In this work, photocatalytic materials constituted by Cr-doped TiO2 (Cr-TiO2) decorated with nobl... more In this work, photocatalytic materials constituted by Cr-doped TiO2 (Cr-TiO2) decorated with noble metals show high effectiveness in the mineralization of Acid Orange 7 (AO7) and in the disinfection of real river water. The materials were firstly obtained by sol-gel method to get Cr-TiO2 that was subsequently modified by photochemical deposition of Ag or Pd nanoparticles (Ag/Cr-TiO2, Pd/Cr-TiO2). Chemical-physical characterization results evidenced that the noble metals were homogeneously distributed on the Cr-TiO2 surface. By using Pd(0.25%)/Cr-TiO2, the AO7 discoloration efficiency was about 91.4% after only 60 min of visible irradiation, which can be due to the lowest band gap of this material. Moreover, nitrates, chlorides, total hardness, and coliform bacteria content significantly decreased after the treatment of real river water samples (that is contaminated by industrial and domestic effluents) under UV and visible light irradiation in the presence of TiCrOx decorated with n...
XIX Congresso Nazionale Divisione di Chimica Industriale della Società Chimica Italiana, 2015
Improving visible light active photocatalyst performances through photoactive supports in the pho... more Improving visible light active photocatalyst performances through photoactive supports in the photocatalytic removal of emerging contaminant
Nanomaterials for the Detection and Removal of Wastewater Pollutants, 2020
Abstract This chapter starts with an introduction to photocatalysts active under visible light. T... more Abstract This chapter starts with an introduction to photocatalysts active under visible light. Then, the different doping modes for TiO2 are discussed. For its importance, nitrogen-doped TiO2 is described in great detail: in particular the synthesis of nitrogen-doped TiO2 was reported, focusing on the optimization of nitrogen-doped TiO2 photocatalytic activity using ammonia as nitrogen source. Finally, some applications of nitrogen-doped TiO2 in environmental remediation are presented, discussing the characteristic of structured supported photocatalysts, and briefly the photocatalytic performances when nitrogen-doped TiO2 is supported on glass spheres or on phosphors, luminescent materials able to convert light energy into photons of different energy. Nitrogen-doped TiO2 coupled with up-conversion phosphors and nitrogen-doped TiO2 coupled with down-conversion phosphors preparation and behaviors are summarized.
Waters coming from dyeing and finishing processes by leather industries produce serious problems ... more Waters coming from dyeing and finishing processes by leather industries produce serious problems because they contain dyes and other pollutants. Toxic and recalcitrant for the environmental, these pollutants are difficult to remove by conventional treatments. For this reason, the heterogeneous photocatalysis is a promising and efficient method to remove them. ZnO is an excellent and promising photocatalytic material to oxidize organic pollutants into CO2 and H2O. In order to enhance the photocatalytic activity of ZnO, in this work, the doping of ZnO with praseodymium (Pr) has been realized and studied in the photocatalytic treatment of dyeing and finishing waters with a total organic carbon (TOC) values in the range 540-1200 mg·L-1. ZnO particles doped with Pr were prepared by a modified precipitation method and characterized by different techniques (XRD, Raman, UV-Vis DRS). The photocatalytic activities of the synthesized samples were investigated under UV light with a specifically...
Photocatalytic Removal of Phenol by Ferromagnetic NTiO2/SiO2/Fe3O4 Nanoparticles in presence of V... more Photocatalytic Removal of Phenol by Ferromagnetic NTiO2/SiO2/Fe3O4 Nanoparticles in presence of Visible Light Irradiation Vincenzo Vaiano, Olga Sacco, Diana Sannino, Marco Stoller, Paolo Ciambelli, Angelo Chianese Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II 132, 84084 Fisciano (SA), Italy Department of Chemical Material Environmental Engineering, University of Rome “La Sapienza”, Via Eudossiana 18, 00184 Rome, Italy. [email protected]
The aim of the work was to increase the photoactivity of N-doped TiO2 photocatalyst, active in vi... more The aim of the work was to increase the photoactivity of N-doped TiO2 photocatalyst, active in visible light region, through the improving of the illumination efficiency. Microradiators like phosphors (namely, ZPS) which absorb an electromagnetic radiation by the external light source (UV) and, with no time delay, emit visible light, opportunely selected to be able to excite N-doped TiO2 photocatalyst. Preliminary investigations were performed on physical mixtures of phosphors and N-doped TiO2, evaluating the decolourization of methylene blue (MB). The simultaneous presence of N-doped TiO2 and light carriers showed an increased decolourization activity, reaching about 100 % with a total TOC removal after 3 h of irradiation. To get core-shell photocatalysts, N-doped TiO2 was supported on ZPS (NTiO2-ZPS) by a modified sol–gel method. The content of N-doped TiO2 was varied in the range 5-50 wt % to find an optimum loading. The photocatalytic activity of NTiO2-ZPS was evaluated for the ...
In this work, TiO2-Ag-zeolite was supported on porous ceramic tiles to enhance the self-cleaning ... more In this work, TiO2-Ag-zeolite was supported on porous ceramic tiles to enhance the self-cleaning properties. The influence on adsorption and photocatalytic properties of the anchored composite with respect to a coating with only TiO2 has been evaluated. Functionalized tiles were obtained through a method that involves a sol- gel preparation followed by calcination at 550 °C for 2 h and different samples at different titanium and silver surface loads were prepared. The verification of the self-cleaning properties was conducted through adsorption and photocatalytic tests realized using aqueous solutions containing methylene blue (MB).Characterization results evidenced that the deposition method induced the formation of TiO2/Ag-zeolite layer, strongly adherent to the tile surface, in which TiO2 is present in anatase phase. The photocatalytic performances are strongly influenced by the amount of TiO2-Ag-zeolite composite deposited on the tile surface.
Photocatalytic Conversion of Glucose to H2 over LaFeO3 Perovskite Nanoparticles Giuseppina Iervol... more Photocatalytic Conversion of Glucose to H2 over LaFeO3 Perovskite Nanoparticles Giuseppina Iervolino, Vincenzo Vaiano, Diana Sannino, Luigi Rizzo, Paolo Ciambelli a Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano (SA), Italy b Department of Civil Engineering, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano (SA) Italy [email protected]
Unlike traditional catalysts that drive chemical reactions by thermal energy, photocatalysts can ... more Unlike traditional catalysts that drive chemical reactions by thermal energy, photocatalysts can induce chemical reactions by light activation. It is well known that greenhouse gases, such as CO2, are the primary causes of global warming. From an environmental point of view, it is interesting to transform CO2 into hydrocarbons, such as CH4. Since this transformation has high energy duty, a photocatalytic process can be an effective way. There are few examples in literature concerning the use of photocatalytic fluidized bed photoreactor for the reduction of CO2 into CH4. The aim of this work is to investigate the performances of a high efficiency two-dimensional fluidized bed catalytic photoreactor with Cu/TiO2, Ru/TiO2 and Pd/TiO2. CH4 was the main product with very few amounts of CO. No deactivation phenomena were observed. Pd/TiO2 photocatalysts showed the best performances. At Pd load of 1 wt. %, CH4 photoproduction was 64 μmol g-1 h-1 , against 15 μmol g-1 h-1 achieved with bare TiO2. The photoreactivity reached with Pd/TiO2 is significantly higher than that reported in the current literature on gas-solid photocatalytic systems for the photoreduction of CO2. 2. Experimental 2.1 Catalysts preparation and characterization Me/TiO2 (Me=Cu, Ru, Pd) catalysts were prepared by wet impregnation of anatase titania (PC500, Crystal Global) with solutions of different precursor salts, followed by drying at 120°C and calcination in air at 450°C for 2 h. In particular, (C5H8O2)3Ru, CuN2O6, Pd(NH3)4(NO3)2 were used for Ru/TiO2, Cu/TiO2 and Pd/TiO2,
An optimized Ru-doped LaFeO 3 photocatalyst was coupled with magnetic Fe 2 O 3 particles and was ... more An optimized Ru-doped LaFeO 3 photocatalyst was coupled with magnetic Fe 2 O 3 particles and was tested in the photocatalytic hydrogen production from glucose degradation under visible light irradiation. The catalysts were successfully synthesized by solution combustion synthesis using citric acid as organic fuel. Complete glucose degradation and hydrogen production of 5460 mmol/L was obtained after 4 h of irradiation using composite containing 67 wt% of Ru-doped LaFeO 3. After seven cycles of reuse, the photocatalytic activity did not change, evidencing the high stability of the magnetic photocatalyst, which can be recovered from the photoreactor using an external magnetic force. The recyclable sample was finally tested in the treatment of real wastewater from cherries washing process, and a very high hydrogen production (12344 mmol/L) was achieved. Finally, the possibility to couple the photocatalytic process (used for the production of hydrogen) with a heterogeneous photo-Fenton process was investigated in order to mineralize the unconverted organics in the wastewater coming from the photoreactor.
Abstract Imogolite-like nanomaterials were tested as heterogeneous catalysts for the photo-cataly... more Abstract Imogolite-like nanomaterials were tested as heterogeneous catalysts for the photo-catalytic degradation of tartrazine (a food dye recalcitrant to biodegradation and responsible of allergic and/or intolerance reactions) in the presence of H 2 O 2 . Methyl-imogolite, a hybrid organic/inorganic material with chemical composition (OH) 3 Al 2 O 3 SiCH 3 , occurs as single-walled nanotubes with an inner surface lined by Si-CH 3 groups and an aluminum oxo-hydroxide outer surface, where octahedral Al 3+ ions may be isomorphically substituted by Fe 3+ ions. Besides bare methyl-imogolite, novel Fe doped nanotubes (with nominal composition (OH) 3 Al 2-x Fe x O 3 SiCH 3 , where x = 0.025 or 0.050) were prepared by ion exchange of preformed methyl-imogolite with FeCl 3 × 6H 2 O in water. Physico-chemical characterization of the materials showed that Fe doping positively modifies nanotubes light absorption capacity by lowering the band gap of methyl-imogolite from 4.9 eV to 2.4 eV. At higher Fe content (sample with nominal composition (OH) 3 Al 1.950 Fe 0.050 O 3 SiCH 3 ), some Fe oxo-hydroxide clusters form, due to the natural tendency of Fe to form aggregates. Photo-degradation tests of tartrazine show that both bare and Fe-doped methyl-imogolite efficiently remove the dye from aqueous mixtures through different mechanisms. With bare methyl-imogolite, under UV light almost 65% Total Organic Carbon (TOC) is removed within 2 h, likely due to the formation of reactive AlOOH groups promptly generating HO radicals. With sample having nominal composition (OH) 3 Al 1.975 Fe 0.025 O 3 SiCH 3 , Fe 3+ species undergo efficient photo-Fenton reaction under UV light, leading to 90% TOC removal after 2 h. Conversely, the Fe oxo-hydroxide clusters at nanotubes outer surface likely worsen the photo-Fenton activity of the sample with (OH) 3 Al 1.950 Fe 0.050 O 3 SiCH 3 nominal composition as far as the TOC removal is concerned.
In this work the photocatalytic activity of Pr-doped ZnO (Pr-ZnO) photocatalysts has been address... more In this work the photocatalytic activity of Pr-doped ZnO (Pr-ZnO) photocatalysts has been addressed for the first time in the treatment of aqueous solutions at high concentration of organic dyes under UV or visible light irradiation. Pr-ZnO photocatalysts were prepared by a precipitation method. The catalysts have been characterized by different techniques such as X-ray diffraction (XRD), UV-Vis diffuse reflectance (UV-Vis DRS) and Raman spectroscopy. XRD results showed that Pr 3+ ions were successfully incorporated into the ZnO lattice. UV-Vis DRS spectra evidenced that Pr-ZnO samples present band-gap values of about 3.0 eV, lower than undoped ZnO (3.3 eV). The efficiency of photocatalysts has been tested in the photocatalytic removal of the azo dye Eriochrome Black T (EBT) under UV or visible light irradiation. The experimental results showed that the values of discoloration and mineralization rate are correlated to the Pr doping level, evidencing that the optimal loading of Pr in the ZnO structure is 0.46 mol %. The influence of process parameters (catalyst dosage, initial dye concentration and presence of carbonate ions) on the extent of photocatalytic performances has been investigated. The efficiency of the optimized photocatalyst was also evaluated in the photocatalytic treatment of aqueous solutions containing the triphenylmethane Patent Blue V (PB) dye and in the treatment of a solution containing simultaneously the two selected dyes (EBT and PB). Photocatalytic activity tests in presence of ion scavengers (carbonate ions) showed that the formulated Pr-ZnO photocatalyst is not subjected to deactivation phenomena. At last, a very interesting result was observed for the treatment of a real *Revised Manuscript Click here to view linked References A c c e p t e d M a n u s c r i p t 2 wastewater containing Basic Red 51 dye, showing that the complete discoloration and mineralization was achieved.
In the present study, we investigated the effect of cerium and erbium doping of the zirconium dio... more In the present study, we investigated the effect of cerium and erbium doping of the zirconium dioxide matrix. We synthesized doped samples using hydrothermal process. The amounts of dopant used were 0.5%, 1% and 5% molar (rare earth oxide over zirconium dioxide) respectively. The samples have been studied via X-ray Diffraction measurements for the structural characterization. UV visible diffuse reflectance was used for the optical analysis, Brunauer-Emmett-Teller (BET) model for the measurement of the surface area. Finally the samples have been analysed via electron paramagnetic resonance (EPR) for the electronic characterization. Then we tested the new synthetized materials to determine their photocatalytic activity in the reaction of degradation of methylene blue performed under irradiation by diodes (LEDs) emitting exclusively visible light.
In this work, photocatalytic materials constituted by Cr-doped TiO2 (Cr-TiO2) decorated with nobl... more In this work, photocatalytic materials constituted by Cr-doped TiO2 (Cr-TiO2) decorated with noble metals show high effectiveness in the mineralization of Acid Orange 7 (AO7) and in the disinfection of real river water. The materials were firstly obtained by sol-gel method to get Cr-TiO2 that was subsequently modified by photochemical deposition of Ag or Pd nanoparticles (Ag/Cr-TiO2, Pd/Cr-TiO2). Chemical-physical characterization results evidenced that the noble metals were homogeneously distributed on the Cr-TiO2 surface. By using Pd(0.25%)/Cr-TiO2, the AO7 discoloration efficiency was about 91.4% after only 60 min of visible irradiation, which can be due to the lowest band gap of this material. Moreover, nitrates, chlorides, total hardness, and coliform bacteria content significantly decreased after the treatment of real river water samples (that is contaminated by industrial and domestic effluents) under UV and visible light irradiation in the presence of TiCrOx decorated with n...
XIX Congresso Nazionale Divisione di Chimica Industriale della Società Chimica Italiana, 2015
Improving visible light active photocatalyst performances through photoactive supports in the pho... more Improving visible light active photocatalyst performances through photoactive supports in the photocatalytic removal of emerging contaminant
Nanomaterials for the Detection and Removal of Wastewater Pollutants, 2020
Abstract This chapter starts with an introduction to photocatalysts active under visible light. T... more Abstract This chapter starts with an introduction to photocatalysts active under visible light. Then, the different doping modes for TiO2 are discussed. For its importance, nitrogen-doped TiO2 is described in great detail: in particular the synthesis of nitrogen-doped TiO2 was reported, focusing on the optimization of nitrogen-doped TiO2 photocatalytic activity using ammonia as nitrogen source. Finally, some applications of nitrogen-doped TiO2 in environmental remediation are presented, discussing the characteristic of structured supported photocatalysts, and briefly the photocatalytic performances when nitrogen-doped TiO2 is supported on glass spheres or on phosphors, luminescent materials able to convert light energy into photons of different energy. Nitrogen-doped TiO2 coupled with up-conversion phosphors and nitrogen-doped TiO2 coupled with down-conversion phosphors preparation and behaviors are summarized.
Waters coming from dyeing and finishing processes by leather industries produce serious problems ... more Waters coming from dyeing and finishing processes by leather industries produce serious problems because they contain dyes and other pollutants. Toxic and recalcitrant for the environmental, these pollutants are difficult to remove by conventional treatments. For this reason, the heterogeneous photocatalysis is a promising and efficient method to remove them. ZnO is an excellent and promising photocatalytic material to oxidize organic pollutants into CO2 and H2O. In order to enhance the photocatalytic activity of ZnO, in this work, the doping of ZnO with praseodymium (Pr) has been realized and studied in the photocatalytic treatment of dyeing and finishing waters with a total organic carbon (TOC) values in the range 540-1200 mg·L-1. ZnO particles doped with Pr were prepared by a modified precipitation method and characterized by different techniques (XRD, Raman, UV-Vis DRS). The photocatalytic activities of the synthesized samples were investigated under UV light with a specifically...
Photocatalytic Removal of Phenol by Ferromagnetic NTiO2/SiO2/Fe3O4 Nanoparticles in presence of V... more Photocatalytic Removal of Phenol by Ferromagnetic NTiO2/SiO2/Fe3O4 Nanoparticles in presence of Visible Light Irradiation Vincenzo Vaiano, Olga Sacco, Diana Sannino, Marco Stoller, Paolo Ciambelli, Angelo Chianese Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II 132, 84084 Fisciano (SA), Italy Department of Chemical Material Environmental Engineering, University of Rome “La Sapienza”, Via Eudossiana 18, 00184 Rome, Italy. [email protected]
The aim of the work was to increase the photoactivity of N-doped TiO2 photocatalyst, active in vi... more The aim of the work was to increase the photoactivity of N-doped TiO2 photocatalyst, active in visible light region, through the improving of the illumination efficiency. Microradiators like phosphors (namely, ZPS) which absorb an electromagnetic radiation by the external light source (UV) and, with no time delay, emit visible light, opportunely selected to be able to excite N-doped TiO2 photocatalyst. Preliminary investigations were performed on physical mixtures of phosphors and N-doped TiO2, evaluating the decolourization of methylene blue (MB). The simultaneous presence of N-doped TiO2 and light carriers showed an increased decolourization activity, reaching about 100 % with a total TOC removal after 3 h of irradiation. To get core-shell photocatalysts, N-doped TiO2 was supported on ZPS (NTiO2-ZPS) by a modified sol–gel method. The content of N-doped TiO2 was varied in the range 5-50 wt % to find an optimum loading. The photocatalytic activity of NTiO2-ZPS was evaluated for the ...
In this work, TiO2-Ag-zeolite was supported on porous ceramic tiles to enhance the self-cleaning ... more In this work, TiO2-Ag-zeolite was supported on porous ceramic tiles to enhance the self-cleaning properties. The influence on adsorption and photocatalytic properties of the anchored composite with respect to a coating with only TiO2 has been evaluated. Functionalized tiles were obtained through a method that involves a sol- gel preparation followed by calcination at 550 °C for 2 h and different samples at different titanium and silver surface loads were prepared. The verification of the self-cleaning properties was conducted through adsorption and photocatalytic tests realized using aqueous solutions containing methylene blue (MB).Characterization results evidenced that the deposition method induced the formation of TiO2/Ag-zeolite layer, strongly adherent to the tile surface, in which TiO2 is present in anatase phase. The photocatalytic performances are strongly influenced by the amount of TiO2-Ag-zeolite composite deposited on the tile surface.
Photocatalytic Conversion of Glucose to H2 over LaFeO3 Perovskite Nanoparticles Giuseppina Iervol... more Photocatalytic Conversion of Glucose to H2 over LaFeO3 Perovskite Nanoparticles Giuseppina Iervolino, Vincenzo Vaiano, Diana Sannino, Luigi Rizzo, Paolo Ciambelli a Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano (SA), Italy b Department of Civil Engineering, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano (SA) Italy [email protected]
Unlike traditional catalysts that drive chemical reactions by thermal energy, photocatalysts can ... more Unlike traditional catalysts that drive chemical reactions by thermal energy, photocatalysts can induce chemical reactions by light activation. It is well known that greenhouse gases, such as CO2, are the primary causes of global warming. From an environmental point of view, it is interesting to transform CO2 into hydrocarbons, such as CH4. Since this transformation has high energy duty, a photocatalytic process can be an effective way. There are few examples in literature concerning the use of photocatalytic fluidized bed photoreactor for the reduction of CO2 into CH4. The aim of this work is to investigate the performances of a high efficiency two-dimensional fluidized bed catalytic photoreactor with Cu/TiO2, Ru/TiO2 and Pd/TiO2. CH4 was the main product with very few amounts of CO. No deactivation phenomena were observed. Pd/TiO2 photocatalysts showed the best performances. At Pd load of 1 wt. %, CH4 photoproduction was 64 μmol g-1 h-1 , against 15 μmol g-1 h-1 achieved with bare TiO2. The photoreactivity reached with Pd/TiO2 is significantly higher than that reported in the current literature on gas-solid photocatalytic systems for the photoreduction of CO2. 2. Experimental 2.1 Catalysts preparation and characterization Me/TiO2 (Me=Cu, Ru, Pd) catalysts were prepared by wet impregnation of anatase titania (PC500, Crystal Global) with solutions of different precursor salts, followed by drying at 120°C and calcination in air at 450°C for 2 h. In particular, (C5H8O2)3Ru, CuN2O6, Pd(NH3)4(NO3)2 were used for Ru/TiO2, Cu/TiO2 and Pd/TiO2,
An optimized Ru-doped LaFeO 3 photocatalyst was coupled with magnetic Fe 2 O 3 particles and was ... more An optimized Ru-doped LaFeO 3 photocatalyst was coupled with magnetic Fe 2 O 3 particles and was tested in the photocatalytic hydrogen production from glucose degradation under visible light irradiation. The catalysts were successfully synthesized by solution combustion synthesis using citric acid as organic fuel. Complete glucose degradation and hydrogen production of 5460 mmol/L was obtained after 4 h of irradiation using composite containing 67 wt% of Ru-doped LaFeO 3. After seven cycles of reuse, the photocatalytic activity did not change, evidencing the high stability of the magnetic photocatalyst, which can be recovered from the photoreactor using an external magnetic force. The recyclable sample was finally tested in the treatment of real wastewater from cherries washing process, and a very high hydrogen production (12344 mmol/L) was achieved. Finally, the possibility to couple the photocatalytic process (used for the production of hydrogen) with a heterogeneous photo-Fenton process was investigated in order to mineralize the unconverted organics in the wastewater coming from the photoreactor.
Abstract Imogolite-like nanomaterials were tested as heterogeneous catalysts for the photo-cataly... more Abstract Imogolite-like nanomaterials were tested as heterogeneous catalysts for the photo-catalytic degradation of tartrazine (a food dye recalcitrant to biodegradation and responsible of allergic and/or intolerance reactions) in the presence of H 2 O 2 . Methyl-imogolite, a hybrid organic/inorganic material with chemical composition (OH) 3 Al 2 O 3 SiCH 3 , occurs as single-walled nanotubes with an inner surface lined by Si-CH 3 groups and an aluminum oxo-hydroxide outer surface, where octahedral Al 3+ ions may be isomorphically substituted by Fe 3+ ions. Besides bare methyl-imogolite, novel Fe doped nanotubes (with nominal composition (OH) 3 Al 2-x Fe x O 3 SiCH 3 , where x = 0.025 or 0.050) were prepared by ion exchange of preformed methyl-imogolite with FeCl 3 × 6H 2 O in water. Physico-chemical characterization of the materials showed that Fe doping positively modifies nanotubes light absorption capacity by lowering the band gap of methyl-imogolite from 4.9 eV to 2.4 eV. At higher Fe content (sample with nominal composition (OH) 3 Al 1.950 Fe 0.050 O 3 SiCH 3 ), some Fe oxo-hydroxide clusters form, due to the natural tendency of Fe to form aggregates. Photo-degradation tests of tartrazine show that both bare and Fe-doped methyl-imogolite efficiently remove the dye from aqueous mixtures through different mechanisms. With bare methyl-imogolite, under UV light almost 65% Total Organic Carbon (TOC) is removed within 2 h, likely due to the formation of reactive AlOOH groups promptly generating HO radicals. With sample having nominal composition (OH) 3 Al 1.975 Fe 0.025 O 3 SiCH 3 , Fe 3+ species undergo efficient photo-Fenton reaction under UV light, leading to 90% TOC removal after 2 h. Conversely, the Fe oxo-hydroxide clusters at nanotubes outer surface likely worsen the photo-Fenton activity of the sample with (OH) 3 Al 1.950 Fe 0.050 O 3 SiCH 3 nominal composition as far as the TOC removal is concerned.
In this work the photocatalytic activity of Pr-doped ZnO (Pr-ZnO) photocatalysts has been address... more In this work the photocatalytic activity of Pr-doped ZnO (Pr-ZnO) photocatalysts has been addressed for the first time in the treatment of aqueous solutions at high concentration of organic dyes under UV or visible light irradiation. Pr-ZnO photocatalysts were prepared by a precipitation method. The catalysts have been characterized by different techniques such as X-ray diffraction (XRD), UV-Vis diffuse reflectance (UV-Vis DRS) and Raman spectroscopy. XRD results showed that Pr 3+ ions were successfully incorporated into the ZnO lattice. UV-Vis DRS spectra evidenced that Pr-ZnO samples present band-gap values of about 3.0 eV, lower than undoped ZnO (3.3 eV). The efficiency of photocatalysts has been tested in the photocatalytic removal of the azo dye Eriochrome Black T (EBT) under UV or visible light irradiation. The experimental results showed that the values of discoloration and mineralization rate are correlated to the Pr doping level, evidencing that the optimal loading of Pr in the ZnO structure is 0.46 mol %. The influence of process parameters (catalyst dosage, initial dye concentration and presence of carbonate ions) on the extent of photocatalytic performances has been investigated. The efficiency of the optimized photocatalyst was also evaluated in the photocatalytic treatment of aqueous solutions containing the triphenylmethane Patent Blue V (PB) dye and in the treatment of a solution containing simultaneously the two selected dyes (EBT and PB). Photocatalytic activity tests in presence of ion scavengers (carbonate ions) showed that the formulated Pr-ZnO photocatalyst is not subjected to deactivation phenomena. At last, a very interesting result was observed for the treatment of a real *Revised Manuscript Click here to view linked References A c c e p t e d M a n u s c r i p t 2 wastewater containing Basic Red 51 dye, showing that the complete discoloration and mineralization was achieved.
In the present study, we investigated the effect of cerium and erbium doping of the zirconium dio... more In the present study, we investigated the effect of cerium and erbium doping of the zirconium dioxide matrix. We synthesized doped samples using hydrothermal process. The amounts of dopant used were 0.5%, 1% and 5% molar (rare earth oxide over zirconium dioxide) respectively. The samples have been studied via X-ray Diffraction measurements for the structural characterization. UV visible diffuse reflectance was used for the optical analysis, Brunauer-Emmett-Teller (BET) model for the measurement of the surface area. Finally the samples have been analysed via electron paramagnetic resonance (EPR) for the electronic characterization. Then we tested the new synthetized materials to determine their photocatalytic activity in the reaction of degradation of methylene blue performed under irradiation by diodes (LEDs) emitting exclusively visible light.
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