蒽醌类有机质对针铁矿异化还原解离特征影响

基于希瓦氏金属还原菌(Shewanella decolorationis S12)和针铁矿相互作用,讨论了蒽醌类有机质(AQS)对该针铁矿异化还原过程的调控机制.结果表明:AQS作为电子运移载体,使得还原解离态铁总量(Fetot)和可溶态铁含量(Fedis)均快速增加;不同含量的AQS加入前后,针铁矿还原平均速率得到显著上升,速率比在2.4~4.0之间,且该比值和AQS含量呈显著的线性关系,可决系数为0.9947.Fedis/Fetot比值随AQS含量升高而降低,当AQS含量由0.05 mmol·L-1增加至0.3 mmol·L-1时,Fedis/Fetot比值由0.935减小至0.705.Feads含量随AQS含量增加而增加,当体系中无AQS时,Feads含量维持在较低的水平(0.05 mmol·L-1).AQS参与下的铁异化还原过程实际上是由两个独立的子过程组成,即微生物呼吸作用驱动了AQS和还原态蒽二酚(AH2QS)的循环转变过程以及AH2QS进一步还原解离针铁矿的非生物过程.     

催化型连续再生颗粒捕集器对生物柴油发动机排放颗粒理化特性的影响

以某重型柴油机为原机,研究氧化催化转化器(Diesel Oxidation Catalyst,简称"DOC")与催化型颗粒捕集器(Catalyzed Diesel Particulate Filter,简称"CDPF")结合而成的催化型连续再生颗粒捕集器(Catalyzed Continuously Regeneration Trap,简称"CCRT")对燃用B20混合燃料柴油机颗粒排放理化特性的影响.试验结果表明:生物柴油发动机安装CCRT装置后排放的颗粒质量和数量均显著低于原机.CCRT装置对不同粒径颗粒的捕集效率不同,对聚集态颗粒的捕集效果略优于核态颗粒.与原机相比,安装CCRT后PAHs总排放量下降,在检测到的20种PAHs中有17种排放量减少.按环数比较,原机及安装CCRT装置后PAHs均以三环和四环为主.CCRT装置的安装使生物柴油发动机排放颗粒中化学成分毒性降低.     

腐殖酸改性针铁矿对铀U（Ⅵ）的吸附性能及机理研究

通过人工合成的方法制得腐殖酸改性针铁矿(HA-α-FeOOH),考察了吸附时间、吸附剂用量、U(Ⅵ)初始浓度和pH值等因素对吸附U(Ⅵ)过程的影响.同时,利用傅里叶红外光谱(FTIR)、扫描电镜(SEM)和X射线能谱(EDS)分析了其对U(Ⅵ)的吸附机理.试验结果表明,在25℃、pH为4的条件下,腐殖酸改性针铁矿作用4 h对5 mg·L-1的含铀废水的去除率几乎达到100%.Freundlich等温吸附模型、准二级动力学模型对吸附过程的拟合效果较好,主要吸附模式为多层吸附;改性针铁矿对U(Ⅵ)的吸附是自发的吸热反应.SEM-EDS和FIIR分析结果表明,改性针铁矿吸附U(Ⅵ)的机理主要表现为内层络合作用及离子交换,与U(Ⅵ)作用的基团主要是羟基、酚羟基和羧基.     

表面活性剂对以污泥为铝源制得的纳米Al（OH）3性质的影响研究

以污泥碳(SC)中回收的铝酸钠为铝源,在制备Al(OH)3的过程中加入表面活性剂PEG-1000(比例在0.01%~0.6%变化),考察其对Al(OH)3表面形貌和结构的影响.研究发现,当加入PEG-1000比例较小时,其空间位阻作用抑制了粒子之间的键合作用,使得Al(OH)3的沉淀效率较高、粒子尺寸较小,也能有效地阻止颗粒的团聚,SBET可以达到340 m2·g-1以上.当PEG-1000加入比例较大时,Al3+的沉淀效率逐渐降低,所得Al(OH)3粒子的尺寸变大,Al(OH)3的SBET和孔体积逐渐变小,平均孔径变大;原因是增多的PEG-1000分子会被包进Al(OH)3的结构中,限制了PEG-1000的表面交联和吸附,使空间位阻效应变差.—CH2—振动峰的出现说明PEG-1000是通过形成化学键的方式连接在Al(OH)3的表面基团上.PEG-1000的使用对于以污泥为铝源制备分散性好、尺寸较小和SBET较大的非晶态Al(OH)3具有重要作用.     

WC/TiO2纳米复合界面光催化剂制备及其光催化降解酚类污染物研究

设计并制备了新型WC/TiO2纳米复合界面光催化剂应用于酚类污染物的光催化降解反应中.采用X射线衍射(XRD)和扫描电子显微镜(SEM)技术分析了WC/TiO2纳米复合界面光催化剂的晶型和表面形貌.结果显示锐钛矿型TiO2纳米颗粒均匀地分散在WC纳米球表面并很好地构筑了WC/TiO2界面.研究了不同WC负载比例的WC/TiO2光催化剂在模拟太阳光照射下降解苯酚的光催化性能.结果表明:WC/TiO2复合界面的形成可以有效地提高TiO2光催化降解性能;其中,3%WC/TiO2(质量分数)光催化降解苯酚的活性最高.利用紫外-可见光谱(UV-Vis)和高效液相色谱-质谱联用技术(HPLC-MS)分析了WC/TiO2纳米复合界面光催化剂降解苯酚的中间产物,提出了苯酚在WC/TiO2界面上可能的降解机理.     

冻融对内蒙古温带贝加尔针茅草甸草原N2O通量的影响

本研究以内蒙古呼伦贝尔草甸草原为研究对象,通过室内模拟实验与野外观测实验相结合,分析不同土层、放牧与封育、长期与短期冻融、不同冻融频率与冻融温差强度对草地土壤N2O产生与排放的影响.结果表明:冻融期间,从地表到下层15cm土壤N2O的产生速率随深度的增加而逐渐减少,N2O的产生主要来源于0~9cm的表层土壤;冻融期间温差相同的情况下,冻融次数越多,N2O的产生速率越小;N2O的产生速率随着温差的变小而减少;冻融期间封育样地的N2O排放量大于放牧样地,且封育样地的N2O排放量占全年排放总量的25.09%,大于放牧样地(12.38%),但从观测年排放总量看,放牧却促进了草地N2O源的功能;草地春融期间的N2O排放量是整个冻融期N2O排放量的最大贡献者.     

Understanding the sources and composition of the incremental excess of fine particles across multiple sampling locations in one air shed

Well-designed health studies and the development of effective regulatory policies need to rely on an understanding of the incremental differences in particulate matter concentrations and their sources. Although only a limited number of studies have been conducted to examine spatial differences in sources to particulate matter within an air shed, routine monitoring data can be used to better understand these differences. Measurements from the US EPA Chemical Speciation Network （CSN） collected between 2002-2008 were analyzed to demonstrate the utility of regulatory data across three sites located within 100 km of each other. Trends in concentrations, source contribution, and incremental excesses across three sites were investigated using the Positive Matrix Factorization model. Similar yearly trends in chemical composition were observed across all sites, however, excesses of organic matter and elemental carbon were observed in the urban center that originated from local emissions of mobile sources and biomass buming. Secondary sulfate and secondary nitrate constituted over half of the PM2.5 with no spatial differences observed across sites. For these components, the excess of emissions from industrial sources could be directly quantified. This study demonstrates that CSN data from multiple sites can be successfully used to derive consistent source profiles and source contributions for regional pollution, and that CSN data can be used to quantify incremental differences in source contributions of across these sites. The analysis strategy can be used in other regions of the world to take advantage of existing ambient particulate matter monitoring data to better the understanding of spatial differences in source contributions within a given air shed.     

基于PM_(2.5)的气囊式隐形防尘鼻塞设计

最近环境恶化,雾霾天气比较严重,人们身心健康严重受到大气中粉尘的影响,而我们研发的隐形防尘鼻塞就可以很好地解决这一问题。防尘鼻塞外部由环形气囊包裹,环形气囊目的是将鼻塞固定在鼻孔里面;内部由外壳包裹的五层阻滤结构,分别为挡尘网、滤布层、两层泡沫过滤层、活性碳层、杀菌层。不同的粉尘环境条件,防尘鼻塞内部的阻滤结构及阻滤层厚度都有所不同。对PM2.5粉尘的过滤效率:标准要求>95%,实测>95.43%;气流阻力85 L/min,标准要求<343Pa,实测<276 Pa。该防尘鼻塞可以很好的解决因雾霾天气对人们造成的身心危害,同时更加适合排尘严重的企业工人佩戴。具有很好的开发生产应用价值和社会效益。     

Performance and microbial diversity of an expanded granular sludge bed reactor for high sulfate and nitrate waste brine treatment

The disposal of waste brines has become a major challenge that hinders the wide application of ion- exchange resins in the water industry in recent decades. In this study, high sulfate removal efficiency （80%-90%） was achieved at the influent sulfate concentration of 3600 mg/L and 3% NaC1 after 145 days in an expanded granular sludge bed （EGSB） reactor. Furthermore, the feasibility of treating synthetic waste brine containing high levels of sulfate and nitrate was investigated in a single EGSB reactor during an operation period of 261 days. The highest nitrate and sulfate loading rate reached 6.38 and 5.78 kg/（m3-day） at SO42--S/NO3-N mass ratio of 4/3, and the corresponding removal efficiency was 99.97% and 82.26% at 3% NaC1, respectively. Meanwhile, 454-pyrosequencing technology was used to analyze the bacterial diversity of the sludge on the 240th day for stable operation of phase X. Results showed that a total of 9194 sequences were obtained, which could be affiliated to 14 phyla, including Proteobacteria, Firmicutes, Chlorobi, Bacteroidetes, Synergistetes and so on. Proteobacteria （77.66%） was the dominant microbial population, followed by Firmicutes （12.23%） and Chlorobi （2.71%）.     

Graphene-supported nanoscale zero-valent iron：Removal of phosphorus from aqueous solution and mechanistic study

Excess phosphorus from non-point pollution sources is one of the key factors causing eutrophication in many lakes in China,so finding a cost-effective method to remove phosphorus from non-point pollution sources is very important for the health of the aqueous environment. Graphene was selected to support nanoscale zero-valent iron(nZVI)for phosphorus removal from synthetic rainwater runoff in this article. Compared with nZVI supported on other porous materials,graphene-supported nZVI(G-nZVI) could remove phosphorus more efficiently. The amount of nZVI in G-nZVI was an important factor in the removal of phosphorus by G-nZVI,and G-nZVI with 20 wt.% nZVI(20% G-nZVI)could remove phosphorus most efficiently. The nZVI was very stable and could disperse very well on graphene,as characterized by transmission electron microscopy(TEM) and scanning electron microscopy(SEM). X-ray photoelectron spectroscopy(XPS),Fourier Transform infrared spectroscopy(FT-IR) and Raman spectroscopy were used to elucidate the reaction process,and the results indicated that Fe-O-P was formed after phosphorus was adsorbed by G-nZVI. The results obtained from X-ray diffraction(XRD) indicated that the reaction product between nZVI supported on graphene and phosphorus was Fe3(PO4)2·8H2O(Vivianite). It was confirmed that the specific reaction mechanism for the removal of phosphorus with nZVI or G-nZVI was mainly due to chemical reaction between nZVI and phosphorus.