磁溅射法制备TiO2/PTFE复合膜及其性能研究

目的研究磁控溅射法在聚四氟乙烯(PTFE)微孔膜上负载TiO_2,制备TiO_2/PTFE复合膜。方法利用接触角、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)、拉伸强度等对复合膜亲水性、元素、形貌和机械强度进行测试,通过控制变量法研究了溅射时间、溅射功率对膜性能的影响及对复合膜对甲基橙的降解性能。结果在溅射功率为40 W,溅射时间为90 s时,TiO_2/PTFE复合膜的亲水性和拉伸强度相对较好,甲基橙的去除率达97%,降解效果好。结论通过实验可以优化出磁控溅射的工艺参数,制备出物理性能优异,并具有较高的光催化活性的负载型纳米催化剂。     

等离子喷涂制备 ZrB2-SiC 复合涂层及其静态烧蚀性能

目的提高C/C复合材料的抗静态烧蚀性能。方法利用大气等离子喷涂技术在C/C复合材料表面制备ZrB_2-SiC复合涂层,对其进行1500℃的静态烧蚀实验。利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)及能谱分析仪(EDS)对涂层的物相成分、微观形貌等进行检测分析。结果采用大气等离子喷涂制备的ZrB_2-SiC涂层是由熔融的粉末粒子紧密堆积而成,呈现典型的层状结构,涂层均匀完整地覆盖于C/C基体表面,厚度约为200μm。涂覆有ZrB_2-SiC复合涂层的C/C复合材料试样在1500℃分别氧化2,3,4 h后,试样依旧保持完整,C/C基体未遭受损伤,试样的质量增加率依次为3.39%,2.95%,4.25%。结论采用大气等离子喷涂技术能够在C/C复合材料表面制备出厚度均匀、结构致密的ZrB_2-SiC复合涂层,ZrB_2-SiC复合涂层使C/C复合材料的抗静态烧蚀性能显著提高。     

功能化层状复合材料的制备及其电催化性能

目的制备一种新型功能化离子液体修饰层状复合材料,研究其对L-酪氨酸(L-Tyr)的电催化氧化行为。方法通过静电自组装方式将氮氧自由基功能化离子液体(TEMPO-IL)与钙铌酸钾(KCa_2Nb_3O_(10))进行复合,并运用XRD,FTIR,SEM,HRTEM等测试手段对所作材料的微观形貌和结构进行分析表征。另外,将其作为电极修饰剂修饰于电极表面通过电化学工作站测试其电化学性质。结果该修饰电极对于电催化氧化L-Tyr有着较高的电化学活性。同时实验还表明,当L-Tyr的浓度在1×10~(-4)~1.16×10~(-2) mol/L之间时,峰电流值与L-Tyr浓度呈良好的线性相关,检测下限为6.2×10~(-5) mol/L(信噪比为3)。结论静电自组装是一种能够快捷、高效的制备层状复合材料方法,且得到的复合材料显示出在生物传感器方面的应用前景。     

The velocity of DNAPL fingering in water-saturated porous media: laboratory experiments and a mobile–immobile–zone model

Dense nonaqueous phase liquids (DNAPLs) are immiscible with water and can give rise to highly fingered fluid distributions when infiltrating through water-saturated porous media. In this paper, a conceptual mobile–immobile–zone (MIZ) model is presented to describe the structure of a DNAPL finger in water-saturated porous media and the velocity of finger propagation. A finger is composed of a finger body and a tip. The finger body has a mobile core and an immobile sheath. All the DNAPL within the tip of a finger is mobile. Lab experiments utilizing image analyses of a DNAPL (PCE) penetrating into water-saturated homogeneous glass beads were carried out in a two-dimensional transparent chamber. The results show that the fingers elongated almost linearly with time. The fingers did not grow laterally after the tip of the finger had passed. The average finger diameters were between 3.9 and 5.4 mm for PCE propagation in water-saturated glass bead porous media with mean particle diameters from 0.32 to 1.36 mm. The estimated mobile core diameters were 51–60% of the average finger diameters.     

危险废物多目标规划模型研究

根据危险废物系统管理的原则,采用全过程管理理念,运用最优化理论和系统分析方法,充分考虑各种因素,建立了危险废物多目标规划模型,并提出模型的求解方法。考虑废物间的相容性和复合效用函数,将所建立的危险废物多目标规划模型应用于重庆市主城区危险废物系统管理规划。结果表明,在设计的案例和场景下,分别以环境影响、经济因素、综合考虑环境因素和经济因素为首要因素考虑时,得到不同的优化方案。该模型的应用为环境管理者对危险废物系统管理提供了决策支持。     

Hydrothermal carbonization of food waste and associated packaging materials for energy source generation

Hydrothermal carbonization (HTC) is a thermal conversion technique that converts food wastes and associated packaging materials to a valuable, energy-rich resource. Food waste collected from local restaurants was carbonized over time at different temperatures (225, 250 and 275 °C) and solids concentrations to determine how process conditions influence carbonization product properties and composition. Experiments were also conducted to determine the influence of packaging material on food waste carbonization. Results indicate the majority of initial carbon remains integrated within the solid-phase at the solids concentrations and reaction temperatures evaluated. Initial solids concentration influences carbon distribution because of increased compound solubilization, while changes in reaction temperature imparted little change on carbon distribution. The presence of packaging materials significantly influences the energy content of the recovered solids. As the proportion of packaging materials increase, the energy content of recovered solids decreases because of the low energetic retention associated with the packaging materials. HTC results in net positive energy balances at all conditions, except at a 5% (dry wt.) solids concentration. Carbonization of food waste and associated packaging materials also results in net positive balances, but energy needs for solids post-processing are significant. Advantages associated with carbonization are not fully realized when only evaluating process energetics. A more detailed life cycle assessment is needed for a more complete comparison of processes.     

高温烟气除尘用纤维滤料研究进展

本文对上程上高温烟气来源进行了分类，对当前高温烟气过滤的核心技术的耐高温过滤材料的使用现状进行了分析，对高温玄武岩纤维过滤材料进行了重点探讨与展望，指出玄武岩纤维滤材当前在高温烟气过滤行业中急需解决的问题和产业科技成果转化方向。     

An analysis of variables influencing the material composition of automobiles

The use of materials is studied broadly, because of the environmental problems related to extraction, production, consumption and waste treatment. The use and substitution of materials in products is therefore a relevant issue for environmental policy making. Studies have been done to describe the material flow or to measure the impact of materials or products on the environment. However, these studies do not often consider economic, substitution and dynamic aspects of material flows. Other studies on material flows analyse the relationship between the use of materials and economic growth, but they do not consider substitution between materials. For environmental policy making economic, technological and environmental aspects of the use of materials need to be considered. Especially, substitution of materials is important. In various countries material and product policies are imposed on a variety of materials and products. For evaluation of these policies their environmental and economic effects need to be examined in detail. This study aims to analyse the economic and technological factors influencing the use of materials and the substitution between different materials dynamically. The goal is to obtain an insight in the effect that material levies may have on the use and substitution of materials. The statistical analysis is performed on a specific product-group because decisions on the use of materials are taken on a product-level. The case study is performed on automobiles. The results show that the material use is largely an autonomous development. The price of aluminium has a positive, significant effect on the use of that material. The price of plastics has a positive, but not significant effect on the use of plastics. Reasons may be that the costs of a raw material are small relative to the processing costs, and that the production process can only be changed slowly. Other factors, like competitiveness and consumers' tastes, may be more important for substitution. This implies that levies or subsidies on certain materials is not a promising policy to change the use of materials. Besides time, there are two other factors that have a positive and significant relationship with the use of aluminium and plastics: the fuel efficiency, which is the distance driven divided by the energy used; and, the road tax, which depends on the weight of a car. However, these effects are caused by their positive relationship with time. The main conclusion of the case study is that imposing a levy on materials may not have the desired or expected effect of reduction in material use.     

The significance of various factors for GHG emissions of buildings

The objective of the research was to create improved understanding of the significance of diverse factors for the total greenhouse gas (GHG) emissions of buildings. The specific focus of the study was on the assessment of the significance of building materials and embodied carbon. The scope of the study covers multi-storey residential buildings in Finland. This research was based on a literature survey and supported by a parametric case study. The parametric study assessed the building-material-related GHG emissions relative to total GHG emissions and the possible range of variation. The research assesses the minimum and maximum GHG emissions for production of buildings with similar spaces, to reveal the likely range of variation for the emissions. The calculations for the ‘minimum’ and ‘maximum’ scenarios assume a similar purpose of use, occupancy and spaces in the building, while the production methods, materials, site conditions and location are varied. The research also assesses the relative importance of various building components and other calculation parameters in terms of GHGs. Total material-related GHG emissions were compared with the GHG emissions caused by the operation of the building, at three distinct levels of energy performance. In addition, the material- and operation-related GHG emissions were compared with the location-related GHG emissions arising from people's mobility.     

A novel and stretchable carbon-nanotube/Ni@TiO2:W photocatalytic composite for the complete removal of diclofenac drug from the drinking water

We present the structural, morphological and photocatalytic properties of stretchable composites made with carbon nanotubes (CNTs), silicon rubber and Ni@TiO₂:W nanoparticles (TiWNi NPs) with average size of 37 ± 2 nm. Microscopy images showed that the TiWNi NPs decorated the surface of the CNT fibers, which are oriented in a preferential direction. TiWNi NPs presented a mixture of anatase/rutile phases with cubic structure. The performance of the TiWNi powders and stretchable composites was evaluated for the photocatalytic degradation of diclofenac (DCF) anti-inflammatory drug under ultraviolet-visible light. The results revealed that the maximum DCF degradation percentages were 34.6%, 91.9%, 97.1%, 98.5% and 100% for the CNT composite (stretched at 0%), TiWNi powders, CNT + TiWNi (stretched at 0%), CNT + TiWNi (stretched at 50%) and CNT + TiWNi (stretched at 100%), respectively. Thus, stretching the CNT + TiWNi composites was a good strategy to enhance the DCF degradation percentage from 97.1% to 100%, since stretching created additional defects (oxygen vacancies) that acted as electron sink, delaying the electron-hole recombination, and favors the DCF degradation. Raman/absorbance measurements confirmed the presence of such defects. Moreover, the reactive oxygen species (ROS) were determined by the scavenger's experiments and found that the main ROS were the ·OH and O₂⁻ radicals, which attacked the DCF molecules, causing their degradation. The results of this investigation confirmed that the stretchable CNT/TiWNi-based composites are a viable alternative to remove pharmaceutical contaminants from water and can be manually separated from the decontaminated water, which is unviable using photocatalytic powders.