重金属元素在冻土与融土中迁移的对比试验

随着寒区经济的发展,冻土地区的矿山开采活动不断加剧,随之产生的重金属污染问题也越来越严重.冻土地区生态环境脆弱,一旦受到破坏就很难恢复.针对此问题,室内模拟了尾矿矿渣在冻土与融土中的填埋及其对填埋场周边土体的影响,通过检测填埋场各处土壤的温度、含水量以及重金属元素的含量,发现温度和水分对重金属元素的迁移影响很大.土壤温度越低,重金属元素的迁移越慢;在温度梯度的作用下,重金属元素均随着水分从土体的暖端向冷端迁徙并聚集于冻结锋面.重金属元素在冻土中的迁移比融土中慢,表明冻土环境不利于重金属元素的迁移.在土壤质地、温度和含水量等相同的情况下,Zn的迁移性较强,Pb和Cu的迁移性相对较弱.     

Ag/Cu合金触点废料回收铜粉的工艺研究

Ag/Cu合金触点废料含Ag量在30%(质量分数)以上,含Cu量在60%(质量分数)以上、含Sn量在2%(质量分数)以上.先将Ag/Cu合金触点废料中的Cu分离,然后采用葡萄糖预还原、水合肼再还原制得了粒径在0.3～O.6 pm的类球形超细铜粉(纯度≥99.9%).研究表明,适量聚乙烯吡咯烷酮(PVP)的加入有助于超细铜粉粒径均匀且形貌趋于一致;量佳反应温度为70℃;抗氧化剂苯并三氮唑可以有效防止超细铜粉的表面氧化.     

湘江霞湾港段底泥的含镉量分布研究

为了研究湘江霞湾港段底泥中镉的含量分布和释放特性,对该河段底泥采样以测定含镉量,并采用Tessier连续提取法对镉形态进行分析测定.结果表明,湘江霞湾港段受到严重的镉污染,其底泥含镉量最高达359.8μg/g.湘江底泥和间隙水中含镉量的吸附-解吸平衡可采用Freundlich吸附等温式描述.对新霞湾和老霞湾排污口附近河流底泥的镉形态分析表明,镉污染物以有机质-硫化物结合态为主,分别占总量的73.3%(质量分数,下同)、65.3%,其次是残渣晶格结合态,分别占总量的26.5%、34.4%.     

Investigation of the positive artifact formation during sampling semi-volatile aerosol using wet denuders

Wet denuders are used in several steam-based semi-continuous aerosol monitors to avoid gaseous absorption artifacts and pre-humidify the air stream, while simultaneously allowing measurements of water-soluble gaseous species. Unlike dry denuders, wet denuders saturate the sample air stream with water vapor, which can lead to re-partitioning of water-soluble volatile species to the aerosol phase, thereby causing a positive artifact in aerosol measurements. This paper investigates the magnitude of the positive artifact formation occurring in wet denuders using modeling techniques. Gaseous nitric acid was used as an example of volatile water-soluble gas in both flat and annular wet denuders. We have also verified the occurrence of the positive artifact in a flat wet denuder through a laboratory experiment. The model results indicate that the magnitude of the artifact is rather limited under typical conditions being less than 2.5% of ambient nitric acid concentration for the flat denuder and less than 0.6% for the annular denuder. The magnitude of the artifact increases with condensational sink of the aerosol (i.e. with the mean aerosol size and number concentration) and aerosol water solubility. While the artifact is relatively small in the absolute sense, it could be substantial for aerosol nitrate measurements, especially in ammonia limited conditions, when the concentration of the nitric acid is high and the concentration of nitrate is low. Therefore, we recommend that the artifact is assessed regularly by replacing the wet denuder with a dry denuder.     

鲢鱼、草鱼和尼罗罗非鱼热休克蛋白70基因cDNA全序列的克隆与分析

采用RT-PCR技术和RACE技术分别从淡水食毒藻鱼类鲢鱼（Hypophthalmichthys molitrix）、尼罗罗非鱼（Oreochromis nilotica）及草食性鱼类草鱼（Ctenopharyngodon idella）肝脏扩增出热休克蛋白70（HSP70）cDNA全序列,并与其它鱼类、两栖类和哺乳类动物的HSP70氨基酸进行了同源性比较. 结果表明,鲢鱼、草鱼和尼罗罗非鱼肝脏HSP70基因cDNA全长分别为2356 bp、2348 bp和2242 bp,分别编码649、649和638个氨基酸.鲢鱼、草鱼和尼罗罗非鱼HSP70与其它鱼类、两栖类和哺乳类动物HSP70氨基酸同源性均较高,表明其在进化上高度保守,且承担着重要的生理功能.构建系统进化树发现,鲢鱼、草鱼与其它鲤科鱼类斑马鱼、银鲫（Carassius auratus gibelio）的HSP70氨基酸同源性较高,处于同一进化树分枝;而尼罗罗非鱼HSP70未与其它鲈形目鱼类,如鲷科鱼类聚为一枝,而是占据一个独立的分枝,这与克隆得到的鲢鱼、草鱼肝脏HSP70基因可能为结构型HSP70,而尼罗罗非鱼肝脏HSP70基因可能为诱导型HSP70的结果相一致.     

Recycling thin film transistor liquid crystal display (TFT-LCD) waste glass produced as glass–ceramics

The waste electrical and electronic equipment (WEEE) directives are designed to deal with the rapidly increasing waste stream comprised of electrical and electronic equipment. Recycling electrical and electronic equipment reduces the quantity of waste going to final disposal. The demand for thin film transistor liquid crystal display (TFT-LCD) panels, commonly used in everyday electronic products, is increasing. Conventionally adopted treatments of TFT-LCD waste glass cannot meet WEEE directives. This study adopts the following operating conditions in fabricating glass–ceramics: sintering temperature of 800–950 °C; sintering time of 6 h; and, temperature increase rate of 5 °C/min. The glass–ceramic samples then underwent a series of tests, including the Vickers hardness, water absorption and porosity tests, to determine product quality. The Vickers hardness was 12.1 GPa when fired at 900 °C for 6 h, and density was 2.4 g/cm³ and water absorption was 0%. Thus, TFT-LCD waste glass can be regarded as a good glass–ceramic material.     

湿地植物对污水中氮、磷去除效果的试验研究

采用室内试验和现场试验考察了黄花鸢尾、水葱和梭鱼草3种挺水植物对类污水处理厂二级出水中氮、磷的吸收速率、吸收容量和吸收贡献。结果表明:短期内,各种湿地植物污水中氮、磷的吸收速率比较稳定,但在整个生长周期内,各种植物对氮、磷的吸收速率却有较大变化,4月份,水葱对氮、磷的吸收速率最大,8月份,梭鱼草对氮、磷的吸收速率最大。在整个生长期内,黄花鸢尾对氮、磷的吸收容量一直保持最大,在10月下旬分别达到21.5和4.16 g/m2,因此其对二级出水中氮、磷去除的吸收贡献也最大,分别为30%和73%。这表明湿地植物的选择不仅要考查其对污染物的吸收速率,更要关注其对污染物的吸收容量,并且湿地植物的吸收作用对类二级出水中氮、磷的去除具有更加重要的意义。     

纳米ZnO对嗜热四膜虫的生态毒性研究

为评价纳米ZnO的生态安全性,研究了其对嗜热四膜虫(Tetrahymena thermophila)的水生生态毒性. 显微成像表明,嗜热四膜虫食物泡是摄取纳米ZnO的主要部位. 低ρ(纳米ZnO)对嗜热四膜虫的增殖具有促进作用(即“兴奋反应),其中100 mg/L时促进作用最明显,随着ρ(纳米ZnO)的进一步增加,其对嗜热四膜虫增殖的促进作用逐渐减弱. 随着时间的延长,“兴奋反应逐渐减弱. 纳米ZnO能降低嗜热四膜虫的超氧化物歧化酶活性,且ρ(纳米ZnO)越高,抑制效应越强. 纳米ZnO使嗜热四膜虫自由基清除能力下降,可能是其产生毒害作用的主要原因之一.      

节能型焦化污水生物脱氮新工艺的生产性试验研究

采用节能型生物脱氮新工艺对黑龙江某焦化厂的污水处理站进行生产性试验研究,结果表明:处理后出水达到GB8978-1996《污水综合排放标准》一级,并可回用于熄焦。该工艺适合推广应用于焦化污水、垃圾渗滤液、养殖、化肥等高含氮有机污水的处理。     

六氯苯和重金属复合污染沉积物的电动力学修复研究

以某化工厂排污沟渠中受六氯苯(hexachlorobenzene,HCB)、锌和镍复合污染的实际沉积物为对象,研究非离子表面活性剂OP-10对沉积物中污染物的增溶解吸效果和电动力学修复污染物的强化迁移效果。解吸实验结果表明:OP-10对HCB增溶解吸效果较好,对重金属离子的解吸有一定的促进作用。电动力学修复发现,随电渗析流进入沉积物中的OP-10很快的吸附在靠近阳极沉积物上,从而阻碍了助剂的输送并影响HCB的迁移,而靠近阴极区域沉积物中的有机质迁移会促进HCB的去除。沉积物pH变化引起的重金属沉淀是制约锌迁移的主要因素。镍的整体迁移效果不明显。