Mechanistic insights into the selective photocatalytic degradation of dyes over TiO2/ZSM-11

● TiO₂/ZSM-11 was prepared by a facile solid state dispersion method. ● Mechanism for photocatalytic degradation of dyes was investigated. ● Both experimental and MD simulations were conducted. ● Chemisorption instead of electrostatic interaction played a critical role. Photocatalytic degradation is a promising way to eliminate dye contaminants. In this work, a series of TiO₂/ZSM-11 (TZ) nanocomposites were prepared using a facile solid state dispersion method. Methyl orange (MO), methylene blue (MB), and rhodamine B (RhB) were intentionally chosen as target substrates in the photocatalytic degradation reactions. Compared to pristine TiO₂, negative effect was observed on MO degradation while promoted kinetics were collected on MB and RhB over TZ composites. Moreover, a much higher photocatalytic rate was interestingly achieved on RhB than MB, which indicated that a new factor has to be included other than the widely accepted electrostatic interaction mechanism to fully understand the selective photodegradation reactions. Systematic characterizations showed that TiO₂ and ZSM-11 physically mixed and maintained both the whole framework and local structure without chemical interaction. The different trends observed in surface area and the photo-absorption ability of TZ composites with reaction performance further excluded both as the promotion mechanism. Instead, adsorption energies predicted by molecular dynamics simulations suggested that differences in the adsorption strength played a critical role. This work provided a deep mechanistic understanding of the selective photocatalytic degradation of dyes reactions, which helps to rationally design highly efficient photocatalysts.     

金属微孔管制造微气泡的研究

用金属微孔管制造微气泡是一种比较新颖的气泡制造方法.研究了由金属微孔管内外压差提供推动力,推动管内气体从管上的微孔流出,在管外壁形成微气泡,管外高速流过的剪切流把气泡带走,形成气液混合水的气泡制造方法.微气泡的大小和数量通过改变管内外的压差和管外剪切流速度来控制.实验结果表明,产生的微气泡直径在20～70μm之间变化,数密度在0.53×103～1.01×103个/mm3之间.     

萃取－同步荧光光谱法测定大气飘尘中苯并(a)芘

提出用浓Ｈ２ＳＯ４从大气飘尘样品的环己烷提取液中一次萃取后,用同步荧光光谱测定苯并（ａ）芘的方法,选用△λ为２０ｎｍ时可获最佳效果,用浓硫酸萃取的时间仅１ｍｉｎ,苯并（ａ）芘在浓硫酸相中１ｈ内稳定,样品加标的回收率为８５％,其它多环芳烃化合物在５３０－６００ｎｍ的测定波长范围不干扰苯并（ａ）芘的测定,用乙酰化滤纸层析－荧光分光光度的统一方法作为对比对实际样品进行了测定,结果与后者的偏差在±１５％以     

浅谈风险评价与风险管理

本文简要介绍环境风险评价与风险营理的概念、主要内容、工作程序和相互关系。并介绍了西方国家用风险概念制定环境政策的情况。认为环境与健康的风险评价已成为当今环境保护工作中一个重要的新兴领域。展望了对有毒化学品进行研究和管理的前景。     

积极推进新时期城市环境保护工作

作为2005年世界环境日系列活动之一,国家环境保护模范城市市长峰会于6月3日在人民大会堂召开。会上,国家环境保护总局局长解振华发表重要讲话,对新形势下的城市环境保护工作做出了要求和部署,在此全文发表讲话内容,以期指导下阶段环境保护工作。     

景观水不同防腐技术的效果对比研究

从实际应用的角度研究景观水防腐技术,采用生物滤池、紫外线照射、投加次氯酸钠三种方法处理景观水,对景观水水质的TN、TP、COD、chla等指标进行检测,计算景观水的营养化指数,从而探索景观水防腐的最佳方法,为防止景观水富营养化提供科学依据.结果表明:经生物滤池处理的景观水可使TN、TP等营养物质下降到0.3 mg/L和...     

中国改革开放40年生态环境保护的历史变革——从“三废”治理走向生态文明建设

中国改革开放的40年也是生态环境保护管理体制不断改革和飞跃的40年。自1972年开展生态环境保护工作起,围绕着解决不同发展阶段突出环境问题的需要,每10年左右实现一次环境管理体制改革"大跨跃",不断改革、创新和发展了具有中国特色的生态环境保护治理体系与模式。坚持在发展中解决环境问题,以改善生态环境质量为核心,逐步构建了符合不同发展阶段特征的生态环境保护管理体系,包括完备的生态环境规划政策体系、完善的生态环境治理体系、完整的生态环境保护法律体系。在新时代中国特色社会主义建设过程中,应瞄准建设美丽中国的战略目标,立足中国、放眼世界,坚持绿色发展,做好顶层设计,构建生态环境管理体系新格局,共建清洁美丽世界。     

^15N isotope fractionation in an aquatic food chain： Bellamya aeruginosa （Reeve） as an algal control agent

15N isotope tracer techniques and ecological modeling were adopted to investigate the fractionation of nitrogen,its uptake and transformation in algae and snail(Bellamya aeruginosa Reeve).Different algal species were found to differ in their uptake of nitrogen isotopes.Microcystis aeruginisa Ktz.demonstrated the greatest 15N accumulation capacity,with the natural variation in isotopic ratio(δ 15N) and the isotope fractionation factor(ε,‰) being the highest among the species investigated.The transformation and utilization of 15N by snails differed depending on the specific algae consumed(highest for Chlorella pyrenoidosa Chick.,lowest for M.aeruginisa).When snails was seeded in the experimental pond,the algae population structure changed significantly,and total algal biomass as well as the concentration of all nitrogen species decreased,causing an increase in water transparency.A model,incorporating several chemical and biological parameters,was developed to predict algal biomass in an aquatic system when snails was present.The data collected during this investigation indicated that the gastropods such as snails could significantly impact biological community and water quality of small water bodies,suggesting a role for biological control of noxious algal blooms associated with eutrophication.     

坚持积极应对气候变化战略定力继续做全球生态文明建设的重要参与者、贡献者和引领者 ——纪念《巴黎协定》达成五周年

习近平总书记在2020年9月22日第七十五届联合国大会一般性辩论上表示:"中国将提高国家自主贡献力度,采取更加有力的政策和措施,二氧化碳排放力争于2030年前达到峰值,努力争取在2060年前实现碳中和。"在应对气候变化领域,在全球低碳转型的关键时刻,中国以大国担当更新了国家自主贡献方案,这是中国向世界发出的又一个强有力信号。国家自主贡献方案之所以备受全球关注,是因为这是《巴黎协定》最核心的制度,它很大程度上决定了各国的减排力度、低碳转型进程,乃至全球气候行动势头。为此我刊特转发《中国环境报》2020年12月14日第二版刊载的中国气候变化事务特使、生态环境部气候变化事务特别顾问解振华关于纪念《巴黎协定》达成五周年一文,以飨读者。     

图书馆勤工助学岗位的设立与管理

以中国环境管理干部学院图书馆为例,分析了图书馆开展勤工助学工作对加强师生沟通交流、缓解图书馆人力资源不足以及对学生完成学业和参与市场竞争等方面的积极意义,指出图书馆在勤工助学工作中应合理设置助学岗位,加强相关制度建设,做好学生的心理疏导工作,以实现图书馆与学生间的双赢。