Fast screening compositions of PM2.5 by ATR-FTIR: Comparison with results from IC andOC/EC analyzers

Chemical speciation of fine particles or PM_(2.5) collected on filters is still a costly and timeconsuming task. In this study, filter-based PM_(2.5) samples were collected during November–December 2013 at four sites in Guangzhou, and the major components were fast screened(~7 min per filter sample) by Attenuated Total Reflectance(ATR)-Fourier Transform Infrared Spectroscopic(FTIR) in comparison with that measured by Organic carbon/Element carbon(OC/EC) analyzer and Ion Chromatography(IC). The concentrations of nitrate, ammonium, sulfate,primary organic carbon(POC) and secondary organic carbon(SOC) measured by OC/EC and IC analyzers were better correlated with their infrared absorption peak heights at 1320 cm~(-1) for nitrate, 1435, 3045 and 3215 cm~(-1) for ammonium, 615 cm~(-1) for sulfate, 690, 760 and 890 cm~(-1) for POC and 1640 and 1660 cm~(-1) for SOC respectively, during polluted days(PM_(2.5) 75 μg/m~3) than during clean days(PM_(2.5)≤ 75 μg/m~3). With the evolution of a haze episode during our field campaign, the concentrations of the major PM_(2.5) components displayed consistent variations with their infrared absorption peak heights, suggesting ATR-FTIR could be a fast and useful technique to characterize filter-based PM_(2.5) compositions particularly during pollution events although cautions should be taken when PM_(2.5) levels are low. Notably, elevated PM_(2.5) mass concentrations occurred with enhanced ratios of [NO_(-3)]/[SO_4~(2-)] and [NH~(+4)]/[SO_4~(2-)], implying that nitrogenous components play vital roles in the PM_(2.5) pollution events in the study region.     

Sorption behavior of tetracyclines on suspended organic matters originating from swine wastewater

Tetracyclines(TCs) discharged from livestock wastewater have aroused public concerns due to their pharmacological threats to ecosystems and human health. As an important medium in the wastewater, suspended organic matters(SOMs) play vital roles in antibiotics transport and degradation. However, limited information has been reported in the relevant literature. This study investigated TCs sorption behavior on SOM, withdrawn from swine wastewater. High TCs sorption capacities were detected, with the maximum values ranging from 0.337 to 0.679 mg/g. Increasing p H and temperature led to the decline of sorption capacity. Results from three-dimensional excitation–emission matrix fluorescence spectroscopy and Fourier transform infrared spectrometry revealed that amide and carboxyl groups were the main functional groups for TCs adsorption. The interactions between SOM and TCs were clarified as predominated by hydrogen-bonding and cation-exchange in acid conditions, and electrostatic repulsion in neutral or alkaline conditions. Adsorption kinetics modeling was conducted, and a satisfactory fitting was achieved with the Freundlich equation. These results indicated that the adsorption process was a rather complex process, involving a combination of cation-exchange and hydrogen-bonding. The results will provide a better understanding of the capability of SOM for TCs transport and abatement in the wastewater treatment process.     

分子筛在铅污染土壤修复中的应用研究

采用溶液试验,从待选钝化材料中初步筛选出对Pb具有较好钝化效果的钝化材料,运用经典混料设计的试验方法,将优选出的13X分子筛、凹凸棒土、粉煤灰三种钝化材料复配成钝化剂,添加到Pb含量为1 500mg/kg的污染土中,添加量为污染土的20％,并保持土壤的含水率35％,3天后取钝化后土壤,采用(HJ/T 300-2007)(固体废物浸出毒性浸出方法醋酸缓冲溶液法)测其浸出液中的重金属Pb含量,采用Minitab软件对混料设计试验数据进行处理,优选出钝化重金属Pb的最佳钝化剂配方:分子筛25％,凹凸棒土42.6％,粉煤灰32.4％,钝化后浸出液中重金属Pb含量为0.027 1 mg/L,明显低于地表水质量标准的Ⅲ类标准0.05 mg/L.     

Lambda-cyhalothrin disrupts the up-regulation effect of 17β-estradiol on post-synaptic density 95 protein expression via estrogen receptor α-dependent Akt pathway

Lambda-cyhalothrin(LCT),one of the type II pyrethroids,has been widely used throughout the world.The estrogenic effect of LCT to increase cell proliferation has been well established.However,whether the estrogenic effect of LCT will influence neurodevelopment has not been investigated.In addition,17β-Estradiol(E2)plays a crucial role in neurodevelopment and induces an increase in synaptic proteins.The post-synaptic density 95(PSD95)protein,which is involved in the development of the structure and function of new spines and localized with estrogen receptor α(ERα)at the post-synaptic density(PSD),was detected in our study by using hippocampal neuron cell line HT22.We found that LCT up-regulated PSD95 and ERα expression,estrogen receptor(ER)antagonist ICI182,780 and phosphatidylinositol-4;5-bisphosphate 3-kinase(PI3K)inhibitor LY294,002 blocked this effect.In addition,LCT disrupted the promotion effect of E2 on PSD95.To investigate whether the observed changes are caused by ERα-dependent signaling activation,we next detected the effects of LCT on the ERα-mediated PI3K-Protein kinase B(PKB/Akt)-eukaryotic initiation factor(e IF)4E-binding protein 1(4E-BP1)pathway.There existed an activation of Akt and the downstream factor 4E-BP1 after LCT treatment.In addition,LCT could disrupt the activation effect of E2 on the Akt pathway.However,no changes in c AMP response element-binding protein(CREB)activation and PSD95 messenger ribonucleic acid(m RNA)were observed.Our findings demonstrated that LCT could increase the PSD95 protein level via the ERα-dependent Akt pathway,and LCT might disrupt the up-regulation effect of E2 on PSD95 protein expression via this signaling pathway.     

Human bronchial epithelial cell injuries induced by fine particulate matter from sandstorm and non-sandstorm periods: Association with particle constituents

Epidemiological studies have demonstrated the exacerbation of respiratory diseases following sandstorm-derived particulate matter(PM) exposure.The presence of anthropogenic and biological agents on the sandstorm PM and the escalation of PM 2.5 μm(PM2.5)pollution in China have led to serious concerns regarding the health effects of PM2.5during Asian sandstorms.We investigated how changes in PM2.5composition,as the weather transitioned towards a sandstorm,affected human airway epithelial cells.Six PM2.5samples covering two sandstorm events and their respective background and transition periods were collected in Baotou,an industrial city near the Gobi Desert in China.PM samples from all three periods had mild cytotoxicity in human bronchial epithelial cell line BEAS-2B,which was positively correlated with the contents of polycyclic aromatic hydrocarbons and several metals.All PM samples potently increased the release of interleukin-6(IL-6) and interleukin-8(IL-8).Endotoxin in all samples contributed significantly to the IL-6 response,with only a minor effect on IL-8.Cr was positively correlated with both IL-6 and IL-8 release,while Si was only associated with the increase of IL-6.Our study suggests that local agricultural and industrial surroundings in addition to the sandstorm play important roles in the respiratory effects of sandstorm-derived PM.     

二氧化钛光催化降解甲醛反应动力学研究

以钛酸丁酯为前驱体，应用溶胶一凝胶法制备TiO2粉体和负载TiO2薄膜，考察了不同活化温度和活化时间对TiO2光催化降解甲醛性能的影响，并对TiO2薄膜光催化降解甲醛的反应动力学进行了研究。试验结果表明，在活化温度450℃、活化时间5h条件下，所得TiO2粉体及薄膜的光催化活性较好。不同初始浓度下甲醛光催化降解率与时间关系的动力学研究表明，一级反应动力学模型与试验数据拟合较好，方差R^2大于或等于0．99。     

气质联用法测定空气中挥发性有机物的方法研究

通过美国Entech公司Summa罐采集大气样品,7100型大气预浓缩系统提取和富集样品中的挥发性有机物,省去了繁琐的有机物提取和净化工序,避免和有机溶剂接触,将样品直接输入气质联机进行分析。利用这种方法定性分析了某油罐区的大气成分,结果表明该地区大气中含有成分复杂的环己烷、苯和萘的衍生物,这些化合物的浓度远远大于居民区同类化合物的含量。     

燃煤电厂烟气脱硝装置的仿真设计研究

文章以选择性催化还原法(SCR)烟气脱硝系统为研究对象,通过对系统工艺特点和反应机理的研究,建立了一系列仿真数学模型,并以这些模型为基础,设计开发了SCR烟气脱硝系统的仿真设计软件。软件最终编译成可安装的应用软件包,能够脱离开发环境在Windows系统下独立运行。     

广西钦州湾近岸海域“十一·五”期间营养盐变化趋势分析及污染控制重点

通过2006年-2010年N、P、Si数据分析广西钦州湾海域N、P、Si的变化趋势、富营养化状况以及限制因子。分析表明:钦州外湾DIN、DIP、SiO3-Si含量呈波浪形变化并有所下降,钦州外湾2006年-2010年均为贫营养,外湾海水水质良好。茅尾海DIN值含量较高,海域受到N的影响。茅尾海2006年-2010年为轻度～中度富营养。茅尾海属于磷中等限制富营养,磷酸盐仅表现为相对不足,仍然有爆发赤潮的危险。控制茅尾海富营养化的关键在于控制磷的入海量。     

中国排污权交易制度的实现条件研究

排污权交易目前在中国非常受重视,但其中也存在一些问题,主要是企业和政府尚没有处理好经济发展和环境保护的关系,也存在着制度设置不合理的问题。今后应重视排污权交易中的内部和外部条件的建设。内部条件主要有排污总量的确定和排污许可证的发放,外部条件主要包括政府加强环境执法力度和提供有效的排污信息。