活性污泥系统中微型动物与水质净化效果的相关分析

活性污泥系统中微型动物的种类、数量和变化情况与活性污泥状况和出水水质密切相关.在某大型炼油厂污水处理车间曝气池活性污泥系统中,通过微生物镜检监测出30多种微型动物.实验研究发现,固着型纤毛虫的种类最多,出现频率也较高.对微型动物密度与曝气池出水水质和污泥指标的相关性分析表明,小口钟虫可作为曝气池混合液DO浓度的指示生物,小口钟虫密度越大,DO浓度越高;小口钟虫、八钟虫和转轮虫可作为曝气池出水COD的指示生物,其数量增加是水质净化程度提高的标志.     

Kinetic studies of O3 reactions with 3-bromopropene and 3-iodopropene in the temperature range 288–328 K

The kinetics of the reactions of O₃ with 3-bromopropene and 3-iodopropene has been studied over the temperature range of 288–328 K at atmospheric pressure. The results obtained for the room temperature rate constants are (1.88 ± 0.22) × 10^?18 and (3.52 ± 0.43) × 10^?18 cm³ molecule^?1 s^?1, and the proposed Arrhenius expressions are k = (3.47 ± 1.28) × 10^?15 exp[(?2233 ± 110)/T] and k = (8.17 ± 2.12) × 10^?14 exp[(?2991 ± 80)/T] cm³ molecule^?1 s^?1 for 3-bromopropene and 3-iodopropene, respectively. The atmospheric chemical lifetimes of these two compounds with O₃ were also estimated from these values.     

农药内分泌干扰效应研究进展

农药作为农业生产过程中的一类重要生产资料,主要用作杀虫剂、杀菌剂和除草剂等。由于农药的大量使用,目前在各类农产品及各种环境介质中都能被检测到,对饮食健康和环境安全带来潜在危害。研究发现,许多农药为内分泌干扰物,其能够干扰人类和其他生物体的内分泌系统正常功能。本文在总结国内外相关研究的基础上,对农药内分泌干扰效应的作用机理及筛选模型进行总结,对有机氯、有机磷和拟除虫菊酯等各类农药的内分泌干扰效应研究进展进行综述,并提出深入探究农药致毒作用机制和低剂量下多种农药联合毒性是本领域的重要研究方向。     

Determination of PM2.5 Sulfate and Nitrate with a PC-BOSS Designed for Routine Sampling for Semi-Volatile Particulate Matter

ABSTRACT

Ambient particles contain substantial quantities of material that can be lost from the particles during sample collection on a filter. These include ammonium nitrate and semi-volatile organic compounds. As a result, the concentrations of these species are often significantly in error for results obtained with a filter pack sampler. The accurate measurement of these semi-volatile fine particulate species is essential for a complete understanding of the possible causes of health effects associated with exposure to fine particles. Past organic compound diffusion denuder samplers developed by the authors (e.g., the Brigham Young University Organic Sampling System [BOSS]) are not amenable to routine field use because of the need to independently determine the gas-phase semi-volatile organic material efficiency of the denuder for each sample. This problem has been eliminated using a combined virtual impactor, particle-concentrator inlet to provide a concentrated stream of 0.1-2.5-μm particles. This is followed by a BOSS diffusion denuder and filter packs to collect particles, including any semi-volatile species lost from the particles during sampling. The samp ler (Particle Concentrator-Brigham Young University Organic Sampling System [PC-BOSS]) contains a post-denuder multifilter pack unit to allow for the routine collection of several sequential samples. The PC-BOSS can be used for the determination of both fine particulate nitrate and semi-volatile organic material without significant “positive” or “negative” sampling artifacts. Validation of the sampler for the determination of PM_2.5 sulfate and nitrate based on comparison of results obtained at Riverside, CA with collocated PC-BOSS, annular denuder, and Chem Spec samplers indicates the PC-BOSS gives accurate results for these species with a precision of ±5-8%. An average of 33% of the PM_2.5 nitrate was lost from the particles during sampling for both denuder and single filter samplers.     

功能季铵盐改性蒙脱土吸附刚果红染料

以1,3-双[二(2-羟乙基)十二烷基溴化铵]丙烷(12-3-12(OH))对钠基蒙脱土(Na-Mt)进行插层改性,制备了有机蒙脱土(OMt)。采用FTIR、XRD和SEM等方法对用不同改性剂用量改性的OMt进行了表征,考察了吸附剂用量和体系pH对OMt吸附刚果红(CR)性能的影响,并探究了其吸附规律。表征结果显示:OMt表面有明显的褶皱,层间空隙随着改性剂用量的增加而增大。OMt作为吸附剂去除水中CR的最佳条件为:吸附剂用量0.4 g/L,自然pH (pH=7.12)。准二级动力学模型可以较好地描述1.0 OMt(12-3-12(OH)与Na-Mt可交换阳离子的摩尔比为1∶1)对CR的吸附过程,1.0 OMt吸附CR的过程更符合Langmuir模型,最大吸附量为248.14 mg/g,且为自发的吸热过程。重复使用3次,CR去除率保持在90%左右。     

宁夏电网新能源电站快速频率响应特性研究分析

针对宁夏电网新能源占比不断升高,常规水、火电机组出力逐步减少,电网调频裕量日显不足,且直流大功率闭锁进一步加剧电网频率安全运行风险的现状,提出了一种适用于宁夏电网的新能源电站快速频率研究方法。通过开展试点研究,掌握光伏电站、风电场参与电网频率调节的特性,结合日常电网运行频率波动情况和试点场站挂网实测响应效果,制定了快速频率响应参数设置策略,西北全网试验验证了该方法的可行性。     

膨润土对海水中重油分散途径的影响研究

石油泄漏对海洋生态造成极大威胁。通过实验室模拟重油在海水中悬浮与扩散的情况,考察了膨润土在模拟海水中促进油滴分散的作用机制,以及振荡时间、膨润土表面特性和膨润土投加量对重油分散效率的影响。实验结果表明,2种膨润土颗粒均可以通过与重油形成聚结物(OMA)将油分散。改性膨润土(CTAB-B)与重油形成稳定OMA所需的时间远远小于未改性钠基膨润土(Na-B),形成时间分别为40、180min;CTAB-B与重油生成OMA的效率高于Na-B,在低膨润土投加量(为重油质量的10%)条件下,CTAB-B、Na-B与重油形成OMA的效率分别是70%和36%;Na-B参与形成的OMA结构单一,CTAB-B与重油形成多种OMA结构,油滴粒径有所增大,但油滴颗粒在水中的稳定性增强。研究结果对于海洋石油泄露的防治具有一定指导意义。     

2种UASB的ANAMMOX与反硝化协同作用对比研究

采用2套UASB-ANAMMOX反应器处理垃圾渗滤液,其中反应器2具有生物膜,对反应器在有机环境下的ANAMMOX与反硝化协同作用进行对比研究。在稳定期,反应器1和反应器2对氨氮、亚硝氮、TIN、COD的平均去除率分别为95.7%、95.9%、77.3%、70.3%和97.4%、96.4%、87.2%、74.8%。反应器1对TIN和COD最大容积去除率为112.2和107.7 g/(m3.d),反应器2对TIN和COD最大容积去除率为120.5和119.9 g/(m3.d)。结果表明,过高的负荷会对反应器产生抑制作用,且当抑制产生后协同作用难以恢复到原来水平。在厌氧氨氧化与反硝化协同作用良好时,pH值和碱度均存在特征性变化。总体上,反应器2比反应器1具有更强的厌氧氨氧化与反硝化协同作用和抗负荷冲击能力。     

薄膜负载型TiO_2光催化降解乙酸

利用TiCl_4水解法在玻璃表面制备纳米TiO_2光催化膜,考察了TiO_2光催化膜对乙酸光催化降解过程的影响因素.实验结果表明:使用活化温度为460℃、镀膜4次、表面积168 cm~2的TiO_2光催化膜处理500 mL0.667 mmoL/L的乙酸350 min时,乙酸降解率为80.0%,与等量TiO_2粉末相比光催化膜活性显著增加;当乙酸初始浓度c_0小于0.667 mmoL/L时,光催化降解过程可用Langmuir-Hinshelwood动力学方程来描述;TiO_2膜连续使用5次(30 h)时的光催化活性基本不变;用质量分数为5%的HCl溶液浸泡失去活性的光催化膜1 h,TiO_2光催化膜的活性可完全恢复.