡时间分别30 min和50 min时,吸附脱色效果最好。随染料浓度增大,温度升高,插层四钛酸材料会发生板层分离,表现为常规的物理吸附过程。在50℃时,正辛胺﹑正十二胺﹑正十六插层四钛酸对直接湖蓝5B染料的吸附量分别达到636 mg/g﹑3 349 mg/g﹑2 856 mg/g。