磁性氮掺石墨烯活化过硫酸钾降解水中亚甲基蓝

活化过硫酸盐产生硫酸根自由基的高级氧化技术在水环境污染物治理中引起了广泛的关注和研究.本研究采用水热法制备磁性氮掺石墨烯(M-N-G)作为催化剂.利用SEM、BET、XRD和VSM等手段表征材料,系统研究了该材料活化过硫酸盐降解亚甲基蓝的效能.结果表明:M-N-G的比表面积为94.35 m2·g-1,磁性Fe3O4分布在材料表面,能有效的活化过硫酸钾降解亚甲基蓝.当催化剂的用量为200 mg·L~(-1),过硫酸钾浓度为0.4~0.5 mmol·L~(-1)时,在p H=3~6时对10 mg·L~(-1)亚甲基蓝的降解率达90%以上.体系温度在15~32℃时,降解速率常数在0.0227~0.0488 min-1,反应活化能为33.7 k J·mol-1.EPR分析及自由基漼灭实验证明了体系中有羟基自由基和硫酸根自由基产生.TOC分析结果表明:TOC去除率可达50%.M-N-G经过简单的稀硫酸和水洗后,可高效重复利用4次.该技术方法简单、高效、无二次污染,能为有机污染物废水处理提供一种新的方法选择.     

Ionic dye adsorption by zinc oxide nanoparticles

The adsorption behaviour of Basic Red 12, Acid Orange 7 and Acid Blue 1 on zinc oxide nanoparticles (ZNP) has been investigated to understand the physicochemical process involved and to explore the possible use of nanoparticles in the treatment and management of textile waste matter. The dye removal capacity of ZNP towards Basic Red 12, Acid Orange 7 and Acid Blue 1 was found to be 15.64, 6.78 and 6.38 mg g^?1, respectively. The adsorption process was pH dependent and optimum pH values of 9.0, 2.0 and 4.0 were obtained for Basic Red 12, Acid Orange 7 and Acid Blue 1, respectively. Equilibrium was established after 1.0 h for all dyes. Langmuir, Freundlich and Temkin isotherm models were applied to the system. The adsorbent ZNP was characterised using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) and Fourier transform infrared (FTIR) techniques. SEM analysis revealed the noticeable nanoporous morphology of the material. The results of FTIR spectroscopy showed that the process is driven by an electrostatic complexation mechanism. XRD studies revealed the nanocrystalline structure of ZNP. BET surface area measurement suggested a high pore volume and large surface area for the adsorbent. The kinetic measurements suggested pseudo-second-order kinetic processes with high regression coefficients and smaller standard error of estimate values and lower residual sum of squares. The thermodynamic measurements suggested that all processes were exothermic and accompanied by negative values for Δ G⁰, Δ S⁰ and Δ H⁰.     

Poly(ethylene oxide)-coated granular starch-poly(hydroxybutyrate-co-hydroxyvalerate) composite materials

Granular cornstarch was coated with several biodegradable polymers in an effort to improve the mechanical properties of starch-poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) composites. Only samples containing poly(ethylene oxide) (PEO)-coated granular starch showed a large improvement in tensile properties over uncoated starch. For example, a 50/50 blend of PEO-coated starch and PHBV had a tensile strength of 19 MPa and an ultimate elongation of 23%, compared to 10 MPa and 11% for a similar blend containing uncoated starch. PEO may act as an adhesive between the starch and the PHBV and/or increase the toughness and resistance to crack growth of PHBV around the starch granules.Paper presented at the Bio/Environmentally Degradable Polymer Society—Third National Meeting, June 6–8, 1994, Boston, Massachusetts.Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product and the use of the name by the USDA implies no approval of the product to the exclusion of others that may also be suitable.     

尿中氚水和总氚的对比分析测定研究

用蒸馏液闪法测量尿中氚水浓度 ,用氧化蒸馏液闪法测量尿中总氚 (氚水和有机氚 )浓度。同时测量了 1999年核设施退役时接触氚人员的高于本底水平的尿中氚水和总氚浓度 72个样品。比较氚水和有机氚浓度 ,得到有机氚浓度占氚水浓度的平均值为 (5 4± 3 7) % ,其值与理论值和动物实验值基本相符     

Investigation the effect of adding graphene oxide into diesel/higher alcohols blends on a diesel engine performance

ABSTRACT

This article aims to study the influence of the addition of graphene oxide nanoparticles (GO) to diesel/higher alcohols blends on the combustion, emission, and exergy parameters of a CI engine under various engine loads. The higher alcohols mainly n-butanol, n-heptanol, and n-octanol are blended with diesel at a volume fraction of 50%. Then, the 25 and 50 mg/L concentrations of GO are dispersed into diesel/higher alcohols blends using an ultrasonicator. The GO structures are examined using TEM, TGA, XRD and FTIR. The findings show that there is a reduction in p_max. and HRR when adding higher alcohols with diesel fuel. Regarding engine emission, there is a significant improvement in emissions formation with adding higher alcohols. The addition of GO into diesel/higher alcohols blends improves the brake thermal efficiency by 15%. Moreover, the p_max. and HRR are both enhanced by 4%. The CO, UHC and smoke formation are reduced considerably by 40%, 50 and 20%, respectively, while NO_x level is increased by 30% with adding GO. Finally, adding high percentages of n-butanol, n-heptanol, and n-octanol with diesel fuel with the presence of GO has the potential to achieve ultra-low CO, UHC, and smoke formation meanwhile keeping high thermal efficiency level.     

Ethoxylated Soybean Polyols for Polyurethanes

Soybean polyols prepared by ring opening reactions of epoxidized soybean oil with hydrogen active compounds (water, alcohols, organic or inorganic acids, thiols, hydrogen etc.) have a low reactivity in the reaction with isocyanates because the hydroxyl groups are secondary. This paper presents a simple and convenient method to increase the reactivity of soybean polyols with secondary hydroxyl groups by ethoxylation reactions with the preservation of triglyceride ester bonds. The method uses mild reaction conditions: low alkoxylation temperature of 35–45 °C, low pressure of 0.1–0.2 MPa (15–30 p.s.i.) and a superacid as catalyst (HBF₄). The new soybean polyols have a higher reactivity toward isocyanates in polyurethane formation due to the high percentage of primary hydroxyl groups. The primary hydroxyl content was determined by the second order kinetics of polyol reaction with phenyl isocyanate.     

纳米二氧化钛处理含砷废水的研究

研究了无机纳米材料二氧化钛对含砷废水的处理效果.实验主要从纳米二氧化钛的溶液pH值、不同投加量、实验温度、吸附搅拌时间、静置时间等方面对除砷效率进行了研究,并通过模拟水样和实际水样的对比,分析了纳米二氧化钛处理含砷废水的实际可行性.     

钠盐量影响下DD6单晶高温合金的高温热腐蚀规律研究

目的 开展镍基单晶高温合金DD6在950 ℃下的热盐腐蚀试验(95%Na2SO4+5%NaCl)，探明涂盐量和涂盐方式(周期涂盐和单次涂盐)对DD6高温热腐蚀的影响规律和机理。方法 结合扫描电子显微镜、X射线能量色散谱、X射线衍射等设备，对不同涂盐量及涂盐方式下DD6的表面及横截面形貌进行观察分析，分析不同涂盐量和涂盐方式下DD6的高温热腐蚀机理。结果 DD6在950 ℃下主要发生碱性熔融热腐蚀，同时伴随氧化、硫化和氯化等过程。高温热腐蚀使得DD6合金表面生成的保护性氧化膜被熔融态的腐蚀介质破坏，导致O、S、Cl等外部元素通过氧化膜的缺陷进入DD6基体中，在合金的亚表面发生内氧化、内硫化以及内氯化反应，横截面上出现明显的腐蚀层，其主要由氧化物以及硫化物组成。随着热腐蚀的进行，DD6表面物质发生了剥蚀，沉积盐量的增加导致剥蚀现象越加严重，合金内部致密的组织结构也被破坏，横截面上出现了大量孔洞、裂纹等缺陷。在相同涂盐量下，周期涂盐法使得DD6的腐蚀程度高于单次涂盐法。结论 DD6高温热腐蚀行为与涂盐量及涂盐方式密切相关，相同涂盐方式下，涂盐量越大，DD6热腐蚀更加严重。涂盐量一定时，周期涂盐法使得DD6的热腐蚀剧烈程度大于单次涂盐法，且DD6在上述热腐蚀条件下均发生剥蚀破坏。     

Role of nitric oxide in the genotoxic response to chronic microcystin-LR exposure in human–hamster hybrid cells

Microcystin-LR(MC-LR) is the most abundant and toxic microcystin congener and has been classified as a potential human carcinogen(Group 2B) by the International Agency for Research on Cancer. However, the mechanisms underlying the genotoxic effects of MC-LR during chronic exposure are still poorly understood. In the present study, human–hamster hybrid(AL) cells were exposed to MC-LR for varying lengths of time to investigate the role of nitrogen radicals in MC-LR-induced genotoxicity. The mutagenic potential at the CD59 locus was more than 2-fold higher(p 0.01) in ALcells exposed to a cytotoxic concentration(1 μmol/L) of MC-LR for 30 days than in untreated control cells, which was consistent with the formation of micronucleus. MC-LR caused a dose-dependent increase in nitric oxide(NO) production in treated cells. Moreover, this was blocked by concurrent treatment with the NO synthase inhibitor NG-methyl-L-arginine(L-NMMA), which suppressed MC-LRinduced mutations as well. The survival of mitochondrial DNA-depleted(ρ0) ALcells was markedly decreased by MC-LR treatment compared to that in ALcells, while the CD59 mutant fraction was unaltered. These results provided clear evidence that the genotoxicity associated with chronic MC-LR exposure in mammalian cells was mediated by NO and might be considered as a basis for the development of therapeutics that prevent carcinogenesis.     

新型纳米结构铈锰复合氧化物的磷吸附行为与机制研究

采用共沉淀法制备了一种新型铈锰复合氧化物吸附剂,对其进行了表征,并对磷吸附行为与机制进行了研究.表征结果分析表明,此氧化物由纳米级颗粒组成;铈锰复合氧化物中的铈氧化物有类似水合氧化铈的无定形结构;BET比表面积为157 m2·g-1,等电点为6.5.吸附实验结果表明,Langmuir吸附等温线模型可以更好地拟合铈锰复合氧化物对磷的吸附,最大吸附量为28.6 mg·g-1(p H=7.0);铈锰复合氧化物对磷具有较高的吸附速率,更符合准二级动力学模型;溶液p H对铈锰复合氧化物吸附磷的影响较为明显,随p H升高,吸附量降低;离子强度则影响不大;共存阴离子对吸附影响的大小顺序为Si O2-3CO2-3Cl-≥SO2-4.通过对铈锰复合氧化物吸附磷前后Zeta电位和红外谱图(FTIR)分析,可以推断磷在铈锰复合氧化物表面发生了特性吸附,磷酸根主要通过取代复合氧化物表面的金属羟基而被吸附去除.