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2018


Is an alumina-whisker-reinforced alumina composite the most efficient choice for an oxidation-resistant high-temperature ceramic?


Tamura, Y; Moshtaghioun, BM; Zapata-Solvas, E; Gomez-Garcia, D; Dominguez-Rodriguez, A; Cerecedo-Fernandez, C; Valcarcel-Juarez, V
Journal of the European Ceramic Society, 38 (2018) 1812-1818

ABSTRACT

The search of a competitive ceramic material for structural applications demands several requisites: a simple microstructure with easy reproducibility, good intrinsic mechanical properties and most of all, an optimal oxidation resistance. This later point is a challenging point for most ultrahigh refractory materials. 
In this work an alumina (Al2O3) whisker-reinforced Al2O3 composite prepared by spark plasma sintering (SPS) is studied. It will be shown that, although the microstructure is quite similar to that of pure monolithic one, there is a notorious enhancement of the high-temperature deformation resistance, reaching up to one order of magnitude over the pure Al2O3 specimen. On the other hand, the activation energy of these composites increases notably. The results are explained in terms of an original model. A comparison with reported data shows that such composite is as efficient as a SiC-whisker-reinforced Al2O3 composite, with the advantage of its oxidation resistance and much less fabrication cost.


Abril, 2018 | DOI: 10.1016/j.jeurceramsoc.2017.10.006

Synthesis of vaterite CaCO3 as submicron and nanosized particles using inorganic precursors and sucrose in aqueous medium


Perez-Villarejo, L; Takabait, F; Mahtout, L; Carrasco-Hurtado, B; Eliche-Quesada, D; Sanchez-Soto, PJ
Ceramics International, 44 (2018) 5291-5296

ABSTRACT

It is reported the synthesis of CaCO3 vaterite as stable nanoparticles and submicron-sized by a simple and relatively rapid procedure. XRD, SEM and FTIR techniques have been used to characterize the precipitated products. The synthesis is based on chemical precipitation of inorganic salt precursors, calcium nitrate tetra hydrate and sodium bicarbonate, and using the disaccharide sucrose as an additive in aqueous medium. The role of the disaccharide sucrose is to control the vaterite precipitation after nucleation and growth. It has been found that an increase in sugar concentration promotes the crystal precipitation of vaterite with spherulitic morphology, as revealed by SEM, and changed the surface of the precipitated particles. There is a significant difference between CaCO3 precipitation in the absence and presence of sucrose. Addition of 0% of sucrose leads to 83% of calcite as identified by XRD methods. In contrast, addition of 67% of sucrose in aqueous medium produces 100% vaterite. The present results may be useful to provide a quick, simple, inexpensive and novel method for the controlled synthesis of new advanced biomaterials based on vaterite particles without hazardous chemicals and inert atmosphere, with great possibilities for industrial scale production.


Abril, 2018 | DOI: 10.1016/j.ceramint.2017.12.142

Self-propagating mechanosynthesis of HfB2 nanoparticles by a magnesiothermic reaction


Jalaly, M; Gotor, FJ; Sayagues, MJ
Journal of the American Ceramic Society, 101 (2018) 1412-1419

ABSTRACT

A mechanically induced self-sustaining reaction (MSR) was used to synthesize hafnium diboride nanoparticles. Along this route, magnesium was selected as a robust reducing agent for co-reduction in boron and hafnium oxides in a combustive manner. Combustion occurred after a short milling period of 12 minutes. The hafnium diboride nanoparticles had a polygonal faceted morphology and were 50-250 nm in diameter. The assessment of the processing mechanism revealed that the initial combustive reduction in B2O3 to elemental B by Mg was the major step for progressing the overall reaction. After that, HfO2 can be reduced to elemental Hf, followed by the synthesis of HfB2 phase.


Abril, 2018 | DOI: 10.1111/jace.15297

Silver-modified ZnO highly UV-photoactive


Jaramillo-Páez, C.; Navío, J.C.; Hidalgo, M.C.
Journal of Photochemistry and Photobiology A: Chemistry, 356 (2018) 112-122

ABSTRACT

ZnO nanoparticles were successfully synthesized by a controlled precipitation procedure by mixing aqueous solutions of Zn(II) acetate and dissolved Na2CO3 at pH ca. 7.0 without template addition and ulterior calcination at 400 °C for 2 h. The Ag-ZnO catalysts (ranging from 0.5 to 10 Ag wt.-%) were obtained by photochemical deposition method at the surface of the prepared ZnO sample, using AgNO3 as precursor. The as-prepared catalysts (with and without silver) were characterized by XRD, BET, FE-SEM, TEM, and XPS and diffuse reflectance spectroscopy (DRS). The effect of Ag-phodeposition on the photocatalytic properties of ZnO nanoparticles was investigated. Three different probe molecules were used to evaluate the photocatalytic properties under UV-illumination and visible illumination: Methyl Orange and Rhodamine B were chosen as hazardous dyes and Phenol as a transparent substrate. For each of the chosen substrates, it was observed that the UV-photocatalytic properties of ZnO improved with the amount of Ag deposited, up to an optimum percentage around 1–5 wt.-% Ag, being even better than the commercial Evonik-TiO2(P25) in the same conditions. Above this amount, the UV-photocatalytic properties of the Ag-ZnO samples remain unchanged, indicating a maximum for Ag-deposition. While ZnO and Ag-ZnO catalysts can photodegrade Rhodamine B, Methyl Orange and Phenol totally within 60 min under UV-illumination, the process is slightly faster for the case of Ag–ZnO nanoparticles. Under Vis-illumination, the silver-metalized samples did not present photocatalytic activity in the degradation of Methyl Orange. However, a very low photoactivity was present for phenol degradation (10% conversion) and a moderate conversion of ca. 70% for Rhodamine B degradation, after 120 min of Visible-illumination. High conversion values and a total organic carbon (TOC) removal of 86–97% were obtained over the Ag-ZnO photocatalysts after 120 min of UV-illumination, suggesting that these Ag-modified ZnO nanoparticles may have good applications in wastewater treatment, due to its reuse properties.


Abril, 2018 | DOI: 10.1016/j.jphotochem.2017.12.044

Cesium adsorption isotherm on swelling high-charged micas from aqueous solutions: Effect of temperature


Osuna, FJ; Cota, A; Pavon, E; Pazos, MC; Alba, MD
American Mineralogist, 103 (2018) 623-628

ABSTRACT

The potential use of a new family of synthetic swelling micas for cesium immobilization from aqueous solution was evaluated and the structural modifications after adsorption were analyzed. The results have revealed that they are good cesium adsorbents compared to natural clays and as the layer charge increases, the adsorption capacity and affinity increase. The cesium ions are adsorbed through a cation exchange mechanism, but an inner sphere complex with the basal O atoms of the tetrahedral sheet is favored. These findings imply that is possible to design minerals with improved environmental applications. 


Abril, 2018 | DOI: 10.2138/am-2018-6203

Colorimetric energy sensitive scintillator detectors based on luminescent multilayer designs


Ferrer, FJ; Gil-Rostra, J; Gonzalez-Elipe, AR; Yubero, F
Sensors and Actuators A-Physical, 272 (2018) 217-222

ABSTRACT

In this work we present a new concept for energy sensitive radiation-beam scintillator detectors based on a luminescent multilayer design, where each layer within the stack consists of a rare-earth-doped highly transparent oxide. For a given type of particle beam (i.e., protons, a particles, etc.), its penetration depth, and therefore its energy loss at a particular buried layer, depends on its initial kinetic energy. Relying on this principle and since the intensity of the luminescent response of each layer and substrate should be proportional to the energy deposited by the radiation beam, we prove that a characteristic energy dependent color emission is obtained depending on both the phosphors integrated in the luminescent stack and on the primary energy and type of particle beam. Phosphor doping, emission efficiency, layer thickness, and multilayer structure design are key parameters to achieve a broad gamut in colorimetric response. The developed scintillators are designed to operate in a transmission geometry (light detection from the opposite side of the incident radiation) which is well suited for high energy particle detection in fields such as oncotherapy, space radiation, or of fusion studies. The principles of the method are illustrated with a case example typical of ion beam accelerators devoted to materials analysis. It is obtained that the kinetic energy of protons/alpha particle beams can be distinguished and evaluated with a sensitivity of 0.06/0.25 chromaticity units per MeV in the 0.7-2.0 MeV range. 


Abril, 2018 | DOI: 10.1016/j.sna.2018.01.062

Bimetallic Ni-Co/SBA-15 catalysts for reforming of ethanol: How cobalt modifies the nickel metal phase and product distribution


Rodriguez-Gomez, A; Caballero, A
Molecular Catalysis, 449 (2018) 122-130

ABSTRACT

In this study, five mono and bimetallic xNi-(10-x)Co/SBA-15 catalysts (x = 10, 8, 5, 2 and 0, with a total metallic content of 10 wt%) have been synthesized using a deposition-precipitation (DP) methodology. Catalytic performances on the steam reforming of ethanol reaction (SRE) have been determined and correlated with their physical and chemical state. A nickel content of 5% or higher yields catalytic systems with good activity, high selectivity to hydrogen and a low production of acetaldehyde (less than 5%). However, in the systems where the cobalt is the main component of the metallic phase (8-10%), the selectivity changes, mainly due to the production of an excess of acetaldehyde, which is also reflected in the larger H-2/CO2 ratio. In agreement with previous findings, this important modification in the selectivity comes from the formation of a cobalt carbide phase, where only takes place in the cobalt enriched systems, and is inhibited with nickel content larger than 5%. The formation of this carbide phase seems to be responsible for the decrease of cobalt particle size during the SRE reaction. Even though this cobalt carbide phase is thermodynamically metastable against decomposition to metallic cobalt and graphite carbon, our results have shown that it only reacts and decomposes after a hydrogen treatment at 600 degrees C.


Abril, 2018 | DOI: 10.1016/j.mcat.2018.02.011

Tailoring structured WGS catalysts: Impact of multilayered concept on the water surface interactions


Gonzalez-Castano, M; Le Sache, E; Ivanova, S; Romero-Sarria, F; Centeno, MA; Odriozola, JA
Applied Catalysis B-Environmental, 222 (2018) 124-132

ABSTRACT

A novel multilayer approach for designing structured WGS catalyst is employed in this study as a response to the lack of new strategies in the literature. The approach proposes the use of two successive layers with different functionalities on metallic micromonolith substrate. The WGS catalyst behavior is modulated by the nature of the inner layer which determines the active species surface population by acting on the water activation step. The catalytic promotion attained by introducing inner ceria containing solids with increasing number of oxygen defects is intensely analyzed through FT-IR and H2O-TPD. Several evidences about the participation of the oxygen vacancies, as key sites, for water absorption processes are established. Besides, remarkable relationships between the water absorption strengths and the water splitting processes within their influence on the catalyst performance are also discussed.


Marzo, 2018 | DOI: 10.1016/j.apcatb.2017.10.018

Epimerization of glucose over ionic liquid/phosphomolybdate hybrids: structure-activity relationship


Megias-Sayago, C; Alvarez, E; Ivanova, S; Odriozola, JA
Green Chemistry, 20 (2018) 1042-1049

ABSTRACT

The influence of the crystal structure and chemical nature of some ionic liquid/phosphomolybdate hybrids on their catalytic activity in the epimerization of glucose was studied. A clear evidence of structure-activity relationship was found. The inorganic part of the hybrid ensured the availability of active sites for the reaction, while the organic cation part organized the structure and controled the diffusion of the reactants. This study can be used as a first approach to predict the symmetry, long range order and availability of active sites in the presented class of imidazolium based polyoxometalate hybrids.


Marzo, 2018 | DOI: 10.1039/c7gc03738d

Dye Giant Absorption and Light Confinement Effects in Porous Bragg Microcavities


Oliva-Ramirez, M; Gil-Rostra, J; Simonsen, AC; Yubero, F; Gonzalez-Elipe, AR
ACS Photonics, 5 (2018) 984-991

ABSTRACT

This work presents a simple experimental procedure to probe light confinement effects in photonic structures. Two types of porous 1D Bragg microcavities with two resonant peaks in the reflection gap were prepared by physical vapor deposition at oblique angle configurations and then infiltrated with dye solutions of increasing concentrations. The unusual position shift and intensity drop of the transmitted resonant peak observed when it was scanned through the dye absorption band have been accounted for by the effect of the light trapped at their optical defect layer. An experimentally observed giant absorption of the dye molecules and a strong anomalous dispersion in the refractive index of the solution are claimed as the reasons for the observed variations in the Bragg microcavity resonant feature. Determining the giant absorption of infiltrated dye solutions is proposed as a general and simple methodology to experimentally assess light trapping effects in porous photonic structures.


Marzo, 2018 | DOI: 10.1021/acsphotonics.7b01283

Copper-containing mesoporous bioactive glass promotes angiogenesis in an in vivo zebrafish model


Romero-Sanchez, LB; Mari-Beffa, M; Carrillo, P; Medina, MA; Diaz-Cuenca, A
Acta Biomaterialia, 68 (2018) 272-285

ABSTRACT

The osteogenic and angiogenic responses of organisms to the ionic products of degradation of bioactive glasses (BGs) are being intensively investigated. The promotion of angiogenesis by copper (Cu) has been known for more than three decades. This element can be incorporated to delivery carriers, such as BGs, and the materials used in biological assays. In this work, Cu-containing mesoporous bioactive glass (MBG) in the SiO2-CaO-P2O5compositional system was prepared incorporating 5% mol Cu (MBG-5Cu) by replacement of the corresponding amount of Ca. The biological effects of the ionic products of MBG biodegradation were evaluated on a well-known endothelial cell line, the bovine aorta endothelial cells (BAEC), as well as in an in vivo zebrafish (Danio rerio) embryo assay. The results suggest that ionic products of both MBG (Cu free) and MBG-5Cu materials promote angiogenesis. In vitro cell cultures show that the ionic dissolution products of these materials are not toxic and promote BAEC viability and migration. In addition, the in vivo assay indicates that both exposition and microinjection of zebrafish embryos with Cu free MBG material increase vessel number and thickness of the subintestinal venous plexus (SIVP), whereas assays using MBG-5Cu enhance this effect.


Marzo, 2018 | DOI: 10.1016/j.actbio.2017.12.032

Robust polarization active nanostructured 1D Bragg Microcavities as optofluidic label-free refractive index sensor


Oliva-Ramirez, M; Gil-Rostra, J; Yubero, F; Gonzalez-Elipe, AR
Sensors and Actuators B-Chemical, 256 (2018) 590-599

ABSTRACT

In this work we report the use of polarization active porous 1D Bragg microcavities (BM) prepared by physical vapor deposition at oblique angles for the optofluidic analysis of liquid solutions. These photonic structures consist of a series of stacked highly porous layers of two materials with different refractive indices and high birefringence. Their operational principle implies filling the pores with the analyzed liquid while monitoring with linearly polarized light the associated changes in optical response as a function of the solution refractive index. The response of both polarization active and inactive BMs as optofluidic sensors for the determination of glucose concentration in water solutions has been systematically compared. Different methods of detection, including monitoring the BM wave retarder behavior, are critically compared for both low and high glucose concentrations. Data are taken in transmission and reflection modes and different options explored to prove the incorporation of these nanostructured transducers into microfluidic systems and/or onto the tip of an optical fiber. This analysis has proven the advantages of the polarization active transducer sensors for the optofluidic analysis of liquids and their robustness even in the presence of light source instabilities or misalignments of the optical system used for detection.


Marzo, 2018 | DOI: 10.1016/j.snb.2017.10.060

CO2 reforming of methane over Ni-Ru supported catalysts: On the nature of active sites by operando DRIFTS study


Alvarez, A; Bobadilla, LF; Garcilaso, V; Centeno, MA; Odriozola, JA
Journal of CO2 utilization, 24 (2018) 509-515

ABSTRACT

The present paper addresses the nature of the active sites of a bimetallic Ni-Ru supported catalyst on the dry reforming of methane (DRM). The structural characterization by XRD and Raman spectroscopy, along with the reducibility study (TPR-H-2) of the samples, evidenced the existence of a strong Ni-Ru interaction in the bimetallic system. We have assumed that Ru atoms block the most reactive Ni sites (step-edge sites) leaving less reactive centers for methane activation (terraces). In this way, operando DRIFTS measurements revealed that Ru decreases the catalytic activity but favors the carbon gasification and prevents the CO dissociation.


Marzo, 2018 | DOI: 10.1016/j.jcou.2018.01.027

Synthesis of Pd-Al/biomorphic carbon catalysts using cellulose as carbon precursor


Cazana, F; Galetti, A; Meyer, C; Sebastian, V; Centeno, MA; Romeo, E; Monzon, A
Catalysis Today, 301 (2018) 226-238

ABSTRACT

This work presents the results obtained with novel Pd and Pd-Al catalysts supported on carbon, which have been prepared using a biomorphic mineralization technique. The catalyst synthesis procedure includes a stage of thermal decomposition under reductive atmosphere of cellulose previously impregnated with the metallic precursors. We have studied the influence of the temperature and time of decomposition, and of the Al precursor addition, on the textural and catalytic properties. The characterisation results indicate that the preparation method used leads to the formation of carbonaceous supports with a high microporosity (up to 97% micropore volume) and values of the BET surface up to 470 m2/g while maintaining the original external structure. The use of low temperatures (ca. 600 °C) during the decomposition step allows the preparation of highly dispersed catalysts with narrow Pd particle size distributions. However, the thermal decomposition at elevated temperatures (ca. 800 °C) increases the Pd particle size due to the sintering of the metallic phase. This phenomenon is augmented with the decomposition time and is not affected by the presence of Al. Consequently, the catalytic activity of these materials in cyclohexene hydrogenation is strongly affected by the operational conditions used during the thermal decomposition step. Unexpectedly, the more sintered catalysts, i.e. those prepared at 800 °C, show the highest activity. According to the characterization results, this fact can be explained considering that the smaller Pd particles obtained after preparation at e.g. 600 °C are quite inactive because they are confined in the internal structure of the micropores of the support and/or embedded inside the carbon matrix. In contrast, after decomposition at 800 °C, the larger Pd particles formed are placed at the external surface of the catalyst, being accessible to the reactants. In addition, for the specific conditions under which the Pd is accessible, the presence of Al favours the cyclohexene conversion due to the enhancement of the adsorption on the Pd surface as a consequence of a charge transfer phenomenon. These results can serve as a guideline for the preparation of these catalysts based on raw lignocellulosic materials in order to maximize their catalytic performance.


Marzo, 2018 | DOI: 10.1016/j.cattod.2017.05.026

Gold catalyst recycling study in base-free glucose oxidation reaction


Megias-Sayago, C.; Bobadilla, L. F.; Ivanova, S.; Penkova, A.; Centeno, M. A.; Odriozola, J. A.
Catalysis Today, 301 (2018) 72-77

ABSTRACT

This work is devoted to the study of viability of immobilized gold colloids on carbon as catalysts for the base-free glucose oxidation reaction with a special emphasis made on catalysts' recycling, operational life and possible routes for deactivation/reactivation under batch conditions. The observed catalytic behavior is related to all possible manners of deactivation, like gold metal state changes (particle size agglomeration or leaching), support modifications or active sites blocking by intermediates. In an attempt to recover the initial catalytic activity, the samples are subjected to different treatments such as H2O and NaOH washings and calcination. The failure of the regeneration procedures to recover the initial activity and after detailed catalyst' characterization allows us to find out the main cause of deactivation


Marzo, 2018 | DOI: 10.1016/j.cattod.2017.03.022

Synthesis and optical properties of environmentally benign and highly uniform NaCe(MoO4)(2) based yellow nanopigments


Laguna, M; Nuñez, NO; Fernandez, M; Ocaña, M
Journal of Alloys and Compounds, 739 (2018) 542-548

ABSTRACT

A method for the synthesis of uniform and aggregation free NaCeMoO4 based nanospheroids with tunable size is reported. The procedure is based on a precipitation reaction at 120 degrees C for 20 h from solutions containing Na2MoO4, sodium citrate and Ce(NO3)(3) and different amounts of Y(NO3)(3) or Gd(NO3)(3). The role played by the later compounds on the formation of the particles and their morphological and structural characteristics is analyzed through the analysis of the mechanism of particle formation. The chromaticity coordinates of the obtained samples are also evaluated showing that the here reported nanoparticles constitute an ecofriendly alternative to more toxic commercial yellow pigments. The synthesized nanoparticles are also free of aggregation in water suspensions and might be suitable for injet-printing technologies. 


Marzo, 2018 | DOI: 10.1016/j.jallcom.2017.12.158

Investigation of use of coal fly ash in eco-friendly construction materials: fired clay bricks and silica-calcareous non fired bricks


Eliche-Quesada, D; Sandalio-Perez, JA; Martinez-Martinez, S; Perez-Villarejo, L; Sanchez-Soto, PJ
Ceramics International, 44 (2018) 4400-4412

ABSTRACT

The use of coal fly ash (CFA) as raw material for the manufacture of two construction materials, fired clay bricks and silica-calcareous non-fired bricks, was investigated. Fired clay bricks were manufactured using a commercial clay and different waste ratios (0-50 wt%), moulded at 10 MPa and fired at 1000 degrees C (4 h). Silica-calcareous non fired bricks were prepared using two wastes as raw material: CFA and "geosilex"(G), a hidrated lime residue which comes entirely from acetylene industry waste. Different proportions CFA (80-30 wt%) G (20-70 wt%) were investigated. Raw materials were moulded at 10 MPa and cured in water at room temperature during 28 days. The results indicated that the incorporation of up to 20 wt% of CFA produced fired clay bricks with physical and mechanical properties similar to control bricks without waste. However, additions of a higher amount (30-50 wt%) of residue resulted in a more pronounced decrease in mechanical properties (between 25-50%) due to an increase in open porosity. The technological characterization of the silica-calcareous non fired bricks showed a reduction in the values of bulk density and water absorption when the coal fly ash content decreases. Silica-calcareous non-fired bricks containing between 40 and 60 wt% of CFA had the highest values of compressive strength in the range 46-43 MPa. These silica-calcareous non-fired bricks, 60CFA-40 G, 50CFA-50 G and 40CFA-60 G, presented the optimum amount of pozzolanic materials (SiO2 and Al2O3) in the coal fly ash and calcium hydroxide in the geosilex to give rise to the formation of calcium silicate hydrates and calcium aluminate hydrates, the phases responsible for the mechanical resistance increase of the construction materials. Therefore, CFA-clay fired bricks and silica-calcareous CFA-Geosilex non-fired bricks presented optimal technological properties that attain the quality standards.


Marzo, 2018 | DOI: 10.1016/j.ceramint.2017.12.039

LaFeO3 ceramics as selective oxygen sensors at mild temperature


Jaouali, I; Hamrouni, H; Moussa, N; Nsib, MF; Centeno, MA; Bonavita, A; Neri, G; Leonardi, SG
Ceramics International, 44 (2018) 4183-4189

ABSTRACT

In this study, an investigation about the oxygen sensing properties of lanthanum orthoferrite (LaFeO3) ceramics is reported. LaFeO3 nanoparticles were synthesized by using tartaric sol-gel route and annealed in air at different temperatures (500, 700 and 900 degrees C). The samples have been characterized by using thermal analysis (TA), BET surface area and porosity, Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). Results of sensing tests indicate that LaFeO3 nanoparticles exhibit good response to oxygen at mild temperatures (300-450 degrees C). The effect of annealing temperature on gas sensing performance was investigated, demonstrating that LaFeO3 ceramics obtained after annealing at 500 degrees C display better characteristics with respect to others. The oxygen sensor developed shows also high stability in humid environment and excellent selectivity to oxygen over other interfering gases such as CO, NO2, CO2, H-2 and ethanol.


Marzo, 2018 | DOI: 10.1016/j.ceramint.2017.11.221

Numerical study of the accuracy of temperature measurement by thermocouples in small-scale reactors


Blay, V; Bobadilla, LF
Chemical Engineering Research & Design, 131 (2018) 545-556

ABSTRACT

Proper temperature measurement is imperative in any laboratory study if reliable data are to be obtained, particularly in the field of chemical kinetics. In this paper we analyze in silico some typical thermowell configurations used in small-scale reactors by coupling computational fluid dynamics (CFD) with conjugated heat transfer phenomena. This allows us to identify deviations in measurements arising from thermal radiation and self-conductivity in mid and high temperature ranges, in addition to radial temperature gradients. A novel design is proposed and optimized by additional simulation, showing potential for faster and more accurate temperature measurements.


Marzo, 2018 | DOI: 10.1016/j.cherd.2017.06.003

Urban wastewater treatment by using Ag/ZnO and Pt/TiO2 photocatalysts


J.J. Murcia, L.G. Arias Bolivar, H.A. Rojas Sarmiento, E.G. Ávila Martínez, C. Jaramillo Páez, M.A. Lara, J.A. Navío Santos, M.C. Hidalgo López
Environmental Science and Pollution Research (2018) 1-9

ABSTRACT

In this study, the treatment of wastewater coming from a river highly polluted with domestic and industrial effluents was evaluated. For this purpose, series of photocatalysts obtained by ZnO and TiO2 modification were evaluated. The effect of metal addition and Ti precursor (in the case of the titania series) over the physicochemical and photocatalytic properties of the materials obtained was also analyzed. The evaluation of the photocatalytic activity showed that semiconductor modification and precursor used in the materials synthesis are important factors influencing the physicochemical and therefore the photocatalytic properties of the materials obtained. The water samples analyzed in the present work were taken from a highly polluted river, and it was found that the effectiveness of the photocatalytic treatment increases when the reaction time increases and for both, wastewater samples and isolated Escherichia coli strain follow the next order Pt/TiO2 << ZnO. It was also observed that biochemical and chemical demand oxygen and turbidity significantly decrease after treatment, thus indicating that photocatalysis is a non-selective technology, which can lead to recover wastewater containing different pollutants.


Marzo, 2018 | DOI: 10.1007/s11356-018-1592-3

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