温度对悬浮生物膜法工艺影响的研究

通过污水好氧生物处理的悬浮生物膜法工艺的实验，研究温度对动力学参数的影响，为优化设计和运行管理提供一定参数依据。     

氮掺杂二氧化钛复合催化膜降解甲苯气体研究

采用溶胶-凝胶法以聚丙烯(PP)中空纤维膜为载体制备了N-Ti O2/PP复合催化膜,并考察了其催化降解甲苯有机废气的性能.结果发现,紫外光催化的甲苯降解率可达84%,去除负荷为89.8 g·m-3·h~(-1),自然光催化的甲苯降解率可达63.9%,去除负荷为69.25 g·m-3·h~(-1).同时,采用紫外-可见光谱(UV-Vis)、X-射线光电子能谱(XPS)和傅里叶变换红外光谱(FT-IR)表征了N-Ti O2/PP复合催化膜,并采用GC-MS分析甲苯降解过程的中间产物并推测甲苯反应过程机理.采用GC-MS分析出口气样的研究结果表明,苯(C6H6)、苯甲醛(C7H6O)、苯乙酸(C8H8O2)、丙烯醛(C3H4O)、甲酸甲酯(C2H4O2)为甲苯光催化降解的中间产物.N-Ti O2/PP复合催化膜降解甲苯的机制为甲苯气体通过中空纤维膜传质到N-Ti O2/PP复合催化膜,光催化产生羟基自由基,甲苯气体被羟基自由基氧化成中间产物,并继续降解为最终产物二氧化碳和水.     

镁硼硅晶膜改性技术对镍-磷复合镀层组织性能的影响

目的 通过研究镁硼硅晶膜改性技术对镍-磷复合镀层组织性能的影响,开发并提升工业应用价值较高的非晶态镍-磷镀层.方法 采用镁硼硅晶膜改性处理技术,在45#钢基材上制备Ni-P化学镀层,通过扫描电子显微镜等设备,检测处理后镀层的微观形貌、组织结构和耐磨耐蚀性能,结合镁硼硅水体活化表征,分析镁硼硅晶膜改性技术对镍-磷镀层的强化机理.结果 相比传统的Ni-P镀层,镁硼硅改性晶膜处理的Ni-P镀层表面平整,分布均匀,表面致密度明显提升,摩擦因数减小了约32％,腐蚀电位正移221 mV,腐蚀电流为原来的1/2,腐蚀质量损失速率明显较低,耐腐蚀性能更为优异.经过镁硼硅改性晶膜处理的水体分子团明显减小,活性提升,这说明经过处理后的水体易于溶解来自复合陶瓷中的硅石和硼素等物质,在Ni-P镀层形成致密的晶膜,提高镀层的综合防护性能.结论 经过镁硼硅晶膜改性处理后,Ni-P镀层表面致密度和耐磨耐蚀性能有了明显的提升,具有更为宽广的工业应用价值.     

固废填埋长期环境安全和寿命预测研究综述

我国固废填埋场数量多、运行水平低、设施老化快、预期寿命偏短且寿命到期后老化严重.与此相对,固废填埋场寿命相关研究却存在关注度较少、研究方向不明确、研究内容不系统等问题.本文综述了通用工程领域寿命预测的基本概念及其发展历程,分门别类地梳理工程寿命预测的主要研究对象和研究方法;在此基础上,结合固体废物填埋工程和实际特征,系...     

冰雪表面HNO3的紫外光解机理

利用308 nm激光与cavity ring-down spectroscopy技术对HNO3的气相与冰表面光解进行了研究,考察了其光解量子产额与吸收系数,结果表明,.OH+NO2*是其光解反应的主要通道;HNO3在253 K、308 nm冰表面的吸收系数为(1.21±0.31)×10-18cm2.molecule-1,比其在气相的吸收系数(1.24±0.19)×10-21 cm.2molecule-1(295 K)及(8.50±0.24)×10-22cm.2molecule-1(253 K)均高约3个数量级;HNO3在253K冰表面光解产生NO2*的量子产额为0.60±0.34.     

塑料增塑剂对凡纳滨对虾存活、生长和免疫的影响(Effects of Plastic Plasticizers on Survival, Growth and Immune Factors of Litopenaeus vannamei)

研究了塑料增塑剂邻苯二甲酸二甲酯(DMP)、邻苯二甲酸二乙酯(DEP)、邻苯二甲酸二丁酯(DBP)和邻苯二甲酸二辛酯(DOP)对凡纳滨对虾(Litopenaeus vannamei)存活、生长和免疫的影响.96h急性毒性实验表明,在助溶剂Tween20的安全浓度范围内,随着DMP、DEP、DBP和DOP水平的升高,凡纳滨对虾存活率呈下降趋势,24h、48h、72h和96h的LC50分别为40.33、35.29、25.48、19.14mg·L-1,30.52、23.45、16.96、15.38mg·L-1,7.51、6.97、6.57、6.06mg·L-1和6.85、5.87、5.01、4.47mg·L-1;DMP、DEP、DBP和DOP对凡纳滨对虾的安全浓度随塑料增塑剂碳链的增加呈下降趋势,分别为8.11、4.15、1.80和1.29mg·L-1.90d慢性毒性实验表明,凡纳滨对虾存活率、特定生长率、血清蛋白含量、血清酚氧化酶和超氧化物歧化酶活性均以对照组和0.0400mg·L-1助溶剂Tween20处理组最高,而且显著高于1/100倍DMP、DEP、DBP和DOP安全浓度处理组(p<0.05).     

Recycling disposable cups into paper plastic composites

The majority of disposable cups are made from paper plastic laminates (PPL) which consist of high quality cellulose fibre with a thin internal polyethylene coating. There are limited recycling options for PPLs and this has contributed to disposable cups becoming a high profile, problematic waste. In this work disposable cups have been shredded to form PPL flakes and these have been used to reinforce polypropylene to form novel paper plastic composites (PPCs). The PPL flakes and polypropylene were mixed, extruded, pelletised and injection moulded at low temperatures to prevent degradation of the cellulose fibres. The level of PPL flake addition and the use of a maleated polyolefin coupling agent to enhance interfacial adhesion have been investigated. Samples have been characterised using tensile testing, dynamic mechanical analysis (DMA) and thermogravimetric analysis. Use of a coupling agent allows composites containing 40 wt.% of PPL flakes to increase tensile strength of PP by 50% to 30 MPa. The Young modulus also increases from 1 to 2.5 GPa and the work to fracture increases by a factor of 5. The work demonstrates that PPL disposable cups have potential to be beneficially reused as reinforcement in novel polypropylene composites.     

Numerical studies on the thermal regimes of the horizontal tube falling film evaporation under varying feeder height

ABSTRACT

This paper discusses about the effect of feeder height and heat flux on the heat transfer characteristics of horizontal tube falling film evaporation in the thermal regimes. In order to investigate this, a two- dimensional CFD model was developed to perform simulation and results were compared and validated with published data available in the literature. Heat transfer co-efficients in the thermal regimes were determined from the CFD simulation and the results were recorded, analyzed and validated with the mathematical models available in the literature. The novelty of the current study is to predict the commencement of the fully developed thermal region over the tube from the simulation model under varying feeder height and heat flux. An effort was also made to measure the liquid film thickness around the tube from the CFD model in the thermal regimes. It is observed that angle of thermally developing region contracts and fully developed thermal region extends with the increase of the feeder height and heat flux. It is observed from the study that increase of heat flux by 10 kW/m² resulted in increase of heat transfer co-efficient value by 10–12% average in thermally developing region and 12–15% average in fully developed region. Thinnest liquid film thickness observed between 85 and 127°angle. Shifting of thinnest region of liquid film upward from the mid tube with the increase of the feeder height and heat flux is noted.     

Study on the optical property and surface morphology of N doped TiO2 film deposited with different N2 flow rates by DCPMS

N doped TiO₂ films were deposited by direct current pulse magnetron sputtering system at room temperature. By using UV-Vis spectrophotometer and atomic force microscope, we studied the influence of N₂ flow rate on the optical property and surface morphology of films. The results indicate that the optical property and surface morphology of N doped TiO₂ film was dominated by the N₂ flow rate. The mean absorbency in visible range of pure TiO₂ films is near to 0%, which means that the pure TiO₂ could hardly display the photocatalytic property in visible range. When N₂ flow rate is 2 sccm, the mean absorbency in visible range of N doped TiO₂ film could reach at 24%. In this case, the film could be used as photocatalyst induced by visible light. While with increasing N₂ flow rate, the mean absorbency in visible range of N doped TiO₂ film decreased abruptly. Especially when N₂ flow rate exceeded 8 sccm, the mean absorbency in visible range of N doped TiO₂ film decreased to about 0%, which is like pure TiO₂ fimls.     

磷酸盐对铁锰复合氧化膜去除地表水中氨氮的影响

利用中试实验系统,研究磷酸盐对石英砂滤料表面负载的铁锰复合氧化膜去除地表水中氨氮的影响.结果表明,当水温为17.2~21.9℃时,随着运行时间的推移,未投加磷酸盐滤柱的氨氮去除效果有所下降;而投加5~15μg·L~(-1)磷酸盐滤柱的氨氮去除效果稳定,且去除率大于95.3%.当水温低于10.5℃时,滤柱出水氨氮浓度超标,此时通过提高磷酸盐投加量至30μg·L~(-1)或增加滤层厚度均可实现出水氨氮浓度达标.但随着系统持续运行,仅增加滤层厚度的滤柱出水氨氮浓度会再次超标.水温在6.5~10.5℃之间,投加30μg·L~(-1)磷酸盐的条件下,120 cm和80 cm活性滤层的最大安全进水氨氮浓度分别为2.34 mg·L~(-1)和1.95 mg·L~(-1).滤柱中生物灭活实验表明活性氧化膜对氨氮的去除同时包括催化氧化作用和生物作用;投加磷酸盐条件下,活性氧化膜的总活性和催化氧化活性分别是未投加磷酸盐条件的1.36倍和1.79倍,这表明磷酸盐促进了活性氧化膜的催化氧化活性.