Graphene-Based Catalysts for Ozone Processes to Decontaminate Water.

The use of graphene-based materials as catalysts in both ozone and ozone/radiation processes is creating interest among researchers devoted to the study of advanced oxidation processes (AOPs) for the degradation of organic pollutants in water. In this review, detailed explanations of catalytic and photocatalytic ozonation processes mediated by graphene-based materials are presented, focusing on aspects related to the preparation and characterization of catalysts, the nature of the water pollutants treated, the type of reactors and radiation sources applied, the influence of the main operating variables, catalyst activity and stability, and kinetics and mechanisms.

Sunlight driven photolytic ozonation as an advanced oxidation process in the oxidation of bezafibrate, cotinine and iopamidol.

This study investigates the efficacy of the system O/sunlight radiation compared to dark ozonation when treating pharmaceuticals compounds of different reactivity, namely bezafibrate, cotinine, and iopamidol. Results show the beneficial effects of simulated sunlight radiation (300-800 nm) when treating ozone recalcitrant compounds such as cotinine and iopamidol. The system O/sunlight radiation increased mineralization extent in all cases if compared to dark ozonation.

Simulated solar driven photolytic ozonation for the oxidation of aqueous recalcitrant-to-ozone tritosulfuron. Transformation products and toxicity.

This work reports the combination of ozone and solar radiation as an advanced oxidation process to remove the herbicide tritosufuron (TSF) in water. Firstly, the recalcitrance of TSF has been assessed, obtaining an ozonation second order rate constant of 5-154 M min in the range of pH from 5 to 8; while the rate constant with HO was found to be (1.8-3.

Iron-based catalysts for photocatalytic ozonation of some emerging pollutants of wastewater.

A synthetic secondary effluent containing an aqueous mixture of emerging contaminants (ECs) has been treated by photocatalytic ozonation using Fe(3+) or Fe3O4 as catalysts and black light lamps as the radiation source. For comparative purposes, ECs have also been treated by ultraviolet radiation (UVA radiation, black light) and ozonation (pH 3 and 7). With the exception of UVA radiation, O3-based processes lead to the total removal of ECs in the mixture.

Hypoglycaemia and somnambulism: a case report.

Sleepwalking (somnambulism) is a sleep disorder classified as a parasomnia. Sleepwalkers develop motor activities that may be simple or complex: they can get out of bed, walk, urinate and even leave the house while remaining unconscious and unable to communicate. It is difficult to wake a sleepwalker, but it is not dangerous - as many people think.

UV-C radiation based methods for aqueous metoprolol elimination.

The endocrine disruptor metoprolol has been oxidised in aqueous solution by means of the systems UV-C, UV-C/H(2)O(2), UV-C/percarbonate, UV-C/monopersulfate, UV-C/TiO(2), UV-C/H(2)O(2)/TiO(2) and photo-Fenton. From simple photolysis experiments the quantum yield of metoprolol has been calculated (roughly 5x10(-3) mol Einstein(-1) at circumneutral pH). Addition of free radicals promoters significantly enhanced the metoprolol depletion rate.

UV-C photolysis of endocrine disruptors. The influence of inorganic peroxides.

Norfloxacin, doxycycline and mefenamic acid have been photolysed with UV-C radiation (254 nm) in the presence and absence of inorganic peroxides (hydrogen peroxide or sodium monopersulfate). Quantum yields in the range (1.1-4.

Ozonation of the pharmaceutical compound ranitidine: reactivity and kinetic aspects.

Ranitidine has been ozonated under different operating conditions of pH, applied ozone dose, initial ranitidine concentration and presence or absence of free radical inhibitors. Results of ranitidine evolution with time indicate a high reactivity of this compound with molecular ozone. Mineralization levels achieved in the order of 20-25% suggest that the (CH3)2-N-CH2- moiety bonded to the furan ring could be separated from the rest of the ranitidine structure and further mineralized.

Ozone treatment of PAH contaminated soils: operating variables effect.

A three-level full factorial design has been conducted to assess the influence of gas flow-rate, ozone concentration and reaction time on the remediation of soil contaminated with four PAHs (namely acenaphthene, phenanthrene, anthracene and fluoranthene). Under the operating conditions investigated, reaction time and ozone concentration seem to exert a slight positive effect, whereas gas flow-rate does not affect the process efficiency. Average conversions (related to non-ozonated samples) are in the proximity of 50, 70, 60 and 100% for acenaphthene, phenanthrene, anthracene and fluoranthene, respectively.

Remediation of PAH spiked soils: concentrated H2O2 treatment/continuous hot water extraction-oxidation.

Artificially contaminated soil with four different polynuclear aromatic hydrocarbons (acenaphthene, phenathrene, anthracene and fluoranthene) has been separately treated by two different processes: (A) concentrated hydrogen peroxide at mild conditions of temperature (343-393 K) and pressure (0.5 MPa) and (B) hot water extraction at relatively high temperature (523-657 K) and pressure (10 MPa). Both methods achieve acceptable PAH removal percentages from soil.

Wastewater recycling: application of ozone based treatments to secondary effluents.

A secondary effluent from a municipal wastewater plant has been treated by means of several processes based on the use of ozone. Application of O(3) as the only oxidising reagent is capable of halving the initial COD (35 ppm at a flowrate of 40 L h(-1)) with a roughly 40% of mineralization degree. The system O(3)/H(2)O(2) slightly enhances COD removal albeit it is capable of significantly increasing the mineralization level up to 70% (35 ppm of O(3) at a flowrate of 40 L h(-1) in the presence of 0.

Supercritical CO(2) extraction of PAHs on spiked soil Co-solvent effect and solvent regeneration by ozonization.

The supercritical CO(2) extraction of four PAHs (acenaphthene, phenanthrene, anthracene and fluoranthene) from an artificially contaminated soil has been investigated. The effect of temperature (40-60 degrees C), pressure (300-500 bar) and extraction time (90-150 min) has been assessed by conducting a Box-Behnken experimental design. The results suggest the existence of perturbation variables other than the aforementioned controlled variables leading to a significant dispersion of extraction recoveries.

New approaches for education and training in veterinary public health: the SAPUVET projects.

Continued contact between humans and animals, in combination with the ever-increasing movement of human and animal populations that is one effect of globalization, contributes to the spread of diseases, often with detrimental effects on public health. This has led professionals involved in both animal health and public health to recognize veterinary public health (VPH) as a key area for their activities to address the human-animal interface. Veterinarians, a profession with major involvement in this field, are in need of specific knowledge and skills to prevent and control public-health problems.

Comparison of different advanced oxidation processes (AOPs) in the presence of perovskites.

The efficacy of the oxidation systems: O3, UV radiation, O3/UV radiation, O3/perovskite, UV radiation/perovskite, O3/UV radiation/perovskite, H2O2/UV radiation, H2O2/UV radiation/perovskite, has been investigated by using pyruvic acid as probe compound. Under the operating conditions used, the combination of UV radiation and hydrogen peroxide (with or without perovskites) leads to the fastest pyruvic acid removal while the best results in terms of mineralization degree are obtained when combining O3/UV radiation/perovskite. The effect of the variables: inlet ozone (15-75 mg L(-1)) and initial pyruvic acid (10(-3) to 10(-2)M) concentrations, catalyst load (0.

Photocatalytic ozonation of phenolic wastewaters: Syringic acid, tyrosol and gallic acid.

The photocatalytic ozonation of a mixture of 3 phenols (gallic acid, tyrosol and syringic acid) has been conducted under different operating conditions. The individual adsorption of the phenol type compounds onto titanium dioxide (photocatalyst) has been first evaluated. Equilibrium conditions are attained in less than an hour while the isotherm curves reveal that adsorption intensity increases in order: syringic acid < tyrosol < gallic acid.

Photocatalytic ozonation of winery wastewaters.

The combination of UV-A/vis radiation and ozone, in the presence of titanium dioxide, has been investigated as a potential destructive technology for the treatment of winery wastewaters. The contribution of the adsorption stage, single ozonation, photolytic ozonation, and photocatalysis has previously been assessed. Adsorption onto the TiO 2 surface accounts for a 15-20% removal of the initial chemical oxygen demand (COD).

Promoted wet air oxidation of polynuclear aromatic hydrocarbons.

The treatment of an aqueous solution of four polycyclic aromatic hydrocarbons, namely acenaphthene, phenanthrene, anthracene and fluoranthene, under moderate conditions of temperature and pressure has been conducted in the presence and absence of free radical promoters (hydrogen peroxide or potassium monopersulfate). With no addition of promoters, the process achieves PAH conversion values in the range 80-100% at 190 degrees C and 50 bars of air pressure (80 min of reaction). Similar results are obtained in the presence of hydrogen peroxide, however, in this case, the time required is just 60 min with a sharp decrease in PAH concentration in the first 10-20 min.

Photocatalytic promoted oxidation of phenolic mixtures: an insight into the operating and mechanistic aspects.

The photocatalytic oxidation of a phenolic mixture (gallic acid, tyrosol and syringic acid) has been carried out in the presence of titanium dioxide and a selected inorganic peroxide, namely persulphate, monopersulphate or hydrogen peroxide. The results obtained in UVA irradiated solutions reveal that hydrogen peroxide is the most effective option. The influence of some relevant operating parameters (i.

Photocatalysis of fluorene adsorbed onto TiO2.

The adsorption of fluorene onto TiO2 has been investigated by conducting equilibrium and kinetic experiments. Adsorption isotherms have been evaluated at two different pHs in the range of temperatures 296-325 K. The type III isotherm shapes obtained were modelled by considering several expressions taken from the literature.

[Health risks associated with the migration of Atlantic salmon (Salmo salar L.): an epidemiological surveillance programme in Northern Spain].

The authors present the results of an epidemiological surveillance programme involving Atlantic salmon (Salmo salar) populations in north-eastern Spain. The study investigates the risk factors critical in disease transmission, which include the presence of potentially pathogenic micro-organisms, the innate cell-mediated immune response of the salmon, and the potential interactions between the two. Also taken into account are the biological and migratory cycles of these salmon populations.

Adsorption of landfill leachates onto activated carbon. Equilibrium and kinetics.

The adsorption of stabilized leachates generated in a municipal landfill onto three commercial activated carbons has been investigated. Norit 0.8, Chemviron AQ40 and Picacarb 1240 have been used as adsorbents.

Phenol and substituted phenols AOPs remediation.

The oxidation of phenol and two substituted species (4-nitrophenol and 4-chlorophenol) has been carried out by means of the O3, UV-vis, O3+UV-vis, TiO2+UV-vis, O(3)+UV-vis+TiO2 and O3+TiO2 systems. From UV-vis experiments, the quantum yield of these organics has been calculated (0.018, 0.

Stabilized leachates: sequential coagulation-flocculation + chemical oxidation process.

The combined sedimentation-chemical oxidation treatment of medium-stabilized landfill leachates has been investigated. The sequence of stages implemented was: (a) coagulation-flocculation by pH decrease (pH 2) to acidic conditions (COD removal approximately 25% related to COD0 approximately 7500 ppm); (b) coagulation-flocculation by Fe(III) addition (0.01 M) at pH 3.

Aqueous ozone decomposition onto a Co2O3-alumina supported catalyst.

The aqueous ozone decomposition in the presence of a Co2O3-Alumina catalyst was investigated. Activity and estability assays were conducted by reusing the same catalyst in consecutive runs. The catalyst was shown to significantly increase the ozone abatement rate without loss in activity after five consecutive experiments.