改性方解石的除磷能力研究

选用颗粒方解石,对其表面进行改性,便于磷在其表面的吸附、结晶、沉淀,形成永久性固态磷,加速磷的自然沉淀过程。考察了改性的最佳条件和改性方解石除磷的影响因素。结果表明,方解石的最佳改性条件:改性液TP、Ca2+、HCO-3分别为93.00、120.00、244.00 mg/L,浸泡时间2d;改性方解石具有持续的除磷能力,在实验前76h的平均除磷速率为0.053 0mg/(g·d),而稳定阶段的除磷速率为0.021 4mg/(g·d);待处理水样的Ca2+浓度对改性方解石的除磷效果有较大影响,Ca2+为120.00mg/L时除磷效果最好,碱度对除磷效果的影响很小;pH≤7.30,投加改性方解石系统中磷的去除以改性方解石表面Ca-P结晶为主,而当pH≥8.15时,溶液中发生Ca-P沉淀,而Ca-P结晶逐步减少;水温对改性方解石的除磷效果具有显著影响。     

Catalytic reductive dechlorination of p–chlorophenol in water using Ni/Fe nanoscale particles

Nanoscale bimetallic Ni/Fe particles were synthesized from the reaction of sodium borohydride （NaBH4） with reduction of Ni^2＋ and Fe^2＋ in aqueous solution. The obtained Ni/Fe particles were characterized by TEM （transmission electron microscope）, XRD （X-ray diffractometer）, and N2-BET. The dechlorination activity of the Ni/Fe was investigated using p-chlorophenol （p-CP） as a probe agent. Results demonstrated that the nanoscale Ni/Fe could effectively dechlorinate p-CP at relatively low metal to solution ratio of 0.4 g/L （Ni 5 wt%）. The target with initial concentration ofp-CP 0.625 mmol/L was dechlorinted completely in 60 rain under ambient temperature and pressure. Factors affecting dechlorination efficiency, including reaction temperature, pH, Ni loading percentage over Fe, and metal to solution ratio, were investigated. The possible mechanism of dechlorination ofp-CP was proposed and discussed. The pseudo-first- order reaction took place on the surface of the Ni/Fe bimetallic particles, and the activation energy of the dechlorination reaction was determined to be 21.2 kJ/mol at the temperature rang of 287-313 K.     

聚丙烯酰胺复配物提高微细粉尘湿润效果的试验

为了提高微细粉尘的除尘效果,将聚丙烯酰胺（PAM）与琥珀酸二辛酯磺酸钠（AOT）等进行复配,并分别测定了粉尘的沉降时间、溶液表面张力及其紫外吸收光谱。结果表明,AOT与PAM复配后,形成了新的物质,可降低溶液表面张力和粉尘沉降时间,从而提高微尘湿润效果。     

Characterization of coal burning-derived individual particles emitted from an experimental domestic stove

Coal combustion in the domestic stoves, which is common in most parts of the Chinese countryside, can release harmful substances into the air and cause health issues. In this study, particles emitted from laboratory stove combustion of the raw powder coals were analyzed for morphologies and chemical compositions by using transmission electron microscopy(TEM) coupled with energy-dispersive X-ray spectrometry(EDX). The coal burning-derived individual particles were classified into two groups: carbonaceous particles(including soot aggregates and organic particles) and non-carbonaceous particles(including sulfate, mineral and metal particles). The non-carbonaceous particles, which constituted a majority of the coal burning-derived emissions, were subdivided into Si-rich, S-rich, K-rich,Ca-rich, and Fe-rich particles according to the elemental compositions. The Si-rich, S-rich and K-rich particles are commonly observed in the coal burning emission. The proportions for particles of different types exhibit obvious coal-issue dependence. Burning of coal with high ash yield could emit more non-carbonaceous particles, and burning of coal with high sulfur content can emit more S-rich particles. By comparing the S-rich particles from this coal burning experiment with those in the atmosphere, we draw a conclusion that some S-rich particles in the atmosphere in China could be mainly sourced from coal combustion.     

北京地区空气中PM10的元素组分及其变化

2000年6—7月,12月和2001年4—5月在北京北郊分别采集了代表夏季、冬季和春季的大气颗粒物样品,经分析后获得了不同季节、不同大气污染情况下气溶胶中Ca,S,Al,Fe,K,Zn等30种元素质量浓度。对不同污染情况下PM₁₀中元素组分的变化分析表明,PM₁₀中的元素总质量浓度呈现出明显的季节变化,即春季最高,冬季次之,夏季最低,Ca,Fe,K,Al,S是PM₁₀中的5种主要元素。随着空气污染的加重,PM₁₀中的元素总质量浓度明显增加,在春季这一增加达到7倍之多。在重污染情况下,无论在近地面,还是在边界层,PM₁₀中的主要元素排序夏季以地壳元素为首,而冬春季均以污染元素为首。一般情况下,PM₁₀中的元素总质量浓度在近地层中随高度升高而降低,降低幅度约为20%。分析结果还表明,随着空气污染的加重,PM₁₀中的污染元素,尤其是As,Cr,Co,Cu,Ni,PPb,Se,Zn等低浓度污染元素的浓度明显增加。      

中国大气重金属污染研究进展与趋势

大气重金属污染是当前环保工作中的重点、难点、热点以及突发性环境事件的高发领域。简要介绍了大气重金属污染的特征、危害及来源,综述了近年来中国大气重金属污染研究方面的进展。当前,中国大气重金属的研究主要有以下几个方向,(1)大气颗粒物中重金属分析检测方法的研究,(2)大气颗粒物中重金属的污染行为特征研究,(3)大气颗粒物中重金属的化学形态分析与生物危害性研究,(4)大气颗粒物中重金属的来源解析,(5)大气颗粒物中重金属的生物有效性研究等,并取得了一定的研究成果。最后,对今后的主要研究趋势进行了展望。     

南京大气PM10谱分布和细粒子中多环芳烃的研究

文章使用分级采样器采集夏秋两季南京市不同功能区的大气PM10样品,运用GC-MS等方法,研究细粒子中的多环芳烃(PAHs)的分布特征和污染来源。结果表明:各功能区秋季细粒子质量浓度均大于夏季,本底区细粒子质量浓度最低,为41.7～59.0μg/m3;交通商业区浓度最高,为206.5～467.0μg/m3。各功能区PM1...     

饮用水源中不同粒径颗粒物吸附抗生素特征研究

天然水体中存在大量的细小颗粒,它们往往与污染物相互作用并成为其载体,在饮用水传统处理工艺中亦不能被很好去除,进而随水厂出水进入人体,对人体健康造成潜在威胁.抗生素在饮用水源中的固、液相分配规律以及不同粒径颗粒对抗生素的吸附能力及影响因素亟待研究.实验利用微波萃取(MAE)和高效液相色谱与质谱联用(HPLC-MS/MS)的方法分别对颗粒物上吸附的抗生素进行了前处理和测定,进而分析了饮用水源颗粒物对4种典型抗生素的吸附特征.连续吸附平衡实验在360 min达到平衡,平衡时抗生素有32%~44%分布在颗粒上;除青霉素外,粒径0.05~1μm小颗粒的吸附量又占颗粒总吸附量的56%~70%.同时p H是影响饮用水源中颗粒吸附抗生素的重要因素,无论对于所有颗粒还是0.05~1μm的小颗粒,其吸附能力的最大值均出现在中性条件(p H=7)下.     

南京市生活区夏秋季节大气颗粒物垂直分布特征

文章实验研究了2008年7月24日-28日（夏季）和2008年10月13日-17日（秋季）南京市河西生活区距地面1.5 m、54 m和80 m高度处大气颗粒物质量浓度垂直分布特征。夏季和秋季监测结果的对比分析表明：随着高度的增加,采样期间夏季和秋季的PM10和PM2.5平均质量浓度均呈现逐渐减小的趋势,其中秋季衰减幅度明显比夏季小,而且秋季采样期间PM10和PM2.5平均质量浓度远远高于夏季;另一方面,夏秋两季不同尺度颗粒物浓度的相对含量也发生了明显变化,相比于夏季1.5 m高度处秋季细颗粒物的所占比例明显增加,而80 m处却明显降低。