Effects Of Ozone On The Production Of Biodegradable Dissolved Organic Carbon (BDOC) During Water Treatment

This article deals with the oxidation effect of ozone on the increasing fraction of biodegradable organic matter with the “ozotest” method, a laboratory technique which simulates the effect of ozonation and allows a complete oxidation assessment. Ozone treatment was performed on river water samples and sand filter effluent samples. Ozone consumption, reduction of UV absorbance and BDOC formation were monitored with applied ozone doses from 0 to 10 mg/L and with contact times from 0 to 60 min. The BDOC formation was optimum at an applied ozone dose of 0.25-0.5 mg O₃ per mg DOC (contact time = 5 min) corresponding to apparition of traces of residual ozone and maximum UV reduction. Maximum ozone consumption, UV reduction and BDOC formation occurred simultaneously during the first two minutes of treatment. Concerning BDOC formation, applied ozone dose showed a greater effectiveness than contact time. For the same quantity of consumed ozone, a short contact time associated with a high ozone dose was preferable to a long contact time and a low ozone dose.     

航空胶片显影液调整的计算机处理方法

为解决航空胶片显影液调整问题，采用了Visual Basic6.0开发了“显影液化学分析调整软件，该系统具有一定的应用价值。     

超分子化学与环糊精

超分子化学是上世纪八十年代末兴起的一门新兴边缘学科,它的发展为各个学科的研究和新技术、新材料的研发开拓了一个崭新的领域。环糊精是超分子化学的重要研究内容之一。本文对环糊精的来源和分子结构特点作了简单介绍,论述了环糊精及其衍生物任超分子化学领域中的地位和作用,显示出超分子化学及环糊精研究和应用的无限潜力。     

Preparation of DNA-encapsulated polyethersulfone hollow microspheres for organic compounds and heavy metal ions removal

DNA-encapsulated polyethersulfone (PES) hollow microspheres are fabricated by means of a liquid-liquid phase separation technique; the hollow microspheres are then used to remove environmental pollutant organic compounds and heavy metal ions. The amounts of DNA encapsulated in the microspheres are dependent on the PES concentration, the DNA concentration used to prepare the particles, and the diameter of the syringe needle. The hollow microspheres can be used to remove harmful organic compounds including ethidium bromide (EB), acridine orange (AO) and endocrine disruptors. With the increase of the DNA amount encapsulated into the hollow microspheres, the removal ratios of these compounds increased. Additionally, the DNA-encapsulated PES hollow microspheres can selectively accumulate and remove heavy metal ions such as Ag⁺, Cu²⁺ and Zn²⁺ These results suggested that the DNA-encapsulated PES hollow microspheres have a potential to be used in environmental applications.     

Agricultural use of three organic residues: effect on orange production and on properties of a soil of the ‘Comarca Costa de Huelva’ (SW Spain)

Disposal of urban, agricultural and industrial organic residues impliesan increasing problem because of all the economic and environmentalrepercussions involved. One of the most adequate ways of managing this problemis the agricultural use of these wastes as organic amendments. Three organicresidues (AC, olive mill waste water sludge compost; MWC, municipal solid wastecompost; and PS, paper mill sludge) were used in a 3-year field experimentinvolving orange production. The effect of their application on crop productionand on soil quality was investigated. Soil samples (0–20 cm depth)collected 11 months after the last soil amendment were analysed for: pH and EC,Kjeldahl-N, available-P, available-K, total organic carbon, humic substances,dehydrogenase, phosphatase, -glucosidase, urease andbenzoyl-argininamidehydrolysing protease (BAA-protease) activities. Generally, the application of the MWC and PSincreased orange yield when compared to control. Moreover, total organic carbonand humic substances significantly increased in soils treated with all theorganic amendments. Organic fertilisation increased the Kjeldahl-N andavailable-P contents of the soil. The application of the organic residues also causedsignificant increases in dehydrogenase, -glucosidase, urease andBAA-protease activities of the soil. Significant positive correlations (p <0.01) between these enzymatic activities and total organic carbon were foundforall treatments. Significant positive correlation between dehydrogenase, urease,-glucosidase, and BAA-protease and orange yield was also found. However,a clear inhibition of phosphatase activity was observed in soils treated withPS. The results indicate that the repeated application to the soil of moderateamounts of organic amendments has positive effects on the chemical andbiochemical properties of the soil, as well as on the orange yield.     

Ozonation of Drinking Water: A Design Methodology

The formation of potentially carcinogenic organic halides has been shown to result from drinking water disinfection with chlorine. xidative treatment of organic halide precursors with ozone prior to chlorination has surfaced as an attractive technique for reducing the formation of these compounds. In addition to reduction of precursor levels, preozonation has been reported to effect other beneficial results in water treatment. This paper presents design methodologies to optimize the implementation of the ozonation process for water treatment applications. Pre-design considerations common to all ozonation design processes are discussed. Subsequently, design procedures for the ozone generation and contacting systems are reviewed.     

Theoretical Aspects Of The Kinetics Of Competitive First Reactions Of Ozone In The O3/H2O2 And O3/UV Oxidation Processes

Kinetics of competition between the ozone direct reaction with compounds in water, ozone-hydroperoxide ion reaction leading to free radicals in the O₃/H₂O₂ process, and the photolysis of ozone in the O₃/UV process are discussed in terms of diffusion and reaction times to establish conditions for these reactions to be competitive. Film theory and chemical kinetic concepts then are applied to estimate initial rates of ozone absorption and consumption, removal rates of compounds present in water, and the importance of the radical oxidation path versus direct ozone and/or photolysis reactions.     

Electrochemical cell current requirements for toxic organic waste destruction in Ce(IV)-mediated electrochemical oxidation process

The electrochemical cell for cerium oxidation and reactor for organic destruction are the most important operation units for the successful working mediated electrochemical oxidation (MEO) process. In this study, electrochemical cells with DSA electrodes of two types, single stack and double stack connected in series, were used. The performances towards the electrochemical generation of Ce(IV) in nitric acid media at 80 °C were studied. The current-voltage curves and cerium electrolysis kinetics showed the dependence on number of cell stacks needed to be connected in series for the destruction of a given quantity of organic pollutant. The presence of an optimum region for Ce(III) oxidation with a contribution of oxygen evolution, especially at low Ce(III) concentration (high conversion ratios), was found. The cells were applied for the Ce(IV) regeneration during the organic destruction. The cell and reactor processes were fitted in a simple model proposed and used to calculate the current needed in terms of Ce(III) oxidation rate and the number of cell stacks required for maintaining Ce(IV)/Ce(III) ratio at the same level during the organic destruction. This consideration was based on the kinetic model previously developed by us for the organic destruction in the MEO process.     

The kinetics of gasification of carbon deposited on nickel catalysts

The kinetics of gasification of carbon deposited on nickel foils and nickel-alumina catalysts by steam, carbon dioxide and hydrogen are reported for the temperature range 450–850°C. At atmospheric pressure steam is the most effective gasifying agent. In all cases, the kinetic data obtained at lower temperatures (below 600°C) is consistent with control of the process by the chemical reaction. As the temperature increases, the rates of gasification by steam and carbon dioxide are limited by mass transfer effects. The concentration of methane near reaction sites affects the rate of hydrogen gasification above 650°C.     

CO2／酚基树脂的合成实践

本文对ＣＯ２／酚基树脂──冷芯盒工艺用树脂的合成工艺进行了一定程度的实验研究，提出了可行的几种有机合成方法，并从理论分析入手，对该类树脂的分子结构类型进行了设计和预测。