沿海城市珠海PM2.5中水溶性离子特征及来源分析

PM_2.5水溶性离子特征研究主要集中在大中型城市,为探讨珠海市PM_2.5水溶性离子特征及来源,2016年6月至12月采集PM_2.5样品,用离子色谱分析9种水溶性离子浓度。结果表明：珠海PM_2.5总离子浓度处于较低水平,离子浓度有季节变化特征,表现为冬季＞秋季＞夏季;夏、秋季PM_2.5呈碱性,冬季显酸性;从夏季到冬季,SO₄^2-和NH₄⁺在总离子中比例有减小趋势,NO₃^-比例有增大趋势。SO₄^2-、NO₃^-、NH₄⁺为主要组成成分,占离子总成分的85.07%,表明珠海市大气PM_2.5二次污染较严重,NO₃^-/ SO₄^2-均值0.2,表明以固定源污染为主。从气团聚类、离子相关性、富集因子分析和主因子分析等角度讨论来源和存在形式,珠海PM_2.5水溶性离子受气团影响较大,来自陆地气团的离子浓度高于海洋气团;夏季到冬季,PM_2.5受到80.2%的人为源和海洋源的混合源和16%的农业源贡献,离子主要存在形式有NH₄HSO₄、Mg(NO₃)₂、KNO₃、Ca(NO₃)₂、NH₄NO₃、NaCl、KCl和CaCl₂。     

溪流生态系统次生盐化的生态学研究进展

溪流次生盐化是人类活动干扰导致可溶性盐向水体迁移从而造成盐浓度异常增高的现象,由于干扰类型(如农业生产、河岸带植被破坏、采矿废水与污水排放等)的不同,溪流次生盐化呈现出溶解性无机离子组成复杂、盐浓度间歇性波动等特点. 已有研究发现:①溪流次生盐化会造成藻类、底栖动物和鱼类的群落结构产生变化,主要包括物种丰度、生物量、生物多样性、功能摄食类群等方面;②高盐环境对非耐盐物种产生胁迫从而降低其出现频率,敏感底栖动物会增加漂移行为以选择低盐环境,而敏感鱼类则消失;③耐盐物种应对高盐胁迫有不同策略,如卵胎生的产卵方式以减少在高盐环境中的时间,或拥有较强的渗透调节能力维持体内渗透平衡. 主要问题:①影响水生生物的可能是单一离子又或是离子组合,不同盐化水体所增加的离子类型及浓度都有很大差别,而要逐一探明单一离子及离子组合的影响需要巨大的工作量;②野外研究常以电导率或ρ(TDS)(TDS为总溶解性固体)表征盐化程度,而电导率或ρ(TDS)会改变有机污染物、重金属的生物毒性,也会与营养盐、悬浮物等因子产生交互作用,难以确定盐化对水生生物的独立影响. 因此,今后需关注全球变暖背景下次生盐化与营养盐、重金属的耦合作用,注重我国本土水生生物的耐受性及其适应调节机制,并重视基于野外调查与室内试验两类不同数据所获得水生生物适盐范围的对比验证;同时为满足水生生物健康保护,应加强对溪流次生盐化有指示作用的水质监测指标的开发及阈值的制订.      

鼠李糖脂胶团强化超滤处理含铅废水研究

以实验室配制的模拟含铅废水为研究对象,探讨了生物表面活性剂鼠李糖脂强化超滤技术对含铅废水的处理效果。实验结果表明,影响重金属离子铅去除率因素的主次顺序为:p H值鼠李糖脂浓度重金属离子铅的初始浓度操作压力,去除重金属铅离子的最佳条件是:鼠李糖脂浓度为8 CMC,p H值为9,操作压力为300 k Pa,最大去除率可达到89.66%。     

利用负离子的油烟多级净化装置的研究探讨

针对目前餐饮油烟净化技术去除细小颗粒物的不足,在总结现阶段油烟净化技术的研究应用现状的基础上,分析湿式+过滤的复合式油烟净化装置基础上应用空气负离子除污技术的可能性,提出了基于空气负离子技术的新型多级油烟净化装置设想及其发展途径与研究方向。     

金属离子对双氧水热稳定性的影响研究

为了研究金属离子对双氧水在绝热条件下分解特性的影响,利用泄放尺寸设计装置VSP2模拟双氧水及分别掺杂0.01%质量分数Fe~(2+)、Fe~(3+)、Gu~(2+)的双氧水在绝热条件下的反应失控过程,得到绝热分解过程的热力学和动力学参数,依此推算出该4种试样25 kg包装下的自加速分解温度SADT,以及绝热条件下到达最大反应速率的时间TMRad。结果表明,Fe~(2+)、Fe~(3+)、Gu~(2+)使双氧水的起始分解温度T0、SADT、TMRad均降低,提高了双氧水的热危险性。在Fe~(3+)的作用下,双氧水在常温下就发生缓慢分解,发生失控的可能性最大;掺杂了Gu~(2+)的双氧水分解反应最剧烈,热失控严重度最高。     

Fenton试剂对孔雀绿废水的脱色处理研究

对Fenton试剂(过氧化氢与催化剂亚铁离子构成的氧化体系)氧化孔雀绿染料褪色的条件进行了研究,运用条件变化前后吸光度变化的方法,计算孔雀绿染料的脱色率,考察了过氧化氢、孔雀绿、亚铁离子的用量比例以及溶液pH值的大小、反应温度和反应时间对孔雀绿废水脱色率的影响.得出如下结论:在pH为3.0,过氧化氢浓度为4.87毫摩尔每升,亚铁离子浓度为0.12毫摩尔每升,孔雀绿浓度为12毫克每升比例条件下,30℃反应0.5小时以上,孔雀绿废水的脱色率达到99.7％.用该方法处理孔雀绿废水,操作简单、快速、消耗低、无二次污染.     

Recent progress of arsenic adsorption on TiO2 in the presence of coexisting ions: A review

Arsenic (As)-contaminated wastewater and groundwater pose a pressing environmental issue and worldwide concern. Adsorption of As using TiO₂ materials, in combination with filtration, introduces a promising technology for the treatment of As-contaminated water. This review presents an overview on the recent progress of the application of TiO₂ for removal of As from wastewater and groundwater. The main focus is on the following three pressing issues that limit the field applications of TiO₂ for As removal: coexisting ions, simulation of breakthrough curves, and regeneration and reuse of spent TiO₂ materials. We first examined how the coexisting ions in water, especially high concentrations of cations in industrial wastewater, affect the efficacy of As removal using the TiO₂ materials. We then discussed As breakthrough curves and the effect of compounded ions on the breakthrough curves. We successfully simulated the breakthrough curves by PHREEQC after integrating the CD-MUSIC model. We further discussed challenges facing the regeneration and reuse of TiO₂ media for practical applications. We offer our perspectives on remaining issues and future research needs.     

油田水平井合金防垢器研制与效果评价

目的探寻合金防垢在某油田的适用性。方法利用设计的模拟试验装置,以防垢效果为评价指标,优选出作为合金防垢器核心部件合金扇形片的元素配比,设计并研制扇形合金片螺旋排列结构的串联式合金防垢器,选择油田的油井进行5个月的现场试验。结果地层水中的钙镁离子质量浓度提高了260%,防垢率较化学阻垢提高了76%。结论该合金防垢器防垢效果较好。     

Recent trends in the decomposition of chlorinated aromatic hydrocarbons by ultrasound irradiation and Fenton's reagent

Over the past few years, a large number of studies have been conducted on the use of ultrasound for decomposition of harmful organic pollutants, particularly chlorinated aromatic hydrocarbons (CAH) in wastewater. The published reports cover a variety of applications, including both ultrasonic treatment alone and in combination with other methods, e.g., advanced chemical oxidation processes. This article presents a review of recent work on ultrasonic-based methods of CAH decomposition, with emphasis on the applications of ultrasound alone and in combination with Fenton's reagent, as attractive advanced oxidation systems. In the first part of this review, the basic principles of sonochemical treatment are presented, followed by a review of the applications of ultrasound alone for CAH degradation. In the second part, the mechanisms of CAH degradation with Fenton's reagent and its application for CAH degradation are summarized. In the final part, studies on the applications of ultrasound together with Fenton's reagent are reviewed. The reported results suggest that a combination of ultrasound and Fenton's reagent is more attractive for practical application than the use of either method separately. Further studies, however, are required in this area because the reaction mechanism and the relationship between the reaction rates and process parameters for such a combined process are not yet well established.     

介孔磁性微球的制备表征及其在环境中的应用

文章在Fe3O4(magnetite)纳米粒子的表面包覆一层SiO2(silica),再以十六烷基三甲基溴化铵(CTAB)表面活性剂作为结构导向剂,包覆一层介孔SiO2,形成一种核壳式介孔磁性二氧化硅材料(MS),然后在其表面引进巯基(mercapto)从而成为一种新型巯基修饰的磁性二氧化硅载体(MMS).这种材料是介...