Effects of pH and ionic strength on sulfamethoxazole and ciprofloxacin transport in saturated porous media

Many antibiotics regarded as emerging contaminants have been frequently detected in soils and groundwater; however, their transport behaviors in soils remain largely unknown. This study examined the transport of two antibiotics, sulfamethoxazole (SMZ) and ciprofloxacin (CIP), in saturated porous media. Laboratory columns packed with quartz sand was used to test the effects of solution pH and ionic strength (IS) on their retention and transport. The results showed that these two antibiotics behaved differently in the saturated sand columns. In general, SMZ manifested a much higher mobility than CIP for all experimental conditions tested. Almost all SMZ transported through the columns within one pore volume in deionized water (i.e., pH=5.6, IS=0), but no CIP was detected in the effluents under the same condition after extended column flushing. Perturbations in solution pH (5.6 and 9.5) and IS (0 and 0.1M) showed no effect on SMZ transport in the saturated columns. When pH increased to 9.5, however, ~93% of CIP was eluted from the sand columns. Increase of IS from 0 to 0.1M also slightly changed the distribution of adsorbed CIP within the sand column at pH 5.6, but still no CIP was detected in the effluents. A mathematical model based on advection-dispersion equation coupled with equilibrium and kinetic reactions successfully simulated the transport of the antibiotics in water-saturated porous media with R(2)=0.99.     

Modeling of a combined ultraviolet-biofilter system to treat gaseous chlorobenzene I: model development and parametric sensitivity

A new type of a combined ultraviolet (UV)-biofilter system for air pollution control is developed. In this paper, two conceptual mathematical submodels of the UV reactor and standalone biofilter are developed. All model parameters have been determined by independent experiments or have been taken from literature. Results from UV and the standalone biofilter submodels are in a good agreement with experimental data. However, the performance of the combined system has significantly deviated from those of the UV or standalone submodels because of the stimulating effects of UV irradiation products on the subsequent biofilter performance. A modified model that considers the stimulating effects has agreed well with experimental data over a wide range of operating conditions. Further analysis of the primary parametric sensitivity of the model has shown that inlet chlorobenzene concentrations, gas empty-bed residence time in the UV reactor, and light intensity are important operating conditions.     

Investigation of PM2.5 pollution during COVID-19 pandemic in Guangzhou, China

The COVID-19 pandemic has raised awareness about various environmental issues,including PM_2.5 pollution.Here,PM_2.5 pollution during the COVID-19 lockdown was traced and analyzed to clarify the sources and factors influencing PM_2.5 in Guangzhou,with an emphasis on heavy pollution.The lockdown led to large reductions in industrial and traffic emissions,which significantly reduced PM_2.5 concentrations in Guangzhou.Interestingly,the trend of PM_2.5     

A statistic comparison of multi-element analysis of low atmospheric fine particles (PM2.5) using different spectroscopy techniques

Over the past few decades, the metal elements(MEs) in atmospheric particles have aroused great attention. Some well-established techniques have been used to measure particlebound MEs. However, each method has its own advantages and disadvantages in terms of complexity, accuracy, and specific elements of interest. In this study, the performances of inductively coupled plasma–optical emission spectrometry(ICP-OES) and total reflection X-ray fluorescence spectroscopy(TXRF) were evaluated for qualit...     

Determination of 27 pharmaceuticals and personal care products (PPCPs) in water: The benefit of isotope dilution

• Isotope dilution method was developed for the determination of 27 PPCPs in water. • The established method was successfully applied to different types of water samples. • The correction effect of corresponding 27 ILSs over 70 d was investigated. • Benefit of isotopic dilution method was illustrated for three examples. Pharmaceuticals and personal care products (PPCPs) are a unique group of emerging and non-persistent contaminants. In this study, 27 PPCPs in various water samples were extracted by solid phase extraction (SPE), and determined by isotope dilution method using liquid chromatography coupled to tandem triple quadruple mass spectrometer (LC-MS/MS). A total of 27 isotopically labeled standards (ILSs) were applied to correct the concentration of PPCPs in spiked ultrapure water, drinking water, river, effluent and influent sewage. The corrected recoveries were 73%–122% with the relative standard deviation (RSD)<16%, except for acetaminophen. The matrix effect for all kinds of water samples was<22% and the method quantitation limits (MQLs) were 0.45–8.6 ng/L. The developed method was successfully applied on environmental water samples. The SPE extracts of spiked ultrapure water, drinking water, river and wastewater effluent were stored for 70 days, and the ILSs-corrected recoveries of 27 PPCPs were obtained to evaluate the correction ability of ILSs in the presence of variety interferences. The recoveries of 27 PPCPs over 70 days were within the scope of 72%–140% with the recovery variation<37% in all cases. The isotope dilution method seems to be of benefit when the extract has to be stored for long time before the instrument analysis.     

Analysis of the PM2.5 emission inventory and source apportionment in Jilin City,Northeast of China

Environmental Science and Pollution Research - This study collected and compiled statistical data on atmospheric pollution in Jilin City, China during 2013–2014, using models and methods to...     

荧光化学传感器的制备及其在环境分析监测中的应用

随着荧光分析技术和传感技术的发展,荧光化学传感器已经成为一种重要的连续分析测量装置.它具有很高的选择性和灵敏度,可以实现对pH、溶解氧、含氮化合物、有毒害重金属离子、有机污染物进行实时和在线测定,因此在环境分析监测方面具有广泛的应用前景.简要介绍了荧光化学传感器的原理、制备及分类,综述了近年来荧光化学传感器的发展及其在环境分析监测中的最新研究成果,并探讨了荧光化学传感器在环境分析监测领域的应用前景和发展方向.     

三峡水库135 m蓄水前后水体重金属环境健康风险评价

三峡水库135 m蓄水后,水体中各重金属的单因子污染指数和Nemerow综合污染指数均有不同程度的增大,特别是Pb污染应该引起重视.健康风险评价结果表明,成库前后非致癌有毒化学物质(Hg、Pb和Cu)所引起的健康危害的个人年风险为Pb＞Cu＞Hg,致癌物质对人体健康危害的个人年风险均大于非致癌物.各类污染物所致个人平均健康危害成库前后均低于国际辐射防护委员会(ICRP)推荐的标准,为可接受水平.     

粉末活性炭对膜过滤性能的影响

向一体式膜生物反应器中投加粉末活性炭(PAC),可以显著提高膜的过滤性能,有效缓解膜的污染.研究结果表明:投加PAC的吸附作用减少了由于胞外聚合物(EPS)而引起的膜污染;膜表面PAC颗粒的存在减小了浓差极化层的厚度和水力边界层的厚度,提高了过滤物质的传递速率;膜表面形成的PAC层还可过滤微生物和胶体颗粒,减少了它们到达膜表面的数量.     

常规水处理厂中小隐孢子虫卵囊的去除效果

介绍了小隐孢子虫卵囊的特点及其对人体的危害，分析了pH、混凝剂种类与投加量、电导率和天然有机物含量等对小隐孢子虫卵囊的Zeta电位的影响，总结了混凝－沉淀－过滤和直接过滤对小隐孢子虫卵囊的去除效果，探讨了水温、水质、混凝剂种类与投加量、滤料层组成和滤速等对去除效果的影响。