碳纳米管溶胶的制备及其去除水中异狄氏剂的研究

采用强酸表面氧化法对碳纳米管表面进行处理,促进碳纳米管在水中的分散,制备碳纳米管溶胶,用于去除水中低浓度持久性有机污染物异狄氏剂.扫描电镜观测表明,氧化后的碳纳米管团簇被分散开,碳纳米管被打断.碳纳米管溶胶对异狄氏剂的吸附性能研究表明,制备的碳纳米管溶胶对异狄氏剂吸附去除效能优于原始碳纳米管,优化的pH值为6,此时碳纳米管溶胶对18μg/L异狄氏剂去除率达到100%;水中的腐殖质提高了吸附去除效能;碳纳米管溶胶对异狄氏剂的吸附等温线呈线性,碳纳米管溶胶的吸附性能优于原始碳纳米管吸附性能.吸附去除后,溶胶态碳纳米管以0.05 mmol/L氯化铝从水中沉淀分离.     

在线超声作用下流化床膜生物反应器的膜污染机制

在流化床膜生物反应器中引用在线超声技术来控制膜污染,考察了在线超声对污泥混合液特性的影响,探讨了在线超声作用下的膜污染机制。结果表明：在线超声流化床膜生物反应器的跨膜压差（TMP）增长速度明显慢于普通流化床膜生物反应器,可延长膜清洗周期约51％。在线超声作用下,污泥平均粒径降低约70μm,污泥胞外聚合物（EPS）含量增加（14±5）mg／g,混合液溶解性微生物产物（SMP）有所降低;同时,在线超声使得污泥浓度和混合液粘度降低,从而改善了混合液的过滤性,有助于膜污染的控制。分析表明,在线超声能够减少膜表面不可逆污染的发生,膜的主要污染机制为泥饼层污染。     

对一台循环流化床锅炉能效测试的分析

近年来,我国陆续出台了一系列的节能、环保政策,有力地推进了各地锅炉能效测试工作的开展.本文针对一台循环流化床锅炉进行了能效测试,并依据测试结果和锅炉运行中出现的问题进行分析,对锅炉运行工况进行了调整,极大地提高了锅炉运行热效率,有效地减少了锅炉使用单位对于能源的浪费,对以后循环流化床锅炉的能效测试工作具有一定的借鉴意义.     

Seasonal variations and source apportionment of atmospheric PM2.5-bound polycyclic aromatic hydrocarbons in a mixed multi-function area of Hangzhou,China

Environmental Science and Pollution Research - To reveal the seasonal variations and sources of PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) during haze and non-haze episodes, daily PM2.5...     

Effects of soil water and nitrogen availability on photosynthesis and water use efficiency of Robinia pseudoacacia seedlings

The efficient use of water and nitrogen (N) to promote growth and increase yield of fruit trees and crops is well studied.However,little is known about their effects on woody plants growing in arid and semiarid areas with limited water and N availability.To examine the effects of water and N supply on early growth and water use efficiency (WUE) of trees on dry soils,one-year-old seedlings of Robinia pseudoacacia were exposed to three soil water contents (non-limiting,medium drought,and severe drought) as well as to low and high N levels,for four months.Photosynthetic parameters,leaf instantaneous WUE (WUEi) and whole tree WUE (WUEb) were determined.Results showed that,independent of N levels,increasing soil water content enhanced the tree transpiration rate (Tr),stomatal conductance (Gs),intercellular CO2 concentration (Ci),maximum net assimilation rate (Amax),apparent quantum yield (AQY),the range of photosynthetically active radiation (PAR) due to both reduced light compensation point and enhanced light saturation point,and dark respiration rate (Rd),resulting in a higher net photosynthetic rate (Pn) and a significantly increased whole tree biomass.Consequently,WUEi and WUEb were reduced at low N,whereas WUE i was enhanced at high N levels.Irrespective of soil water availability,N supply enhanced Pn in association with an increase of Gs and Ci and a decrease of the stomatal limitation value (Ls),while Tr remained unchanged.Biomass and WUEi increased under non-limiting water conditions and medium drought,as well as WUEb under all water conditions;but under severe drought,WUEi and biomass were not affected by N application.In conclusion,increasing soil water availability improves photosynthetic capacity and biomass accumulation under low and high N levels,but its effects on WUE vary with soil N levels.N supply increased Pn and WUE,but under severe drought,N supply did not enhance WUEi and biomass.     

Degradation mechanism of Direct Pink 12B treated by iron-carbon micro-electrolysis and Fenton reaction

The Direct Pink 12B dye was treated by iron-carbon micro-electrolysis (ICME) and Fenton oxidation. The degradation pathway of Direct Pink 12B dye was inferred by ultraviolet visible (UV-Vis), infrared absorption spectrum (IR) and high performance liquid chromatography-mass spectrometry (HPLC-MS). The major reason of decolorization was that the conjugate structure was disrupted in the iron-carbon micro-electrolysis (ICME) process. However, the dye was not degraded completely because benzene rings and naphthalene rings were not broken. In the Fenton oxidation process, the azo bond groups surrounded by higher electron cloud density were first attacked by hydroxyl radicals to decolorize the dye molecule. Finally benzene rings and naphthalene rings were mineralized to H₂O and CO₂ under the oxidation of hydroxyl radicals.     

连续流动分析法测定废水中的总氮

本文初步探讨了连续流动分析法测定废水中总氮的方法。通过将测量量程扩大至20mg/L,对混浊的废水进行过滤处理,实验结果表明,该方法的相关系数达0．9999,方法检出限为0．02mg/L,加标回收率在99．5％-108％之间,RSD为0．2％-0．6％,可适用于废水中总氮的分析。     

关于烟蒂环境危害及其管理措施的研究

烟蒂作为随处可见的丢弃物,已成为目前环境中数量最多的固体废物,所致污染日趋严重,但是常被忽视。近年来国外的相关研究报告表明烟蒂具有很强的危害性,但国内各界对烟蒂污染的关注较少。本研究通过系统分析了烟蒂毒性的来源,综述了国外关于烟蒂渗滤液毒性试验的结果,阐明了烟蒂对水生生态系统中代表性物种的危害,并总结了烟蒂的其他潜在环境危害,以呼吁国内各界引起对烟蒂污染和烟蒂危害的重视。最后,提出一些管理方面的建议以破解当前烟蒂的环境管理难题。     

正交实验在气浮法条件筛选中的应用研究

正交试验是研究多因素多水平的一种设计方法,它是根据正交性从全面试验中挑选出部分有代表一t~．ej点进行试验,这些有代表性的点具备了“均匀分散,齐整可比”的特点,正交试验设计是分析因式设计的主要方法。是一种高效率、快速、经济的实验设计方法。将正交试验选择的水平组合列成表格,称为正交表。本文选择对溶气气浮法为研究对象。通过PAC的加入量、沉降时间、搅拌强度和搅拌时间等因素对废水的混凝处理效果有较大影响,为确定各因素的最佳值和影响效果的主次关系,选择影响较大的因素,采用正交实验确定设备最佳的运行条件。     

城市雨水系统中低影响开发与绿色水基础设施及其实例

城市化进程的急剧加快使得中国城市饱受暴雨侵袭的困扰。传统的排水机制是雨水排得越快越好,这就需要加大排水管径、增加排水泵站等,因此更多的的成本和更大的地下空间不可避免。另一方面,雨水完全可以成为资源,而不是污染源。基于以上事实,低影响开发(LID)技术被提出并正在成为城市雨水系统发展的趋势。LID技术从源头减少并延迟暴雨径流和峰值,使开发后的城市水文循环接近开发前的自然水文状态。而基于LID技术的绿色水基础设施如雨水花园、透水性铺装、植被浅沟和景观雨水调蓄池等正在越来越多的应用在城市,尤其是一些发达国家在这方面的技术十分成熟。中国起步较晚,只有少数发达城市进行了LID技术的尝试。但从可持续发展的角度来看,LID技术必将得到推广和应用。可以将LID技术与现有的雨水处理设施相结合,构建符合中国国情的城市雨水系统。