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131.
Internally mixed sea salt, soot, and sulfates at Macao, a coastal city in South China 总被引:1,自引:0,他引:1
Li W Shao L Shen R Yang S Wang Z Tang U 《Journal of the Air & Waste Management Association (1995)》2011,61(11):1166-1173
Direct observation of the mixing state of aerosol particles in a coastal urban city is critical to understand atmospheric processing and hygroscopic growth in humid air. Morphology, composition, and mixing state of individual aerosol particles from Macao, located south of the Pearl River Delta (PRD) and 100 km west of Hong Kong, were investigated using scanning electron microscopy (SEM) and transmission electron microscopy coupled with energy-dispersive X-ray spectrometry (TEM/EDX). SEM images show that soot and roughly spherical particles are prevalent in the samples. Based on the compositions of individual aerosol particles, aerosol particles with roughly spherical shape are classified into coarse Na-rich and fine S-rich particles. TEM/EDX indicates that each Na-rich particle consists of a Na-S core and NaNO3 shell. Even in the absence of heavy pollution, the marine sea salt particles were completely depleted in chloride, and Na-related sulfates and nitrates were enriched in Macao air. The reason could be that SO2 from the polluted PRD and ships in the South China Sea and NO2 from vehicles in the city sped up the chlorine depletion in sea salt through heterogeneous reactions. Fresh soot particles from vehicular emissions mainly occur near curbside. However, there are many aged soot particles in the sampling site surrounded by main roads 200 to 400 m away, suggesting that the fresh soot likely underwent a quick aging. Overall, secondary nitrates and sulfates internally mixed with soot and sea salt particles can totally change their surface hygroscopicity in coastal cities. 相似文献
132.
133.
采用固相合成法制备了Zr掺杂TiO_2(Zr-TiO_2),运用XRD技术对其进行了表征,并将其用于水中头孢氨苄的光催化降解,通过单因素实验及正交实验优化了光催化反应条件。结果表明:制备的Zr-TiO_2为锐钛矿型介孔材料,孔径约为8.12 nm;各因素对头孢氨苄去除率的影响由大到小依次为光照时间、Zr-TiO_2投加量、初始头孢氨苄质量浓度;在Zr-TiO_2投加量为1.5 g/L、初始头孢氨苄质量浓度为10 mg/L、溶液pH为7.0、光照(300 W UV)时间为1.5 h的优化条件下,头孢氨苄去除率高达99.46%;Zr-TiO_2光催化剂的重复使用性能良好。 相似文献
134.
Hua-Yun Xiao Cong-Guo Tang Hong-Wei Xiao Yan-Li Wang Xue-Yan Liu Cong-Qiang Liu 《Environmental pollution (Barking, Essex : 1987)》2010,158(5):1726-1732
In urban cities in Southern China, the tissue S/N ratios of epilithic mosses (Haplocladium microphyllum), varied widely from 0.11 to 0.19, are strongly related to some atmospheric chemical parameters (e.g. rainwater SO42−/NH4+ ratios, each people SO2 emission). If tissue S/N ratios in the healthy moss species tend to maintain a constant ratio of 0.15 in unpolluted area, our study cities can be divided into two classes: class I (S/N > 0.15, S excess) and class II (S/N < 0.15, N excess), possibly indicative of stronger industrial activity and higher density of population, respectively. Mosses in all these cities obtained S and N from rainwater at a similar ratio. Sulphur and N isotope ratios in mosses are found significantly linearly correlated with local coal δ34S and NH4+-N wet deposition, respectively, indicating that local coal and animal NH3 are the major atmospheric S and N sources. 相似文献
135.
Xiang-Yu Tang Noam Weisbrod 《Environmental pollution (Barking, Essex : 1987)》2009,157(8-9):2266-2274
Colloid-facilitated transport of lead (Pb) was explored in a natural chalk fracture with an average equivalent hydraulic aperture of 139 μm. Tracer solution was prepared by adding montmorillonite (100 mg L?1) and/or humic acid (HA) (10 mg L?1) to modified artificial rainwater containing dissolved Pb (21.4 mg Pb L?1), naturally precipitated PbCO3 particles (16.4 mg Pb L?1) and LiBr (39.0 mg L?1). We found that Pb is only mobile when associated with colloids. PbCO3 particles were not mobile in the fracture. The addition of HA to the montmorillonite suspension increased the suspension's mobility and therefore promoted the colloid-facilitated transport of Pb. The increases in pH and sodium absorption ratio induced by the chalk-tracer solution interactions appeared to increase the dispersion and mobilization of colloids entering the fracture. The dominant colloid-facilitated transport of Pb reported in this study has significant implications for risk assessment of Pb mobility in fractured rocks. 相似文献
136.
基于GIS的耕地土壤重金属污染与农业功能定位研究——以山东省聊城市为例 总被引:1,自引:0,他引:1
按8km×8km的网格将聊城市耕地分为137个采样点,调查砷、镉、铬、铜、汞、镍、铅、锌等重金属的污染状况。采用国家土壤环境质量标准、农产品安全质量标准和绿色食品产地环境条件作为评价标准,采用单因子指数和综合指数为评价方法进行污染评价。研究表明,聊城市土壤污染强度依次为铜〉镍〉锌〉砷〉铬〉镉〉铅〉汞,但均未超标。以GIS为操作平台显示聊城市重金属空间分布状况,并对区域耕地进行了功能的定位。聊城市西南部土壤质量最优,适宜种植绿色食品;无公害蔬菜和安全粮食种植区在各县市均有不同程度的分布。 相似文献
137.
138.
采用气质联用分析,并结合自动识别与定量系统(AIQS-DB)考察2种再生水厂采用的深度处理工艺对微量有机污染物的去除效果。结果表明,以污水为原水的膜生物反应器(MBR)+臭氧氧化+生物活性炭滤池(BAC)工艺用于再生水生产,MBR工艺对有机污染物的去除起主要作用;城市污水厂二级出水为原水的混凝沉降+浸没式超滤(SMF)/连续微滤(CMF)+部分反渗透(RO)+臭氧氧化工艺用于再生水生产,其SMF和CMF工艺段的膜截留作用均可有效消减有机污染物含量,SMF的效果优于CMF;2种工艺中采用的臭氧技术都能进一步加强部分物质的去除效果。气质联用结合AIQS-DB可用于再生水中污染物的筛查和不同污水再生工艺对微污染物消减效果的评价。 相似文献
139.
微波强化有机改性膨润土对磷的吸附特性研究 总被引:5,自引:2,他引:3
利用十六烷基三甲基溴化铵(CTMAB)在微波辐射条件下对浙江临安膨润土进行改性,制得有机改性膨润土,利用其含磷模拟废水进行处理,考察了不同的工艺条件如有机改性剂用量、微波辐射强度、辐照时间、吸附时间、改性膨润土投加量、pH值对废水中磷去除效果的影响。结果表明:在有机改性剂用量为3 mmol/g,微波辐照强度为96 W/g,微波辐照时间8 min为最佳制备条件。改性膨润土用量为12 mg/L,反应时间为15 min,溶液pH为7及常温条件下,改性膨润土对浓度为50 mg/L的含磷废水去除率达到97.3%,吸附符合Freundlich吸附等温方程。 相似文献
140.
污泥含炭吸附剂对挥发性有机废气吸附实验研究 总被引:1,自引:0,他引:1
研究了污泥含炭吸附剂对挥发性有机污染物的吸附特性。结果表明,污泥含炭吸附剂对苯系物的吸附为典型的物理吸附,其吸附甲苯等温线的类型系优惠型吸附等温线,表明具有良好的吸附能力;在吸附反应温度为20℃,气体流量为500 mL/m in(停留时间为0.424 s),甲苯浓度为2 700 mg/m3时,甲苯的饱和吸附容量为150.0 mg/g;同时,研究表明污泥含炭吸附剂对苯系物的饱和吸附容量和吸附强弱次序为二甲苯甲苯苯。结果表明污泥含炭吸附剂适合对中低浓度有机废气的吸附净化。 相似文献