J. M. Doña Rodríguez

J. M. Doña Rodríguez
Universidad de Las Palmas de Gran Canaria | ULPGC · Department of Chemistry

Professor Doctor

About

170
Publications
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5,147
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February 1995 - present
Universidad de Las Palmas de Gran Canaria
Position
  • Professor (Full)

Publications

Publications (170)
Article
Full-text available
This work reports a key factor, the H2SO4 concentration, in controlling the physicochemical properties of TiO2 photocatalysts during the sol-gel synthesis. The photocatalysts synthesized using different concentrations of H2SO4 possess specific anatase/rutile ratios and crystallite sizes as well as surface areas, resulting in different photocatalyti...
Article
Full-text available
Photocatalysis is one of the most promising processes within catalysis, due to its increasing potential and the possibility of its being combined with renewable solar energy. There are countless applications, such as hydrogen production from wastewater, decontamination and disinfection of gaseous and water effluents, and more specific applications...
Article
Phenol removal as organic pollutant model has been studied on new composite adsorbents prepared from carbon and natural diatomaceous silica mixtures in different proportions (KCp1, KCp2, and KCp3 with 10, 20, and 30% of carbonaceous matter, respectively). SEM observations clearly showed the porous aspect evolution when mixing carbon with the macrop...
Article
Full-text available
Two series of new photocatalysts were synthesized based on modification with Pd of the commercial P25 photocatalyst (EVONIK®). Two techniques were employed to incorporate Pd nanoparticles on the P25 surface: photodeposition (series Pd-P) and impregnation (series Pd-I). Both series were characterized in depth using a variety of instrumental techniqu...
Article
In this study, the photocatalytic activity in hydrogen production of a TiO2 catalyst with hierarchical structure and microsphere morphology was tested. This catalyst was synthesised by hydrolysis and condensation processes from a Ti(OBut)4 precursor and calcined at 150 °C, 400 °C and 630 °C. Hydrogen production of the subsequent photocatalysts rose...
Article
Full-text available
In this study, mortar specimens were prepared with a cement:sand:water ratio of 1:3:0.5, in accordance with standard EN196-1. Portland CEM I 52.5 R grey (G) and white (W) cements were used, together with normalised sand and distilled water. Different amounts of TiO2 photocatalyst were incorporated in the preparation of the mortar samples. The effec...
Article
Full-text available
The copper-impregnated pyrophyllite (Cu/RC) was prepared and used as catalyst in catalytic wet peroxide oxidation (CWPO) of phenol. The catalyst was prepared by impregnation of copper (2.5 wt%) into pyrophyllite-type clay and characterized by X-ray diffraction, X-ray fluorescence, X-ray photoelectron spectroscopy, Fourier transform infrared spectro...
Article
Full-text available
Pyrophyllite–TiO2 nanocomposite PTi750 was successfully synthesized using a sol–gel method at ambient temperature based on exfoliation of the pyrophyllite layered clay by incorporation of the TiO2 precursor titanium(IV) t-butoxide. PTi750 exhibited higher photocatalytic activity in phenol degradation compared with commercial TiO2 Aeroxide P25. Ag-p...
Article
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A study was undertaken of the adsorption and photocatalytic conversion of NO, NO2 and NO3⁻/HNO3 using two photocatalysts (P25 and HT-ET). The HT-ET is a catalyst synthesized in our laboratory comprised only of anatase phase and with a surface area three times larger than that of the P25. In powder form, the catalyst was introduced into and extended...
Article
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Magnetite (Fe3O4), a core-shell material (SiO2@Fe3O4), and reduced graphene oxide-Fe3O4 (referred as rGO-MN) were used as supports of a specific highly active TiO2 photocatalyst. Thermal treatments at 200 or 450 °C, different atmospheres (air or N2), and TiO2:support weight ratios (1.0, 1.5, or 2.0) were investigated. X-ray diffractograms revealed...
Article
We successfully synthesized an efficient photoactive pyrophyllite/TiO2 heterostructures using a sol-gel route at ambient temperature. The samples were prepared by exfoliation of a pyrophyllite layered-type clay by TiO2. The prepared samples exhibited strong photocatalytic activity for the degradation of phenol. The heterostructure PTi750 (SBET = 16...
Article
Full-text available
In this work, novel TiO2-based nanobelts with various phases were synthesized: biphasic TiO2(B)/anatase, pure TiO2(B) and pure anatase. These catalysts were obtained via hydrothermal reaction using two nanoparticulated TiO2 photocatalysts as precursors: Aeroxide TiO2 P25 (P25) and TiO2 synthesized via a sol-gel process (SG). In addition, the surfac...
Article
TiO 2 was obtained by a simple sol–gel synthesis and subsequently modified by the addition of Pt and/or Pd particles on the surface by photodeposition. These photocatalysts were characterised by X-ray diffraction analysis, UV–Vis diffuse reflectance spectra, Brunauer–Emmett–Teller measurements, Fourier transform infrared spectroscopy, transmission...
Article
Fenton-based processes have been studied for the mineralization and detoxification of wastewaters from the postharvest of fruit, which were contaminated with the fungicide imazalil (IMZ). For this purpose, studies were carried out in a simulated agro-industrial wastewater. Statistical design of experiments was used to assess the influence of IMZ, F...
Article
A study is undertaken of the effect of fluorinating two TiO2 catalysts, both with the same surface area but one composed only of pure anatase phase (SA) and the other of mixed anatase and rutile phases (P25), on the degradation of phenol, formic acid and aniline. The catalysts were characterised by FTIR, BET, EDAXs, SEM, XRD and DRS-UV–vis studies....
Article
TiO2 deactivation processes during gas-phase degradation of ethanol were studied. To force the deactivation processes, various cycles were performed, avoiding the degradation of acetates. It was observed that acetates adsorbed on the anatase phase of catalysts provoke the transference of electrons to surface traps which modify the electron states o...
Article
In this study, a comparative analysis is made of TiO2 modified with Pt or Au in NO photoxidation under different radiation and humidity conditions. The metals were deposited on the TiO2 surface using two methods, photodeposition and chemical reduction. All catalysts were supported on borosilicate 3.3 plates using a dip-coating technique. These modi...
Article
This work analyses the treatment of ornamental aquaculture wastewater contaminated with the antibiotic metronidazole (MTZ) using a reactor with supported TiO2. Preliminary photolysis and hydrolysis studies revealed inefficient elimination of this pollutant under the study conditions. The activity of various photocatalysts in suspension in the elimi...
Article
The performance and economic cost of the removal of phenol with TiO2-photocatalysis, photo-Fenton, biological aerated filter (BAF) and constructed wetland (CW) reactors has been studied. The BAF achieved complete removal with a phenol loading rate (LR) of 1.44 g·L-1·d-1. The BAF-CW combination provided a phenol-free effluent with a LR for the BAF o...
Article
In this study, a comparative analysis is made of TiO2 modified with Pt or Au in NO photoxidation under different radiation and humidity conditions. The metals were deposited on the TiO2 surface using two methods, photodeposition and chemical reduction. All catalysts were supported on borosilicate 3.3 plates using a dip-coating technique. These modi...
Article
This work studied the degradation and adsorption of dimethylphthalate (DMP) using various TiO2-based photocatalysts: TiO2 Aeroxide P25, Kronos vlp7000, Hombikat UV-100, Kemira 650 and a synthesized photocatalyst named SG750. As the photocatalysts with mixed anatase and rutile phases, P25 and SG750, showed greater activity than those of pure phase,...
Article
In this work, the effectiveness of UV and UV/H2O2 to degrade twenty-three pharmaceutical compounds present in microfiltered secondary effluent of an urban wastewater treatment plant was investigated. Apparent kinetic constant and UV doses required for effective removal of the studied compounds were calculated using a custom-made photochemical react...
Article
The effects of silver and palladium metals on the photocatalytic degradation of diclofenac sodium salt (DCF), isoproturon (IP) and phenol (PHL) in water over lab-made TiO2 synthesized following a sol–gel method were investigated. Silver and palladium catalysts were prepared by photodeposition at 1 wt.% of loading metal. The resulting materials were...
Article
The aim of this study was to find a recycling use for waste material (WTiO 2) that results from the extraction process of TiO 2 from ilmenite in the pigment industry. In view of its high TiO 2 content, the photocatalytic activity of this material was tested in the degradation of humic and fulvic acid substances (HFAs) and showed low levels of photo...
Article
The aim of this study was to find a recycling use for waste material (WTiO2) that results from the extraction process of TiO2 from ilmenite in the pigment industry. In view of its high TiO2 content, the photocatalytic activity of this material was tested in the degradation of humic and fulvic acid substances (HFAs) and showed low levels of photoact...
Article
Full-text available
The structural-microstructural characteristics and interfacial charge transfer are key issues to the development of efficient mixed phase TiO2 photocatalysts. In this work, the interplay of lattice deformation and microstrains as well as the identification of charge trapping sites and electron transfer were investigated for a series of nanostructur...
Article
Full-text available
The treatment of groundwater contaminated with gasoline and diesel with H2O2, H2O2 + UV, Fenton, and photo-Fenton was studied. Fenton reactions provided the best results with 1 mM of Fe2+ and 200 mM of H2O2. High contaminant removals were achieved, in particular those of COD (Fenton: 69%, photo-Fenton: 97%), Diesel Range Organics (99.9% both reacti...
Article
Full-text available
Fenton and photo-Fenton processes were tested for the treatment of wastewater from a local textile industry in Ecuador. The goal of this research was to obtain an efficient, easy-to-apply method for the removal of colour, organic compounds, biodegradability, resistant pollutants, and toxicity according to the Vibrio fischeri bioluminescence test. T...
Article
In this work, titanium dioxide has been modified by sulfation, fluorination and simultaneous Pt nanoparticles deposition; the influence of these treatments on the photocatalytic activity of this oxide has been studied. A complete characterization study was carried out and it was observed that sulfation, fluorination and metallization were important...
Article
In this work we present the results of the application of photocatalytic techniques to organic pollutants in water. Such aqueous wastes are produced during the UV–Vis spectrophotometric determination of the NH 4 + ion in water. Processes taking place during the photocatalytic degradation of such organics have been studied by using FTIR, HLPC and TO...
Article
A comparison is made in this study of the effectiveness of various commercial catalysts in the oxidation of NOx by heterogeneous photocatalysis. The following catalysts were considered: Aeroxide TiO2 P25, Aeroxide TiO2 P90, Hombikat UV-100, Kronos vlp7000, CristalACTIV PC105, CristalACTIV PC500, Kemira 650 and Anatasa Aldrich. All catalysts were de...
Article
This work demonstrates the efficiency of a hybrid photocatalysis/ultrafiltration process to eliminate or reduce the contents of synthetic dyes in water. The process involves highly active photocatalytic ceramic ultrafiltration (UF) membranes prepared with the deposition of various photocatalysts on the external and internal (pore) surface of UF mon...
Article
TiO2 coatings of highly photoactive lab-made titania were prepared on the outer wall of the inner tube of a glass tubular reactor by dip-coating method. The effect of decreasing the size of the aggregates to improve adhesion and photoactivity of the coatings to degrade phenol, diclofenac and isoproturon was also investigated. Chemical disaggregatio...
Article
A detailed study is undertaken of the photocatalytic activity in hydrogen production of the commercial photocatalyst Kronos vlp7000 (KR) surface-modified with photodeposited platinum particles (2.1 wt% Pt). The influence of different photocatalytic variables is studied: photocatalyst loading, suspension pH value and the nature and concentration of...
Article
Differences in the gas-phase photocatalytic degradation of NH3 and ethanol in the presence of water over two commercial TiO2 materials with different structural characteristics (Evonik's P25 (P25) and Sigma Aldrich's anatase (SA)) were established here using FTIR. The materials were characterized using different techniques including BET, XRD, UV-vi...
Conference Paper
Full-text available
INTRODUCTION This work focuses on the development of materials for hydrogen production by heterogeneous photocatalysis. Given the huge energy demands of modern society there is a need not only to exploit renewable resources like solar energy but also to accumulate that energy through energy vectors, like hydrogen, of clean combustion. Photocatalyti...
Article
In this work, a TiO2 photocatalyst synthesized using a sol-gel procedure (SG750) was Pt modified through photodeposition (SG750-2.1 wt%Pt) and tested for its efficiency in hydrogen production by heterogeneous photocatalysis in the presence of different alcohols as sacrificial agents. The tested alcohols were: methanol, ethanol, ethyleneglycol and g...
Article
This work studies the elimination, mineralization and detoxification through Fenton-based processes of wastewaters contaminated with the fungicide imazalil as a result of the postharvest treatment of bananas. Fe(II) and H2O2 concentrations were optimized for degradation of the corresponding imazalil concentrations. The activity of the imazalil degr...
Conference Paper
Full-text available
Heterogeneous photocatalysis using nanostructured titanium dioxide (TiO2) supported on borosilicate tubes and alumina blocks has been studied for the elimination of emerging contaminants from wastewater effluents. Adherence and aging of the catalyst were studied as well as the influence of the matrix in the photocatalytic kinetics. Operational para...
Article
Abstract In this study, the photoactivity of commercial and lab-made TiO2 when immobilized on different supports, namely borosilicate glass, alumina foam and refractory brick, was examined for the removal of the fungicide imazalil from different water matrices. Alumina foam provided the largest exposed photocatalyst surface but degradation kinetics...
Article
In this work we studied the elimination, mineralization and detoxification of wastewaters from banana postharvest industries, contaminated with the fungicide imazalil, by means of heterogeneous advanced oxidation processes. We compared the activity of the commercial photocatalyst Evonik P25 and the lab-made EST-1023t in the degradation of imazalil...
Article
Sol–gel synthesised TiO2 developed by our group was modified through the addition of nickel nitrate and ammonium carbonate in the synthesis process. Photocatalysts were synthesised with different Ni/Ti molar ratios (0.015, 0.030, 0.045) and constant Ni/N ratio equal to 1.5 and subjected to post-calcination at temperatures of between 400 °C and 700...
Article
H2 production from methanol/water photo-splitting was compared using various commercial photocatalysts (Evonik P25 (P25), Hombikat UV-100 (HB) and Kronos vlp7000 (KR)) and others synthesised with a sol-gel-hydrothermal (HT) process and a sol-gel method followed by calcination (SG400 and SG750). All photocatalysts had been surface modified with Au a...
Article
Full-text available
This article describes a photocatalytic nanostructured anatase coating deposited by cold gas spray (CGS) supported on titanium sub-oxide (TiO2−x ) coatings obtained by atmospheric plasma spray (APS) onto stainless steel cylinders. The photocatalytic coating was homogeneous and preserved the composition and nanostructure of the starting powder. The...
Article
Full-text available
Fluorine species adsorbed on the surface of TiO2 anatase nanoparticles improve their photocatalytic performance by reducing the recombination rate of photogenerated electrons and holes. Trifluoroacetic acid (TFAA) has been recently proposed as a promising harmless substitute for hydrofluoric acid (HF) in preparing fluorine-modified anatase with goo...
Article
Full-text available
Banana leaves, which represent the second major residue generated in banana cultivations, were used as raw material for the preparation of six different activated carbons. The adsorbents were developed from this lignocellulosic precursor by means of chemical activation with phosphoric acid, modifying the concentration of the activating agent and th...
Article
TiO2 Degussa P25, TiO2 prepared by sol–gel submitted to sulfation pre-treatment and some metallized catalysts obtained by photodeposition of Au or Pt over the sulfated TiO2, were evaluated in the reaction of ethanol photo-oxidation. FT-IR spectroscopy was used to investigate the surface features of the photocatalysts, identifying adsorbed species a...
Article
A series of synthesised TiO2-based and commercial photocatalysts were modified by Pt photodeposition and a study made of their photocatalytic activity in hydrogen production. The modified commercial photocatalysts were Evonik P25, Kronos vlp7000 and Hombikat UV-100, and the other modified photocatalysts were synthesised by our group using sol-gel a...
Article
The elimination and mineralization of the fungicide imazalil and its by-products has been studied by means of heterogeneous photocatalysis. The activity of different photocatalysts, including the commercial TiO2 benchmark photocatalyst (Evonik P25) and several TiO2-based lab-made catalysts, is compared. The best results were achieved with the new l...
Article
In this work the photocatalytic activity between a TiO2 catalyst synthesized by a modified sol–gel method (ECT), TiO2 nanoparticles surface modified with organic shell layer (m-TiO2) and a graphene oxide-TiO2 composite (GOT-3.3) was compared. Diphenhydramine (DP) pharmaceutical and methyl orange (MO) azo-dye were used as model water pollutants unde...
Article
Nanostructured titanium materials with high UV-visible activity were synthesized in the collaborative project Clean Water FP7. In this study, the efficiency of some of these catalysts to degrade endocrine disruptor compounds, using bisphenol A as the model compound, was evaluated. Titanium dioxide P25 (AEROXIDE(®) TiO2, Evonik Degussa) was used as...
Article
TiO2 particles were prepared by sol-gel method alone and by sol-gel method combined with hydrothermal treatment. The structural and photocatalytic properties of the two series of photocatalysts were compared. XRD studies revealed that rutilization was faster in the series of photocatalysts, which had been additionally subjected to a hydrothermal pr...
Article
2,4-dichlorophenol (DCP) was decomposed in the presence of TiO2 suspensions by illumination. The operating variables that were studied included initial DCP concentration, photocatalyst doses and initial pH. Mineralisation was slow at the optimum pH (12) for DCP degradation, with the optimum pH for both degradation and mineralisation being pHo 5. Th...
Article
TiO2-based photocatalyst materials were synthesized through a sol–gel method, followed either by: (1) hydrothermal treatment (150 °C/24 h), or (2) heat treatment (calcination) in a temperature range between 400 and 900 °C. The resulting materials were characterized through BET, XRD, TEM, FTIR, RAMAN, laser diffraction and UV–Vis Diffuse Reflectance...
Article
Banana leaves, which represent the second major residue generated in banana cultivations, were used as raw material for the preparation of six different activated carbons. The adsorbents were developed from this lignocellulosic precursor by means of chemical activation with phosphoric acid, modifying the concentration of the activating agent and th...
Article
245th National Meeting of the American-Chemical-Society (ACS), New Orleans, LA, APR 07-11, 2013
Article
A Ti–H2O2–phenol complex, not described until now, has been identified on the surface of Degussa P-25 and the new catalyst ECT-1023. This complex is considered to be responsible for the higher hydroquinone to catechol concentration ratio. It has been also shown that phenolates identified on the surface modify electrodonation that controls the gener...
Article
The photocatalytic degradation of the commercial dye Lanaset Sun Yellow 180 was studied in the presence and absence of the different additives used in the dye's formulation. The experiments were performed with Degussa P25 as received and doped with Fe (Fe-TiO(2)) and a new catalyst synthesized by our research group (ECT-1023). The best efficiency w...
Article
a b s t r a c t The homemade bare TiO 2 photocatalyst obtained in a previous work was modified with nanosized silver particles by liquid impregnation and photodeposition methods to obtain different noble metal load-ings (0.3–1 at.%). Characterization of the synthesized photocatalysts was carried out by the BET method, XPS, TEM, SEM-EDX, XRD and dif...