石墨相氮化碳协同UV-H_2O_2光催化降解亚甲基蓝

以三聚氰胺为前驱体,经热解—回流法制备了石墨相氮化碳(g-C3N4),采用XRD、FTIR、SEM、EDS、PL等技术对g-C_3N_4进行了表征。研究了g-C_3N_4在UV-H_2O_2体系中对废水中亚甲基蓝(MB)的光降解效果。实验结果表明,UV+g-C_3N_4催化剂+H_2O_2体系能协同降解MB,在初始MB质量浓度为20 mg/L、初始废水p H为5、废水体积为250 mL、g-C_3N_4加入量为0.10 g、H_2O_2浓度为0.4 mmol/L、反应温度为25℃的优化工艺条件下,紫外光照射70 min时MB脱色率达98.32%。g-C_3N_4催化剂具有较好的重复使用性能,使用5次后MB脱色率仍保持在95.10%。     

微生物-光-电化学耦合技术降解污染物和回收能源的研究进展

微生物电化学技术能同时实现污染物去除和能量回收,但存在污染物去除种类有限及产能效率低的局限,近几年将可再生的太阳能引入微生物电化学技术的微生物-光-电化学耦合技术应运而生。本文简要介绍了微生物-光-电化学耦合技术的发展背景和研究现状,对该技术现有的耦合形式进行分类,并对各种形式的耦合机理进行详细的阐释,最后对其未来的发展进行了展望。     

Comparative study on performances of a heat-pipe PV/T system and a heat-pipe solar water heating system

The heat-pipe solar water heating (HP-SWH) system and the heat-pipe photovoltaic/thermal (HP-PV/T) system are two practical solar systems, both of which use heat pipes to transfer heat. By selecting appropriate working fluid of the heat-pipes, these systems can be used in the cold region without being frozen. However, performances of these two solar systems are different because the HP-PV/T system can simultaneously provide electricity and heat, whereas the HP-SWH system provides heat only. In order to understand these two systems, this work presents a mathematical model for each system to study their one-day and annual performances. One-day simulation results showed that the HP-SWH system obtained more thermal energy and total energy than the HP-PV/T system while the HP-PV/T system achieved higher exergy efficiency than the HP-SWH system. Annual simulation results indicated that the HP-SWH system can heat the water to the available temperature (45°C) solely by solar energy for more than 121 days per year in typical climate regions of China, Hong Kong, Lhasa, and Beijing, while the HP-PV/T system can only work for not more than 102 days. The HP-PV/T system, however, can provide an additional electricity output of 73.019 kWh/m², 129.472 kWh/m², and 90.309 kWh/m² per unit collector area in the three regions, respectively.     

Modeling urban solar energy with high spatiotemporal resolution: A case study in Toronto,Canada

This research presents a method to determine the maximum potential for the capturing of solar radiation on the rooftop of buildings in an urban environment. This involves the modeling of solar energy potential and comparison to historical building energy demand profiles through the use of 3-D solar simulation software tools and geographic information systems (GIS). The objective is to accurately identify the amount of surface area that is suitable for solar photovoltaic (PV) installations and to estimate the hourly PV electricity generation potential of existing building rooftops in an urban environment. This study demonstrates a viable approach for modeling urban solar energy and offers valuable information for electricity distributors, policy makers, and urban energy planners to facilitate the substantial design of a green built environment. The developed methodology is comprised of three main sections: (1) determination of suitable rooftop area, (2) determination of the amount of incident solar radiation available per rooftop, and (3) estimation of hourly solar PV electricity generation potential. A case study was performed using this method for Ryerson University, located in Toronto, Canada. It was found that solar PV could supply up to 19% of the study area’s electricity demands during peak consumption hours. The potential benefits of solar PV was also estimated based upon hourly greenhouse gas emission intensity factors as well as Time-of-Use (TOU) savings through the Ontario Feed-in-Tariff (FIT) program, which allows for better representation of the positive impacts of solar technologies.     

超滤处理洗涤污水循环利用的中试研究

采用不同材质国产超滤膜聚丙烯（PP）、聚丙烯腈（PAN）和聚砜（PS）,进行了洗涤污水处理循环利用的现场中试研究.结合超滤工艺出水水质和膜污染分析,3种膜材质中PAN膜较优,有效去除了水中浊度、悬浮物、油脂等污染物,一定程度保留了游离阴离子表面活性剂（LAS）,长期循环洗涤对衣物的白度无不良影响.根据相关性分析,超滤出水较高COD值很大程度上是由水中LAS引起的.超滤膜对细菌、大肠菌群的去除率较低,出水通过紫外消毒,当紫外线密度≥3?750 J/m²时,微生物水平能够达到国家饮用水水质标准.根据不同水力反冲洗条件下膜渗透通量和净产水量比较,PAN膜最佳水力反冲洗条件为0.5 h反冲洗2 min.长期运行时超滤膜化学清洗方法采用碱洗法方便有效.     

Ce(Ⅲ)对UV-B辐射胁迫下大豆幼苗光化学反应的影响

用水培法研究Ce(Ⅲ)对UV-B辐射胁迫下大豆幼苗光化学反应的影响.结果表明, 20 mg·L^-1 CeCl₃使大豆幼苗净光合速率(Pn)、Hill反应、Mg²⁺-ATPase活性与光合磷酸化活力4项指标较对照提高23.2%～14.3%; 有效抑制UV-B辐射(T₁=0.15 W·m^-2和T₂=0.45 W·m^-2)胁迫下4项指标下降, 4项指标降幅［Ce(Ⅲ)+T₁为36.6%～15.9%,Ce(Ⅲ)+T₂为65.6%～33.2%］小于对应的UV-B辐射组(T₁为50.9%～23.3%,T₂为77.3%～51.4%). 动态变化显示, Ce(Ⅲ)减缓了胁迫期4项指标的下降趋势,促进了恢复期4项指标上升幅度. 说明Ce(Ⅲ)通过减轻UV-B辐射对大豆幼苗光化学反应的伤害, 遏制UV-B辐射胁迫下大豆幼苗Pn下降.     

An efficient technology to treat heavy metal--lead--contaminated soil by microwave radiation

Microwave (MW) technology can be used to vitrify contaminated soil wastes and immobilize heavy metal ions in soils. More than 93% of the Pb(II)-contaminated soil was vitrified to a glass/ceramic formation after 30 min of MW radiation. In a 6-year study, the Pb(II) concentration of the vitrified soil in the leaching test was less than 1.0 mg/l, which is substantially below the USEPA regulatory limit of 5.0 mg/l.     

GSM移动通信基站电磁辐射污染状况研究

介绍了GSM移动通信基站系统,指出,在进行GSM移动通信基站环境影响分析时,要注意采样点位的设置和测量要求.现场监测结果表明,GSM移动通信基站对环境电磁辐射水平有一定的影响,特别是对50 m内建筑物影响显著,但绝大多数基站基本符合国家有关电磁辐射环境影响标准的要求,在设备正常运行情况下,不会对周围环境造成电磁辐射污染.     

青藏铁路用空气弹簧橡胶胶料耐紫外线老化试验研究

我国正在建设的青藏铁路是世界上海拔最高、线路最长的高原铁路.其气候特点对橡胶制品提出了新的技术要求,为适应在该气候条件下的运用需要,进行了针对空气弹簧胶囊用橡胶的耐紫外线老化试验研究工作,试验表明随着紫外线老化时间的增加,其硬度和300%定伸强度均提高,但拉伸强度和扯断伸长率随着紫外线老化时间的增加而降低;通过与胶料的耐臭氧试验和大气老化试验比较,基本可以认为引起空气弹簧胶囊表面龟裂的主要原因是受力状况、臭氧和大气老化的作用,而紫外线对橡胶的表面龟裂影响作用不大,因此,为提高空气弹簧胶囊的耐老化性能,主要考虑降低橡胶的受力,提高耐臭氧和耐大气老化性能.     

氯对紫外线灭活枯草芽孢杆菌的协同作用

以枯草芽孢杆菌为研究对象,研究了紫外线和氯单独及联合作用时的灭菌效果.结果表明,单独氯消毒时,对枯草芽孢杆菌的灭活效果很低,CT值为300(mg·min)/L时,灭活率仅为0.53个对数级;单独紫外线消毒对枯草芽孢杆菌有较好的灭活效果,紫外线剂量为40mJ/cm²时,对其有3.3个对数级的灭活效果.紫外线和氯联合消毒时,对枯草芽孢杆菌的灭活效果大大增强,当紫外线剂量为40mJ/cm²,氯的CT值为300(mg·min)/L时,对枯草芽孢杆菌的灭活率可达6.2个对数级,远高于二者单独作用效果之和.紫外线与氯的作用顺序对消毒效果有明显影响,以先紫外线照射后再加氯的效果最好.通过Berenbaum公式计算可知,紫外线与氯联合灭菌是一种协同作用,并且随着紫外线剂量及氯投量的增加,协同作用增强.