鼎湖山PM2.5 中水溶性离子浓度特征分析

为研究珠江三角洲背景区域大气气溶胶中水溶性离子的特征及其来源,于2007年1月～2008年12月,在鼎湖山利用大流量滤膜采样器采集PM2.5样品,并用离子色谱(IC)分析其中的水溶性离子成分含量.结果表明,PM2.5中总水溶性离子年平均浓度为(36.3±16.4)μg.m-3.其中,3种主要离子SO24-、NH4+和NO3-占总离子浓度的89%;夏季受到来自海洋气团的影响,Na+和Cl-相关性明显增强,相关系数R2为0.91;NO3-/SO24-的平均值为0.32,表明固定源对鼎湖山地区污染的贡献更大;PM2.5中Σ阳离子电荷/Σ阴离子电荷的变化范围为0.44～2.59,平均值是1.03,水溶性离子电荷基本平衡.     

气浮+磷酸铵镁化学沉淀法处理铝材行业氟化氢铵表面处理废水

针对铝材企业NH4HF2表面处理废水含有高浓度的NHs-N和F-等特点,采用气浮+磷酸铵镁(MAP)化学沉淀法对NH4HF2废水进行预处理,可达到目标处理效果,再引入氧化废水池进一步处理,继而达标排放.经验证,该方法是一种技术可行、经济合理的NH4 HF2废水处理方法.     

Physiological mechanisms of degradation of fish populations in acidified water bodies

Disturbances in fish that result from water acidification and related factors are analyzed in the context of generalizations based on the results of experimental and field studies. It is shown that low pH, monomeric aluminum, and other metal ions have an adverse effect on physiological processes in fish and are a major cause of their death in acidified lakes and rivers. The vulnerability of fish to low water pH at different stages of their life cycle and mechanisms of delayed mortality are discussed.     

Composition, source, mass closure of PM2:5 aerosols for four forests in eastern China

PM2.5 aerosols were collected in forests along north latitude in boreal-temperate, temperate, subtropical and tropical climatic zones in eastern China, i.e., Changbai Mountain Nature Reserve (CB), Dongping National Forest Park in Chongming Island (CM), Dinghu Mountain Nature Reserve (DH), Jianfengling Nature Reserve in Hainan Island (HN). The mass concentrations of PM2.5, organic carbon (OC), elemental carbon (EC), water soluble organic carbon (WSOC) as well as concentrations of ten inorganic ions (F-, Cl-, NO3-, SO42-, C2O42-, NH4+, Na+, K+, Ca2+, Mg2+) were determined. Aerosol chemical mass closures were achieved. The 24-hr average concentrations of PM2.5 were 38.8, 89.2, 30.4, 18 μg/m3 at CB, CM, DH and HN, respectively. Organic matter and EC accounted for 21%-33% and 1.3%-2.3% of PM2.5 mass, respectively. The sum of three dominant secondary ions (SO42-, NO3-, NH4+) accounted for 44%, 50%, 45% and 16% of local PM2.5 mass at CB, CM, DH and HN, respectively. WSOC comprised 35%-65% of OC. The sources of PM2.5 include especially important regional anthropogenic pollutions at Chinese forest areas.     

TiO_2光催化还原重金属离子的研究进展

光催化还原技术越来越得到人们的认可。文章综述了TiO2光催化还原技术在废水中重金属离子处理方面的应用,从重金属离子的光催化还原机理、反应驱动力、光催化剂的失活与再生以及各种光催化还原重金属的影响因素等方面,阐述了重金属离子的光催化还原新进展。     

二氧化锰氧化降解五氯酚的动力学模拟研究

研究了五氯酚(PCP)在二氧化锰(MnO2)氧化作用下的降解反应动力学,并讨论了无机离子和有机组分对PCP降解动力学的影响.采用n级反应速率模型对PCP降解动力学进行非线性拟合,结果显示n＞0.999,这表明一级反应速率模型适用于模拟PCP降解反应.在保证95%置信区间的条件下,采用准一级反应速率模型对0.5 h内的PCP降解动力学进行了非线性拟合,得到的离心法和维生素C破坏法下PcP降解表观速率常数kobs分别是2.86和2.14 h-1.二价金属离子的加入能降低PCP的kobs;当超过MnO2初始浓度2%以上的Mn2 存在时,Mn2 能对PCP的kobs产生显著影响,而其它不同类型和浓度的离子对kobs不产生显著影响.8种酚酸中的咖啡酸、丁香酸和五倍子酸对kobs的抑制作用达到了显著性水平;而肉桂酸、香豆酸、阿魏酸和邻(对)羟基苯甲酸的影响不明显.研究表明,降低PCP降解速率的主要原因是由于导致PCP在MnO2表面的吸附作用减弱或在MnO2表面与PCP发生竞争反应造成的.     

纳滤膜在地下水除氟中对Cl^-／F^-的选择性分离

荷负电型纳滤（NF）膜在地下饮用水除氟中,对离子F^-的截留率（65％-78％）要高于对离子Cl^-的截留率,且表现出较好的Cl^-／F^-的选择性（离子选择性系数S〉1．5）和Donnan排斥作用。当水溶液中离子F^-和Cl^-单独存在时,随原水F^-浓度增加,NF膜对F^-的截留率由64．3％增至73．0％,当原水F^-浓度小于3．3mg／L时,NF膜出水F^-浓度小于1．0mg／L;而随Cr浓度增加,NF膜对Cl^-截留率由44．7％减小至20％以下。当F^-和Cr共存时,受F^-浓度增加的影响,NF膜Cl^-的截留率逐渐减小;受Cl^-浓度增加的影响,NF膜F^-截留率同样表现出减小的趋势。由S值随r浓度的增加而增大,可知NF在地下水除氟中F^-与Cl^-之间存在明显的竞争关系。     

Effect of dye-metal complexation on photocatalytic decomposition of the dyes on TiO2 under visible irradiation

The photocatalytic degradation of dyes (Acid Chrome Blue K (ACBK) and Alizarin Red (AR)) with strong complexation ability was investigated in the presence of metal ions under visible light irradiation.It was found that, at low dye-metal ratio, the photodegradation of ACBK was markedly inhibited by the addition of high oxidative potential Cu2+.However, at high dye-metal ratio, the presence of Cu2+ enhanced the photodegradation of ACBK.The negtive effect of Cu2+ on the photodegradation of AR was observed for all dye-metal ratios.The relative chemical inert Zn2+ tended to enhance the photodegradation of both anionic dyes.The mechanism underlying the different effect of Cu2+ is discussed from the different roles of surface-adsorbed and dye-coordinated Cu2+ in the photodegradation of dyes.     

A simple formula for calculating the ionization potential of two-electron ions

The ionization potential of one-electron ions can be calculated from a well-known simple equation, but no such equation has been available for calculating the ionization potential of multi-electron ions. I report here an equation that accurately gives the ionization potential of helium-like (i.e., two-electron) ions as a function of the atomic number, the relative difference from experimental values being below 1% for all ions for which reliable experimental data were found (Z = 3–29). The equation also predicts the stability of the negative hydrogen ion (the hydride ion), H⁻, although with twice too large a value for the ionization potential.     

丽江市冬季大气总悬浮颗粒物（TSP）中水溶性离子化学特征

2008年12月～2009年1月在丽江市共采集25个TSP样品,目的是研究丽江市冬季TSP中水溶性离子的化学特征及它们的来源情况.结果表明,样品中主要水溶性离子的电荷浓度:Cl-、NO3-、SO42-、Na+、NH4+、K+、Mg2+、Ca2+分别为16.00、14.95、49.40、3.12、44.75、8.65、2...