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Papers by Juan Ramon Moran Arana
Toxicological & Environmental Chemistry, 2003
Different methods such as KMnO4 oxidation, TiO2-photocatalysis and photo-Fenton reaction have bee... more Different methods such as KMnO4 oxidation, TiO2-photocatalysis and photo-Fenton reaction have been employed for the degradation of wastes from the spectrophotometric determination of in seawater. The optimisation of the degradation process was determined by total organic carbon (TOC) measurements. Experimental parameters such as pH, TiO2, H2O2, Fe or Fe concentrations have been checked. The highest TOC reduction was achieved by
Chemosphere, 2000
In this paper we present the results of the photocatalytic disinfection of urban waste water. Two... more In this paper we present the results of the photocatalytic disinfection of urban waste water. Two microbial groups, total coliforms and Streptoccocus faecalis, have been used as indexes to test disinfection eciencies. Dierent experimental parameters have been checked, such as the eect of TiO 2 , solar or UV-lamp light and pH. Disinfection of water samples has been achieved employing both UV-lamp and solar light in agreement with data shown by other authors. The higher disinfection rates obtained employing an UV-lamp may be explained by the stronger incident light intensity. Nevertheless no consistent dierences have been found between TiO 2-photocatalysis and direct solar or UV-lamp light irradiation at natural sample pH (7.8). At pH 5 the presence of TiO 2 increases the relative inactivation rate compared with the absence of the catalyst. After the photocatalytic bacterial inactivation, the later bacterial reappearance was checked for total coliforms at natural pH and pH 5, with and without TiO 2. Two h after the photocatalytic treatment, CFU increment was almost nill. But 24 and 48 h later an important bacterial CFU increment was observed. This CFU increment is slower after irradiation with TiO 2 at pH 5 in non-air-purged samples.
Chemosphere, 2004
The photocatalytic destruction of methanol, formaline (mixture of formaldehyde, methanol and wate... more The photocatalytic destruction of methanol, formaline (mixture of formaldehyde, methanol and water) and formaline wastes from the preservation of vertinarian physiologic samples has been attempted by two different processes, at high concentrations of reagents and by dossification of reagents, varying pH in both. Experiment evolution has been monitored by measuring the organic matter such as TOC and formaldehyde concentrations [H2CO]. Also, methanol and methanol-formaldehyde interactions with the TiO2 surface have been analysed by FTIR spectroscopy. Results indicate that at high concentrations the catalyst surfacial alterations given by methoxy, formates or carbonates, according to the pH of the sample can profoundly affect catalyst behaviour. It has been established that reagent dossification is advantageous for enhancing photonic efficiency as it minimizes the adsorbate presence that hampers the photocatalytic process.
Chemosphere, 2008
In the present work the photocatalytic and biological degradation of two commercial mixtures of p... more In the present work the photocatalytic and biological degradation of two commercial mixtures of pesticides (Folimat and Ronstar) and two fungicides (pyrimethanil and triadimenol) has been studied. The evolution of some components of these commercial products (dicofol, tetradifon and oxadiazon) and that of the two fungicides has been monitored by means of HPLC, GC-MS, TOC and toxicity (Lemna minor toxicity test) measurements. The photocatalytic method was able to degrade dicofol, tetradifon, pyrimethanil, triadimenol and the components of Ronstar with the exception of oxadiazon. In addition to this, the photocatalytic method eliminated pyrimethanil toxicity and reduced that of triadimenol by a 90%, Ronstar by a 78% and Folimat by an 87%. Nevertheless, the wetland reactors alone could reduce the toxicity of only the former. Finally, the proper dosage of the water containing the pesticides to a photocatalytic reactor followed by a wetland reactor resulted to be the most successful strategy for the detoxification of the studied compounds and their mixtures.
Chemosphere, 2001
Phenol degradation by Photo-Fenton reaction has been studied in highly concentrated wastewaters a... more Phenol degradation by Photo-Fenton reaction has been studied in highly concentrated wastewaters and most intermediate species have been identi®ed by Fourier Transform IR-Spectroscopy with ATR device. During the photodegradation of highly concentrated phenol solutions, the formation of dissolved and precipitate tannin has been observed. The possibility of a Fe 3-Pyrogallol complex formation, previous to the tannin formation, has been proposed too. The complex formation involving Fe 3 ions could be related to the observed Photo-Fenton activity decrease. Tannin formation inhibits the complete mineralization of phenol because Å OH radicals attack will produce further condensation steps and the polymer size increase. This fact limits the applicability of the process for highly concentrated phenolic wastes mineralization. However, the tannin precipitation allows its separation from the solution by conventional ®ltration, and reduction of the corresponding dissolved organic carbon. These observations have been proved from the identi®cation of primary degradation products, catechol and hydroquinone. Catechol is considered to be the ®rst step for the formation of tannins. Degradation process for phenol, catechol and hydroquinone have been monitored by total organic carbon (TOC) measurements along the reaction time span. From these results, a global mechanism for the Photo-Fenton degradation of phenol is proposed.
Toxicological & Environmental Chemistry, 2003
Different methods such as KMnO4 oxidation, TiO2-photocatalysis and photo-Fenton reaction have bee... more Different methods such as KMnO4 oxidation, TiO2-photocatalysis and photo-Fenton reaction have been employed for the degradation of wastes from the spectrophotometric determination of in seawater. The optimisation of the degradation process was determined by total organic carbon (TOC) measurements. Experimental parameters such as pH, TiO2, H2O2, Fe or Fe concentrations have been checked. The highest TOC reduction was achieved by
Chemosphere, 2000
In this paper we present the results of the photocatalytic disinfection of urban waste water. Two... more In this paper we present the results of the photocatalytic disinfection of urban waste water. Two microbial groups, total coliforms and Streptoccocus faecalis, have been used as indexes to test disinfection eciencies. Dierent experimental parameters have been checked, such as the eect of TiO 2 , solar or UV-lamp light and pH. Disinfection of water samples has been achieved employing both UV-lamp and solar light in agreement with data shown by other authors. The higher disinfection rates obtained employing an UV-lamp may be explained by the stronger incident light intensity. Nevertheless no consistent dierences have been found between TiO 2-photocatalysis and direct solar or UV-lamp light irradiation at natural sample pH (7.8). At pH 5 the presence of TiO 2 increases the relative inactivation rate compared with the absence of the catalyst. After the photocatalytic bacterial inactivation, the later bacterial reappearance was checked for total coliforms at natural pH and pH 5, with and without TiO 2. Two h after the photocatalytic treatment, CFU increment was almost nill. But 24 and 48 h later an important bacterial CFU increment was observed. This CFU increment is slower after irradiation with TiO 2 at pH 5 in non-air-purged samples.
Chemosphere, 2004
The photocatalytic destruction of methanol, formaline (mixture of formaldehyde, methanol and wate... more The photocatalytic destruction of methanol, formaline (mixture of formaldehyde, methanol and water) and formaline wastes from the preservation of vertinarian physiologic samples has been attempted by two different processes, at high concentrations of reagents and by dossification of reagents, varying pH in both. Experiment evolution has been monitored by measuring the organic matter such as TOC and formaldehyde concentrations [H2CO]. Also, methanol and methanol-formaldehyde interactions with the TiO2 surface have been analysed by FTIR spectroscopy. Results indicate that at high concentrations the catalyst surfacial alterations given by methoxy, formates or carbonates, according to the pH of the sample can profoundly affect catalyst behaviour. It has been established that reagent dossification is advantageous for enhancing photonic efficiency as it minimizes the adsorbate presence that hampers the photocatalytic process.
Chemosphere, 2008
In the present work the photocatalytic and biological degradation of two commercial mixtures of p... more In the present work the photocatalytic and biological degradation of two commercial mixtures of pesticides (Folimat and Ronstar) and two fungicides (pyrimethanil and triadimenol) has been studied. The evolution of some components of these commercial products (dicofol, tetradifon and oxadiazon) and that of the two fungicides has been monitored by means of HPLC, GC-MS, TOC and toxicity (Lemna minor toxicity test) measurements. The photocatalytic method was able to degrade dicofol, tetradifon, pyrimethanil, triadimenol and the components of Ronstar with the exception of oxadiazon. In addition to this, the photocatalytic method eliminated pyrimethanil toxicity and reduced that of triadimenol by a 90%, Ronstar by a 78% and Folimat by an 87%. Nevertheless, the wetland reactors alone could reduce the toxicity of only the former. Finally, the proper dosage of the water containing the pesticides to a photocatalytic reactor followed by a wetland reactor resulted to be the most successful strategy for the detoxification of the studied compounds and their mixtures.
Chemosphere, 2001
Phenol degradation by Photo-Fenton reaction has been studied in highly concentrated wastewaters a... more Phenol degradation by Photo-Fenton reaction has been studied in highly concentrated wastewaters and most intermediate species have been identi®ed by Fourier Transform IR-Spectroscopy with ATR device. During the photodegradation of highly concentrated phenol solutions, the formation of dissolved and precipitate tannin has been observed. The possibility of a Fe 3-Pyrogallol complex formation, previous to the tannin formation, has been proposed too. The complex formation involving Fe 3 ions could be related to the observed Photo-Fenton activity decrease. Tannin formation inhibits the complete mineralization of phenol because Å OH radicals attack will produce further condensation steps and the polymer size increase. This fact limits the applicability of the process for highly concentrated phenolic wastes mineralization. However, the tannin precipitation allows its separation from the solution by conventional ®ltration, and reduction of the corresponding dissolved organic carbon. These observations have been proved from the identi®cation of primary degradation products, catechol and hydroquinone. Catechol is considered to be the ®rst step for the formation of tannins. Degradation process for phenol, catechol and hydroquinone have been monitored by total organic carbon (TOC) measurements along the reaction time span. From these results, a global mechanism for the Photo-Fenton degradation of phenol is proposed.