BPA和EE2在PA微塑料上竞争吸附的位点能量

为研究微塑料上雌激素共存的吸附行为,以17α-乙炔基雌二醇（EE2）和双酚A （BPA）为目标污染物,微塑料聚酰胺（PA）为吸附剂,通过等温吸附实验研究二者在单溶质和双溶质体系下的吸附性能,基于位点能量分布理论进一步剖析二者在PA微塑料上的的吸附特性.同时,采用X射线光谱（XPS）以及傅里叶变换红外光谱（FTIR）对吸附前后的PA微塑料进行表征,探究其可能存在的吸附机理.等温吸附拟合结果及XPS、FTIR的表征结果表明BPA和EE2及二者混合溶液在PA上的吸附属于非均质吸附,疏水分配及氢键作用为主要的吸附机制.位点能量分布分析结果表明,相同浓度（1～4mg/L）条件下,BPA吸附位点主要分布于高能量区;单溶质体系的EE2吸附位点主要集中于低能量区.双溶质体系下,相同浓度的两种物质位点分布函数均随着位点能量的增大而呈指数降低,BPA下降趋势较为平缓,吸附位点分布更集中.两种体系相比较,BPA平均位点能量和位点能量非均质性分别增加了0.749%和2.483%,吸附位点数量减少了10.852%;双溶质体系下EE2平均位点能量降低0.813%,位点能量非均质性增加1.870%,吸附位点数量增加42.429%.双酚A和EE2在PA微塑料上的竞争吸附中,EE2占优势.     

喀斯特地区生态系统服务变化及权衡协同关系

为探明喀斯特地区生态系统服务的时空变化特征,厘清服务间的权衡协同关系,文章以典型喀斯特区贵州省毕节市撒拉溪示范区为例,借助InVEST模型评估2010年、2015年和2018年土壤保持、产水量、碳储量与生境质量,分析不同年度的时空变化特征,并基于逐像元空间相关分析探究服务之间的权衡与协同关系进行探究.结果 表明:(1)2010-2018年,该区各生态系统服务均呈增长趋势,土壤保持、产水量、碳储量和生境质量指数分别增长了3.51×104t/a、164.95×104mm/a、1.28×104t/a和565.18.(2)土壤保持、碳储量和生境质量在不同时段均表现为增长趋势,2015年增长幅度大于2015-2018年;产水量在不同时段存较大差异,2010-2015年为增长趋势,增幅为56.53％,2015-2018年为下降趋势,降幅为15.40％.(3)土壤保持、碳储量与生境质量在空间上呈北高南低的格局,产水量则为南高北低.(4)产水量与土壤保持、碳储量和产水量均表现为权衡关系,土壤保持与碳储量和生境质量两两服务间均表现为协同关系,两两生态系统服务间在空间上均呈北部协同、南部权衡的空间分布特征.     

Spatiotemporal trends of PM2.5 and its major chemical components at urban sites in Canada

To evaluate the effectiveness of emission control regulations designed for reducing air pollution, chemically resolved PM_2.5 data have been collected across Canada through the National Air Pollution Surveillance network in the past decade. 24-hr time integrated PM_2.5 collected at seven urban and two rural sites during 2010-2016 were analyzed to characterize geographical and seasonal patterns and associated potential causes. Site-specific seven-year mean gravimetric PM_2.5 mass concentrations ranged from 5.7 to 9.6 µg/m³. Seven-year mean concentrations of SO₄^2?, NO₃^?, NH₄⁺, organic carbon (OC), and elemental carbon (EC) were in the range of 0.68 to 1.6, 0.21 to 1.5, 0.27 to 0.71, 1.1 to 1.9, and 0.37 to 0.71 µg /m³, accounting for 10.8%-18.1%, 3.7%-16.7%, 4.7%-7.4%, 18.4%-21.0%, and 6.4%-10.6%, respectively, of gravimetric PM_2.5 mass. PM_2.5 and its five major chemical components showed higher concentrations in southeastern Canada and lower values in Atlantic Canada, with the seven-year mean ratios between the two regions being on the order of 1.7 for PM_2.5 and 1.8-7.1 for its chemical components. When comparing the concentrations between urban and rural sites within the same region, those of SO₄^2? and NH₄⁺ were comparable, while those of NO₃^?, OC, and EC were around 20%, 40%-50%, and 70%-80%, respectively, higher at urban than rural sites, indicating the regional scale impacts of SO₄^2? and NH₄⁺ and effects of local sources on OC and EC. Monthly variations generally showed summertime peaks for SO₄^2? and wintertime peaks for NO₃^?, but those of NH₄⁺, OC, and EC exhibited different seasonality at different locations.     

Spatiotemporal variations of ambient air pollutants and meteorological influences over typical urban agglomerations in China during the COVID-19 lockdown

To investigate the air quality change during the COVID-19 pandemic, we analyzed spatiotemporal variations of six criteria pollutants in nine typical urban agglomerations in China using ground-based data and examined meteorological influences through correlation analysis and backward trajectory analysis under different responses. Concentrations of PM_2.5, PM₁₀, NO₂, SO₂ and CO in urban agglomerations respectively decreased by 18%–45% (30%–62%), 17%–53% (22%–39%), 47%-64% (14%–41%), 9%–34% (0%–53%) and 16%-52% (23%–56%) during Lockdown (Post-lockdown) period relative to Pre-lockdown period. PM_2.5 pollution events occurred during Lockdown in Beijing-Tianjin-Hebe (BTH) and Middle and South Liaoning (MSL), and daily O₃ concentration rose to grade Ⅱ standard in Post-lockdown period. Distinct from the nationwide slump of NO₂ during Lockdown period, a rebound (～40%) in Post-lockdown period was observed in Cheng-Yu (CY), Yangtze River Middle-Reach (YRMR), Yangtze River Delta (YRD) and Pearl River Delta (PRD). With slightly higher wind speed compared with 2019, the reduction of PM_2.5 (51%–62%) in Post-lockdown period is more than 2019 (15%–46%) in HC (Harbin-Changchun), MSL, BTH, CP (Central Plain) and SP (Shandong-Peninsula), suggesting lockdown measures are effective to PM_2.5 alleviation. Although O₃ concentrations generally increased during the lockdown, its increment rate declined compared with 2019 under similar sunlight duration and temperature. Additionally, unlike HC, MSL and BTH, which suffered from additional (> 30%) air masses from surrounding areas after the lockdown, the polluted air masses reaching YRD and PRD mostly originated from the long-distance transport, highlighting the importance of joint regional governance.     

Degradation of poly(butylene adipate-co-terephthalate) by Stenotrophomonas sp. YCJ1 isolated from farmland soil

In recent years, poly (butylene adipate-co-terephthalate) (PBAT) has been widely used. However, PBAT-degrading bacteria have rarely been reported. PBAT-degrading bacteria were isolated from farmland soil and identified. The effects of growth factors on the degradation of PBAT and the lipase activity of PBAT-degrading bacteria were assessed. The degradation mechanism was analyzed using scanning electron microscopy, attenuated total reflection Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, X-ray diffraction, and liquid chromatography-mass spectrometry. The results showed that Stenotrophomonas sp. YCJ1 had a significant degrading effect on PBAT. Under certain conditions, the strain could secrete 10.53 U/mL of lipase activity and degrade 10.14 wt.% of PBAT films. The strain secreted lipase to catalyze the degradation of the ester bonds in PBAT, resulting in the production of degradation products such as terephthalic acid, 1,4-butanediol, and adipic acid. Furthermore, the degradation products could participate in the metabolism of YCJ1 as carbon sources to facilitate complete degradation of PBAT, indicating that the strain has potential value for the bioremediation of PBAT in the environment.     

A large-scale outdoor atmospheric simulation smog chamber for studying atmospheric photochemical processes: Characterization and preliminary application

Understanding the formation mechanisms of secondary air pollution is very important for the formulation of air pollution control countermeasures in China. Thus, a large-scale outdoor atmospheric simulation smog chamber was constructed at Chinese Research Academy of Environmental Sciences (the CRAES Chamber), which was designed for simulating the atmospheric photochemical processes under the conditions close to the real atmospheric environment. The chamber consisted of a 56-m³ fluorinated ethylene propylene (FEP) Teflon film reactor, an electrically-driven stainless steel alloy shield, an auxiliary system, and multiple detection instrumentations. By performing a series of characterization experiments, we obtained basic parameters of the CRAES chamber, such as the mixing ability, the background reactivity, and the wall loss rates of gaseous compounds (propene, NO, NO₂, ozone) and aerosols (ammonium sulfate). Oxidation experiments were also performed to study the formation of ozone and secondary organic aerosol (SOA), including α-pinene ozonolysis, propene and 1,3,5-trimethylbenzene photooxidation. Temperature and seed effects on the vapor wall loss and SOA yields were obtained in this work: higher temperature and the presence of seed could reduce the vapor wall loss; SOA yield was found to depend inversely on temperature, and the presence of seed could increase SOA yield. The seed was suggested to be used in the chamber to reduce the interaction between the gas phase and chamber walls. The results above showed that the CRAES chamber was reliable and could meet the demands for investigating tropospheric chemistry.     

Application of FeIII-TAML/H2O2 system for treatment of fluoroquinolone antibiotics

Over the recent past, fluoroquinolone antibiotics (FQs) have raised extensive attention due to their potential to induce the formation of resistance genes and “superbugs”, thus various advanced oxidation techniques have been developed to eliminate their release into the environment. In the present study, the prototype tetraamido macrocyclic ligand (Fe^III-TAML)/hydrogen peroxide (H₂O₂) system is employed to degrade FQs (i.e., norfloxacin and ciprofloxacin) over a wide pH range (i.e., pH 6-10), and the reaction rate increases with the increase in pH level. The effect of dosage of Fe^III-TAML and H₂O₂ on the degradation of FQs is evaluated, and the reaction rate is linearly correlated with the added amount of chemicals. Moreover, the impact of natural organic matters (NOM) on the removal of FQs is investigated, and the degradation kinetics show that both NOM type and experimental concentration exhibit negligible influence on the oxidative degradation of selected antibiotics. Based on the results of liquid chromatography-high resolution mass spectrometry and theoretical calculations, the reaction sites and pathways of FQs by Fe^III-TAML/H₂O₂ system are further predicted and elucidated.     

基坑开挖影响下下卧盾构隧道变形及控制措施研究

近年来地铁建设不断加快,在地铁隧道上方施工已成常态。为研究基坑开挖影响下下卧盾构隧道的隆起变形,评价不同变形控制措施的实际控制效果,以武汉市轨道交通6号线琴台变电站地下电缆通道工程为例,采用两阶段法计算了基坑开挖影响下下卧盾构隧道的隆起变形,同时采用数值模拟方法对无加固、压力注浆加固、水泥土搅拌桩加固和压力注浆+水泥土搅拌桩综合加固控制措施4种工况下下卧隧道的隆起变形值进行了数值模拟计算,并将数值模拟结果与实际工程监测数据进行了对比分析。结果表明:对于初步预测基坑开挖引起下卧盾构隧道的隆起变形,该理论计算方法可靠、实用;压力注浆+水泥土搅拌桩综合加固控制措施使下卧盾构隧道的隆起变形和横断面收敛变形值分别减小至2.3 mm和0.35 mm,控制效果良好,具有一定的实际推广意义,可为类似工程提供参考。     

假微型海链藻对不同氮培养条件的响应

本文选取假微型海链藻为目标微藻,研究其在不同氮源（硝酸盐、亚硝酸盐、铵盐和尿素）和氮饥饿条件下的生长速率和光合作用,以期为阐述海洋微藻对近岸复杂多变的氮环境适应机制提供依据。结果表明,在氮饥饿条件下,假微型海链藻的种群生长受阻,细胞内色素分解,光合作用被显著抑制;在不同氮源条件下,假微型海链藻均能生长但表现出不同的生长模式,但高浓度的铵盐能够对其产生抑制,各条件下藻细胞叶绿素a、叶绿素c 和总类胡萝卜素含量在指数生长期无显著差异,而在平台末期,尿素处理组各色素水平显著提高;假微型海链藻光系统Ⅱ的不同光合作用参数在实验末期均表现为铵盐处理组显著高于其他处理组。综上所述,假微型海链藻能够利用不同氮源进行生长,但在不同氮源条件下,种群增长的变化模式与光合作用的响应并不一致,由此推测假微型海链藻在不同氮源条件下光合作用并不是导致其生长模式差异的主要原因。     

油田井口加热炉烟尘排放超标原因分析及治理方法

针对井口加热炉燃用套管气出现的烟尘排放超标问题,从燃烧方式及燃料组成方面分析发现,加热炉所采用的扩散式燃烧,火焰面燃料侧缺少氧气,燃料产生热分解生成炭黑颗粒;另外,套管气含有大量的重碳烷烃,其稳定性差、分解温度低,加剧了热分解反应。因此,控制套管气质量和改变燃烧方式是治理烟尘排放超标的基本途径。但是井口加装轻烃回收装置,分离出套管气中的重碳烷烃,成本高不可行。最终,基于预混燃烧理论,设计了双调风预混燃烧装置,现场实施结果表明,不仅烟尘排放降低了87.8%,而且NOx排放降低了58.6%、热效率提升了8.2%。实践证明,预混燃烧是治理井口加热炉烟尘排放超标的有效方法。