Improved atmospheric mercury simulation using updated gas-particle partition and organic aerosol concentrations

The gaseous or particulate forms of divalent mercury (Hg^II) significantly impact the spatial distribution of atmospheric mercury concentration and deposition flux (FLX). In the new nested-grid GEOS-Chem model, we try to modify the Hg^II gas-particle partitioning relationship with synchronous and hourly observations at four sites in China. Observations of gaseous oxidized Hg (GOM), particulate-bound Hg (PBM), and PM_2.5 were used to derive an empirical gas-particle partitioning coefficient as a function of temperature (T) and organic aerosol (OA) concentrations under different relative humidity (RH). Results showed that with increasing RH, the dominant process of Hg^II gas-particle partitioning changed from physical adsorption to chemical desorption. And the dominant factor of Hg^II gas-particle partitioning changed from T to OA concentrations. We thus improved the simulated OA concentration field by introducing intermediate-volatility and semi-volatile organic compounds (I/SVOCs) emission inventory into the model framework and refining the volatile distributions of I/SVOCs according to new filed tests in the recent literatures. Finally, normalized mean biases (NMBs) of monthly gaseous element mercury (GEM), GOM, PBM, WFLX were reduced from −33%–29%, 95%–300%, 64%–261%, 117%–122% to −13%–0%, −20%–80%, −31%–50%, −17%–23%. The improved model explains 69%–98% of the observed atmospheric Hg decrease during 2013–2020 and can serve as a useful tool to evaluate the effectiveness of the Minamata Convention on Mercury.     

杭锦土负载硫化零价铁的研制及除磷性能

以具有较大比表面积和良好吸附性能的天然杭锦土为载体制备杭锦土负载硫化零价铁（HJ@S-nZVI）。优化铁负载比、硫铁摩尔比（S/Fe）以及陈化时间等制备条件,利用扫描电子显微镜（SEM）、能量色散光谱(energy dispersive spectroscopy,EDS)、X射线光电子能谱（XPS）及比表面积（specific surface area,SSA）等手段对HJ@S-nZVI进行综合表征分析。考察投加量、初始pH以及共存离子等因素对HJ@S-nZVI去除磷酸盐效果的影响,并结合吸附等温线和吸附动力学研究其吸附性能和吸附机理。结果表明：HJ@S-nZVI的优化制备条件为铁负载比为0.25,S/Fe为0.01,陈化时间为10 d;SEM、EDS和元素分布图分析表明,硫化零价铁以球状颗粒形式成功负载于杭锦土表面,XPS表明HJ@S-nZVI表面铁的主要存在形态为FeS和FeOOH等;投加量、初始pH和SiO₃ ²⁻共存对HJ@S-nZVI去除磷酸盐的效果影响较大,而SO₄ ²⁻、CO₃ ²⁻和Cl⁻共存对磷酸盐的去除效果无明显竞争影响;HJ@S-nZVI对磷酸盐的吸附过程符合Freundlich等温模型（R²=0.992）,不同初始浓度下,准二级动力学模型可较好地描述磷酸盐的去除过程（R²>0.995）。     

一次航班飞行全过程大气污染物排放特征

飞机发动机以航空煤油为燃料,在运行过程中会排放多种大气污染物,对空气质量和人体健康存在较大影响.选择A320作为典型机型,提取了一次真实航班飞行过程中的机载飞行数据,基于BM2及BM2-FOA耦合模型,获得了其在飞行全过程中每一时刻CO、UHC、NO_x及PM_(2.5)的排放指数,并计算了CO、UHC、NO_x、SO_2、CO_2及PM_(2.5)的精确排放量.结果表明,飞行过程中CO和UHC排放指数与推力变化趋势相反,数值范围分别为0.67~595.34 g·kg~(-1)和0.05~0.43 g·kg~(-1).NO_x排放指数与燃油流量变化趋势一致,数值范围是0.96~114.25 g·kg~(-1).PM_(2.5)排放指数全过程变化较小,约为0.25~0.36 g·kg~(-1).飞行全过程中,CO_2排放总量最大,约为2.0×10~4kg.同时,NO_x的排放量约为213.4 kg,SO_2也排放了24.5 kg.CO、PM_(2.5)和UHC的排放量分别为7.5、2.2和0.5 kg.将本次精确计算结果与使用ICAO基准模型对LTO起降阶段的估算结果进行对比后发现,基准模型LTO飞行时间较真实时间偏长37%.基准模型估算LTO阶段CO、UHC污染物排放量偏高,NO_x偏低,且偏差较大;而SO_2、CO_2和PM_(2.5)的排放量估算结果偏差相对较小.与机动车相比,A320飞机的一次LTO起飞着陆飞行,NO_x排放量约等于一辆小客车行驶8.6×10~4km,或相当于1274辆小客车1 d的排放量.     

碳同位素解析厌氧产酸过程挥发性有机酸来源

针对厌氧产酸条件下挥发性有机酸（VFAs）来源不明确及定向合成无依据的问题,基于同位素示踪技术对VFAs来源与合成比例进行研究.构建完全的厌氧产酸体系,采用牛血清蛋白、植物油和稳定同位素型葡萄糖（碳13丰度99%）作为反应底物,利用碳同位素示踪原理,定量分析VFAs的来源及其比例.结果表明：碳水化合物（碳13丰度99%）主要贡献偶数型短链脂肪酸的生成,其中对乙酸（HAc）和丁酸（HBu）的贡献率分别为77%和86%;而蛋白质（碳12）主要贡献奇数型短链脂肪酸的生成,其中对丙酸（HPr）和戊酸（HVa）的贡献率分别为85%和99%.通过改变发酵底物中碳水化合物和蛋白质比例,可以有效调节水解液中奇数型与偶数型短链脂肪酸的浓度和比例,为后期微生物合成高品质聚羟基脂肪酸酯（PHA）提供物质基础.     

Pollution characteristics of polycyclic aromatic hydrocarbons in common used mineral oils and their transformation during oil regeneration

The pollution characteristic of polycyclic aromatic hydrocarbons(PAHs) in common used mineral oils, semi-refined oils, refined oils and solid wastes produced during the used mineral oil regeneration process was analyzed. The results showed that total PAHs content in six common used mineral oils was as follows: used engine oil used quenching oil used casting oil used hydraulic oil used antirust oil used industrial lubricating oil. Furthermore, this order was dependent on the source of PAHs and oil working temperatures. Additionally, total PAHs content in regenerated oils was as follows: semi-refined oil refined oil crude oil, which was related to the catalytic cracking process of crude oil and adsorption refining process of semi-refined oil. The ranking of total PAHs content in regenerated wastes varied depending on the regeneration technology used as follows: waste adsorption sand acid sludge waste clay precipitation sludge cracked residue. In all types of used mineral oils and regenerated wastes, the maximum and minimum proportions of the total PAHs content were composed of 2–3 ring-PAHs and 5–6 ring-PAHs, respectively. The majority of PAHs in the used mineral oils entered into regenerated wastes during regeneration process, while a small number remained in the regenerated oil.     

奇异变形杆菌TJ-1产絮凝剂的培养基优化研究

从活性污泥中分离出1株新型高效产絮凝剂菌TJ-1,经16S rDNA相似性分析鉴定为奇异变形杆菌(Proteus mirabilis),这是首次发现奇异变形杆菌能产微生物絮凝剂,对其进行了产絮凝剂培养条件优化研究.结果表明,TJ-1菌产絮凝剂的最佳培养基成分为:葡萄糖10g,蛋白胨1g,MgS040.3g,KH2PO42g,K2HP04 5g,去离子水1L,pH=7.0.絮凝实验结果表明,该菌在最佳培养条件下所产絮凝剂对高岭土悬液的絮凝率达到92%.     

Preparation and characterization of a lipoid adsorption material and its atrazine removal performance

A novel adsorbent named lipoid adsorption material (LAM), with a hydrophobic nucleolus (triolein) and a hydrophilic membrane structure (polyamide), was synthesized to remove hydrophobic organic chemicals (HOCs) from solution. Triolein, a type of lipoid, was entrapped by the polyamide membrane through an interfacial polymerization reaction. The method of preparation and the structure of the LAM were investigated and subsequent experiments were conducted to determine the characteristics of atrazine (a type of HOC) removal from wastewater using LAM as the adsorbent. The results showed that LAM had a regular structure compared with the prepolymer, where compact particles were linked with each other and openings were present in the structure of the LAM in which the fat drops formed from triolein were entrapped. In contrast to the atrazine adsorption behavior of powdered activated carbon (PAC), LAM showed a persistent adsorption capacity for atrazine when initial concentrations of 0.57, 1.12, 8.31 and 19.01 mg/L were present, and the equilibrium time was 12 hr. Using an 8 mg/L initial concentration of atrazine as an indicator of HOCs in aqueous solution, experiments on the adsorption capacity of the LAM showed 69.3% removal within 6–12 hr contact time, which was close to the 75.5% removal of atrazine by PAC. Results indicated that LAM has two atrazine removal mechanisms, namely the bioaccumulation of atrazine by the nucleous material and physical adsorption to the LAM membrane. Bioaccumulation was the main removal mechanism.     

呼和浩特交通扬尘排放清单研究

颗粒物污染是影响中国城市空气质量的首要因素,交通扬尘是城市大气颗粒物污染的主要来源之一,排放清单及排放特征研究是进行环境影响分析、控制措施成本效益分析、控制方案制定以及进行环境管理的基础。本文对呼和浩特城区典型道路路面尘负荷进行采样分析,现场调研不同类型道路车流量和车辆构成,应用AP-42排放因子计算典型道路交通扬尘排放因子,建立了基于G IS的排放清单数据库。结果显示:胡同的PM10排放因子最大,其次分别为环城路、支路、次干道和主干道;环城路的PM10排放强度最大,其次为主干道、次干道、支路和胡同;基准年2006年呼和浩特城区交通扬尘PM10排放量为22 715 t;从空间分布看,环城路以内网格排放源强较高,中心城区排放强度最大。     

西安国际化大都市生态环境建设研究

生态环境建设是城市可持续健康发展的重要途径,也是建设国际化大都市的内在要求。结合西安市创建国际化大都市的实际情况,阐述了西安市生态城市建设现状和发展中出现的问题、生态建设的优势和制约因素等,建立了国际化大都市城市生态建设指标体系,提出了西安市建成生态城市的相关对策和措施。对西安市生态建设提出了系统的设想,阐明国际化大都市建设对改善人居环境及创建和谐社会的重要意义。     

基于问卷调查的个人生态足迹测算及分析——以厦门大学在读学生为例

文章运用世界自然基金会提供的个人年生态足迹计算软件,通过问卷调查收集资料,测算厦门大学在读学生个人生态足迹,并分析探讨高校在读学生个人生态足迹的组成及影响因素。结果表明,厦门大学在读学生的个人生态足迹介于0.4 gh～1.6 gh之间,平均值为0.83 gh,远低于中国人均生态足迹;在各组成部分中,耕地、水域和碳足迹为主要用地类型,占人均足迹的90%以上;被访者的性别、学科和学历对其个人生态足迹的影响不明显,而个人月可支配收入及其出行方式与个人生态足迹的大小存在明显正相关性,即月可支配收入越高个人足迹越大,选择环保的出行方式则个人生态足迹较小。