Papers by Pablo Martin-Ramos
One of the ways of stopping science would be only to do experiments in the region where you know ... more One of the ways of stopping science would be only to do experiments in the region where you know the law. But experimenters search most diligently, and with the greatest effort, in exactly those places where it seems most likely that we can prove our theories wrong. In other words, we are trying to prove ourselves wrong as quickly as possible, because only in that way can we find progress.
Cellulose Chemistry and Technology, Mar 30, 2015
ABSTRACT In this study an example of the reuse and revalorization of lignocellulosic waste from c... more ABSTRACT In this study an example of the reuse and revalorization of lignocellulosic waste from carnauba palm (Copernicia prunifera) leaves, macauba palm (Acrocomia aculeata) endocarp (shell) and European stone pine (Pinus pinea) nut shell is presented for the first time. The physical-chemical adsorption of Rhodamine B (RhB) dye for the different materials is studied in detail, together with the thermodynamic feasibility and the spontaneous and endothermic nature of the biosorption process. Subsequently, the production of total reducing sugars (TRS) is compared by enzymatic hydrolysis (before and after the adsorption process of the RhB pollutant), confirming the viability of TRS production in all cases, with yields ranging from 65.9% for pine nut shell (after adsorption) to 74.9% for the carnauba endocarp and to 84.0% for carnauba leaves (before adsorption). Hence the use of lignocellulosic materials as adsorbents does not preclude their ulterior reuse for obtaining fermentable sugars by enzymatic hydrolysis.
El contenido del presente artículo es relativo al hallazgo de la inscripción "T(flor-de-lis)MPLOS... more El contenido del presente artículo es relativo al hallazgo de la inscripción "T(flor-de-lis)MPLOS+" en las rosas de los vientos de algunos portulanos, principalmente de los siglos XVI y XVII, procedentes de cartógrafos como Bartolommeo dalli Sonetti, Albino de Canepa, Jacopo Russo, Battista Agnese, Mateus Prunes, Diogo Homem, Joan Martínes, Bartolomeu Olives y Juan Oliva. La primera referencia a esta inscripción se encuentra en el Atlas Catalán (1375) en torno a la última circunferencia de la carta de mareas, en la hoja relativa a los diagramas astronómico y cosmográfico, junto al hombre zodiacal. La última referencia a ella está presente en una brújula fabricada en Livorno en 1719. El conjunto de letras considerado (TMPLOS) constituye bien un acrónimo o un criptograma. En el primer caso, es posible atribuir las letras T, M, P, L, O y S a los vientos Tramontana (N), Maestro (NW), Ponente (W), Libeccio (SW), Ostro (S) y Sirocco (SE). En el segundo caso, si se acepta como buena la asignación de la letra E a la flor de lis y se procede a una lectura en sentido contrario a las agujas del reloj (como realmente aparece en las rosas de los vientos), es posible reconstruir la palabra TEMPLOS (un término hispano-portugués) sin ambigüedad alguna. No obstante, el carácter rotario de la disposición de las letras ofrece varias interpretaciones que evocan a la Orden de los caballeros Templarios. Así, LOSTEMP pudiera significar L(aus) O(rdo) S(upremus) TEMP(li).
International Journal of Hydrogen Energy, 2015
ABSTRACT Se-modified g-C3N4 was synthesized from sonicated aqueous suspensions of melamine cyanur... more ABSTRACT Se-modified g-C3N4 was synthesized from sonicated aqueous suspensions of melamine cyanurate and SeO2. The different thermal condensation temperatures in the 500-650 ºC range were found to influence the photophysical properties and hydrogen evolution rates. H2 evolution increased dramatically by two orders of magnitude when Pt co-catalyst (1 wt.%) was incorporated, reaching an HER of 75 µmol H2/h.
This article presents an infrared spectroscopy and X-ray diffraction analysis of residue adhering... more This article presents an infrared spectroscopy and X-ray diffraction analysis of residue adhering to a Celtiberian pottery sherd of late Iron Age date from the Arevacian site of Cerro del Castillo, in Ayllón (Segovia, Spain). This residue may be a paste used since antiquity for protective aims. Orange-sepia in colour, made from crushed bones and glue, the paste was used by Greeks and Romans and later in the construction of the cathedrals and monasteries of Europe to confer a warm colour to the stone and to protect it against environmental deterioration. In this article we also suggest a possible ritual use of this paste in the protection of the skin of the Arevaci and Edetani warriors, and the previously unreported pleasant aroma of this material is highlighted. The possible nutritional use of this paste is also considered.
Cellulose Chemistry and Technology
Different types of lignocellulosic materials (carnauba leaves, macauba shell and pine nut shell) ... more Different types of lignocellulosic materials (carnauba leaves, macauba shell and pine nut shell) and native cellulose have been studied for the production of total reducing sugars (TRS) through microwave-assisted acid-catalyzed hydrolysis in ionic liquids (ILs). Four reaction media have been assessed: two deep eutectic solvents (DES), choline chloride-oxalic acid (ChCl/ox) and choline chloride-urea (ChCl/urea), and two conventional ionic liquids, tetraethylammonium chloride (TEAC) and tetraethylammonium bromide (TEAB). Five acids (H2SO4, HCl, HNO3, H3PO4 and p-toluensulfonic acid) have been evaluated in varying concentrations (5-30%) and time intervals (0-60 min), at different temperatures (100-140ºC). Significant TRS production yields (as high as 83.7% in ChCl/ox for carnauba leaves) have been attained for both DES in combination with HNO3 10%, at 120ºC for 30 min, with the additional advantage of low furfural and HMF by-products generation.
Materials Chemistry and Physics, 2015
ABSTRACT The magnetic properties of a perfluorinated Er3+ complex, with record luminescent proper... more ABSTRACT The magnetic properties of a perfluorinated Er3+ complex, with record luminescent properties, have been investigated. [Er(F-TPIP)3] displays thermally activated slow relaxation of the magnetisation under an applied HDC field of 500 Oe. The effective relaxation barrier Eeff is found to be 26.8 K (18.6 cm-1). At zero static field, efficient quantum tunnelling of the magnetization occurs.
Dalton Transactions
Seven new tris(β-diketonear-nate)ytterbium(iii) complexes with the general formula [Yb(β-diketona... more Seven new tris(β-diketonear-nate)ytterbium(iii) complexes with the general formula [Yb(β-diketonate)3(5NO2phen)] (where the β-diketone is either 4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedione, 4,4,4-trifluoro-1-(2-furyl)-1,3-butanedione, 1,1,1-trifluoro-2,4-pentanedione, 1,1,1-trifluoro-5,5-dimethyl-2,4-hexanedione, 1,1,1,5,5,6,6,7,7,7-decafluoro-2,4-heptanedione, 2,4-hexanedione or 2,6-dimethyl-3,5-heptanedione, and 5NO2phen = 5-nitro-1,10-phenanthroline) were synthesized and characterized by elemental analysis, attenuated total reflectance Fourier transform infrared spectroscopy and photoluminescence spectroscopy. Single crystal X-ray structures have been determined for three fluorinated complexes and ground state geometries of the other four complexes have been predicted using the Sparkle/PM6 model. These experimental structures and those designed by semi-empirical models reveal octacoordination around the Yb(3+) ion. Photoluminescence studies and lifetime measurements show that ...
New Journal of Chemistry
A new Er(III) β-diketonate complex, tris(dibenzoylmethanate)mono(2,2´-bipyridine) erbium(III) or ... more A new Er(III) β-diketonate complex, tris(dibenzoylmethanate)mono(2,2´-bipyridine) erbium(III) or [Er(dbm)3(bipy)], has been synthesized and its structural, thermal, photophysical and low temperature magnetic properties have been characterized. In the new complex, Er(III) ions are coordinated by six O atoms and two N atoms in a distorted square antiprismatic geometry. The Er(III) complex exhibits out-of-phase (χ_M^") ac susceptibility signals, when a static magnetic field is applied, signaling that at zero field a quantum tunneling regime occurs. The nearly semi-circular and symmetrical shape of the Cole-Cole plots sustain the existence of a single magnetic relaxation process. The solid state luminescent studies show an intense, sharp and narrow emission band in the near infrared region. The combined results demonstrate the ability of dbm and bipy to provide an environment that yields both interesting magnetic and optical properties.
All reagents and solvents employed were commercially available and used as supplied without furth... more All reagents and solvents employed were commercially available and used as supplied without further purification: 2,4-nonanedione (CAS No. 6175-23-1, Alfa Aesar, >98%); 2,2'-bipyridine (CAS No. 366-18-7, Sigma-Aldrich, >99%); Er(NO 3 )·5H 2 O (CAS No. 10031-51-3, Sigma-Aldrich, 99.999%); CH 3 OK (CAS No. 865-33-8, Sigma-Aldrich, 95%); CH 3 OH (CAS No. 67-56-1, Sigma-Aldrich, 99.8%); and 1,4-dioxane (CAS No. 123-91-1, Sigma-Aldrich, 99.8%). All the procedures for complex preparation were carried out under nitrogen environment and using dry reagents to avoid the presence of water and oxygen, which can quench Er 3+ luminescence.
Patent No. or CCP: ES 2388091 A1 Application No.: P 201130329 (X) International Patent Clasificat... more Patent No. or CCP: ES 2388091 A1 Application No.: P 201130329 (X) International Patent Clasification: C01F 17/00 ( 2006.01); C01F 1/00 ( 2006.01); H01L 51/50 ( 2006.01); H05B 33/14 ( 2006.01) INTERNATIONAL PATENT: Pub. No.: WO/2012/120175 International Application No.: PCT/ES2012/070143 Publication Date: 13/09/2012 International Filing Date: 07/03/2012 Applicants: UNIVERSIDAD DE VALLADOLID [ES/ES]; Ctt. Otri. Casa del Estudiante C/ Real de Burgos E-47001 Valladolid (ES) (For All Designated States Except US).
International Journal of Polymer Science, 2015
The synthesis and characterization of composites of oligomeric chitosan with propolis extract whi... more The synthesis and characterization of composites of oligomeric chitosan with propolis extract which allow the incorporation of a third component (silver nanoparticles) are reported, together with their application in aqueous or hydroalcoholic solutions with a view to the formation of adhesive substances or nanofilms for the protection of vineyards against harmful xylophagous fungi. The antimicrobial properties of the association of the two biological products or those resulting from the incorporation of silver nanoparticles (NPs) are studied and discussed. The efficacy of the chitosan oligomers/propolis/silver NPs ternary system is assessedin vitroforDiplodiafungi. A preliminary study on the convenience of replacing propolis with gentisic acid is also presented.
Journal of Environmental Management, 2015
By-products from the wax production process from carnauba palm (leaves), from the extraction of o... more By-products from the wax production process from carnauba palm (leaves), from the extraction of oil from macauba seeds (endocarp) and from pine nut production (shell) have been assessed for activated carbon production, using H3PO4 or CaCl2 for their chemical activation. The resulting activated charcoals have been thoroughly characterized by elemental and thermal analysis, X-ray diffraction, infrared spectroscopy, electron scanning microscopy and N2 adsorption behavior. Subsequently, their adsorption capacity for the removal of rhodamine B (RhB) from aqueous solutions has been evaluated by studying different parameters: contact time, pH, adsorbent dose, initial dye concentration and solution temperature. The adsorption of RhB followed Freundlich's model in all cases. Kinetic studies indicate that the pseudo-second order model can be used for describing the dynamics of the adsorption process. Thermodynamic parameters have also been evaluated, indicating its endothermic and spontaneous nature. Finally, a preliminary analysis of the impact of cellulose content in the carbon precursor materials has been conducted, by using a mixture of native cellulose with one of the lignocellulosic materials.
Patent No. or CCP: ES 2510990 A1; Application No.: P 201330569 (9); Filing date: 19-04-2013; Inte... more Patent No. or CCP: ES 2510990 A1; Application No.: P 201330569 (9); Filing date: 19-04-2013; International Patent Classification: C01B 21/082 (2006.01), C08F 226/02 (2006.01)
In this study, lignocellulosic residues obtained from Macaúba Palm (Acrocomia aculeata) –i.e. pul... more In this study, lignocellulosic residues obtained from Macaúba Palm (Acrocomia aculeata) –i.e. pulp, peel, almond and endocarp- and from the shell of Stone Pine (Pinus pinea) nuts have been used for the production of second-generation liquid biofuels, primary and/or secondary bio-products with high added value (namely 5-hydroxymethylfurfural (5-HMF), furfural and activated carbon). So as to obtain biofuels, we have started from Macaw Palm and/or Stone Pine residues, chipped to portions smaller than 250 μm, and the solvolysis of the biomass has been conducted by means of ionic liquids (ILs) in a microwave oven at 130°C (two minutes at 900W). The selected ionic liquids have been eutectic mixtures of choline chloride and oxalic/citric acid. TiO2 has been used as a catalyst and a mixture of H2O and sulfolane/DMSO2 -in various proportions- has been the solvent of choice. 5-HMF/furfural extraction has been carried out in butyl acetate and quantitated by HPLC at 280 nm. The behavior of the ...
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Papers by Pablo Martin-Ramos