双氧水生产废水的治理工程实例

对蒽醌法双氧水生产的废水的性质作了简要介绍,针对该类污染物提出了隔油+气浮+催化氧化+生物碳塔为核心的治理工艺。着重介绍了该工程的实际运行情况及运行中遇到的问题,并加以分析。     

催化湿式氧化农药废水及催化剂的研究

通过浸渍法制备了4种氧化物为主活性组分的负载固定型催化剂,用于过氧化氢催化湿式氧化(CWHPO)处理有机农药废水。用实验确定了催化湿式氧化的条件,不同催化剂处理效果的比较表明,四元组合MnO2CuOCeO2CoO催化剂性能较好,当反应在常温常压下,维持pH=7～9,反应时间为40min时,COD的去除率大于80%,色度去除率大于90%。     

Numerical simulation of deflagration-to-detonation transition in large confined volumes

A methodology for the computationally efficient CFD simulation of hydrogen-air explosions (including transition to detonation) in large volumes is presented. The model is validated by means of the largest ever conducted indoor DDT experiments in the RUT facility. A combination of models is proposed with a particular focus on the influence of flame-instabilities, especially of thermal-diffusive nature, which are crucial for very lean mixtures. Excellent agreement is achieved in terms of flame acceleration. The quality of DDT predictions itself depends on the underlying mechanism. Whereas DDT by shock-focusing is successfully simulated on under-resolved meshes, DDT by local explosions in the vicinity of the turbulent flame brush remains a challenge. Adaptive mesh refinement therefore emerges as a key technique to resolve more of the essential phenomena at reasonable computational costs affordable by industry. Finally, a generic case demonstrates the influence of mixture inhomogeneity, which can promote flame acceleration and ultimately DDT.     

雅鲁藏布江河水氢氧同位素时空变化特征

为揭示流域内水汽循环过程变化规律、揭示河水稳定同位素与气象要素及海拔之间的关系,2018年先后采集雅鲁藏布江干流丰、平、枯,水期水样90个,对河水的氢氧同位素组成进行了分析.结果表明：利用δ¹⁸O与纬度和海拔定量关系模型研究了雅江流域降水氢氧同位素空间变化特征,发现降水中δ¹⁸O值变化呈现东西部（雅江上、下游）高中部（雅江中游）低的趋势;建立了雅江丰、平、枯水期河水氢氧同位素方程,研究发现δD与δ¹⁸O的线性方程斜率低于中国大气降水线,河水δD与δ¹⁸O有一定的季节性特征,其受大气降水的影响较大,且丰水期较平水期以及枯水期相比更为明显;雅江河水中δ¹⁸O空间特征表现为,从上游至下游整体表现出先降低再升高的变化趋势.南北空间上表现为河水δD-δ¹⁸O从南至北逐步增高的趋势.δD-δ¹⁸O值与海拔高度具有较弱的负相关关系;受地表蒸发分馏、降水云团迁移以及流域岩石风化的影响,雅江河水d值季节性、空间性变化明显.     

臭氧与过氧化钙协同降解甲基红废水

对单独臭氧（O₃）、臭氧与过氧化钙（O₃/CaO₂）联用技术降解甲基红染料废水进行了研究,考察了O₃流量、温度、废水初始pH值、CaO₂投加量、处理时间以及不同水基质等因素对甲基红降解效果的影响.结果表明,在O₃流量为48L/h,温度为26℃,初始pH值为6.2的纯水中降解10min,单独O₃处理对甲基红的降解率为86.1%.在此条件下投加CaO₂,投加量为6.9mmol/L时,O₃/CaO₂联用技术对甲基红废水的脱色率可达到94%.水基质中草酸的存在并不会对O₃/CaO₂联用体系的降解作用造成抑制.O₃/CaO₂联用体系在多种复杂水基质中都能达到较好的脱色效果.通过对比试验发现,O₃/CaO₂联用对甲基红的降解起协同作用,CaO₂不仅可以产生H₂O₂促进染料被O₃降解,而且CaO₂的吸附作用也有利于染料和污染物质的氧化去除.该联用工艺可高效地去除印染废水的色度,达到出水水质处理标准.     

以淀粉为模板多孔纳米氧化铈的制备及其催化性能研究

为获得多孔纳米CeO₂（氧化铈）,以淀粉为生物模板,以Ce（NO₃）₃·6H₂O为铈源,在温和条件下制备出海绵状的多孔纳米CeO₂,同时考察了焙烧温度、碱液、铈源投加量对样品形貌的影响.利用XRD（X射线衍射光谱）、SEM（扫描电镜）、N₂吸附-脱附等表征手段对合成的多孔纳米CeO₂进行物相组成、微观形貌及孔径大小分布的分析.通过湿式催化过氧化试验,探究其对腈纶废水中有机物COD_Cr的催化降解性能.结果表明:①所制备的多孔纳米CeO₂具有多孔结构,孔径分布范围为2~4 nm,孔容为0.225 cm3/g,BET比表面积为256.426 m2/g;②多孔纳米CeO₂的最佳制备条件为1 g淀粉溶解于20 mL水中,加入0.02 mol Ce（NO₃）₃·6H₂O,以5%的氨水调节前驱体混合液pH,以1℃/min升至400℃,焙烧4 h,得到海绵状的多孔纳米CeO₂.③以不同形貌的CeO₂作为湿式催化反应中的催化剂,催化降解腈纶废水中有机物,其中以制备的多孔纳米CeO₂催化性能最佳,COD_Cr去除率可达82.5%.研究显示,焙烧温度、碱液、铈源投加量均可影响样品的形貌,在湿式催化过氧化处理腈纶废水试验中,多孔纳米CeO₂能显著提高废水COD_Cr的去除率.      

CaO2不同投加方式对黑臭河道底泥内源磷释放抑制作用

以S市某黑臭河道底泥和上覆水为研究材料,研究了CaO_2在3种不同投加方式下对内源磷释放的抑制效果.结果表明CaO_2在3种投加方式下,均导致上覆水中pH和DO有所增加.注射条件下,上覆水DO浓度明显低于覆盖,说明注射确实延缓了CaO_2的氧化速度,有利于创造底泥微氧化环境.CaO_2覆盖和注射条件下,上覆水中TP和DIP浓度以及变化趋势基本一致,均明显低于混匀条件.但是,覆盖条件下,间隙水中DIP浓度最高,达到注射条件下的120.33~142.18倍.相反,注射条件下,间隙水中DIP浓度最低,并且上覆水中DIP浓度也较低,说明注射条件下CaO_2对内源磷的释放确有抑制作用,这与其创造的微氧化环境密切相关.底泥中不同形态磷数量分布也证实了这一点.投加CaO_2加快了有机磷的矿化速度,铁铝结合态磷和钙结合态磷也明显增加,使得内源磷持留能力增强.     

基于过氧化物的消毒技术研究进展

对环境友好消毒技术需求的增长,推动了过氧化物消毒技术的快速发展,并已被广泛应用于反化学和生物恐怖袭击、化生灾害处置、环境污染治理等领域.在综述了过氧化物消毒剂α亲核取代/氧化消毒反应机制研究进展的基础上,介绍了以过氧化物为活性组分的水基消毒溶液、消毒泡沫、消毒乳液、消毒凝胶、消毒气雾、自消毒材料、纳米材料催化消毒技术等典型消毒体系.针对现有过氧化物消毒技术消毒效率偏低、对个别毒剂消毒效果不理想的缺点,建议在过氧化物消毒技术研究中,加强消毒反应机制、多相体系界面相互作用研究,开发新型催化剂、多功能表面活性剂、自消毒材料和消毒剂缓蚀技术,以实现真正的绿色消毒.     

Explosion hazards related to hydrogen releases in nuclear facilities

Hydrogen explosion risk needs to be carefully assessed and evaluated in nuclear facilities because of the potential catastrophic consequences: breakdown of safety equipments, failure of containment, dissemination of radioactive materials in the environment.When studying an indoor release, one possible simplification is to assume a perfect gas mixing inside the room. This assumption is effectively often used to evaluate toxic risks in the environment outside a building (Mastellone, Ponte, & Arena, 2003). However, perfect gas mixing assumption is only a rough approximation, as indoor concentrations can largely differ from mean values, due to buoyancy, recirculation zones or obstacles for example.In order to better evaluate the risk of explosion in case of an accidental release of hydrogen, IRSN conducted a numerical study using FLACS CFD software. Several parameters have been studied to identify dangerous situations and draw a representative picture of the risk: room size, position and direction of hydrogen leak, ventilation characteristics. Hydrogen release flow rates used for numerical simulations have been chosen as the highest leak rate which, by applying the assumption of perfect mixing, produces an average concentration in the room equal to hydrogen lower flammability limit (LFL).Simulation results indicate that in some particular configurations, especially for impinging hydrogen jets, hydrogen concentrations can locally be above LFL and then create explosive atmospheres with significant volumes.     

Determination of the minimum ignition energy on the basis of a statistical approach

Based on existing MIE test results and new measurements, a statistical analysis for the MIE of hydrogen, ethene and propane is made by means of the logistic regression. The conditions necessary to carry out such an approach are discussed. It is shown that MIE values which are connected with a certain ignition probability could be determined adequately and lead to a more sophisticated result, also with regard to measurement uncertainties. This, in turn, leads to a better comparability and a higher informative content. At the same time, the MIEs of hydrogen, ethene and propane are reviewed. In doing so, a useful contribution to the discussion concerning the MIE of propane is made.