Francisco Franco | Universidad de Málaga (original) (raw)
Uploads
Papers by Francisco Franco
Ecosistemas, Apr 30, 2021
Clays and Clay Minerals, 2000
En las ultimas decadas la poblacion y las empresas malaguenas que centran su actividad en el sect... more En las ultimas decadas la poblacion y las empresas malaguenas que centran su actividad en el sector turistico vienen demandando que el mayor activo de la provincia de Malaga, sus playas, tengan una calidad adecuada capaz de competir con las playas de otros paises cercanos. Un indicador claro de la calidad actual de las playas de la Costa del Sol lo muestra el numero de banderas azules. En el pasado verano (2018) ondearon 24 banderas azules a lo largo de todo el litoral de la provincia de Malaga. No obstante, existe la necesidad de mantener y mejorar la calidad de nuestras playas a lo largo del tiempo para que la industria que crece a lo largo de todo el litoral se haga sostenible. Una de las mayores preocupaciones del usuario de las playas de la Costa del Sol es la calidad de las aguas de bano. Esta preocupacion se incrementa cuando se observan manchas o espumas dificiles de identificar flotando en las aguas de bano mas cercanas a la orilla. Estas manchas o espumas han sido denomina...
MATEC Web of Conferences, 2018
This keynote lecture will be focused on the strategies for reducing CO2 emissions in the cement p... more This keynote lecture will be focused on the strategies for reducing CO2 emissions in the cement production. Concretely, the production of ecocements with optimised formulations that yield reductions in CO2 emissions of up to 25%, when compared to OPC production. Phase assemblage has to be carefully optimised to be competitive and these new ecocements should develop compressive strengths of at least 50 MPa at 28 days of hydration. Optimised compositions of several ecocements will be discussed, but all of them are ye'elimite or calcium sulphoaluminate containing ones: belite-ye'elimite-ferrite (BYF), belite-alite-ye'elimite (BAY) and ye'elimite rich ones (CSA). The clinkering temperature of BYF and BAY has to be established to obtain the targeted phase assemblages. Moreover, the stabilisation of alpha-forms of belite is needed to develop high mechanical strengths at early ages. The benefits of the use of waste materials (such as fly ash or slag) as additions to ecoceme...
Applied Clay Science, 2004
The differences on the thermal behaviour (DTG-DTA) of three pyrophyllite samples measured before ... more The differences on the thermal behaviour (DTG-DTA) of three pyrophyllite samples measured before and after sonication have been studied. Sonication treatment produces substantial textural modifications but negligible changes in the structure of the material. These modifications produce important changes in the thermal behaviour of pyrophyllite samples. Thus, it produces a decrease of more than 100 jC in the dehydroxylation temperature as measured by DTG and DTA effects. In addition, the exothermic effect of mullite formation shifts to lower temperature (about 30 jC) in sonicated pyrophyllite. These modification in the thermal behaviour are related to the pronounced decrease in particle size. The dehydroxylation effect of kaolinite that accompanies two of the studied samples, overlaps with that of sonicated pyrophyllite; however, the exothermic effect at 975 jC of kaolinite remain unchanged with the treatment.
Clays and Clay Minerals, 2000
The intercalation complex of a low-defect ("well-crystallized") kaolinite from Cornwall, England,... more The intercalation complex of a low-defect ("well-crystallized") kaolinite from Cornwall, England, with hydrazine was studied by high-temperature X-ray diffraction (HTXRD), differential thermal analysis (DTA), and thermogravimetry (TG). The X-ray pattern at room temperature indicated that intercalation of hydrazine into kaolinite causes an increase of the basal spacing from 7.14 to 10.4 A, as previously reported. Heating between 25-200~ produces a structural rearrangement of the complex, which initially causes a contraction of the basal spacing from 10.4 to 9.6 A. In a second stage, the basal spacing reduces to 8.5 A. Finally, in a third stage, a reduction in spacing occurs through a set of intermediate phases, interpreted as interstratifications of intercalated and non-intercalated 1:1 layers. Evidence for these changes was observed by DTA, where three endothermic reactions are observed at low temperature. This behavior suggests that intercalated molecules occupy several well-defined sites in the interlayer of the kaolinite complex. The intercalated molecules deintercalate in an ordered fashion, which explains the successive and discontinuous contraction of the basal spacing of the complex. Heating between 200-400~ caused a limited increase in stacking order of the kaolinite structure, whereas dehydroxylation of kaolinite and the disappearance of its X-ray reflections occurred between 450-640~ Key Vfords-DTA-TG, HTXRD, Hydrazine, Intercalation Complex, Kaolinite.
Minerals, 2020
Titanium and zirconium oxides (TiO2 and ZrO2, respectively) were obtained from alkoxides hydrolys... more Titanium and zirconium oxides (TiO2 and ZrO2, respectively) were obtained from alkoxides hydrolyses, and then deposited into palygorskite clay mineral (Pal) to obtain new materials for photocatalytic applications. The obtained materials were characterized by structural, morphological, and textural techniques. X-ray diffraction (XRD) results confirmed the characteristic peaks of oxides and clay transmission electron microscopy (TEM) and scanning electron microscopy (SEM) images of the modified palygorskite with both oxides showed that the clay was successfully modified by the proposed method. The increase in the specific surface area of the clay occurred when TiO2 and ZrO2 were deposited on the surface. The photocatalytic activity of these materials was investigated using the Remazol Blue anion dye under UV light. The evaluated systems presented high photocatalytic activity, reaching approximately 98% of dye discoloration under light. Thus, TiO2–Pal and ZrO2–TiO2–Pal are promising cl...
Minerals, 2020
A series of clay minerals and clay-based materials have been tested to eliminate one of the most ... more A series of clay minerals and clay-based materials have been tested to eliminate one of the most dangerous bacteria we can find in the water: Salmonella. It has been proven that the use of clays and their PCH materials can be a suitable method for removing Salmonella from water. The results of this initial study show that all the materials analyzed have great salmonella adsorption capacities ranging from the lowest value observed in the mont-PCH sample (0.29 × 1010 CFU g−1) to the highest value observed in the natural palygorskite sample (1.52 × 1010 CFU g−1). Macroporosity, accessible external surface area, and the presence of silanol groups in the external surface of the particles appears to be the controlling factors for Salmonella adsorption capacity while it seems that the structural characteristics of the clay minerals and their respective PCH does not affect the adsorption capacity.
Ecosistemas, Apr 30, 2021
Clays and Clay Minerals, 2000
En las ultimas decadas la poblacion y las empresas malaguenas que centran su actividad en el sect... more En las ultimas decadas la poblacion y las empresas malaguenas que centran su actividad en el sector turistico vienen demandando que el mayor activo de la provincia de Malaga, sus playas, tengan una calidad adecuada capaz de competir con las playas de otros paises cercanos. Un indicador claro de la calidad actual de las playas de la Costa del Sol lo muestra el numero de banderas azules. En el pasado verano (2018) ondearon 24 banderas azules a lo largo de todo el litoral de la provincia de Malaga. No obstante, existe la necesidad de mantener y mejorar la calidad de nuestras playas a lo largo del tiempo para que la industria que crece a lo largo de todo el litoral se haga sostenible. Una de las mayores preocupaciones del usuario de las playas de la Costa del Sol es la calidad de las aguas de bano. Esta preocupacion se incrementa cuando se observan manchas o espumas dificiles de identificar flotando en las aguas de bano mas cercanas a la orilla. Estas manchas o espumas han sido denomina...
MATEC Web of Conferences, 2018
This keynote lecture will be focused on the strategies for reducing CO2 emissions in the cement p... more This keynote lecture will be focused on the strategies for reducing CO2 emissions in the cement production. Concretely, the production of ecocements with optimised formulations that yield reductions in CO2 emissions of up to 25%, when compared to OPC production. Phase assemblage has to be carefully optimised to be competitive and these new ecocements should develop compressive strengths of at least 50 MPa at 28 days of hydration. Optimised compositions of several ecocements will be discussed, but all of them are ye'elimite or calcium sulphoaluminate containing ones: belite-ye'elimite-ferrite (BYF), belite-alite-ye'elimite (BAY) and ye'elimite rich ones (CSA). The clinkering temperature of BYF and BAY has to be established to obtain the targeted phase assemblages. Moreover, the stabilisation of alpha-forms of belite is needed to develop high mechanical strengths at early ages. The benefits of the use of waste materials (such as fly ash or slag) as additions to ecoceme...
Applied Clay Science, 2004
The differences on the thermal behaviour (DTG-DTA) of three pyrophyllite samples measured before ... more The differences on the thermal behaviour (DTG-DTA) of three pyrophyllite samples measured before and after sonication have been studied. Sonication treatment produces substantial textural modifications but negligible changes in the structure of the material. These modifications produce important changes in the thermal behaviour of pyrophyllite samples. Thus, it produces a decrease of more than 100 jC in the dehydroxylation temperature as measured by DTG and DTA effects. In addition, the exothermic effect of mullite formation shifts to lower temperature (about 30 jC) in sonicated pyrophyllite. These modification in the thermal behaviour are related to the pronounced decrease in particle size. The dehydroxylation effect of kaolinite that accompanies two of the studied samples, overlaps with that of sonicated pyrophyllite; however, the exothermic effect at 975 jC of kaolinite remain unchanged with the treatment.
Clays and Clay Minerals, 2000
The intercalation complex of a low-defect ("well-crystallized") kaolinite from Cornwall, England,... more The intercalation complex of a low-defect ("well-crystallized") kaolinite from Cornwall, England, with hydrazine was studied by high-temperature X-ray diffraction (HTXRD), differential thermal analysis (DTA), and thermogravimetry (TG). The X-ray pattern at room temperature indicated that intercalation of hydrazine into kaolinite causes an increase of the basal spacing from 7.14 to 10.4 A, as previously reported. Heating between 25-200~ produces a structural rearrangement of the complex, which initially causes a contraction of the basal spacing from 10.4 to 9.6 A. In a second stage, the basal spacing reduces to 8.5 A. Finally, in a third stage, a reduction in spacing occurs through a set of intermediate phases, interpreted as interstratifications of intercalated and non-intercalated 1:1 layers. Evidence for these changes was observed by DTA, where three endothermic reactions are observed at low temperature. This behavior suggests that intercalated molecules occupy several well-defined sites in the interlayer of the kaolinite complex. The intercalated molecules deintercalate in an ordered fashion, which explains the successive and discontinuous contraction of the basal spacing of the complex. Heating between 200-400~ caused a limited increase in stacking order of the kaolinite structure, whereas dehydroxylation of kaolinite and the disappearance of its X-ray reflections occurred between 450-640~ Key Vfords-DTA-TG, HTXRD, Hydrazine, Intercalation Complex, Kaolinite.
Minerals, 2020
Titanium and zirconium oxides (TiO2 and ZrO2, respectively) were obtained from alkoxides hydrolys... more Titanium and zirconium oxides (TiO2 and ZrO2, respectively) were obtained from alkoxides hydrolyses, and then deposited into palygorskite clay mineral (Pal) to obtain new materials for photocatalytic applications. The obtained materials were characterized by structural, morphological, and textural techniques. X-ray diffraction (XRD) results confirmed the characteristic peaks of oxides and clay transmission electron microscopy (TEM) and scanning electron microscopy (SEM) images of the modified palygorskite with both oxides showed that the clay was successfully modified by the proposed method. The increase in the specific surface area of the clay occurred when TiO2 and ZrO2 were deposited on the surface. The photocatalytic activity of these materials was investigated using the Remazol Blue anion dye under UV light. The evaluated systems presented high photocatalytic activity, reaching approximately 98% of dye discoloration under light. Thus, TiO2–Pal and ZrO2–TiO2–Pal are promising cl...
Minerals, 2020
A series of clay minerals and clay-based materials have been tested to eliminate one of the most ... more A series of clay minerals and clay-based materials have been tested to eliminate one of the most dangerous bacteria we can find in the water: Salmonella. It has been proven that the use of clays and their PCH materials can be a suitable method for removing Salmonella from water. The results of this initial study show that all the materials analyzed have great salmonella adsorption capacities ranging from the lowest value observed in the mont-PCH sample (0.29 × 1010 CFU g−1) to the highest value observed in the natural palygorskite sample (1.52 × 1010 CFU g−1). Macroporosity, accessible external surface area, and the presence of silanol groups in the external surface of the particles appears to be the controlling factors for Salmonella adsorption capacity while it seems that the structural characteristics of the clay minerals and their respective PCH does not affect the adsorption capacity.