Comparative studies of the Fe–UV, H2O2–UV, TiO2–UV/vis systems for the decolorization of a textile dye X-3B in water

The degradation of a common textile dye, Reactive-brilliant red X-3B, by several advanced oxidation technologies was studied in an air-saturated aqueous solution. The dye was resistant to the UV illumination (wavelength λ  320 nm), but was decolorized when one of Fe³⁺, H₂O₂ and TiO₂ components was present. The decolorization rate was observed to be quite different for each system, and the relative order evaluated under comparable conditions followed the order of Fe²⁺–H₂O₂–UV  Fe²⁺–H₂O₂ > Fe³⁺–H₂O₂–UV > Fe³⁺–H₂O₂ > Fe³⁺–TiO₂–UV > TiO₂–UV > Fe³⁺–UV > TiO₂–visible light (λ  450 nm) > H₂O₂–UV > Fe²⁺–UV. The mechanism for each process is discussed, and linked together for understanding the observed differences in reactivity.     

污水在水体中的稀释扩散及稀释度的计算

结合长江白龙港水域水力模型试验对污水排海工程中污水稀释扩散的机理进行了描述，并对污水的两种稀释度（浓度释稀度和体积稀释度）进行了分析比较，得出了在污染物本底值存在时两种稀释度之间的关系。     

生物质型煤成型技术开发实验研究

通过原有成型方式的工业成型观察和模压成型实验，提出并验证了完全利用生物质纤维的交联作用实现成型的新机制。其于中高压下物料的不可再压缩性和单向挤压也会导致更高的成型压力的新认识，设计和研制成按新机制成型的型轮。经此改进的工业成型试验达到了比模压成型更好的效果：不用预实送料，且成型性能；成型压力降至120MPa以下，成型许可水分成倍提高，适合的生物质配比范围15％－60％；仅利用送料螺旋的预实功能，即可实现纯生物质型块的成型。     

染料废水脱色混凝剂(PSDC-Ⅰ) 的制备和效果实验

研究了由固体废物 (炼铁废渣 )制取的含有多种金属离子的染料废水脱色混凝剂 (PSDC Ⅰ ) ,试验了它对染料废水的脱色效果及对印染废水的混凝效果 ,并与PAC进行了比较。考察了影响PSDC Ⅰ混凝及脱色效果的因素。结果表明 ,pH值在 6— 10范围内 ,PSDC Ⅰ具有良好的混凝效果。PSDC Ⅰ的两个最佳脱色区为 pH值 6— 8和 pH值 13左右。与PAC相比 ,PSDC Ⅰ不仅具有良好的混凝效果而且具有良好的脱色效果     

The styrene purification performance of biotrickling filter with toluene-styrene acclimatization under acidic conditions

The obvious disadvantages of biotrickling filters (BTFs) are the long start-up time and low removal efficiency (RE) when treating refractory hydrophobic volatile organic compounds (VOCs), which limits its industrial application. It is worthwhile to investigate how to reduce the start-up period of the BTF for treating hydrophobic VOCs. Here, we present the first study to evaluate the strategy of toluene induction combined with toluene-styrene synchronous acclimatization during start-up in a laboratory-scale BTF inoculated with activated sludge for styrene removal, as well as the effects of styrene inlet concentration (0.279 to 2.659 g·m^?3), empty bed residence time (EBRT) (i.e., 136, 90, 68, 45, 34 sec), humidity (7.7% to 88.9%), and pH (i.e., 4, 3, 2.5, 2) on the performance of the BTF system. The experiments were carried out under acidic conditions (pH 4.5) to make fungi dominant in the BTF. The start-up period for styrene in the BTF was shortened to about 28 days. A maximum elimination capacity (EC_max) of 126 g·m^?3·hr^?1 with an RE of 80% was attained when styrene inlet loading rate (ILR) was below 180 g·m^?3·hr^?1. The highest styrene RE(s) [of BTF] that could be achieved were 95% and 93.4%, respectively, for humidity of 7.7% and at pH 2. A single dominant fungal strain was isolated and identified as Candida palmioleophila strain MA-M11 based on the 26S ribosomal RNA gene. Overall, the styrene induction with the toluene-styrene synchronous acclimatization could markedly reduce the start-up period and enhance the RE of styrene. The BTF dominated by fungi exhibited good performance under low pH and humidity and great potential in treating styrene with higher inlet concentrations.

Implications: The application of the toluene induction combined with toluene-styrene synchronous acclimatization demonstrated to be a promising approach for the highly efficient removal of styrene. The toluene induction can accelerate biofilm formation, and the adaptability of microorganisms to styrene can be improved rapidly by the toluene-styrene synchronous acclimatization. The integrated application of two technologies can shorten the start-up period of biotrickling filters markedly and promote its industrial application.     

Characteristics of single atmospheric particles in a heavily polluted urban area of China: size distributions and mixing states

To investigate the chemical composition, size distribution, and mixing state of aerosol particles on heavy pollution days, single-particle aerosol mass spectrometry was conducted during 9–26 October 2015 in Xi’an, China. The measured particles were classified into six major categories: biomass burning (BB) particles, K-secondary particles, elemental carbon (EC)–related particles, metal-containing particles, dust, and organic carbon (OC) particles. BB and EC-related particles were the dominant types during the study period and mainly originated from biomass burning, vehicle emissions, and coal combustion. According to the ambient air quality index, two typical episodes were defined: clean days (CDs) and polluted days (PDs). Accumulation of BB particles and EC-related particles was the main reason for the pollution in Xi’an. Most types of particle size were larger on PDs than CDs. Each particle type was mixed with secondary species to different degrees on CDs and PDs, indicating that atmospheric aging occurred. The mixing state results demonstrated that the primary tracers were oxidized or vanished and that the amount of secondary species was increased on PDs. This study provides valuable information and a dataset to help control air pollution in the urban areas of Xi’an.

Graphical abstract

     

Prevalence and Bayesian Phylogenetics of Enteroviruses Derived From Environmental Surveillance Around Polio Vaccine Switch Period in Shandong Province,China

Food and Environmental Virology - We present the results of environmental surveillance for poliovirus (PV) and non-poliovirus (NPEV) around the switch from trivalent to bivalent oral polio-vaccine...     

Characterization of submicron particles during autumn in Beijing, China

In this study, we performed a highly time-resolved chemical characterization of nonrefractory submicron particles(NR-PM_1) in Beijing by using an Aerodyne high-resolution time-of-flight aerosol mass spectrometer(HR-ToF-AMS). The results showed the average NR-PM_1 mass concentration to be 56.4 ± 58.0 μg/m~3, with a peak at 307.4 μg/m~3. Due to the high frequency of biomass burning in autumn, submicron particles significantly increased in organic content, which accounted for 51% of NR-PM_1 on average. Secondary inorganic aerosols(sulfate + nitrate + ammonium) accounted for 46% of NR-PM_1, of which sulfate,nitrate, and ammonium contributed 15%, 20%, and 11%, respectively. To determine the intrinsic relationships between the organic and inorganic species, we used the positive matrix factorization(PMF) model to merge the high-resolution mass spectra of the organic species and NO+and NO_2~+ions. The PMF analysis separated the mixed organic and nitrate(NO+and NO_2~+) spectra into four organic factors, including hydrocarbon-like organic aerosol(HOA), oxygenated organic aerosol(OOA), cooking organic aerosol(COA), and biomass burning organic aerosol(BBOA), as well as one nitrate inorganic aerosol(NIA) factor. COA(33%) and OOA(30%) contributed the most to the total organic aerosol(OA) mass, followed by BBOA(20%) and HOA(17%). We successfully quantified the mass concentrations of the organic and inorganic nitrates by the NO+and NO2+ions signal in the organic and NIA factors. The organic nitrate mass varied from 0.01-6.8 μg/m~3, with an average of 1.0 ±1.1 μg/m~3, and organic nitrate components accounted for 10% of the total nitrate mass in this observation.     

Are current Chinese national ambient air quality standards on 24-hour averages for particulate matter sufficient to protect public health?

With rapid economic development and urbanization in recent decades, China has experienced the worsening of ambient air quality. For better air quality management to protect human health, Chinese government revised national ambient air quality standards(NAAQS) for particulate matter(PM) in 2012(GB3095-2012). To assess the effectiveness of current NAAQS for PM on public health in Chinese population, we conducted a metaanalysis on published studies examining the mortality risk of short-term exposure to PM with aerodynamic diameters less than 10 and 2.5 μm(PM_(10) and PM_(2.5)) in China. The reported24-hour concentrations of PM_(10) and PM_(2.5) in studies ranged from 43.5 to 150.1 μg/m~3 and 37.5 to 176.7 μg/m~3. In the pooled excess, mortality risk estimates of short-term exposure to PM.In specific, per 10 μg/m~3 increase in PM_(10), we observed increases of 0.40%(95%CI: 0.33%,0.47%), 0.57%(95%CI: 0.44%, 0.70%) and 0.49%(95%CI: 0.40%, 0.58%) in total, respiratory and cardiovascular mortality, per 10 μg/m~3 increase in PM_(2.5), we observed increases of 0.51%(95%CI: 0.38%, 0.63%), 0.62%(95%CI: 0.52%, 0.73%) and 0.75%(95%CI: 0.54%, 0.95%) in total,respiratory and cardiovascular mortality. Finally, we derived 125 μg/m~3 for PM_(10) and 62.5 μg/m~3 for PM_(2.5) as 24-hour recommendation values based on the pooled estimates. Our results indicated that current Chinese NAAQS for PM could be sufficient in mitigating the excess mortality risk from short-term exposure to ambient PM. However, future research on longterm exposure cohort studies in Chinese population is also essential in revising annual averages for PM in Chinese NAAQS.     

Long-term observations of tropospheric NO2, SO2 and HCHO by MAX-DOAS in Yangtze River Delta area, China

Yangtze River Delta(YRD) area is one of the important economic zones in China. However,this area faces increasing environmental problems. In this study, we use ground-based multi-axis differential optical absorption spectroscopy(MAX-DOAS) network in Eastern China to retrieve variations of NO_2, SO_2, and formaldehyde(HCHO) in the YRD area. Three cities of YRD(Hefei, Nanjing, and Shanghai) were selected for long-term observations. This paper presents technical performance and characteristics of instruments, their distribution in YRD, and results of vertical column densities(VCDs) and profiles of NO_2, SO_2, and HCHO.Average diurnal variations of tropospheric NO_2 and SO_2 in different seasons over the three stations yielded minimum values at noon or in the early afternoon, whereas tropospheric HCHO reached the maximum during midday hours. Slight reduction of the pollutants in weekends occurred in all the three sites. In general trace gas concentrations gradually reduced from Shanghai to Hefei. Tropospheric VCDs of NO_2, SO_2, and HCHO were compared with those from Ozone Monitoring Instrument(OMI) satellite observations, resulting in R~2 of 0.606, 0.5432, and 0.5566, respectively. According to analysis of regional transports of pollutants, pollution process happened in YRD under the north wind with the pollution dissipating in the southeast wind. The feature is significant in exploring transport of tropospheric trace gas pollution in YRD, and provides basis for satellite and model validation.