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García-Martín J López-Garzón R Godino-Salido ML Gutiérrez-Valero MD Arranz-Mascarós P Cuesta R Carrasco-Marín F 《Langmuir : the ACS journal of surfaces and colloids》2005,21(15):6908-6914
The results presented in this work are related to the design of a guideline to develop specific properties at the surface of an activated carbon (AC). For this, two model aromatic compounds have been synthesized and their electrolytic behavior in aqueous solutions was studied by a potentiometric method. The textural characteristics of the activated carbon were determined by porosimetry methods. The nature of oxygen-carrying functions and the acid-base behavior of the AC surface were characterized by TPD and potentiometric titration methods, respectively. The adsorption and desorption equilibria of the aromatic compounds on activated carbon were measured in aqueous solutions, and the hysteresis between adsorption and desorption, which reveals irreversible adsorption, was discussed on the basis of the frontier orbital theory. HOMO and LUMO orbitals of the adsorbent and adsorbates were calculated, and irreversible adsorption was attributed to the small energy difference between HOMO and LUMO of the aromatic adsorbates and the adsorbent. Adsorption equilibria of K2CrO4 in aqueous solution on the AC alone and on the AC-aromatic ligand adsorbents, respectively, prove the efficient development of specific chemical functions at the carbon surface provided by the adsorbed aromatic compounds. 相似文献
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Pérez-Cadenas Agustín López-Garzón Rafael Godino-Salido Luz Arranz-Mascarós Paloma Gutiérrez-Valero Dolores Carillo-Márquez Tomás 《Transition Metal Chemistry》2002,27(2):184-190
Reactions of N-2-(4-amino-1,6-dihydro-1-methyl-5-nitroso-6-oxopyrimidinyl)-L-histidine with AgI and ZnII ions in 1/1 and 4/1 ligand-to-metal molar ratios, in aqueous media at 25 °C and 0.1 M KNO3 and KCl ionic strength, respectively, were followed by potentiometric techniques in order to determine formation equilibria for the complex species. The spectral curves, as a function of ligand-to-metal molar ratio at established pH values, were studied and four solid phases of stoichiometry: AgL·4H2O, Ag(HL)NO3·1.5H2O, AgL(OH)2K2·H2O and Zn(HL)2Cl2·7H2O were isolated and characterised by analytical, spectroscopic and thermal measurements. 相似文献
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M. Luz Godino-Salido Rafael López-Garzón Paloma Arranz-Mascarós M. Dolores Gutiérrez-Valero Antonio Santiago-Medina Javier García-Martín 《Polyhedron》2009,28(17):3781-3787
The retention of Co2+, Ni2+ and Cu2+ metal ions from aqueous solution, on a functionalized hybrid material obtained by the anchorage of N-(4-amino-1,6-dihydro-1-methyl-5-nitroso-6-oxopyrimidin-2-yl)-N′-[bis(2-aminoethyl)] ethylenediamine ligand on a low-functionalized activated carbon, at pH 4.5 has been studied. The adsorption isotherms fit the Langmuir equation and the calculated maximum adsorption capacities were compared to those obtained by using the un-functionalized activated carbon as well as to other analogous hybrid materials as adsorbent of the same metal ions. These studies were carried out by rationalizing the resulting adsorption data regarding the stability constant values of the complexes formed by the three metal ions with the free tri-amine function of the ligand. The results demonstrate that the adsorption capacities of the activated carbon–ligand hybrid material towards the three metal-ions studied correlated with the stabilities of the tri-amine-metal-ion bonds formed during the adsorption processes. 相似文献
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P. Arranz-Mascarós M.D. Gutiérrez-Valero R. López-Garzón M.D. López-León M.L. Godino-Salido A. Santiago-Medina H. Stoeckli-Evans 《Polyhedron》2008
The compound N-(4-amino-1-methyl-5-nitroso-6-oxo-1,6-dihydropyrimidin-2-yl)-(s)-glutamic acid (H3L) was synthesised and structurally characterised by analytical methods and 1H, 13C and 15N NMR spectroscopy. This compound (H3L) shows the same topology as other model receptors previously used to develop chemical functionalization at the surface of an active carbon when they adsorb on it. Protonation of H3L and its coordination ability towards Cd2+, Zn2+, Cu2+ and Mn2+ ions in water solution was also studied by potentiometric methods, UV–Vis and 1H, 13C NMR spectroscopies. The obtained results allow us to fit the operative conditions for the use of the activated carbon–H3L adsorbent for the retaining of the above-mentioned metal ions in aqueous solutions. The molecular structure of {[Cd(HL)H2O] · 3H2O}n was solved by single-crystal X-ray diffraction methods. 相似文献
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Arranz-Mascarós Paloma López-Garzón Rafael Godino-Salido Luz Gutiérrez-Valero Dolores 《Transition Metal Chemistry》1998,23(4):501-505
Reactions of N-(6-amino-3-methyl-5-nitroso-4-oxo-3,4-dihydropyrimidin-2-yl)glycine with NIII and CdII ions in 1:1 and 1:4 metal:ligand ratios, in aqueous media at 35°C and 0.1m KCl ionic strength, were studied by potentiometric methods to determine the complex species equilibria formation and their formation constants.Solid complex species from MII/ligand systems (MII=FeII, CoII, CdII and HgII) in aqueous media were isolated and characterized by analytical data, spectroscopic methods (i.r.,1 H-n.m.r., 13C-n.m.r. and electronic), and thermal and magnetic measurements. 相似文献
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Luz Godino-Salido Rafael López-Garzón Dolores Gutierrez-Valero 《Transition Metal Chemistry》1996,21(2):149-153
Summary The acidity of the nucleoside, 1,6-dihydro-4-gluco-pyranosylamino-2-methylthio-5-nitroso-6-oxo-pyrimidine (H2GP) has been studied by potentiometric methods. Complexes of H2GP with NiII, CuII, ZnII, CdII, HgII and AgI were prepared and characterized by conductivity measurements, i.r., electronic, 1H and 13C-n.m,r. spectroscopies, and magnetic and thermal measurements. The nucleoside shows a number of different coordination modes in the various complexes isolated, acting as a chelating agent, either through C(6)=O and the NO group or through C(6)=O and the N(1) atom, or alternatively as a monodentate ligand through the C(6)=O group. 相似文献
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Pérez-Cadenas Agustín Godino-Salido Luz López-Garzón Rafael Arranz-Mascarós Paloma Gutiérrez-Valero Dolores Cuesta-Martos Rafael 《Transition Metal Chemistry》2001,26(4-5):581-587
The acid–base properties of the N-substituted amino acid HL [HL = N-2-(4-amino-1,6-dihydro-1-methyl-5-nitroso-6-oxopyrimidinyl)-L-histidine] and its reactivity towards the CuII ion have been measured by potentiometric and spectrophotometric techniques in aqueous solution at 25 °C and 0.1 M KCl ionic strength. These studies show that the neutral HL compound is present in aqueous solution (3–7 pH range) in the zwitterionic form with the diprotonated imidazolic residue. Studies of HL/CuII mixtures reveal the existence of complex species with the neutral ligand, HL and containing the deprotonated L ligand. By controlling the reaction conditions, four solid phases of stoichiometry: CuLCl(H2O)6, Cu2LCl3(H2O)8, CuL2(H2O)6 and Cu(HL)2Cl2(H2O)6 were isolated and characterised by i.r. and electronic spectroscopy, thermal techniques and magnetic measurements. 相似文献
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Gutiérrez-Valero MD Godino-Salido ML Arranz-Mascarós P López-Garzón R Cuesta R García-Martín J 《Langmuir : the ACS journal of surfaces and colloids》2007,23(11):5995-6003
The adsorption of five Nalpha-substituted amino acids with a 5-nitroso-6-oxo pyrimidine as substituent on a commercial activated carbon (AC) has been studied in aqueous solution at several pH values. The adsorption processes of these organic compounds have been analyzed on the basis of the electrolytic behavior of the adsorbates. In all cases, the adsorption process is highly irreversible due to strong pi-pi interactions between the arene centers of the AC and the pyrimidine residue of the adsorbates. This interaction is consistent with XPS data and HOMO-LUMO theoretical calculations. The adsorption of these organic compounds provides a new route for the functionalization of the AC surface with carboxyl groups. In addition, the adsorption capacity of the AC/organic compound systems for Cu(II) ions in aqueous solution has been studied at different pH values. These systems show an increase of the adsorption capacity for Cu(II) compared to the AC, which is related to the AC functionalization with carboxyl groups due to the adsorbed organic compounds. 相似文献
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