Chemical characteristics of PM2:5 during a typical haze episode in Guangzhou

The chemical characteristics (water-soluble ions and carbonaceous species) of PM2:5 in Guangzhou were measured during a typical haze episode. Most of the chemical species in PM2:5 showed significant di erence between normal and haze days. The highest contributors to PM2:5 were organic carbon (OC), nitrate, and sulfate in haze days and were OC, sulfate, and elemental carbon (EC) in normal days. The concentrations of secondary species such as, NO3??, SO4 2??, and NH4 + in haze days were 6.5, 3.9, and 5.3 times higher than those in normal days, respectively, while primary species (EC, Ca2+, K+) show similar increase from normal to haze days by a factor about 2.2–2.4. OC/EC ratio ranged from 2.8 to 6.2 with an average of 4.7 and the estimation on a minimum OC/EC ratio showed that SOC (secondary organic carbon) accounted more than 36.6% for the total organic carbon in haze days. The significantly increase in the secondary species (SOC, NO3??, SO4 2??, and NH4 +), especially in NO3??, caused the worst air quality in this region. Simultaneously, the result illustrated that the serious air pollution in haze episodes was strongly correlated with the meteorological conditions. During the sampling periods, air pollution and visibility had a good relationship with the air mass transport distance; the shorter air masses transport distance, the worse air quality and visibility in Guangzhou, indicating the strong domination of local sources contributing to haze formation. High concentration of the secondary aerosol in haze episodes was likely due to the higher oxidation rates of sulfur and nitrogen species.     

改性海带对铜离子的吸附性能

为了开发对重金属离子有很高吸附性能的生物吸附剂,文章对天然海带进行化学处理,研究了改性海带对铜离子的吸附能力。结果表明,天然海带、HCl处理后的海带及NaOH处理后的海带对铜离子的吸附量分别为59.3,38.6和88.0mg/g。化学改性提高了海带对铜离子的吸附能力,在废水处理中有很高的应用价值。     

霾天气南京市大气PM_(2.5)中水溶性离子污染特征

为了讨论南京市大气细颗粒物(PM2.5)及水溶性组分在霾天气下的污染水平和污染特征,2007年6月10日至2008年5月29日对南京市大气细粒子PM2.5进行了采样,用PM2.5在线监测浓度、离子色谱法等分别测得PM2.5的质量浓度、水溶性离子组成,初步研究了南京市大气细粒子(PM2.5)及水溶性组分在霾天气下的污染水平和污染特征。结果表明,南京市大气细颗粒物污染严重,霾天气下PM2.5中总水溶性离子质量浓度为54.28μg/m3,为非霾天气的1.6倍。分析的6种离子中SO42-、NO3-、NH4+是PM2.5的主要组成成分。灰霾期间PM2.5与NO3-、SO42-、NH4+的相关性较高,PM2.5中颗粒物的主要存在形式可能为NH4Cl、NH4NO3,(NH)42SO4或NH4HSO4。对比不同季节不同天气下的SOR(SO2转化率)和NOR(NOx转化率),发现霾天气下SO2和NOX转化率高于正常天气,表明SO2、NO2在霾天气更容易转化为二次粒子。     

离子色谱法测定降水中磷酸根离子

使用青岛普仁公司PIC-10离子色谱仪,测定降水中磷酸根离子,从样品的采集、实验条件选择、标准曲线绘制到方法精密度和准确度等分析,总结了淋洗液最佳流速和配比浓度,归纳了测定磷酸根离子的注意问题。     

Activated carbon supported TiO2-photocatalysis doped with Fe ions for continuous treatment of dye wastewater in a dynamic reactor

Fe-doped TiO2 coated on activated carbon (Fe-TiO2/AC, FTA) composites were prepared by an improved sol-gel method and characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray di ractometry, inductively coupled plasma mass spectrometry and BET surface area analysis. Obtained FTA composites were applied to the continuous treatment of dye wastewater in a dynamic reactor. The e ects of Fe ion content, catalyst content, UV-lamp power and flowrate of the continuous treatment of dye wastewater on degradation e ciency were analyzed to determine the optimum operating conditions of dye wastewater degradation. Continuous photocatalytic experiments provided interesting results that FTA had a high chemical oxygen demand (COD) removal rate compared with TiO2, Fe doped TiO2 (FT) and TiO2 coated on activated carbon (TA). In particular, when using the FTA catalyst with a Fe ion content of 0.33%, the kinetic content (k = 0.0376) of COD removal was more than the sum of both TA (0.0205) and 0.33% FT (0.0166). FTA showed a high photoactivity because of a synergistic e ect between Fe ions and AC on TiO2, which is higher than the individual e ects of AC or Fe ions on TiO2. Additionally, for the photocatalytic degradation of dye wastewater, the optimum Fe ion content, catalyst content, UV-lamp power and flowrate were 0.33%, 6 g/L, 60 W (two lamps) and 300 mL/hr, respectively. An investigation of catalyst reuse revealed that the 0.33% FTA showed almost no deactivation in photocatalytic degradation of naturally treated wastewater.     

铜对两种农药在砂土上吸附的影响

为了考察了铜与有机农药在土壤中吸附行为的交互作用,以阿特拉津(Atrazine,AT)、氰戊菊酯(Fenvalerate,Fen)为研究对象,进行批量平衡吸附实验。实验结果表明,AT的吸附符合线性吸附等温线,氰戊菊酯在土壤上的吸附变异性较大,可能原因是菊酯农药存在一定程度的降解。铜离子的存在使AT的吸附常数Koc由262.3减小为55.22L/kg,AT在土壤上的吸附量减小。氰戊菊酯吸附常数Koc为282.9(L/kg),铜离子与氰戊菊酯共存时,氰戊菊酯吸附Koc值增加为440.1L/kg,实验Cu2+浓度范围内,吸附量明显增加。两种农药土壤吸附实验结果不同,这种差异性可能是由于两种农药具有不同的水溶性和辛醇-水分配系数(Kow)值,铜与AT可能形成可溶性络合物从而减小其吸附。铜与氰戊菊酯可能形成不溶性络合物而使溶剂萃取率降低。     

泰山顶夏季大气气溶胶中水溶性离子的浓度及其粒径分布研究

为研究我国华北地区大气污染区域传输过程,2006-06在泰山日观峰上的泰山气象站,利用Andersen分级采样器同步进行了大气气溶胶采样,样品用离子色谱(IC)进行了分析.结果表明,SO2-4、NH 4、K 的浓度在0.43～0.65 μm出现峰值;Ca2 、Mg2 的浓度在4.7～5.8 μm出现峰值;NO-3、Na 、Cl-的浓度在0.43～0.65 μm和4.7～5.8 μm出现峰值.观测期间,高浓度的硫酸盐的质量中位直径在0.5～0.8 μm,属于"液滴模态".二次离子(SO2-4-、NH 4、NO-3)和K 浓度变化很剧烈,其它离子浓度变化不大.其中SO2-4的变化幅度最大,最低浓度为4.0 μg穖-3,最高浓度达到42.3 μg穖-3.来自泰山南方潮湿的气团是形成二次离子高值的原因.     

北京大气PM10中水溶性金属盐的在线观测与浓度特征研究

研究了北京大气可吸入气溶胶（PM10）中水溶性金属盐的变化特征,并对其来源进行了分析。钠盐、钾盐、镁盐、钙盐浓度的变化范围分别为：0.5～1.4μg/m3、0.5～2.5μg/m3、0.1～0.5μg/m3、0.6～5.8μg/m3,不同水溶性金属盐最高值和最低值出现季节不同。水溶性金属盐没有明显的采暖期和非采暖期的差异,说明冬季采暖不是它们的主要来源。海盐和土壤源是北京大气PM10中Na+的主要来源,K+的主要来源包括秸秆燃烧和生物质排放,土壤源是Mg2+和Ca2+的重要来源。水溶性金属盐的日变化规律不同。降水对Na+、K+、Mg2+、Ca2+的清除分别为10％～70％、20％～80％、10％～77％、5％～80％。     

介孔γ -Al2O3的制备及其对F-的吸附性能研究

以硝酸铝和碳酸氢铵为原料,采用溶胶-凝胶法合成具有较高活性的介孔γ-Al2O3纳米材料.对合成的样品进行XRD、TEM和BET表征.结果表明:在N2气氛下煅烧所得样品与在空气中煅烧所得样品相比,其比表面积略有增加;在溶胶-凝胶过程中,用乙醇洗涤凝胶能显著提高产物的比表面积,所得产物比表面积高达390 m2/g,呈多孔结...     

表面活性剂在胶团强化超滤中的应用

传统的废水处理技术一般有很多缺点,有的需要昂贵的试剂,有的需要很高能耗.近年来,人们开始用胶团强化超滤(MEUF)来处理含金属离子或有机污染物的废水,其中表面活性剂的使用是必不可少的.文章详细介绍了表面活性剂在MEUF技术中的作用、表面活性剂的类型以及影响表面活性剂在超滤中作用的主要因素如表面活性剂的浓度、温度、电解质...