异养硝化细菌Alcaligenes sp.S3除氮特性及动力学

从湘江生活污水排污口分离纯化的一株菌Alcaligenes sp.S3,在氨氮浓度为400 mg/L时,经过192 h的降解,氨氮的去除率达到88%,并且NH2OH和NO2--N并没出现积累。在对不同浓度的氨氮进行一级动力学拟合时发现,只有氨氮浓度较高时才很好地符合,浓度为500 mg/L时R2达到0.9923。酸性环境对Alcaligenes sp.S3生长有抑制作用,在pH7.5～10生长较好。摇床转速对Alcaligenes sp.S3除氮影响不大,C/N过低或过高对Alcaligenes sp.S3除氮都有影响。     

Ce-PbO2/C电极的制备及其去除水中酸性红B

采用电沉积法制备铈修饰的PbO2/C电极,通过SEM、XRD、XPS及循环伏安对PbO2/C、Ce-PbO2/C电极进行表征,结果表明,Ce-PbO2/C电极比PbO2/C颗粒细小,表面均匀致密,电化学氧化能力较强,修饰电极中Ce以CeO2的形态存在。以Ce-PbO2/C为工作电极,电解浓度为1 000 mg/L的高盐酸性红B模拟活性染料废水,考察了电压、pH、电解质浓度、极间距对脱色率、氨氮去除率及COD去除率的影响。确定适宜工艺条件为:初始酸性红B溶液浓度为1 000 mg/L,pH值为6,电压10 V,电解时间1 h,电极间距1.5 cm,该条件下脱色率、氨氮去除率和COD去除率分别为99.98%、97.23%和90.17%。通过UV-Vis及GC-MS初步分析了降解过程可能存在的中间产物及降解途径。     

Accelerated ash accumulation method for diesel particulate filter and its characterization: a review

ABSTRACT

It is well known that high-efficiency wall-flow particulate filter is the most commonly used technology that can effectively reduce both particulate matter (PM) and particulate number (PN) to comply with the latest emission legislations. Ash, defined as the noncombustible, non-evaporative residue derived mostly from lubricants, has critical impact on engine backpressure, particulate filter filtration efficiency and durability performance, therefore, the investigation of ash impact on particulate filter is of great importance. Due to cost-saving potential, several published methods from different laboratories for accelerated ash loading under carefully controlled conditions are described in this review, including some characterization methods that have been used for the evaluation of filter performance. In addition, the impact of ash deposit on back pressure and regeneration performance are also discussed in this review.     

Chemical characterization and source apportionment of atmospheric submicron particles on the western coast of Taiwan Strait, China

Taiwan Strait is a special channel for subtropical East Asian Monsoon and its western coast is an important economic zone in China. In this study, a suburban site in the city of Xiamen on the western coast of Taiwan Strait was selected for fine aerosol study to improve the understanding of air pollution sources in this region. An Aerodyne high-resolution time-of-flight aerosol mass spectrometer(HR-To F-AMS) and an Aethalometer were deployed to measure fine aerosol composition with a time resolution of 5 min from May 1to 18, 2015. The average mass concentration of PM1 was 46.2 ± 26.3 μg/m~3 for the entire campaign. Organics(28.3%), sulfate(24.9%), and nitrate(20.6%) were the major components in the fine particles, followed by ammonium, black carbon(BC), and chloride. Evolution of nitrate concentration and size distribution indicated that local NOx emissions played a key role in high fine particle pollution in Xiamen. In addition, organic nitrate was found to account for 9.0%–13.8% of the total measured nitrate. Positive Matrix Factorization(PMF)conducted with high-resolution organic mass spectra dataset differentiated the organic aerosol into three components, including a hydrocarbon-like organic aerosol(HOA) and two oxygenated organic aerosols(SV-OOA and LV-OOA), which on average accounted for 27.6%,28.8%, and 43.6% of the total organic mass, respectively. The relationship between the mass concentration of submicron particle species and wind further confirmed that all major fine particle species were influenced by both strong local emissions in the southeastern area of Xiamen and regional transport through the Taiwan Strait.     

苯基改性的介孔分子筛SBA-15的合成与表征

采用一步法在酸性条件下以聚乙氧基聚丙氧基聚乙氧基三嵌段共聚物(P123)为模板剂,用正硅酸乙酯(TEOS)和苯基三甲氧基硅烷(PTMS)直接缩合制备了苯基改性介孔分子筛Ph-SBA-15,并用红外光谱(FTIR)、小角X射线衍射(SAXRD)、热重分析(TGA)、透射电镜(TEM)和氮气吸附-脱附对样品进行了表征。结果表明,制备的样品不仅保持了高度有序的SBA-15的二维六角结构,而且具有较高的热稳定性,较大的比表面,孔容和孔径。     

Production,engine performance,combustion, emission characteristics and economic feasibility of biodiesel from waste cooking oil: A review

The depletion of fossil fuel reserves and increasing demands for diesel are considered to be important triggers for many of the initiatives that have been taken to search for possible sources for the production of biodiesel from materials available within the country. It is possible to produce biodiesel from waste/used cooking oils (WCO) that is comparable in quality to that of fresh vegetable oil. Not only does reuse of WCO, which can otherwise harm human health, reduce the burden on the government of treating oily wastewater, disposing of the waste, and maintaining public sewers, it also significantly lowers the production cost of biodiesel. In the process of frying, oil undergoes many reactions, leading to the formation of a number of undesirable compounds, such as polymers, free fatty acids, and many other chemicals. This poses challenges in the transesterification of WCO. This article covers different techniques in the production of biodiesel from WCO. It also compares combustion, emissions, and engine performance characteristics of biodiesel from WCO as well as factors affecting biodiesel production from WCO and its economic feasibility.     

Characterization of a new smog chamber for evaluating SAPRC gas-phase chemical mechanism

A new state-of-the-art indoor smog chamber facility(CAPS-ZJU) has been constructed and characterized at Zhejiang University,which is designed for chemical mechanism evaluation under well-controlled conditions.A series of characterization experiments were performed to validate the well-established experimental protocols,including temperature variation pattern,light spectrum and equivalent intensity(J_NO2),injection and mixing performance,as well as gases and particle wall loss.In additi...     

水环境中溶解性有机物溯源分析及分子结构表征概述

溶解性有机物(DOM)是地球上最大的碳基化合物反应性储层之一,涉及各种生物地化反应并且在污染物溶解度、毒性、生物利用度、流变性和分布中发挥重要作用。本文介绍了当前用于表征水环境中DOM的策略和工具,探讨了当前研究在技术限制(预处理过程复杂、仪器分辨率低、数据处理困)、结构复杂性、结构多变性等方面存在的诸多局限性。分析认为:已有研究主要侧重于溯源分析和分子结构特征解析,未来研究应该在不同的结构层面和角度开展,加强多学科融合、数据库创建、对照实验和协同工作。     

Chemical characterization and source apportionment of PM1 and PM2.5 in Tianjin, China: Impacts of biomass burning and primary biogenic sources

The submicron particulate matter (PM₁) and fine particulate matter (PM_2.5) are very important due to their greater adverse impacts on the natural environment and human health. In this study, the daily PM₁ and PM_2.5 samples were collected during early summer 2018 at a sub-urban site in the urban-industrial port city of Tianjin, China. The collected samples were analyzed for the carbonaceous fractions, inorganic ions, elemental species, and specific marker sugar species. The chemical characterization of PM₁ and PM_2.5 was based on their concentrations, compositions, and characteristic ratios (PM₁/PM_2.5, AE/CE, NO₃^?/SO₄^2?, OC/EC, SOC/OC, OM/TCA, K+/EC, levoglucosan/K⁺, V/Cu, and V/Ni). The average concentrations of PM₁ and PM_2.5 were 32.4 µg/m³ and 53.3 µg/m³, and PM₁ constituted 63% of PM_2.5 on average. The source apportionment of PM₁ and PM_2.5 by positive matrix factorization (PMF) model indicated the main sources of secondary aerosols (25% and 34%), biomass burning (17% and 20%), traffic emission (20% and 14%), and coal combustion (17% and 14%). The biomass burning factor involved agricultural fertilization and waste incineration. The biomass burning and primary biogenic contributions were determined by specific marker sugar species. The anthropogenic sources (combustion, secondary particle formation, etc) contributed significantly to PM₁ and PM_2.5, and the natural sources were more evident in PM_2.5. This work significantly contributes to the chemical characterization and source apportionment of PM₁ and PM_2.5 in near-port cities influenced by the diverse sources.     

兼性厌氧苯胺降解菌的分离鉴定及其特性

从处理印染废水的厌氧折流板反应器(ABR)系统中分离、纯化并筛选出1株能以苯胺为唯一碳氮源进行代谢的兼性厌氧苯胺降解菌株AN29.经过形态、生理生化特征试验和16S rDNA序列分析结果,鉴定菌株AN29为假单胞菌(Pseudomonas sp.),其特性为:降解苯胺的最适温度为37℃,降解苯胺合适的起始pH值为6.5～8.0,可以利用苯胺的最高浓度为4 000mg/L,合适起始浓度为500～2 000mg/L.