纳秒脉冲激光/纳米金悬浮体系催化降解2,4,5-TCP

以脉冲激光为光源、纳米金为催化剂,对2,4,5-三氯苯酚(2,4,5-TCP)进行了光催化降解研究,测定了其反应动力学参数,确定了该降解体系中2,4,5-三氯苯酚的单位能量降解率和平均反应速率.EDX能谱和透射电镜表征结果表明,已成功制备了纳米金颗粒,形态主要呈球状,粒径分布均匀,大小在15~20 nm之间.以亚甲基蓝为底物对纳米金的光催化性能进行了表征,结果表明,所制备的纳米金具有较好的催化性能,添加纳米金组比对照组的亚甲基蓝脱色率增加了约15.7%.以2,4,5-TCP为底物时,脉冲激光照射40 min,最高催化降解率约为85%,单位能量降解率为0.18256%·J-1,平均反应速率为0.04667 min-1,反应符合准一级动力学方程ln(C0/Ct)=-0.1141+0.04667t.     

Response surface methodology analysis of the photocatalytic removal of Methylene Blue using bismuth vanadate prepared via polyol route

Visible-light driven photocatalyst bismuth vanadate (BiVO₄) photocatalyst was synthesized by the polyol route using ethylene glycol. The precipitate was washed, dried and calcined at 450℃ for 3 hr. The sample was characterized by X-ray diffractometry (XRD), field emission scanning electron microscopy (FE-SEM), zeta potential, surface area (BET method) and band gap energy via diffuse reflectance spectroscopy (DRS). The synthesized BiVO₄ has a monoclinic phase with a surface area of 4.3 m²/g and a band gap energy of 2.46 eV. A majority of the particles were in the range of 90-130 nm as obtained from the particle size distribution histrogram. The efficiency of the sample as a visible-light driven photocatalyst was examined by photodegrading Methylene Blue (MB). The effects of some operational photodegradation parameters such as mass loading, initial dye concentration and pH were also examined. Experimental design methodology was applied by response surface modeling and optimization of the removal of MB. The multivariate experimental design was employed to develop a quadratic model as a functional relationship between the percentage removal of MB and three experimental factors (BiVO₄ loading, MB initial concentration and pH). The percentage removal of MB approached 67.21% under optimized conditions. In addition, a satisfactory goodness-of-fit was achieved between the predictive and the experimental results.     

农业废弃秸秆降解菌的筛选及产酶特性研究

从土壤和有机肥样品中分离出微生物菌株,经滤纸崩溃实验和透明圈实验得到了3株高效的农业废弃秸秆降解菌,分别为SA2、MA6和HA4.经鉴定,菌株SA2和MA6均为绿色木霉（Trichoderma viride）,HA4为斜卧青霉（Penicillium decumbens）.经拮抗实验可知,菌株SA2和HA4具有很好的兼容性,并对复合菌系（SA2＋HA4）的产酶特性进行了初步研究.结果表明,复合菌系SA2＋HA4在pH=6、温度30℃、接种量3%的条件下培养3d产酶最优,产酶能力明显高于单一菌株,其纤维素酶、蛋白酶和淀粉酶的活性分别达到了193.5、25.3和55.7U·mL-1.     

EG填充无卤阻燃型LDPE复合薄膜阻燃性能研究

为了改善聚合物低密度聚乙烯(LDPE)薄膜的阻燃性能,通过向其中添加膨胀型阻燃剂聚磷酸铵(APP)/季戊四醇(PER)和可膨胀石墨(EG),制备了无卤阻燃型低密度聚乙烯复合薄膜.实验研究了膨胀阻燃剂填充聚合物LDPE作为阻燃复合薄膜的性能,分析了膨胀阻燃剂的加入对复合膜阻燃性能、残重率和力学性能的影响机理.研究发现,该新型配方中的EG和APP/PER对复合薄膜的阻燃性能具有协同作用,当配方中APP/PER/EG的填充量达到30%质量分数(APP∶PER∶EG∶LDPE质量比16∶8∶6∶100)时,薄膜材料的氧指数可达到27.5%;与纯LDPE薄膜相比,阻燃薄膜的氧指数提高了10.3%,改善了阻燃效果.     

聚苯硫醚（PPS）纤维发展现状与展望

介绍了国内聚苯硫醚纤维生产的发展历程及现状;通过对国内外产品性能对比,指出超细、异形、复合型、改性等产品的开发应用,是高性能聚苯硫醚纤维的发展方向;介绍了几种具有代表性的聚苯硫醚纤维产品。     

粉末活性炭强化常规处理工艺时混凝效能的研究

在水源水质突然变差时,为了保证饮用水水质和水厂的经济低耗运行。以松花江水为原水,采用不同投量的粉末活性炭(PAC)来强化常规处理工艺,通过实验考察了硫酸铝(AS)、聚合氯化铝(PACl)、复合铝铁（PAF）及后2种混凝剂分别与助凝剂高锰酸盐复合药剂（PPC）、活化硅酸配合使用时对浊度和COD_Mn的去除情况。实验结果表明：（1）在进水水质相同的情况下,以浊度和COD_Mn为控制指标,达到同样的处理效果时,制水成本比较的结果为PAF相似文献   

多壁碳纳米管结构对复合光催化剂催化效果的影响

采用溶胶凝胶法制备了多壁碳纳米管负载纳米TiO₂的复合光催化剂（TiO₂/MWCNTs）,以偶氮类染料甲基橙为目标污染物,在自制的光催化反应器上进行了光催化降解反应实验。主要研究同一甲基橙初始浓度（C₀)下,多壁碳纳米管不同管长和管径对复合光催化剂催化效果的影响。结果表明：该降解反应可用一级反应动力学方程描述,反应速率常数k随着多壁碳纳米管管长和管径的增大而增大;与纯纳米TiO₂相比,复合光催化剂对甲基橙的降解率提高了6％～18％,反应速率常数为前者的1.19～2.11倍;采用复合光催化剂的甲基橙光降解溶液自行沉降分离效果较好,静止沉降60 min后达到沉降平衡,剩余浊度为8.5 NTU,下降了90.6％。     

道路车辆电气电子设备温度/湿度组合循环试验要点

温度/湿度组合循环试验本质上是一项气候环境的加速试验,失效较为集中。这里列出了若干关于试验的要点,供产品研发和试验人员把握。     

Wood Modification Effects on Weathering of HDPE-Based Wood Plastic Composites

The effects of weathering on the constituents of wood and polymer matrix behavior in wood plastic composites (WPCs) were investigated. WPCs were produced from pine, extractives-free pine, and pine holocellulose fibers (60%) together with HDPE (40%). These composites were subjected to xenon-arc accelerated and outside weathering for a total of 1200 h and 120 days, respectively. The color and chemical changes that occurred on the surface of the WPCs were analyzed using a set of analytical techniques. For pine and extractive-free pine filled composites, the results showed that the total color change, lightness, and oxidation increased, while the lignin content decreased. In addition, the weight average molecular weight (Mw) and number average molecular weight (Mn) of extracted HDPE decreased with an increase in exposure time of the composites. However, HDPE crystallinity increased with longer exposure time. Lightness of holocellulose-based WPC changed the least while the change in its HDPE crystallinity was not significant compared to the other composite types. Therefore, holocellulose-based WPC may be preferred for applications where color stability is of high priority.     

湖南省山洪灾害综合风险分析及安全减灾研究——以2006年衡阳市山洪灾害为例

利用衡阳市2006年山洪灾情数据,引入综合灾情指数对湖南省衡阳市山洪灾害进行综合灾情损失评估,得出耒阳市的综合灾情指数最大;灾情重的直接原因是暴雨大,水位短时间上升快。同时,暴雨-山体滑坡-泥石流灾害链放大了灾情;农村地区防灾减灾意识淡薄、防洪工程标准偏低以及减灾措施不当也加剧了山洪灾情。为此,要通过加强工程建设与山洪灾害危险性宣传来提高农村抗灾能力,达到安全减灾目的。