国家半导体行业VOC排放标准制订研究

随着近年来我国半导体产业的持续繁荣发展,中国已成为全球半导体制造增长最为迅速的市场。为有效控制监管半导体生产过程中大量使用的各种有机溶剂所产生的废气中可挥发性有机物(VOC)的排放,加强行业污染控制,规范行业环境保护管理工作,对制订半导体行业VOC排放标准进行了研究。概述了半导体行业VOC排放的特点。分析了该行业对VOC排放的治理技术。阐述了美国和中国台湾地区有关半导体行业VOC废气的排放标准。从国内半导体企业VOC治理现状、现有监测技术、VOC排放管理方式等方面探讨了我国半导体行业VOC废气排放标准的制定思路。     

黄河入海主要污染物特征研究

黄河污染严重,在一定程度上导致黄河口及其邻近海域海洋环境不容乐观.针对此种情况,对黄河人海污染物进行分析评价,确定黄河人海主要污染物,对于从源头上控制污染物排放,改善黄河口海洋环境起到重要作用.     

活性炭纤维对定型机油烟废气吸附性能研究

采用动态吸附实验装置研究了粘胶基活性碳纤维的耐温性能以及预处理、采样流速、进气浓度对粘胶基活性碳纤维吸附定型机油烟废气平衡吸附量的影响,实验结果表明粘胶基活性碳纤维耐温性能良好,同时经去离子水煮沸2小时的粘胶基活性碳纤维平衡吸附量最大,采样流速增大平衡吸附量减少,但吸附速率变大,采用一级动力学模型较好地反映了吸附过程,Langmuir、Freundlich方程适合拟合低浓度下的吸附等温线,DR方程则较吻合高浓度下的吸附。     

黄河包头段不同粒径沉积物分形校正下重金属的吸附研究

推导了分粒级的表面分形维数计算公式,根据推导公式计算了分粒级沉积物的分维值.应用已有的表面分形分维计算公式分别计算了黄河包头段沉积物整体的表面分形分维(1.91)及＜63 μm粒级的分维值(1.36),揭示出黄河水环境的磨蚀和分选2个原因引起黄河包头段沉积物低的分维值.用分形校正吸附模型、Freundlich和Langmuir吸附模型对黄河包头段重金属分粒级沉积物吸附进行了拟合,表明分形校正吸附模型具有较好的适用性,同时揭示分形校正吸附模型与MEA理论结合能更好的对热力学吸附结果进行描述;由吸附结果分析得出4种重金属因粒径引起的吸附量变化程度序列为Cu＞Pb＞Zn≈Cd,初始浓度高的吸附量曲线变化较初始浓度低的曲线变化明显,同时指出Cu、Pb的吸附主要与矿物组成有关,而Zn、Cd的吸附则与吸附剂沉积物空间几何性质(或沉积物表面物理特征)有关.     

祁连山七一冰川融水化学组成及演化特征

2006-06～2006-07在祁连山七一冰川采集冰川冰、冰面融水、侧碛河及冰川融水径流样,分析了样品中主要可溶离子浓度、pH及电导率.结果表明,所有样品的pH介于8.05～8.79之间,电导率分布在32.4～134.4 μS·cm-1之间.不同水体中主要可溶离子浓度顺序为:冰面融水＜侧碛河＜七一冰川水文总汇点,水化学类型也由HCO3-Ca2 型演化为(HCO3 SO2-)-(Ca2 Mg2 )型.几乎所有样品中主要可溶阴、阳离子浓度序列为:HCO3＞SO2-4＞CI-＞NO-3,Ca2 ＞Mg2 ＞Na ＞K ,以碳酸盐风化产物为主,也有部分硫酸盐贡献.由于受到各种物理化学因素影响,在水岩作用过程中MG2 和K 浓度增加速率大于Ca2 和Na ,不同于其在地壳中的丰度.七一冰川区融水中离子浓度空间变化主要受水岩作用时间控制,气温影响下的冰川消融量的大小是水化学时间变化的主要控制因素.     

填料型微生物燃料电池产电特性的研究

将石墨和碳毡作为阳极填料组装成填料型微生物燃料电池,其启动期在1 d左右,低于平板型微生物燃料电池的启动期.碳毡作为填料时,微生物燃料电池的最大产电功率密度为1 502 mW/m2(37.6 W/m3),优于石墨作为填料的MFC.将碳毡与碳纸烧结一体以提高填料型微生物燃料电池阳极的导电性,与平板型微生物燃料电池相比,其面积内阻从0.071 Ω穖2下降到0.051 Ω穖2,最大电流密度从3 000 mA上升到8 000 mA,最大产电功率密度从1 100 mW/m2(27.5 W/m3)上升到2426 mW/m2(60.7W/m3),阳极电势平均下降100 mV.循环流量影响填料型微生物燃料电池的产电能力,当流量低于1 mL/min时,其产电功率密度随流速降低而下降.填料型微生物燃料电池在外电阻为600 Ω下长期稳定运行30 d以上,其库仑效率约为10.6%.     

Fenton工艺处理有机废水污染物影响因素研究

Fenton氧化技术能有效地处理有机废水难降解污染物。对电导率不同的废水,Fenton处理污染物效率不同。实验结果显示,在有机废水浓缩液中加入活性炭,活性炭的吸附改变了溶液的电导率,也影响了Fenton工艺降解污染物的效率,对COD和NH_3-N的降解率均有显著提升。对于难降解有机废水浓缩液,要提高Fenton工艺降解效率,可采用适当方式改变反应体系的电导率。     

盐水层中注水促进超临界CO2溶解的数值模拟

采用数值模拟的方法,通过考察不同注水模式、注水速率、注水位置、盐度和孔隙度下CO_2的分布特性和溶解行为,系统地分析了注水对CO_2溶解的影响。结果表明,超临界态CO_2呈倒锥形分布于注入井附近的盐水层顶部,并随时间延长缓慢向外扩展。注水虽不明显改变CO_2的分布,但能促进CO_2的溶解,降低超临界态CO_2的量。增大注水速率、靠近盐水层顶部注水、在注CO_2的过程中同时注水均可有效提高CO_2的溶解率。在一定范围内,CO_2的溶解量随盐水盐度降低而提高,但几乎不随岩石孔隙度变化。研究表明,通过优化注水条件可以显著促进CO_2的溶解封存。     

Pollution sources of atmospheric fine particles and secondary aerosol characteristics in Beijing

To investigate the secondary formation and pollution sources of atmospheric particles in urban Beijing, PM_2.5 and its chemical components were collected and determined by URG-9000D ambient ion monitor (AIM) from March 2016 to January 2017. Among water-soluble ions (WSIs), NO₃^?, SO₄^2- and NH₄⁺ (SNA) had the largest proportion (77.8%) with the total concentration of 23.8 μg/m³. Moreover, as fine particle pollution worsened, the NO₃^?, SO₄^2- and NH₄⁺ concentrations increased basically, which revealed that secondary aerosols were the main cause of particle pollution in Beijing. Furthermore, the particle neutralization ratio (1.1), the ammonia to sulfate molar ratio (3.4) and the nitrate to sulfate molar ratio (2.2) showed that secondary aerosols are under ammonium-rich conditions with the main chemical forms of NH₄NO₃ and (NH₄)₂SO₄, and vehicle emission could be the main anthropogenic source of secondary aerosols in Beijing. Source analysis further indicated that secondary aerosols, solid fuel combustion, dust and marine aerosol were the principal pollution sources of PM_2.5, accounting for about 46.1%, 22.4% and 13.0%, respectively, and Inner Mongolia and Hebei Provinces could be considered as the main potential sources of PM_2.5 in urban Beijing. In addition, secondary formation process was closely related with gaseous precursor emission amounts (SO₂, NO₂, NH₃ and HONO), atmospheric ozone concentration (O₃), meteorological conditions (temperature and relative humidity) and particle components. Sensitive analysis of the thermodynamic equilibrium model (ISORROPIA II) revealed that controlling total nitrate (TN) is the effective measure to mitigate fine particle pollution in Beijing.     

Role of hydrogen bond capacity of solvents in reactions of amines with CO2: A computational study

Various computational methods were employed to investigate the zwitterion formation,a critical step for the reaction of monoethanolamine with CO_2,in five solvents(water,monoethanolamine,propylamine,methanol and chloroform) to probe the effect of hydrogen bond capacity of solvents on the reaction of amine with CO_2 occurring in the amine-based CO_2 capture process.The results indicate that the zwitterion can be formed in all considered solvents except chloroform.For two pairs of solvents(methanol and monoethanolamine,propylamine and chloroform) with similar dielectric constant but different hydrogen bond capacity,the solvents with higher hydrogen bond capacity(monoethanolamine and propylamine) facilitate the zwitterion formation.More importantly,kinetics parameters such as activation free energy for the zwitterion formation are more relevant to the hydrogen bond capacity than to dielectric constant of the considered solvents,clarifying the hydrogen bond capacity could be more important than dielectric constant in determining the kinetics of monoethanolamine with CO_2.