Background: Pyoderma gangrenosum is a rare inflammatory disease of unknown etiology and a poorly ... more Background: Pyoderma gangrenosum is a rare inflammatory disease of unknown etiology and a poorly understood pathogenesis. Its clinical presentation is variable and a large percentage of cases are associated with inflammatory bowel diseases. Peristomal pyoderma gangrenosum represents a variant of the diseases, occurring in patients with colostomy. Multiple cases demonstrate efficacy of infliximab and other anti-TNF-alpha drugs in treatment of pyoderma gangrenosum.
Municipal solid waste (MSW) landfills are usually built on obsolete clay quarries. This study pre... more Municipal solid waste (MSW) landfills are usually built on obsolete clay quarries. This study presents the results of seven boreholes drilled into natural clay materials, placed under the waste of three old Spanish landfills. Electrical conductivity (EC), water soluble organic carbon, Cl-, NH4+ and Na+ (WSOC, Cl-sol, NH4+sol and Na+sol); as well as exchangeable NH4+ and Na+ (NH4+ex and Na+ex) were measured at different depths to track the pollution. WSOC and EC plumes were attenuated between 0.2 and 1.5 m of depth, a short distance taking into account that leachates have been in contact with clays for more than 10-20 years. Furthemore, the materials under the landfills were characterized by measuring the mineralogy, the specific surface and the cationic exchange capacity (CEC). The results show that these kind of clayey substrata are suitable for confining leachate pollution and complying with the European legislation. Finally, a principal component analysis (PCA) combined with a Va...
The study analyzes solid samples from two substrata (kaolinitic clay acid environment (1) and ill... more The study analyzes solid samples from two substrata (kaolinitic clay acid environment (1) and illite-smectite carbonated clay environment (2) under old municipal landfills that were in direct contact with the waste. The main soluble constituents of the leachates (Na+sol, NH4+sol, alkalinity, Clsol) and the composition of the exchangeable complex in the clay minerals (Na+ex, NH4+ex, K+ex) were measured in the solid samples as a function of depth to study the extend of the pollution in the vertical direction. The purpose was to determine the capacity of the natural substrata as geological barriers that can retain leachate pollution (Council Directive 1999/31/EC). In case (1) pollutants were not attenuated, but in case (2) the extent of the potential impact of the main soluble components of the leachate became naturally retained after 1 m depth. The difference was attributed to the mineralogy and the enhancement of the migration potential under acidic conditions.
The landfilling of municipal wastes in the European Union (EU) requires a geological barrier of a... more The landfilling of municipal wastes in the European Union (EU) requires a geological barrier of at least 1m thickness with a hydraulic conductivity (HC) of 1·10-9 m/s. We studied six cores drilled from the contact between waste and natural clay materials in three Spanish old landfills. Several geochemical parameters were measured in aqueous 1:10 solid:liquid extracts as a function of depth. Electrical conductivity (EC), Cl-, NH4+ , Na+ , exchangeable NH4+ and Na+, and total organic carbon (TOC) were used as indicators of the penetration of the landfill leachate. Although leachates have been in contact with clay between 10-20 years, TOC and EC plume is attenuated in 1m depth. Taking into account the thickness of clay under the waste, ((0.5 – 1m) > 50 % sheet-silicates, illite-smectite type), the suitabilty of these natural clays for the confinement of the leachates is being evidenced.
Abstract: Biopolymers such as chitosan, pectin, alginate, ı-carrageenan and gelatin, can be assem... more Abstract: Biopolymers such as chitosan, pectin, alginate, ı-carrageenan and gelatin, can be assembled to layered solids by direct intercalation via ion exchange in the case of smectites or a'co-organised assembly'method in the case of layered double hydroxides (LDHs). Layered perovskites can be delaminated and combined with the biopolymers following a delamination/restacking procedure. The starting cationic exchange ability of smectites such as montmorillonite is turned into an anionic exchange capacity due to the intercalated ...
A new class of bio-nanocomposites based on hybrid gelatin-perovskite hydrogels was prepared by mi... more A new class of bio-nanocomposites based on hybrid gelatin-perovskite hydrogels was prepared by mixing exfoliated perovskite-tetraalkylammonium species in aqueous suspensions with gelatin solutions. Colloidal nanosheets derived from the CsCa2Nb3O10 layered perovskite re-stacked in the gelatin solutions give bio-nanocomposite materials with different content in the inorganic moiety. These films can be easily processed as homogeneous self-supported films. The partial exfoliation of the pristine mixed oxide is produced from alkylammonium exchanged phases, being the tetraalkylammonium ions (tetraethylammonium, TEA+) an efficient intermediate to give the colloid phase constituted by well exfoliated materials useful to generate homogeneous films. The nanosheets are highly oriented in the bio-nanocomposite films in agreement with the XRD patterns and the FTIR dichroism. This orientation could be considered as a characteristic of this type of hybrid materials leading to new potential applica...
The long-term effectiveness of the geological barrier beneath municipal-waste landfills is a crit... more The long-term effectiveness of the geological barrier beneath municipal-waste landfills is a critical issue for soil and groundwater protection. This study examines natural clayey soils directly in contact with the waste deposited in three landfills over 12 years old in Spain. Several physicochemical and geological parameters were measured as a function of depth. Electrical conductivity (EC), water-soluble organic carbon (WSOC), Cl À , NH 4 + , Na + and exchangeable NH 4 + and Na + were used as parameters to measure the penetration of landfill leachate pollution. Mineralogy, specific surface area and cationic-exchange capacities were analyzed to characterize the materials under the landfills. A principal component analysis, combined with a Varimax rotation, was applied to the data to determine patterns of association between samples and variables not evident upon initial inspection. The main factors explaining the variation in the data are related to waste composition and local geology. Although leachates have been in contact with clays for long time periods (13-24 years), WSOC and EC fronts are attenuated at depths of 0.2-1.5 m within the clay layer. Taking into account this depth of the clayey materials, these natural substrata (>45% illite-smectite-type sheet silicates) are suitable for confining leachate pollution and for complying with European legislation. This paper outlines the relevant differences in the clayey materials of the three landfills in which a diffusive flux attenuation capacity (A c ) is defined as a function (1) of the rate of decrease of the parameters per meter of material, (2) of the age and area of the landfill and (3) of the quantity and quality of the wastes. , ratio decrease per metre deep of parameter X, averaged per landfills; Sol_ion, soluble ion; SSA, specific surface area; WSIC, water soluble inorganic carbon; WSOC, water soluble organic carbon.
Acidity decreased the ability of a substratum to retain leachate pollutants, which travelled furt... more Acidity decreased the ability of a substratum to retain leachate pollutants, which travelled further than one-meter depth.
Enhanced sand-clay mixtures have been prepared by using a sandstone arkosic material and have bee... more Enhanced sand-clay mixtures have been prepared by using a sandstone arkosic material and have been evaluated for consideration as landfill liners. A lab-scale test was carried out under controlled conditions with different amended natural sandstones whereby leachate was passed through the compacted mixtures. The compacted samples consisted of siliceous sand (quartz-feldspar sand separated from the arkose sandstone) and clay (purified clay from arkose sandstone and two commercial bentonites) materials that were mixed in different proportions. The separation of mineral materials from a common and abundant natural source, for soil protection purposes, is proposed as an economic and environmentally efficient practice. The liner qualities were compared for their mineralogical, physicochemical and major ions transport and adsorption properties. Although all samples fulfilled hydraulic conductivity requirements, the addition of bentonite to arkose sandstone was determined to be an effective strategy to decrease the permeability of the soil and to improve the pollutants retention. The clay materials from arkose sandstone also contributed to pollutant retention by a significant improvement of the cation exchange capacity of the bulk material. However, the mixtures prepared with clay materials from the arkose, exhibited a slight increase of hydraulic conductivity. This effect has to be further evaluated.
Clay minerals such as the layered silicates montmorillonite and vermiculite, as well as the fibro... more Clay minerals such as the layered silicates montmorillonite and vermiculite, as well as the fibrous clay sepiolite, and a layered double hydroxide ([Zn2Al(OH)6]Cl.nH2O) have been used to prepare gelatin-clay micro- and nano-composites. This biopolymer can be assembled to those inorganic solids through interactions at the nanometric range, but only in the case of montmorillonite intercalation of gelatin takes place. One of the most salient features of the resulting bio-nanocomposites is the possibility to be processed as homogeneous thin films provided of good mechanical properties and transparency. The Young's modulus of gelatin-sepiolite bio-nanocomposites may increase by a factor of 2.5 with respect to neat gelatin. The incorporation of pH indicator dyes to the montmorillonite bio-nanocomposite films allows their application for optical pH sensing.
In this paper, the diffusion of solutes in natural clay from a concentrated solution consisting p... more In this paper, the diffusion of solutes in natural clay from a concentrated solution consisting primarily of ammonium, sodium and chloride ions at a pH level of 8 was studied and was based on an existing 20year-old landfill. Contaminant transport through clay liners was predicted using transport and reaction geochemical codes to help explain the experimental data. The model predicted the chloride anion diffusion and cation exchange processes for three different experiments: (1) small-scale interactions in compacted clay, (2) 1:1 European Union (EU) Directive demonstration experiments (0.5-m-thick clay barrier), and (3) analysis of a bore hole with core recovery drilled in an old landfill located above a similar type of clay as that studied in and . Orders of magnitude between 10 À10 and 10 À9 m 2 s À1 were used for the apparent diffusion coefficient to fit the chloride profiles at the different scales; however, at larger space and time scales, diffusion was retarded due to the presence of more consolidated, non-mechanically disturbed clay materials at large depths in a natural clay-rock emplacement.
Polycrystalline samples of general composition La 1.33 - x Na 3 x Ti 2 O 6 were prepared by the “... more Polycrystalline samples of general composition La 1.33 - x Na 3 x Ti 2 O 6 were prepared by the “liquid mix” technique. The structural analysis carried out from different techniques (XRPD, ED, HREM, and NPD) evidences that these perovskites undergo phase transformations that seem to be mainly related to the number of A-vacancies. For high degrees of substitution, x, that imply low number of vacant A-sites, a random distribution of Na + and La 3+ ions in these sites is observed. When this number increases (for x = 0.16 and 0.11) two ...
Background: Pyoderma gangrenosum is a rare inflammatory disease of unknown etiology and a poorly ... more Background: Pyoderma gangrenosum is a rare inflammatory disease of unknown etiology and a poorly understood pathogenesis. Its clinical presentation is variable and a large percentage of cases are associated with inflammatory bowel diseases. Peristomal pyoderma gangrenosum represents a variant of the diseases, occurring in patients with colostomy. Multiple cases demonstrate efficacy of infliximab and other anti-TNF-alpha drugs in treatment of pyoderma gangrenosum.
Municipal solid waste (MSW) landfills are usually built on obsolete clay quarries. This study pre... more Municipal solid waste (MSW) landfills are usually built on obsolete clay quarries. This study presents the results of seven boreholes drilled into natural clay materials, placed under the waste of three old Spanish landfills. Electrical conductivity (EC), water soluble organic carbon, Cl-, NH4+ and Na+ (WSOC, Cl-sol, NH4+sol and Na+sol); as well as exchangeable NH4+ and Na+ (NH4+ex and Na+ex) were measured at different depths to track the pollution. WSOC and EC plumes were attenuated between 0.2 and 1.5 m of depth, a short distance taking into account that leachates have been in contact with clays for more than 10-20 years. Furthemore, the materials under the landfills were characterized by measuring the mineralogy, the specific surface and the cationic exchange capacity (CEC). The results show that these kind of clayey substrata are suitable for confining leachate pollution and complying with the European legislation. Finally, a principal component analysis (PCA) combined with a Va...
The study analyzes solid samples from two substrata (kaolinitic clay acid environment (1) and ill... more The study analyzes solid samples from two substrata (kaolinitic clay acid environment (1) and illite-smectite carbonated clay environment (2) under old municipal landfills that were in direct contact with the waste. The main soluble constituents of the leachates (Na+sol, NH4+sol, alkalinity, Clsol) and the composition of the exchangeable complex in the clay minerals (Na+ex, NH4+ex, K+ex) were measured in the solid samples as a function of depth to study the extend of the pollution in the vertical direction. The purpose was to determine the capacity of the natural substrata as geological barriers that can retain leachate pollution (Council Directive 1999/31/EC). In case (1) pollutants were not attenuated, but in case (2) the extent of the potential impact of the main soluble components of the leachate became naturally retained after 1 m depth. The difference was attributed to the mineralogy and the enhancement of the migration potential under acidic conditions.
The landfilling of municipal wastes in the European Union (EU) requires a geological barrier of a... more The landfilling of municipal wastes in the European Union (EU) requires a geological barrier of at least 1m thickness with a hydraulic conductivity (HC) of 1·10-9 m/s. We studied six cores drilled from the contact between waste and natural clay materials in three Spanish old landfills. Several geochemical parameters were measured in aqueous 1:10 solid:liquid extracts as a function of depth. Electrical conductivity (EC), Cl-, NH4+ , Na+ , exchangeable NH4+ and Na+, and total organic carbon (TOC) were used as indicators of the penetration of the landfill leachate. Although leachates have been in contact with clay between 10-20 years, TOC and EC plume is attenuated in 1m depth. Taking into account the thickness of clay under the waste, ((0.5 – 1m) > 50 % sheet-silicates, illite-smectite type), the suitabilty of these natural clays for the confinement of the leachates is being evidenced.
Abstract: Biopolymers such as chitosan, pectin, alginate, ı-carrageenan and gelatin, can be assem... more Abstract: Biopolymers such as chitosan, pectin, alginate, ı-carrageenan and gelatin, can be assembled to layered solids by direct intercalation via ion exchange in the case of smectites or a'co-organised assembly'method in the case of layered double hydroxides (LDHs). Layered perovskites can be delaminated and combined with the biopolymers following a delamination/restacking procedure. The starting cationic exchange ability of smectites such as montmorillonite is turned into an anionic exchange capacity due to the intercalated ...
A new class of bio-nanocomposites based on hybrid gelatin-perovskite hydrogels was prepared by mi... more A new class of bio-nanocomposites based on hybrid gelatin-perovskite hydrogels was prepared by mixing exfoliated perovskite-tetraalkylammonium species in aqueous suspensions with gelatin solutions. Colloidal nanosheets derived from the CsCa2Nb3O10 layered perovskite re-stacked in the gelatin solutions give bio-nanocomposite materials with different content in the inorganic moiety. These films can be easily processed as homogeneous self-supported films. The partial exfoliation of the pristine mixed oxide is produced from alkylammonium exchanged phases, being the tetraalkylammonium ions (tetraethylammonium, TEA+) an efficient intermediate to give the colloid phase constituted by well exfoliated materials useful to generate homogeneous films. The nanosheets are highly oriented in the bio-nanocomposite films in agreement with the XRD patterns and the FTIR dichroism. This orientation could be considered as a characteristic of this type of hybrid materials leading to new potential applica...
The long-term effectiveness of the geological barrier beneath municipal-waste landfills is a crit... more The long-term effectiveness of the geological barrier beneath municipal-waste landfills is a critical issue for soil and groundwater protection. This study examines natural clayey soils directly in contact with the waste deposited in three landfills over 12 years old in Spain. Several physicochemical and geological parameters were measured as a function of depth. Electrical conductivity (EC), water-soluble organic carbon (WSOC), Cl À , NH 4 + , Na + and exchangeable NH 4 + and Na + were used as parameters to measure the penetration of landfill leachate pollution. Mineralogy, specific surface area and cationic-exchange capacities were analyzed to characterize the materials under the landfills. A principal component analysis, combined with a Varimax rotation, was applied to the data to determine patterns of association between samples and variables not evident upon initial inspection. The main factors explaining the variation in the data are related to waste composition and local geology. Although leachates have been in contact with clays for long time periods (13-24 years), WSOC and EC fronts are attenuated at depths of 0.2-1.5 m within the clay layer. Taking into account this depth of the clayey materials, these natural substrata (>45% illite-smectite-type sheet silicates) are suitable for confining leachate pollution and for complying with European legislation. This paper outlines the relevant differences in the clayey materials of the three landfills in which a diffusive flux attenuation capacity (A c ) is defined as a function (1) of the rate of decrease of the parameters per meter of material, (2) of the age and area of the landfill and (3) of the quantity and quality of the wastes. , ratio decrease per metre deep of parameter X, averaged per landfills; Sol_ion, soluble ion; SSA, specific surface area; WSIC, water soluble inorganic carbon; WSOC, water soluble organic carbon.
Acidity decreased the ability of a substratum to retain leachate pollutants, which travelled furt... more Acidity decreased the ability of a substratum to retain leachate pollutants, which travelled further than one-meter depth.
Enhanced sand-clay mixtures have been prepared by using a sandstone arkosic material and have bee... more Enhanced sand-clay mixtures have been prepared by using a sandstone arkosic material and have been evaluated for consideration as landfill liners. A lab-scale test was carried out under controlled conditions with different amended natural sandstones whereby leachate was passed through the compacted mixtures. The compacted samples consisted of siliceous sand (quartz-feldspar sand separated from the arkose sandstone) and clay (purified clay from arkose sandstone and two commercial bentonites) materials that were mixed in different proportions. The separation of mineral materials from a common and abundant natural source, for soil protection purposes, is proposed as an economic and environmentally efficient practice. The liner qualities were compared for their mineralogical, physicochemical and major ions transport and adsorption properties. Although all samples fulfilled hydraulic conductivity requirements, the addition of bentonite to arkose sandstone was determined to be an effective strategy to decrease the permeability of the soil and to improve the pollutants retention. The clay materials from arkose sandstone also contributed to pollutant retention by a significant improvement of the cation exchange capacity of the bulk material. However, the mixtures prepared with clay materials from the arkose, exhibited a slight increase of hydraulic conductivity. This effect has to be further evaluated.
Clay minerals such as the layered silicates montmorillonite and vermiculite, as well as the fibro... more Clay minerals such as the layered silicates montmorillonite and vermiculite, as well as the fibrous clay sepiolite, and a layered double hydroxide ([Zn2Al(OH)6]Cl.nH2O) have been used to prepare gelatin-clay micro- and nano-composites. This biopolymer can be assembled to those inorganic solids through interactions at the nanometric range, but only in the case of montmorillonite intercalation of gelatin takes place. One of the most salient features of the resulting bio-nanocomposites is the possibility to be processed as homogeneous thin films provided of good mechanical properties and transparency. The Young's modulus of gelatin-sepiolite bio-nanocomposites may increase by a factor of 2.5 with respect to neat gelatin. The incorporation of pH indicator dyes to the montmorillonite bio-nanocomposite films allows their application for optical pH sensing.
In this paper, the diffusion of solutes in natural clay from a concentrated solution consisting p... more In this paper, the diffusion of solutes in natural clay from a concentrated solution consisting primarily of ammonium, sodium and chloride ions at a pH level of 8 was studied and was based on an existing 20year-old landfill. Contaminant transport through clay liners was predicted using transport and reaction geochemical codes to help explain the experimental data. The model predicted the chloride anion diffusion and cation exchange processes for three different experiments: (1) small-scale interactions in compacted clay, (2) 1:1 European Union (EU) Directive demonstration experiments (0.5-m-thick clay barrier), and (3) analysis of a bore hole with core recovery drilled in an old landfill located above a similar type of clay as that studied in and . Orders of magnitude between 10 À10 and 10 À9 m 2 s À1 were used for the apparent diffusion coefficient to fit the chloride profiles at the different scales; however, at larger space and time scales, diffusion was retarded due to the presence of more consolidated, non-mechanically disturbed clay materials at large depths in a natural clay-rock emplacement.
Polycrystalline samples of general composition La 1.33 - x Na 3 x Ti 2 O 6 were prepared by the “... more Polycrystalline samples of general composition La 1.33 - x Na 3 x Ti 2 O 6 were prepared by the “liquid mix” technique. The structural analysis carried out from different techniques (XRPD, ED, HREM, and NPD) evidences that these perovskites undergo phase transformations that seem to be mainly related to the number of A-vacancies. For high degrees of substitution, x, that imply low number of vacant A-sites, a random distribution of Na + and La 3+ ions in these sites is observed. When this number increases (for x = 0.16 and 0.11) two ...
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Papers by Ana Ruiz