Ultrafine particle emission characteristics of diesel engine by on-board and test bench measurement

This study investigated the emission characteristics of ultrafine particles based on test bench and on-board measurements. The bench test results showed the ultrafine particle number concentration of the diesel engine to be in the range of (0.56-8.35) × 10⁸ cm^-3. The on-board measurement results illustrated that the ultrafine particles were strongly correlated with changes in real-world driving cycles. The particle number concentration was down to 2.0 × 10⁶ cm^-3 and 2.7 × 10⁷ cm^-3 under decelerating and idling operations and as high as 5.0 × 10⁸ cm^-3 under accelerating operation. It was also indicated that the particle number measured by the two methods increased with the growth of engine load at each engine speed in both cases. The particle number presented a "U" shaped distribution with changing speed at high engine load conditions, which implies that the particle number will reach its lowest level at medium engine speeds. The particle sizes of both measurements showed single mode distributions. The peak of particle size was located at about 50-80 nm in the accumulation mode particle range. Nucleation mode particles will significantly increase at low engine load operations like idling and decelerating caused by the high concentration of unburned organic compounds.     

水泥炉窑SNCR及SCR烟气脱硝技术比较

通过分析水泥炉窑氮氧化物(NOx)生成机理、脱除技术以及国内外水泥炉窑脱硝现状并结合我国具体情况,探讨适合我国的水泥炉窑切实可行脱硝技术,为"十二五"期间我国水泥炉窑开展烟气脱硝整治工作提供技术性方向。     

Biological sulfate removal from acrylic fiber manufacturing wastewater using a two-stage UASB reactor

A two-stage UASB reactor was employed to remove sulfate from acrylic fiber manufacturing wastewater. Mesophilic operation (35±0.5℃) was performed with hydraulic retention time (HRT) varied between 28 and 40 hr. Mixed liquor suspended solids (MLSS) in the reactor was maintained about 8000 mg/L. The results indicated that sulfate removal was enhanced with increasing the ratio of COD/SO₄^2-. At low COD/SO₄^2-, the growth of the sulfate-reducing bacteria (SRB) was carbon-limited. The optimal sulfate removal efficiencies were 75% when the HRT was no less than 38 hr. Sulfidogenesis mainly happened in the sulfate-reducing stage, while methanogenesis in the methane-producing stage. Microbes in sulfate-reducing stage performed granulation better than that in methane-producing stage. Higher extracellular polymeric substances (EPS) content in sulfate-reducing stage helped to adhere and connect the flocculent sludge particles together. SRB accounted for about 31% both in sulfate-reducing stage and methane-producing stage at COD/SO₄^2- ratio of 0.5, while it dropped dramatically from 34% in sulfate-reducing stage to 10% in methane-producing stage corresponding to the COD/SO₄^2- ratio of 4.7. SRB and MPA were predominant in sulfate-reducing stage and methane-producing stage respectively.     

地下空间在节能减排中的应用及展望

在能源短缺和环境污染的双重压力下,我国出台多项措施加大节能减排力度。总结概括了地下空间的几种类型,认为盐岩洞穴、废弃矿洞、废弃油井、枯竭油气层等地下空间经过技术改造,可以埋存CO2、固体垃圾、废弃核原料,储存油气,地热利用等,能创造可观的社会价值和环境保护效益,可作为节能减排的一种有效措施。以山东地区为例,调研分析了山东多处地下空间利用现状,给出了地下空间的三种发展方向。     

碳纳米管径向尺寸对碳纳米管自支撑膜孔隙结构及通量的影响

为了探索碳纳米材料膜在水处理中应用的可能性,本实验选取4种径向尺寸的碳纳米管(Carbon Nanotubes, CNTs),采用压力辅助过滤技术制备CNTs自支撑膜.通过对CNTs自支撑膜的平均孔径、孔径分布及截留分子量(Molecular weight Cut-Off,MWCO)等进行分析,研究了CNTs径向尺寸变化对CNTs自支撑膜孔隙结构的影响.结果表明,CNTs的径向尺寸越小,制备得到的CNTs自支撑膜越趋向于形成小孔径的膜孔,且孔径分布更加均匀,孔隙面积比越高,膜的MWCO越小.单壁碳纳米管(Single-walled carbon nanotube, SWNT)与多壁碳纳米管(Multi-walled carbon nanotube, MWNT)相比,前者更容易形成膜平均孔径更小且孔径分布更均匀的CNTs自支撑膜.膜通量测定结果表明,研究制备的CNTs自支撑膜的通量属于低压膜范围,通量在230～347 L·m~(-2)·h~(-1)·bar~(-1)之间.其中,虽然由径向尺寸较小的CNTs所制备的CNTs自支撑膜的平均孔径更小,但由于其具有更高的孔隙面积比和更小的膜厚度,其纯水通量相对高于由大径向尺寸CNTs制备的CNTs自支撑膜.     

铜前驱体对Cu/SSZ-13催化剂选择性催化氧化NH3性能的影响

采用浸渍法制备了一系列Cu/SSZ-13(X)催化剂,考察不同铜前驱体对催化剂选择性催化氧化氨(NH_3-SCO)性能的影响,并通过ICP、N_2吸附-脱附、XRD、XPS、EPR、UV-Vis、NH_3-TPD和H_2-TPR等手段对催化剂进行物化性质表征.活性测试结果表明,不同铜前驱体制备的Cu/SSZ-13催化剂活性顺序为Cu/SSZ-13(N) Cu/SSZ-13(AC) Cu/SSZ-13(Cl) Cu/SSZ-13(O).其中Cu/SSZ-13(N)具有最佳的低温活性,在200℃反应温度下NH_3转化率达85.5%,且N_2选择性达到80%以上.XRD、EPR和UV-Vis分析表明,CuO和孤立Cu~(2+)是Cu/SSZ-13催化剂的主要铜物种.NH_3-TPD分析表明,以硝酸铜为前驱体制备的Cu/SSZ-13(N)具有更多的酸性位点,有利于提高催化剂的NH_3吸附能力.H_2-TPR结果表明,Cu/SSZ-13(N)的氧化还原性最强,具有最优异的NH_3活化能力,从而使催化剂呈现最好的低温NH_3-SCO活性.     

高速公路路面雨水径流下渗系统性能研究

为了分析径流下渗系统在径流削减和污染控制方面的性能,本文对一个高速公路路面雨水径流下渗系统性进行了监测.结果表明,降雨量、径流量、径流削减量和径流排放量之间存在明显的正相关性(r=0.82～0.97,p0.05).该系统表现出高效的径流削减能力,当降雨量小于20 mm时,可以削减70%以上的径流量.与径流削减相比,该系统在污染物负荷控制方面更为有效.当降雨量在0～10 mm之间时,污染负荷的削减率几乎为100%;而当降雨在10～20 mm之间时,污染负荷的削减率仍然可以超过60%.相对总氮(TN)和总磷(TP)而言,下渗系统对悬浮物(SS)和化学需氧量(COD_(Cr))的去除能力要更高、更稳定.研究表明,径流下渗系统作为雨水管理的工具,在径流削减和改善水质方面具有良好的性能.     

太原市夏季大气VOCs污染特征及臭氧生成潜势

2018年8月采集太原市大气样品,分析太原市夏季大气VOCs的污染特征,并利用最大增量反应活性系数法（MIR系数法）估算了VOCs的臭氧生成潜势（OFP）.结果表明,太原市夏季大气VOCs浓度为17.36~89.60μg/m³,其中烷烃占比58.01%、芳香烃占比20.06%、烯烃占比16.52%、炔烃占比5.40%.大气VOCs浓度变化表现为明显的早晚双高峰特征,且以早高峰影响为主.OFP分析显示,烷烃、烯烃、芳香烃、炔烃分别占总OFP的19.16%、47.74%、31.75%、1.35%,C₃~C₅类烯烃是活性较高的物种,对O₃生成贡献较大.     

Effects of typical algae species (Aphanizomenon flosaquae and Microcystis aeruginosa) on photoreduction of Hg2+ in water body

Photoreduction characteristics of divalent inorganic mercury(Hg~(2+)) in the presence of specific algae species are still not well known. Laboratory experiments were conducted in the present study to identify the effects of different concentrations of living/dead algae species, including Aphanizomenon flosaquae(AF) and Microcystis aeruginosa(MA), on the photoreduction rate of Hg~(2+)under various light conditions. The experimental results showed that percentage reduction of Hg~(2+)was significantly influenced by radiation wavelengths, and dramatically decreased with the presence of algae. The highest percentage reduction of Hg~(2+)was induced by UV-A, followed by UV-B, visible light and dark for both living and dead AF, and the order was dark UV-A UV-B visible light for both living and dead MA. There were two aspects, i.e., energy and attenuation rate of light radiation and excrementitious generated from algae metabolisms, were involved in the processes of Hg~(2+)photoreduction with the presence of algae under different light conditions. The percentage reduction of Hg~(2+)decreased from 15% to 11% when living and dead AF concentrations increased by 10 times(from 106 to 105 cells/mL), and decreased from 11% to ～ 9% in the case of living and dead MA increased. Algae can adsorb Hg~(2+)and decrease the concentration of free Hg~(2+), thus inhibiting Hg~(2+)photoreduction, especially under the conditions with high concentrations of algae. No significant differences were found in percentage reduction of Hg~(2+)between living and dead treatments of algae species.The results are of great importance for understanding the role of algae in Hg~(2+)photoreduction.     

辽东湾大气中多环芳烃的含量组成及气粒分配

2016年5月和8月对辽东湾大气环境中气相和颗粒相样品进行了走航和定点采集,并对24种PAHs在气相和颗粒相中的含量和组成进行探讨,对15种PAHs的气粒分配过程进行了分析.结果表明：5月和8月辽东湾大气气相和颗粒相中∑₂₄PAHs总平均含量分别为28.8 ng·m^-3和24.0 ng·m^-3,气相中∑₂₄PAHs含量5月小于8月,颗粒态∑₂₄PAHs含量5月大于8月,低分子量PAHs主要分布在气相中,高分子量PAHs组分主要分布在颗粒相,中等分子量PAHs的气粒分配更容易受到气温等环境条件影响;气粒分配系数K_p随着PAHs分子量增加而增加;lgK_p-lgP_L模型和lgK_p-lgK_OA模型的斜率m分别为-0.35和0.37,偏离平衡态m为-1或+1,辽东湾气粒分配未达到平衡;假设达到平衡态时的lgK_p-lgK_OA模型、lgK_p-lgP_L模型和碳黑-空气模型均表明,5环PAHs的模型预测结果与实际测定结果之间的吻合程度较好,15种PAHs的碳黑-空气模型能够更好地接近野外实际测定值,低分子量和中等分子量PAHs的气粒分配受到碳黑影响较大.