盐度对好氧颗粒污泥硝化过程中N2O产生量的影响

采用好氧SBR反应器,考察盐度在0、5、10 g·L-1条件下好氧颗粒污泥全程硝化过程中N2O产生量的变化情况以及对系统脱氮效果的影响.结果显示,随着污水中盐度增加,N2O产生量呈递增趋势.在3个盐度下(0、5、10 g·L-1),溶解态N2O产生量分别为1.21、8.99、24.81 mg·m-3,释放态N2O产生量分别为0.95、3.46、16.45 mg·m-3.在盐度为5 g·L-1和10g·L-1条件下,N2O释放速率分别为0 g·L-1时的3.6倍和17.4倍.在3种盐度条件下无论是溶解态N2O还是释放态N2O产生量在硝化过程的变化趋势均是先上升后下降,且溶解态N2O产生量大于释放态产量.另外当盐度浓度较低时(低于5 g·L-1),对NH+4-N去除效果影响较小,NH+4-N的去除率与盐度为0 g·L-1时基本相同,均在98%以上;但当盐度升至10 g·L-1后,NH+4-N的去除率降到了70%.因此,污水中盐度增加不仅影响NH+4-N的去除效率,而且增加N2O产生量.     

Gas separation using porous cement membrane

Gas separation is a key issue in various industrial fields. Hydrogen has the potential for application in clean fuel technologies. Therefore, the separation and purification of hydrogen is an important research subject. CO2 capture and storage have important roles in ＂green chemistry＂. As an effective clean technology, gas separation using inorganic membranes has attracted much attention in the last several decades. Membrane processes have many applications in the field of gas separation. Cement is one type of inorganic material, with the advantages of a lower cost and a longer lifespan. An experimental setup has been created and improved to measure twenty different cement membranes. The purpose of this work was to investigate the influence of gas molecule properties on the material transport and to explore the influence of operating conditions and membrane composition on separation efficiency. The influences of the above parameters are determined, the best conditions and membrane type are found, it is shown that cementitious material has the ability to separate gas mixtures, and the gas transport mechanism is studied.     

Heterogeneous Fenton-like degradation of 4-chlorophenol using iron/ordered mesoporous carbon catalyst

Ordered mesoporous carbon supported iron catalysts(Fe/OMC) were prepared by the incipient wetness impregnation method and investigated in Fenton-like degradation of 4-chlorophenol(4CP) in this work. XRD and TEM characterization showed that the iron oxides were well dispersed on the OMC support and grew bigger with the increasing calcination temperature. The catalyst prepared with a lower calcination temperature showed higher decomposition efficiency towards 4CP and H2O2, but more metals were leached. The effect of different operational parameters such as initial pH, H2O2 dosage, and reaction temperature on the catalytic activity was evaluated. The results showed that 96.1% of 4CP and 47.4% of TOC was removed after 270 min at 30°C, initial pH of 3 and 6.6 mmol/L H2O2. 88% of 4CP removal efficiency was retained after three successive runs, indicating Fe/OMC a stable catalyst for Fenton reaction. 4CP was degraded predominately by the attack of hydroxyl radical formed on the catalyst surface and in the bulk solution due to iron leaching. Based on the degradation intermediates detected by high performance liquid chromatography, possible oxidation pathways were proposed during the 4CP degradation.     

Knudsen cell and smog chamber study of the heterogeneous uptake of sulfur dioxide on Chinese mineral dust

The heterogeneous uptake processes of sulfur dioxide on two types of Chinese mineral dust（Inner Mongolia desert dust and Xinjiang sierozem） were investigated using both Knudsen cell and smog chamber system. The temperature dependence of the uptake coefficients was studied over a range from 253 to 313 K using the Knudsen cell reactor, the initial uptake coefficients decreased with the increasing of temperature for these two mineral dust samples, whereas the steady state uptake coefficients of the Xinjiang sierozem increased with the temperature increasing, and these temperature dependence functions were obtained for the first time. In the smog chamber experiments at room temperature, the steady state uptake coefficients of SO2 decreased evidently with the increasing of sulfur dioxide initial concentration from 1.72 × 1012 to 6.15 × 1012mol/cm3. Humid air had effect on the steady state uptake coefficients of SO2 onto Inner Mongolia desert dust.Consequences about the understanding of the uptake processes onto mineral dust samples and the environmental implication were also discussed.     

Comparison of different disinfection processes in the effective removal of antibiotic-resistant bacteria and genes

This study compared three different disinfection processes(chlorination, E-beam, and ozone) and the efficacy of three oxidants(H2O2, S2O-8, and peroxymonosulfate(MPS)) in removing antibiotic resistant bacteria(ARB) and antibiotic resistance genes(ARGs) in a synthetic wastewater. More than30 mg/L of chlorine was needed to remove over 90% of ARB and ARG. For the E-beam method, only1 dose(kGy) was needed to remove ARB and ARG, and ozone could reduce ARB and ARG by more than 90% even at 3 mg/L ozone concentration. In the ozone process, CT values(concentration × time)were compared for ozone alone and combined with different catalysts based on the 2-log removal of ARB and ARG. Ozone treatment yielded a value of 31 and 33(mg·min)/L for ARB and ARGs respectively. On the other hand, ozone with persulfate yielded 15.9 and 18.5(mg·min)/L while ozone with monopersulfate yielded a value of 12 and 14.5(mg·min)/L. This implies that the addition of these catalysts significantly reduces the contact time to achieve a 2-log removal, thus enhancing the process in terms of its kinetics.     

循环经济概念及其影响

<正>循环经济是在可持续发展的思想指导下,按照清洁生产的方式,对能源及其废弃物实行综合利用的生产活动过程。它要求把经济活动组成一个"资源—产品—消费—再生资源"的反馈式流程。其本质是一种生态经济。它要求运用生态     

基于物联网的作业现场安全管控技术研究

针对当前炼化企业作业过程事故频发、本质安全理念不深入、"三基"工作落实不到位的问题,提出了基于物联网的作业现场安全管控技术方案。以现有作业现场安全管控为基础,分别在入场关、作业前审查关、作业过程监护关和离场验收关几个主要业务环节,增加多道自动识别监管防线,构建施工作业安全防护屏障,建立作业现场传统安全+物联网安全管控新模式。经过炼化企业的现场验证,表明该技术能够显著提升作业现场的工作效率,强化责任落实效果。     

新建地方本科高校小学教育专业改造过程中的问题与对策研究

作为服务基层教育的主力军,新建地方本科高校小学教育专业肩负着培养新时代小学教师的使命。目前新建地方本科高校小学教育专业在培养目标的确立、课程体系的设置和师资队伍的建设等方面均存在一定的问题,影响了专业改造的顺利进行。只有将农村小学全科教师作为培养目标来确立、小学教育职业本位作为课程体系设置的依据、专兼结合的双师双能型教师队伍作为师资建设的重点,才能保证新建地方本科高校小学教育专业改造的顺利进行。     

科普知识专栏:小小安全帽蕴藏大道理

在生产作业过程中,意外的高处坠落和物体打击事故时有发生.在建筑、矿山、电力、冶金、石油勘探、隧道工程、森林采伐等作业场所都存在发生高处坠落和物体打击事故的可能.这类事故发生突然,不及躲闪.     

初中学生数学学习共同体建设研究

在学习共同体理论的启发下,笔者立足初中数学课堂教学,在社会建构主义理论基础上对学习共同体建设展开了研究,就如何创建初中生数学学习共同体进行了具体分析。