Effect of surfactants at low concentrations on the sorption of atrazine by natural sediment.

A series of experiments were carried out to determine the effect of surfactants at low concentrations on the sorption of atrazine by natural sediments. With surfactant concentrations ranging from 0 to 20 mg/ L, anionic and cationic surfactants appreciably reduce the adsorption of atrazine, while nonionic surfactant decreases the adsorption of atrazine at concentrations equal to or less than 1 mg/L and increases adsorption at higher concentrations. Desorption of atrazine in the presence of different sodium dodecylbenzene sulfonate (SDBS) concentrations shows that a portion of the bound pesticide resists desorption in the SDBS free system. However, the addition of SDBS accelerates the desorption of atrazine. Furthermore, the nature of sediment and the contacting sequence of SDBS, at 10 mg/L, with the sediment, also influence the adsorption of atrazine. The conclusions in this study could be explained partially by the effect of the type and concentration of surfactants and the characteristics of sediments.     

研究星载IPDA激光雷达探测CO2光谱纯度

光谱纯度是积分路径差分吸收激光雷达最重要的系统参数之一,光谱纯度直接影响CO₂数据的探测精度.在模式研究中要求输入观测的CO₂数据误差小于1×10^-6,对激光器光谱纯度参数设计提出很高要求.本文采用有效吸收截面分析探测反演误差的方法,研究了由光谱纯度带来的CO₂柱浓度探测误差,并基于窄带滤波器对光谱不纯能量的抑制作用,对不同带宽的窄带滤波器进行选择和分析,从而达到降低对光谱纯度的要求,提升探测精度的目的,最后讨论了由于窄带滤波器造成的能量衰减所对随机误差的影响.结果表明：当光谱纯度为99.9%,窄带滤波器带宽1GHz,透射率为0.86,脉冲能量为100mJ时CO₂探测的系统误差小于0.084×10^-6,随机误差小于0.02×10^-6,满足探测精度要求.     

Observation and analysis of atmospheric volatile organic compounds in a typical petrochemical area in Yangtze River Delta, China

Volatile organic compounds (VOCs) are a kind of important precursors for ozone photochemical formation. In this study, VOCs were measured from November 5th, 2013 to January 6th, 2014 at the Second Jinshan Industrial Area, Shanghai, China. The results showed that the measured VOCs were dominated by alkanes (41.8%), followed by aromatics (20.1%), alkenes (17.9%), and halo-hydrocarbons (12.5%). The daily trend of the VOC concentration showed a bimodal feature due to the rush-hour traffic in the morning and at nightfall. Based on the VOC concentration, a receptor model of Positive Matrix Factorization (PMF) coupled with the information related to VOC sources was applied to identify the major VOC emissions. The result showed five major VOC sources: solvent use and industrial processes were responsible for about 30% of the ambient VOCs, followed by rubber chemical industrial emissions (23%), refinery and petrochemical industrial emissions (21%), fuel evaporations (13%) and vehicular emissions (13%). The contribution of generalized industrial emissions was about 74% and significantly higher than that made by vehicle exhaust. Using a propylene-equivalent method, alkenes displayed the highest concentration, followed by aromatics and alkanes. Based on a maximum incremental reactivity (MIR) method, the average hourly ozone formation potential (OFP) of VOCs is 220.49?ppbv. The most significant source for ozone chemical formation was identified to be rubber chemical industrial emissions, following one by vehicular emission. The data shown herein may provide useful information to develop effective VOC pollution control strategies in industrialized area.     

Soot reduction by addition of dimethyl carbonate in normal and inverse ethylene diffusion flames: Nanostructural evidence

Oxygenated fuel represents an attractive alternative as an additive for reducing soot emissions.Dimethyl carbonate(DMC) is an oxygenated compound which is a good option to reduce soot,but the detailed characteristics of soot produced from combustion of hydrocarbon fuels blended with DMC are still lacking. The present research studied the nanostructure and reactivity of soot particles in ethylene/DMC normal and inverse diffusion flames. High resolution transmission electron microscopy(HRTEM), X-ray diffraction(XRD), and thermogravimetric analysis(TGA)were used to analyze the nanostructure and reactivity of soot. It was found that DMC addition was effective in decreasing the average weights of soot formed in flames. The results of HRTEM images showed that soot particles obtained with DMC addition showed liquid-like material and tight bonding, and exhibited more highly disorganized layers, which give it higher reactivity than soot obtained without DMC addition. Furthermore, HRTEM was used to analyze soot fringe characteristics consisting of fringe tortuosity, fringe length, and fringe separation. XRD was used to crosscheck the results for fringe separation, and was consistent with HRTEM results. In addition, the mass loss curve of TGA experiments showed that DMC addition could enhance the reactivity of soot particles.     

不同基质浓度对ANAMMOX菌短期储存的影响

在15℃±1℃条件下,将厌氧氨氧化菌混培物分别置于基质浓度为0、60、120 mg·L~(-1)添加比例为1∶1的NH+4-N和NO-2-N环境中短期(15 d)储存,探究不同基质浓度对厌氧氨氧化污泥短期保存及恢复的影响.经过短期储存后进行恢复实验,结果表明,1、2、3号反应器(分别对应0、60、120 mg·L~(-1)基质浓度中储存的厌氧氨氧化菌混培物)中的厌氧氨氧化活性分别下降41. 8%、17. 4%、33. 4.%,1、3号分别由于过度内源呼吸和高基质浓度抑制,导致活性下降较大,2号反应器由于基质浓度相对合适,避免了过度内源呼吸和高基质浓度抑制,使得菌种活性在该基质浓度下保留较好;储存期间,3个反应器内均发生内源呼吸消耗自身有机物的情况,导致EPS含量下降50. 9%、41. 7%、23. 7%和粒径下降31. 6%、16. 7%、8. 2%,表明在基质匮乏期菌体通过内源呼吸的方式维持自身的活性,较高的基质浓度可以在一定程度上延缓内源呼吸过程;在恢复期间,3个反应器分别经过15、10、7 d实现脱氮性能和厌氧氨氧化活性的恢复,表明同菌种增殖富集相比,原系统通过菌种活性增强的方式脱氮性能恢复更快.     

不同停曝比对连续流亚硝化颗粒污泥运行的影响

在（25~28℃）下,接种成熟亚硝化颗粒污泥于连续流反应器,为避免通过蠕动泵的污泥回流所造成的颗粒污泥破碎,采用内置沉淀区进行内回流,调整停曝比为1：1、2：1和1：2,研究不同停曝比对连续流亚硝化颗粒污泥系统稳定性的影响.结果表明,控制停曝比为1：1和2：1,亚硝化性能良好,阶段末期亚硝酸盐积累率分别为85.2%和94.5%,控制停曝比为1：2,亚硝化性能逐渐恶化,阶段末期氨氧化率和亚硝酸盐积累率下降至64.1%和58.7%.批次试验表明,间歇曝气相对连续曝气可在一定程度上较好地抑制亚硝酸盐氧化菌（NOB）的相对活性,停曝时间越长,对NOB的活性抑制越好,但由于停曝时间过长也将导致氨氧化率降低,故在亚硝化工艺中,可采用1：1停曝比并协同其他控制条件的方式来实现连续流亚硝化工艺的长期稳定运行.污泥性能分析表明,在停曝比为1：1~1：2范围内,停曝时间越长,颗粒污泥结构越稳定,停曝时间越短,反应器内选择压较小,致使污泥沉降性能变差,部分亚硝化颗粒污泥解体,此外,胞外聚合物（EPS）化学分析及三维荧光光谱分析显示,停曝比为2：1条件下,蛋白（PN）含量较高且蛋白/多糖（PN/PS）值也较高.     

奎屯河表层不同粒径沉积物中重金属空间分布及污染评价

在对新疆奎屯河表层沉积物粒径组成分析的基础上,采用原子吸收光谱仪测试了不同粒径沉积物中Co、Cr、Cu、Mn、Ni、Pb、Zn 7种重金属的质量比,研究了奎屯河表层沉积物不同粒径中各种重金属的空间分布特征,并运用单因子污染指数法与内梅罗综合污染指数法评价了各采样点重金属的污染状况。结果表明,奎屯河表层沉积物粒径主要分布在250μm的范围内,其中粉砂所占比例最大,平均质量分数达到63.66%;黏土次之,平均占16.77%。从上游到下游地区,各重金属污染物没有形成一定规律的分布特征。单因子污染指数评价表明除了Co,各采样点不同粒径沉积物中6种重金属存在着不同等级的污染,在粒径4μm、4~63μm、63~125μm、125~250μm的沉积物中,各重金属污染样品所占比例由大到小为Cu、Zn、Cr、Pb、Ni、Mn,Zn、Cu、Ni、Cr、Pb、Mn,Cu、Zn、Pb、Cr、Mn、Ni,Cu、Pb、Zn、Cr、Mn、Ni。内梅罗综合污染评价表明,各采样点均受到不同程度的重金属污染。     

宝钢中厚板分公司煤干燥机除尘系统风量调整技术探究

文章针对宝钢股份中厚板分公司炼铁厂煤干燥机除尘系统吸尘点冒灰,粉尘无组织排放超标的现象进行了测试分析,数据表明主要由除尘系统风量匹配不佳、吸尘点风量不合理造成。笔者通过不断调整阀门及风机档板开摩,测试调整后的风量、除尘性能、岗位粉尘浓度等参数,确定了一个合理的系统风量,不仅可以达到环境排放及职业卫生的要求,而且充分挖掘了除尘系统潜力,达到了节能降耗、经济运行的目的,同时对类似除尘系统风量匹配不佳、扬尘等问题也形成了有效的解决方案。     

清洁发展机制项目运作关键问题分析与管理对策研究

清洁发展机制（CDM）项目要想能够顺利通过一系列审查并最终获得减排量,需要特别重视项目运作流程中的关键环节。针对中国CDM项目审批数量少,通过率低,耗费时间长等问题,本文在分析CDM内涵及项目运作流程的基础上,指出了中国CDM项目运作中面临的主要问题,提出了相应的管理对策与建议,期望能够为中国推进CDM项目实施提供帮助。     

焦作地区岩溶地下水铬(Ⅵ)污染过程研究

岩溶地下水是焦作市主要饮用水水源,受人类活动影响,局部地下水中铬(Ⅵ)浓度逐渐升高。利用氢氧稳定同位素在辨析不同水体水力联系方面的原理,结合不同水体的水化学组成,判定岩溶地下水中铬(Ⅵ)污染来源。结果表明,研究区岩溶地下水铬(Ⅵ)含量升高与粉煤灰有关,主要污染过程为含铬粉煤灰的灰水渗滤液借助凤凰山断层破碎带进入岩溶地下水G6,同时进入下游岩溶地下水G1,泉水、大气降水、河水以及土壤等不会引起岩溶地下水铬(Ⅵ)含量升高。