Plasmonic silver/silver oxide nanoparticles anchored bismuth vanadate as a novel visible-light ternary photocatalyst for degrading pharmaceutical micropollutants

The degradation of pharmaceutical micropollutants is an intensifying environmental problem and synthesis of efficient photocatalysts for this purpose is one of the foremost challenges worldwide. Therefore, this study was conducted to develop novel plasmonic Ag/Ag₂O/BiVO₄ nanocomposite photocatalysts by simple precipitation and thermal decomposition methods, which could exhibit higher photocatalytic activity for mineralized pharmaceutical micropollutants. Among the different treatments, the best performance was observed for the Ag/Ag₂O/BiVO₄ nanocomposites (5 wt.%; 10 min's visible light irradiation) which exhibited 6.57 times higher photodegradation rate than the pure BiVO₄. Further, the effects of different influencing factors on the photodegradation system of tetracycline hydrochloride (TC-HCl) were investigated and the feasibility for its practical application was explored through the specific light sources, water source and cycle experiments. The mechanistic study demonstrated that the photogenerated holes (h⁺), superoxide radicals (?O₂^?) and hydroxyl radicals (?OH) participated in TC-HCl removal process, which is different from the pure BiVO₄ reaction system. Hence, the present work can provide a new approach for the formation of novel plasmonic photocatalysts with high photoactivity and can act as effective practical application for environmental remediation.     

大兴安岭5种乔木树种燃烧释放PM2.5中水溶性元素特性

采用自主设计的生物质燃烧实验装置,在不同燃烧状态（明燃、阴燃）下,对大兴安岭林区5种典型乔木树种的不同部位（枝、叶、皮）燃烧释放PM_2.5中的水溶性元素特性进行研究.结果显示,不同树种间PM_2.5的排放因子差异显著,排放范围为（2.408±0.854）~（9.227±1.172）g/kg.5种乔木树种燃烧释放PM_2.5中主要检测到Mg、Ca、K等16 种元素,其中Ca、K、Zn、Mg 4种元素的排放因子明显大于其它元素.不同树种间元素排放因子差异较大,针叶树的排放因子一般高于阔叶树.除Cd元素外,不同器官间排放的元素总量无明显差异.不同树种不同器官燃烧释放PM_2.5中水溶性元素的占比顺序较为一致,其中Ca、K、Zn和Mg 4种元素的排放因子在枝、叶、皮中均较高.此外,燃烧状态对元素排放特征影响较大,Li、Mg、Ca等7种元素的排放因子均表现为明燃显著高于阴燃.     

宁夏煤田火灾的危害及综合治理研究

针对宁夏回族自治区煤田火灾的状况，指出了宁夏煤田火灾所造成的环境、地质及社会灾害，并根据宁夏煤田火灾的情况，进行了系统的分析，对灭火方法进行了研究和探讨。     

热辐射的破坏准则和池火灾的破坏半径

热辐射破坏是发生在开放气环境中的池火灾的主要破坏机理。本文讨论了热辐射的破坏准则，提出预测池火灾破坏半径的方法，进行了数值模拟计算，分而和时纳了池火灾的基本规律     

池火灾热辐射的数值研究

通过列举储罐火灾事故,提出对池火灾进行研究的重要性。介绍目前池火灾国内外的研究现状及发展情况,描述池火灾燃烧特征和模型。应用化学流体力学基本定律,建立了描述池火灾过程的基本控制方程组,并根据适当的条件选择辐射模型。建立物理模型,做出合理假设,确定初始和边界条件,对池火灾热辐射过程进行数值模拟,得出火焰周围入射热流密度分布图,计算出相邻两罐之间的最小安全距离,应用于工程实际中,给防火间距的制定提供理论依据,计算结果定性合理。     

Ecosystem restoration in fire-managed savanna woodlands: Effects on biodiversity,local livelihoods and fire intensity

Ethiopia aims to restore 15 million ha degraded forests and woodlands, but effects on the potentially contrasting goals of long-term carbon storage, biodiversity and sustainable livelihoods are unknown. To quantify the effects of grazing exclusion on vegetation and fire behaviour, we established six 30 × 30 m fenced exclosures with grazed controls, in a mesic wooded savanna. Experimental burns were done after 1.5 years. Tree seedlings were few but more common inside fences. Field layer cover and biomass increased inside fences, and grass species increased in numbers and cover. Fire intensity was higher inside fences, killing shrubs and saplings but not mature trees. Interviews confirmed that overgrazing has resulted in “cool fires”, causing shrub encroachment. High-intensity fires occurred in the 1980s after a zoonotic disease killed most livestock. Short-term increase in carbon storage through fire and grazing exclusion may lead to loss of pasture, and in the long-term increased wildfire risk.Electronic supplementary materialThe online version of this article (10.1007/s13280-020-01343-7) contains supplementary material, which is available to authorized users.     

好氧MBBR处理含吲哚废水的工艺优化试验研究

为了处理制药企业废水中吲哚类有机污染物,采用好氧MBBR(移动床生物膜反应器)工艺对含吲哚废水进行了试验研究,通过考察HRT、曝气量、吲哚冲击负荷等工艺条件对吲哚、COD和NH_4~+-N等去除效果的影响,确定了好氧MBBR反应器的最佳工艺条件。实验结果表明,在HRT在6~18 h变化时,MBBR工艺对吲哚去除率在8 h以上时达到100%,COD去除率在8 h达到89.65%,而NH_4~+-N去除率在12 h达到最高。在曝气量为0.1~0.12 m L/min时,MBBR工艺对COD和NH_4~+-N去除率分别为88.88%~92.95%和65%~66.83%。进水吲哚浓度25~65 mg/L变化时,好氧MBBR对吲哚去除率保持在100%,而对COD和NH_4~+-N去除率也保持在80%和40%以上,表明好氧MBBR工艺在处理难降解有机污染物方面具有显著优势。     

AOX contamination status and genotoxicity of AOX-bearing pharmaceutical wastewater

Adsorbable organic halogens(AOX) are a general indicator for the total amount of compounds containing organically bonded halogens. AOX concentrations and components were investigated along the wastewater treatment process in four large-scale pharmaceutical factories of China, and genotoxicity based on the SOS/umu test was also evaluated. The results showed that AOX concentrations in wastewater of four factories ranged from 4.6 to 619.4 mg/L, which were high but greatly different owing to differences in the raw materials and products. The wastewater treatment process removed 50.0%–89.9% of AOX, leaving 1.3–302.5 mg/L AOX in the effluents. Genotoxicity levels ranged between 2.1 and 68.0 μg 4-NQO/L in the raw wastewater and decreased to 1.2–41.2 μg 4-NQO/L in the effluents of the wastewater treatment plants(WWTPs). One of the main products of factory I, ciprofloxacin, was identified as the predominant contributor to its genotoxicity. However, for the other three factories, no significant relationship was observed between genotoxicity and detected AOX compounds.     

高浓度制药废水处理技术的研发及应用

制药废水组成复杂,污染物浓度高,污水CODcr浓度达10000mg/l,含有大量有毒、有害物质。本中采用催化氧化预处理+水解酸化+UASB+接触氧化+炭滤吸附的工艺流程,通过改善细部参数及改良配套设备设计,提高了各单元去除效率,降低了能耗及处理成本,出水CODcr浓度达到污水综合排放标准.     

中药工业废水处理研究进展

概述了目前中药工业废水处理应用的各种物化、生物处理技术;对主要处理工艺的应用特点进行了论述;指出了中药工业废水处理技术今后的研究开发方向和思路。