Jose Manuel Gatica

Universidad de Cádiz | UCA · Department of Material Science and Metallurgy Engineering and Inorganic Chemistry

This study assesses the efficacy of natural clays as a cost-effective and ecologically sound method for the removal of tetracycline from water. A notable advancement in the field of antibiotic removal is the utilization of honeycomb monoliths in lieu of traditional powder-based materials. The objective of this approach is to facilitate easier handl...

Rice husk, a byproduct of rice production, presents significant environmental challenges due to its disposal, while the emission of volatile organic compounds into the atmosphere poses additional concerns. This study addresses these issues by exploring the potential of texturally modified SiO₂ derived from Uruguayan rice husk as a catalytic support...

A natural Moroccan illite-smectite clay was investigated as adsorbent of nickel in water. Before its use, it was processed without additives as honeycomb monoliths, an advantageous design in many methods developed to control environmental pollution. The performance of the resulting monoliths was studied in dynamic conditions by flow recirculation t...

Strong Metal−Support Interaction (SMSI) is a well-known phenomenon of heterogeneous catalysis that have not been extensively investigated in photocatalytic applications. Moreover, the reactions previously studied for photocatalysts under SMSI state are mainly restricted to energy related uses. The present work seeks to explore the effect of SMSI in...

Gold nanoparticles (AuNPs) supported on TiO2 are one of the most investigated photocatalysts, however, the positive effect of AuNPs size reduction on Au/TiO2 activity is clear for conventional catalysis, but this relationship not strictly happens in photocatalysis. The present work investigates how small changes in the lower size range of AuNPs can...

A copper-iron-based catalyst has been prepared by a low-temperature co-precipitation and sonication method. The use of high-energy ultrasound reduces the time required for the preparation process from one workweek to one day with respect to the catalysts obtained by conventional coprecipitation and thermal treatment methods. The resulting material...

Exhausted TWCs subjected to chemical/thermal treatments were used as a support of MnOx catalysts for the total combustion of acetone. The so-prepared new devices were characterized by using adherence tests, elemental and thermal analyses, XRD, N2 physisorption, and SEM-EDS. Incorporation of only 2.6 wt.% of the active phase (Mn2O3 and Mn3O4) to the...

Single-phase oxygen stoichiometric LaMnO3 and doped La0.8A0.2MnO3 (A = Ca, Sr, Ba) perovskites have been prepared by a simple one-step auto-combustion method. Cation-deficient LaMnO3+δ and La0.8A0.2MnO3+δ were obtained by calcination of the former samples in air at 750 °C. The samples were characterized by X-ray powder diffraction, X-ray photoelect...

Natural illite–smectite and stevensite Moroccan clays were used for the simultaneous removal of lead and cadmium from aqueous medium. The clays were employed in raw state and extruded as honeycomb monoliths form without any additives, which confirms the novelty of this approach in water treatment. The experiments were done in batch conditions with...

Supported Ni catalysts (4.5 wt%) using a Ce-Zr oxide (18/82 molar ratio and a ceria-rich surface) depicting advanced redox properties, were deposited by washcoating over cordierite honeycombs (230 and 400 cpsi). FIB-STEM unveiled nanostructure details otherwise undistinguishable by conventional techniques. The catalytic performance was evaluated in...

A copper-iron mixed oxide was deposited by the washcoating procedure over cordierite honeycomb monoliths for its use as a heterogeneous catalyst in organic synthesis processes. In particular, the prepared catalyst, characterized by techniques such as X-ray fluorescence, X-ray diffraction, SEM-EDS, laser granulometry, adherence tests, Temperature-Pr...

Clay honeycomb monoliths (MC) washcoated by pillared clay (PILC) obtained from the same starting material were used as support of manganese catalysts for the complete oxidation of acetone. Using the same clay for extrusion and pillaring processes intended to optimize the catalyst preparation respect to previous similar studies through raw materials...

Stainless-steel honeycomb monoliths (square cell-shape/230 cpsi cylinders) were 3D-printed and used as support of a Ni/CeO 2-ZrO 2 powder deposited by washcoating. The resulting catalysts were characterized by XRF, SEM-EDX and H 2-TPR, and tested in the dry reforming of methane reaction. In the 750-900 °C range, they showed competitive conversions...

Wild carob (WC), an abundant and unused lignocellulosic waste in Algeria, has been used as an inexpensive biosorbent for the elimination of methylene blue (MB) from the aqueous solution and as a precursor for the preparation of a new activated carbon by chemical activation with ZnCl2 (ACWC). The adsorbent materials were characterized by N2 physisor...

Wild carob (WC), an abundant and unused lignocellulosic waste in Algeria, has been used as an inexpensive biosorbent for the elimination of methylene blue (MB) from the aqueous solution and as a precursor for the preparation of a new activated carbon by chemical activation with ZnCl2 (ACWC). The adsorbent materials were characterized by N2 physisor...

A Ni/CeO2/ZrO2 catalyst with improved redox properties has been washcoated onto a honeycomb cordierite monolith in the form of a nonconventional alumina-catalyst layer, just a few nanometers thick. In spite of the very low active phase loading, the monolith depicts outstanding performance in dry reforming of methane, both in terms of activity, with...

A natural Moroccan illite–smectite was used as an adsorbent for the removal of methylene blue (MB) from aqueous solutions. The clay was characterized by FTIR spectroscopy, TGA, SEM–EDS, X-ray fluorescence, XRD and N2 physisorption. The influence of pH, temperature and time on the MB adsorption by the clay was investigated. The maximum equilibrium a...

Two factors are key in the design of a TiO2 photocatalyst for building materials that meets the requirements for environmental applications: the TiO2 light absorption restricted to UV and its poor adhesion to the substrates. In this work, two strategies of TiO2 modification, nitrogen doping and AuNPs deposition, were combined in order to promote th...

Au/N-TiO2 photocatalysts with enhanced photoactivity thanks to nitrogen doping and gold nanoparticles (AuNPs) controlled deposition onto titania have been obtained bymeans of a simple and innovative one-pot synthesis promoting synergetic activity between these two approaches. The activity of the materials under study was evaluated by methylene blue...

Nowadays, the occurrence of a large volume of plastic litter in oceanic and coastal zones has increased concern about its impacts on marine organisms. The degradation of plastic polymers leads to the formation of smaller fragments at both micro and nano scale (<5 mm and <1 μm respectively). Nanoplastics (NPs), due to their smaller size and high spe...

The air pollution is becoming one of most important health problems around the world. Thus, the development of depolluting building materials is a crucial challenge. TiO2 is a photocatalyst with demonstrated performance for degradation of NOx and other typical pollutants. However, its limited absorption of solar light reduces its performance. In th...

The removal of Methylene blue (MB) from aqueous medium using alkaline modified Maclura pomifera (NaOH-MMP) has been studied in this work. Results showed that a pH value of 6 was favorable for the adsorption of MB. Rate constants of pseudo-first-order, pseudo-second-order and nth kinetic model were determined to analyze the dynamic of the adsorption...

Different natural Moroccan clays were used as adsorbents for the removal of lead from aqueous solution. The study was performed not only employing the starting clays in the form of powder but also after their extrusion as honeycomb monoliths, this representing the major novelty of this work respect to the current state-of-art. The experiments were...

Resumen Diferentes arcillas naturales del norte de Marruecos se utilizaron como adsorbentes para eliminar plomo de disoluciones acuosas. Este estudio se realizó no sólo empleando las arcillas de partida en forma de polvo sino también tras su extrusión para obtener monolitos en forma de panal de abeja. En el primer caso, los experimentos se realizar...

Resumen Se prepararon por impregnación a humedad incipiente catalizadores de níquel soportado sobre un óxido mixto de Ce-Zr (de relación molar 15/85 y rico superficialmente en cerio) con un 4.5% en peso de Ni, que se depositaron después por washcoating sobre honeycombs de cordierita de 230 celdas/pulgada 2. Los catalizadores, en polvo y monolitos,...

Resumen Se estudió el efecto de la presencia de una montmorillonita uruguaya pilareada (PILC) al incorporarse óxido de manganeso como fase activa mediante impregnación a monolitos honeycomb preparados a partir de la misma montmorillonita sin pilarear. Se realizaron dos ciclos de impregnación al monolito sin PILC a efectos de poder aumentar la carga...

Resumen Se ha llevado a cabo la síntesis de un catalizador mediante el método de impregnación a humedad incipiente a partir de una disolución de níquel obtenida mediante un proceso de biolixiviación de un catalizador comercial, con Acidithiobacillus thiooxidans. Se partió de un catalizador de níquel soportado sobre γ-alúmina. La caracterización del...

Copper oxide (CuO) nanoparticles (NPs) are increasingly investigated, developed and produced for a wide range of industrial and consumer products. Notwithstanding their promising novel applications, concern has been raised that their increased use and disposal could consequently increase their release into marine systems and potentially affect spec...

Over the last decades, the growth in nanotechnology has provoked an increase in the number of its applications and consumer products that incorporate nanomaterials in their formulation. Metal nanoparticles are released to the marine environment and they can interact with cells by colloids forces establish a nano-bio interface. This interface can be...

Copper-iron mixed oxides with Fe/Cu molar ratios ranging from pure CuO to Fe2O3 were synthesised by a low temperature co-precipitation method, and tested in the CO-PROX reaction. The extensive characterization performed by means of different techniques showed the progressive variation of physical and chemical properties including composition, textu...

Mn-Cu mixed oxides were deposited by ultrasonic impregnation on ceramic honeycomb monoliths. Its catalytic performance was evaluated in the combustion of ethanol and n-hexane, VOC molecules of different chemical nature. The catalysts were characterized by N2 physisorption, SEM-EDS, XRD, X-ray fluorescence, XPS, TPR, TPD-O2 and OSC measurements. It...

TiO2 nanoparticles (TiO2 NPs) are employed in many products (paints, personal care products, especially sunscreens, plastics, paper, water potabilization and food products) and are then released into the environment from these products. These nanoparticles present potential risk to freshwater and marine microalgae. The primary toxicity mechanism is...

Use of titanium dioxide nanoparticles (TiO2 NPs) has become a part of our daily life and the high environmental concentrations predicted to accumulate in aquatic ecosystems are cause for concern. Although TiO2 has only limited reactivity, at the nanoscale level its physico-chemical properties and toxicity are different compared with bulk material....

Clay honeycomb monoliths were manufactured from a natural montmorillonite and used for CO2 adsorption, their performance being compared with that of the same clay but in the form of powder. Volumetric adsorption isotherms, thermogravimetric studies, temperature-programmed desorption experiments and transient kinetic analysis, the two latter followe...

Manganese catalysts supported by impregnation onto honeycomb monoliths extruded from commercial clay, previously coated with aluminium-pillared clay, were prepared and tested in the total combustion of propane and acetone. Samples characterization included chemical analysis, nitrogen physisorption, electron microscopies (SEM-EDS, HAADF and EELS), X...

The last decade has seen a considerable increase in the use of silver nanoparticles (AgNPs), which are found in many every-day consumer products including textiles, plastics, cosmetics, household sprays and paints. The release of those AgNPs into aquatic environments could be causing ecological damage. In this study we assess the toxicity of AgNPs...

CeO2 nanoparticles (CeO2 NPs) are well-known for their catalytic properties and antioxidant potential. Recent uses in therapy are based on the Ce+ 3 ions released by CeO2 NPs. Reactions involving redox cycles between Ce+ 3 and Ce+ 4 oxidation stage seem to promote scavenging of reactive oxygen species (ROS), thus protecting cells from oxygen damage...

An integrated process was investigated for the degradation of methylene blue (MB); it was based on the combination of adsorption and photocatalysis. A granular activated carbon (C) was considered for adsorption, which supported TiO2 used as the photocatalyst (TiO2/C). The TiO2/C was directly obtained by an impregnation method using TiCl3; it was al...

Carbon integral honeycomb monoliths prepared from a natural coal were employed as support of copper catalysts for organic synthetic purposes. In particular good to excellent yields (60-100% as function of the carboxylic acid employed) were obtained in the preparation of allylic esters by the Kharasch-Sosnovsky oxidation of cyclohexene. Different ch...

Several semiconductors based on ceria or bismuth tungstate were tested for selective oxidation of alcohols to carbonyl compounds in a search for photocatalysts more selective than TiO2. Gas-phase selective photo-oxidation of propan-2-ol to acetone and liquid-phase transformation of 2-buten-1-ol (crotyl alcohol) to 2-butenal (crotonaldehyde) were st...

Integral honeycomb monoliths were prepared from a Spanish clay by extrusion without using additives. The resulting monoliths were employed as support of manganese catalysts deposited by impregnation method. The supported catalysts were characterized by means of different techniques such as chemical analysis, nitrogen physisorption, scanning electro...

Carbon integral honeycomb monoliths with good performance in the thermocatalytic decomposition of methane were deeply characterized to understand the differences of behaviour resulting from their different pre-treatment. In particular three types of carbon monoliths were investigated, just carbonized, and activated with and without pre-oxidation. A...

The use of a copper-iron mixed oxide as a heterogeneous catalyst for the efficient synthesis of alpha-acyloxy- 1,4-dioxanes and 1,4-dithianes employing t-butyl peroxyesters is reported. The preparation and characterization of the catalyst are described. The effect of the heteroatoms and a plausible mechanism are discussed. The method is operational...

Co3O4/La-modified-CeO2/Al2O3 powders washcoated onto ceramic and metallic monolithic catalysts have been compared in order to evaluate the contribution of both the type of substrate and the total washcoat loading on the actual surface structure of the corresponding monolithic devices. Detailed structural and chemical characterization studies have b...

On the basis of calculated thermodynamic species distribution diagrams and by appropriately controlling the pH of aqueous HAuCl4 solutions, it has been possible to prepare, using a Speciation-controlled Incipient Wetness Impregnation (ScIWI) approach, Au catalysts supported on ceria-zirconia mixed oxides featuring both high gold loadings and excell...

Procedimiento para la obtención de hidrógeno a partir de biogás de vertedero de residuos sólidos urbanos. La presente invención se refiere a un procedimiento para la obtención de hidrógeno a partir de gas de vertedero de residuos sólidos urbanos. El proceso integra dos fases diferentes: depuración del biogás de vertedero y reformado de metano.

Resumen A partir de una arcilla natural española se han preparado monolitos integrales tipo honeycomb mediante extrusión sin uso de aditivos. Los monolitos obtenidos han sido empleados como soporte de catalizadores de manganeso depositados a través de impregnación. Los catalizadores soportados han sido caracterizados por medio de diversas técnicas...

Two commercial high BET surface areas CeO2 are characterized, as received and after calcination at different temperatures, to better understand the relationship between reducibility and micro- and nanostructure. Combination of TPR data, Rietveld analysis of XRD diagrams and HREM/HAADF-STEM suggest that the nano-particles are responsible for Ce4+ re...

The regio- and stereoselective hydroxylation of α,β- or α,β,γ,δ- unsaturated ketones with air in the presence of KOtBu is investigated.

The total oxidation of toluene was studied over a Co3O4/La-CeO2 catalyst in a Temporal Analysis of Products (TAP) set-up in the temperature range 713 K to 873 K in the presence and absence of dioxygen. It has been demonstrated that the reaction proceeds via a Mars-van Krevelen mechanism. The reaction rate increased 8.4 times if both toluene and dio...

A novel Co (15 wt.%)/La-modified-CeO2 catalyst was prepared for the oxidation of toluene and ethyl acetate, showing lower light-off temperature (around 20-40 degrees C) than that of a Pt (3 wt.%)/La-CeO2 catalyst under the same experimental conditions. Upon washcoating onto cordierite it was still more active than the noble metal reference. The act...

The total oxidation of toluene was studied over a Co 3 O 4 /La-CeO 2 catalyst in a Temporal Analysis of Products (TAP) setup in the temperature range 713 K to 873 K in the presence and absence of dioxygen. It has been demonstrated that the reaction proceeds via a Mars–van Krevelen mechanism. The reaction rate increased 8.4 times if both toluene and...

Coal is an abundant and relatively low cost natural resource that can be valorized through its use in environmental applications. For this purpose however, unlike clays, it is mainly employed as powders, granules or tablets, the honeycomb monolithic design being almost completely discarded. This is so in spite of the fact that honeycomb monoliths o...

The allylic hydroxylation of enones using dioxygen as the oxidant has been studied. The reaction was first examined in the absence of any catalyst, using β‐ionone as a model substrate. Then a new copper–aluminium mixed oxide, Cu–Al Ox, was prepared and characterized in order to be used as a catalyst. This oxide showed good activity, and provided th...

A detailed structural and chemical characterization study has been performed, both at the micrometer and nanometer scale levels, throughout the different steps of preparation of a catalytic device consisting in Co3O4/La-modified-CeO2/Al2O3 powders washcoated onto a honeycomb-type cordierite monolith. High-resolution transmission electron microscopy...

In this paper a Ru/Ce 0.8 Tb 0.2 O 2−x /Al 2 O 3 catalyst has been prepared by incipient wetness impregnation method and it has been exhaustively characterized through N 2 physisorption, H 2 and CO chemisorption, temperature programmed desorption, infrared spectroscopy, X-ray diffraction and electron microscopy techniques. The catalyst has been tes...

En este trabajo se ha estudiado la influencia del pretratamiento químico-térmico de monolitos de carbón en su comportamiento como filtros para retener compuestos orgánicos volátiles del tipo o-xileno en fase gas. Se han preparado monolitos integrales de carbón con forma de panal de abeja mediante técnicas de extrusión convencionalmente usadas con m...

The growing interest for using clays in the production of structured materials withapplication in the technological field of environmental protection is emphasized. Inparticular, here we examine the design of clay-containing honeycomb monoliths that canbe employed in the abatement of some of the main hazardous species in pollutedemissions such as n...

The applications of clay-based structured materials, excluding cordierites, for environmental protection are examined. In particular, their use in the abatement of some of the main hazardous species in polluted emissions such as nitrogen oxides, carbon monoxide, volatile organic compounds and heavy metals is discussed. A distinction is made between...

Coal-based honeycomb monoliths extruded using methods developed for ceramic materials have been used to retain methylene blue and p-nitrophenol from aqueous solutions. The influence of the filters’ thermal treatment on their textural properties and performance as adsorbents was examined. Characterization by N2 physisorption, mercury porosimetry and...

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In this study a simple method to activate clay honeycomb monoliths is proposed. It consists of mixing the clay with coal before the extrusion, and further removing the coal from the monolith by heating under air at the lowest possible temperature. This procedure is an easy, non-destructive and economical way of activating clay monoliths by an enhan...

In the present work, honeycomb-shaped monoliths were easily extruded using local natural clays without the need of chemical binders. This finding allows significant cost reduction, in terms of not only additives and solvents but also the energy consumption required for their elimination by thermal treatment. The extruded monoliths were subject to m...

A series of catalysts consisting in Cu or Mn supported on lab-scale carbon-based honeycomb monoliths, which have been previously prepared following an original methodology, have been investigated in the low-temperature selective catalytic reduction of NO with NH3. Special attention has been paid to the effect of changing different preparative varia...

Noble metals highly dispersed on cerium mixed oxide supports Ce(M)O2−x (M=Zr,Tb) are currently being investigated, not only due to their relationship with the so called Three-Ways Catalysts (TWC) but also because of their potential applications in other catalytic processes related to the hydrogen production or the elimination of organic pollutants...

Textural, structural and adsorptive properties of some Moroccan clays were investigated. The minerals were used as raw material for extrusion of honeycomb monoliths. Adsorption and desorption tests were performed with selected model pollutan