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The protection of water resources in the EU has been encouraged through the Water Framework Directive which provides an integrated resource management policy. Wastewater treatment is an important aspect of this strategy: efficient, cost-effective treatment processes are needed in order to return wastewater to the hydrological cycle without any detrimental effects. The disposal of wastewater streams containing highly toxic organic pollutants generated by many industrial processes has emerged as a topic of mounting concern in recent years. Among the numerous classes of pollutants, phenols are of particular importance due to their widespread discharge in the environment and to their toxicity to many living organisms. The effective removal of such pollutants, for safe discharged is a challenging task as environmental lows and regulations are becoming more and more stringent. To meet the requirements of these regulations, biotreatment, adsorption and incineration are traditionally used. However, toxic pollutants are lethal to the microorganisms employed in bioprocesses, whereas incineration or adsorption merely transfers the pollutants from the liquid to air or to the solid leaving combustion by-products or contaminated adsorbent for further disposal. Therefore, there is clear need to test and set-up emerging alternative technologies that can deal with highly concentrated and/or toxic non-biodegradable organic water pollutants. Wet air oxidation (WAO) is an attractive method for the treatment of waste streams which are too dilute to incinerate and too toxic to treat biologically. Unfortunately, the efficient removal of pollutants via WAO requires excessive pressures as well as high temperatures. The use of catalysts makes the process more attractive by achieving high conversion at considerably lower temperature and pressure. Homogeneous catalyst such as copper or iron cations are in general very effective WAO catalyst, but their recovery from the treated effluent requires additional separation cost. This drawback can be overcome by using heterogeneous catalysts which are easily recoverable and reusable. Consequently, heterogeneously catalyzed WO using different oxidizing agents (H2O2, O2, air) and their combinations attracted attention because of its potential as an alternate method of purifying wastewaters. Therefore, the main aim of proposed Project is the search into the catalysts highly active and stable for oxidation of phenols in the aqueous solution under mild conditions. Results of comprehensive research and scientific papers published in relevant international journals, speak in favour of significance and efficacy of this Project, as well as in favour of competence of leaders and associates of proposed Project, their experience in scientific research and accumulated knowledge from the field of catalytic purification of wastewaters polluted by phenols. In addition a group of researches gathered around this Project have proved their excellence through their former work on similar project. The main objective of this Project is to associate the know-how of the groups involved to develop a new oxidative catalytic technology which allows the removal of toxic and recalcitrant phenols or other organic pollutants present in industrial wastewaters. The oxidative catalytic technologies which will be studied in the project are the following: Catalytic wet air oxidation (CWAO) wet hydrogen peroxide catalytic oxidation (CWHPO) hydrogen peroxide promoted CWAO Commercial and newly prepared catalysts for wastewaters purification will be investigated. Various instrumental techniques for the determination of chemical and physical characteristics of catalysts will be employed. Effect of catalyst preparation and pretreatment on its activity, selectivity and lifetime will also be examined. Optimum catalyst preparative conditions will be identified. Trickle-bed, continuous perfectly agitated and batch reactors used for studying kinetic and mechanism of reaction will be employed. Theoretical modelling will be interwoven with experimental work. The optimum values of process parameters will be quantified. Generally, this comprises reaction mechanism, catalyst design, mass and heat transfer, and reactor design. Understanding of the interplay of these elements is crucial for successful development of new cleanup processes.
Short description of the task performed by Croatian partner
The research activities that were performed were situated at the interface between catalysis and reactor engineering with the investigation of reaction kinetics as the core competence. To identify the catalyst design variables in order to obtain more active, selective and stabile catalysts for wastewater purification, the range of activities were:
Synthesis and characterization of two types of heterogeneous catalysts (i) noble metal catalysts deposited on oxides (CeO2, ZrO2-CeO2) and (ii) zeolite based catalyst (type MFI (ZSM5) and FAU (X, Y) containing copper, iron, zinc cations) zeolite based ceramics
Studies on the shape of catalysts (coating of monolith with active phase, extruded materials …) for the use in continuous reactor
Studies of interrelationship between structural and chemical properties of solid materials and their catalytic properties
Screening of the prepared catalysts in lab scale reactors (batch reactor and continuous reactor)
Kinetics and modeling: experimental methods to determine reaction kinetics, development of models for a set of selected laboratory reactor systems to be used for processing experimental data and/or the determination of suitable experimental conditions, methods for the determination of kinetic models from experimental data, including model discrimination, parameter estimation and design of experiments.
Studies of catalyst deactivation (leaching, carbonation, attrition…)
Ovo web sjedište koristi tehnologiju "kolačića" (eng. cookie) da bi se korisnicima prikazao dinamičan i personaliziran sadržaj, te su oni nužni za ispravan rad. Ako nastavite pregledavati ove stranice, kolačići će biti korišteni u suradnji s vašim preglednikom Weba.
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