Abstract The influence of the kind and amount of catalyst, nature of solvent, the reaction time, removal of product from reaction mixture on the selectivity of transformation to 1,3-dichloro-2-propanol, 2,3-dichloro-1-propanol, chloropropanediols in relation to consumed glycerol and glycerol conversion has been presented.

Abstract Water savings, reclamation and reuse in industry are topics of increasing economic interest due to water scarcity and costs. The search for an efficient and economical method to the depuration of two different effluents, namely from vegetable wash (VW) and chemical production (CP), was investigated by advanced oxidation processes as direct ozonation and O

Abstract In this work, the influence of volcanic sand surface hydroxyl groups (Me-OH

Abstract A range of methods are reported for the treatment of Orange II in aqueous solution with a variety of ultrasonic equipment in the absence of oxidants. The frequencies studied were 20 kHz (using a probe system) and a range of baths at 40, 380, 850, 1000 and 1176 kHz using different power inputs. Using ultrasound alone the higher frequencies were more efficient for the decolorization of Orange II. The most effective decolorization of Orange II in terms of power was achieved at 850 kHz and increased from 4.1% to 49.0% with increasing ultrasonic power from 2.04 W to 22.07 W over 2 hours. This trend was in good agreement with the corresponding production of H

Abstract The design of a suitable fixed photocatalytic support for water disinfection in a continuous flow reactor was researched. Computational fluid dynamics (CFD) was used to simulate the percentage of tracked particles coming into contact with the irradiated surface of different support geometries, cylindrical: conical and consecutive frusta and a spring. The number of particles striking each insert was presumed to give a good representation of the respective disinfection efficiencies of each design, as photocatalysis is effectively a surface phenomenon. It was found that a conical frustum design was more than three times as efficient as a similarly-sized conventional cylindrical insert with regard to this parameter, and arrangements of shorter frusta exhibited even more promising traits. A further regime of laboratory testing is proposed in order to determine the practical efficiency of the insert designs, which may have important applications in the solar disinfection of drinking water.

Abstract In the present study, the degradation of organic contaminants by streamer discharge using a pulsed power generator under water is investigated. The experiments are conducted based on the decolorization of two dyes, Acid Red 1 and Acid Blue 74, and the decomposition of 1,4-dioxane. A gas-liquid separated reactor is developed and employed to achieve degradation with high energy efficiency. A tungsten wire electrode is placed in the gas phase, and a grounded 316 stainless steel wire is immersed in the water. The pulsed high voltage is generated by a magnetic pulse compression circuit and is applied to the wire electrode to generate streamer discharges in the gas region, which propagate into the bubble injected into the water. Oxygen and argon gases are injected to identify the dominant reactions of the degradation of organic contaminants. Acid Red 1 and Acid Blue 74 solutions are successfully decolorized by the discharges. The ozone produced by discharges in the gas region primarily decolorizes the dye solutions. The total organic carbon (TOC) of the 1,4-dioxane solution decreases due to discharge when argon is injected. The decrement rate of TOC does not increase through gaseous ozone injection or by discharges in the case of oxygen injection. These results show that the chemical species produced by discharges and by chemical reactions in the solution, such as hydroxyl and hydroperoxyl radicals, primarily decompose 1,4-dioxane. Iron ions dissolved by electrolysis enhanced the TOC decrement rate according to the Fenton reaction in acidic conditions.

Abstract The present paper describes photodegradation of non-steroidal anti-inflammatory drug ibuprofen sodium salt (C

Abstract The aim of this paper is to give a review of the research on the decomposition of trichloroethylene (TCE), a common industrial solvent, with combined use of non-thermal plasma and heterogeneous catalysis, i.e. plasma-catalysis. This air purification technique has been investigated over the last decade in an effort to overcome the disadvantages of non-thermal plasma treatment of waste air containing volatile organic compounds (VOCs). Some examples of different plasma technologies used for plasma-catalysis are given. These include the dielectric barrier discharge, the pulsed corona discharge and the atmospheric pressure glow discharge. In a plasma-catalytic hybrid system the catalyst can either be located in the discharge region or downstream of the plasma reactor. The mechanisms that drive both configurations are briefly discussed, followed by an extended literature overview of the removal of TCE with plasma-catalysis.

Abstract Depending on the process type and raw materials involved, various types of wastewater are discharged from food industry. In the present study the feasibility of Fenton-based treatment, as a part of combined treatment schemes, to degrade high organic content, to eliminate suspended solids, and to improve the overall quality of food-processing plant wastewater was assessed. Fenton oxidation step used in treatment schemes improved significantly the quality of the effluent, enabling additional 62-79% and 53-69% reduction of chemical oxygen demand (COD) and dissolved organic carbon (DOC), respectively, when the H

Abstract The role of titanium dioxide photocatalysis in the frame of green chemistry is discussed on the basis of a review of published life cycle assessments. It appears that the environmental impact of photocatalysis when applied to the mineralization of pollutants is generally worse than that of other advanced oxidation processes when lamps are used, but becomes appealing under solar light. The potential of photocatalysis for organic synthesis - that in principle should minimize the generation of pollutants - is likewise discussed. Here again, however, the method is competitive with thermal procedures only when solar light is used.