Liliana Giraldo

Removal of Mn, Fe, Ni and Cu Ions from Wastewater Using Cow Bone Charcoal

Cow bone charcoal (CBC) was synthesized and used for the removal of metals ions (manganese, iron, nickel and copper) from aqueous solutions. Two different adsorption models were used for analyzing the data. Adsorption capacities were determined: copper ions exhibit the greatest adsorption on cow bone charcoal because of their size and pH conditions. Adsorption capacity varies as a function of pH. Adsorption isotherms from aqueous solution of heavy metals on CBC were determined. Adsorption isotherms are consistent with Langmuir´s adsorption model. Adsorbent quantity and immersion enthalpy were studied.

Synthesis of Activated Carbon Mesoporous from Coffee Waste and Its Application in Adsorption Zinc and Mercury Ions from Aqueous Solution

We obtain activated carbons with high portion of meso pores using coffee residues as precursor for the application of adsorption of large adsorbates. Because of its natural properties, the coffee residue exhibited a large pore size. In this work, the coffee residue were impregnated with ZnCl2 and KOH, and then carbonized under the nitrogen conditions and activated with CO2 respectively. Obtained activated carbons are used in the adsorption of ions Hg(II) and Zn(II). These adsorbents are efficacious to remove these ions from aqueous solution, with monocomponent equilibrium adsorption capacities ranging from from 0.002 to 0.380 mmol∙g-1 for Hg on ACK3 and from 0.002 to 0.330 mmol∙g-1 for ACZ3. For Zn(II) on ACK2 from 0.002 to 0.300 mmol∙g-1, and from 0.001 to 0.274 mmol∙g-1 for ACZ2.

Synthesis of fatty alcohols from oil palm using a catalyst of Ni-Cu supported onto zeolite.

A series of Ni-Cu supported onto zeolite type ZSM-5 has been synthesized by direct hydrothermal method without template agent and characterized using XRD, FT-IR, NRM mass, SEM, CG and N2 adsorption techniques. The catalytic performance of the obtained materials was evaluated and utilized for the hydrogenation of palm oil at 453 K and 40 atmospheres of pressure. The results show that the samples exhibited typical hexagonal arrangement of mesoporous structure with high surface area and the heteroatoms were probably incorporated into the framework of ZSM-5. Catalytic tests show that the bimetallic incorporated materials were effective as catalysts in the hydrogenation of oil palm producing fatty alcohols typical.

Relation Between the Adsorbed Quantity and the Immersion Enthalpy in Catechol Aqueous Solutions on Activated Carbons

An activated carbon, CarbochemTM—PS230, was modified by chemical and thermal treatment in flow of H2, in order to evaluate the influence of the activated carbon chemical characteristics in the adsorption of the catechol. The catechol adsorption in aqueous solution was studied along with the effect of the pH solution in the adsorption process of modified activated carbons and the variation of immersion enthalpy of activated carbons in the aqueous solutions of catechol. The interaction solid-solution is characterized by adsorption isotherms analysis, at 298 K and pH 7, 9 and 11 in order to evaluate the adsorption value above and below that of the catechol pKa. The adsorption capacity of carbons increases when the solution pH decreases. The retained amount increases slightly in the reduced carbon to maximum adsorption pH and diminishes in the oxidized carbon. Similar conclusions are obtained from the immersion enthalpies, whose values increase with the solute quantity retained. In granular activated carbon (CAG), the immersion enthalpies obtained are between 21.5 and 45.7 J·g−1 for catechol aqueous solutions in a range of 20 at 1500 mg·L−1.

Evaluación del Peróxido de Hidrógeno en la Oxidación de Fenol con Hierro Soportado Sobre Tela de Carbón Activado

This study presents the generation and evaluation of three different materials containing activated carbon and iron for the heterogeneous Fenton degradation of phenol. Three different materials: (i) commercial cloth containing activated carbon, and (ii) pellet activated carbon and (iii) a chemically activated carbon with KOH, were explored to support iron by means of impregnation. These three materials were used for the catalytic degradation of phenol with H2O2. The oxidation was performed at 42°C, pH between 2,0-2,5, atmospheric pressure, an initial phenol concentration of 0,01064M and H2O2 0.89M. A relation of impregnation of 1,39gFe/gAC is obtained on the activated carbon cloth. During the oxidation of phenol, the disappearance of the H2O2 was followed as an indirect indication of the kinetics, reaching a minimal concentration of 0.002M of H2O2 by the cloth and the pellet activated carbon. The study shows that the use of cloth activated carbon as catalytic support for the decomposition of phenol is competitive with other conventional porous materials.

Thermodynamic of the Interactions Between Gas-Solidand Solid-Liquid on Carbonaceous Materials

Vanessa Garcia-Cuello1, Diana Vargas-Delgadillo1, Yesid Murillo-Acevedo1, Melina Yara Cantillo-Castrillon 1, Paola Rodriguez-Estupinan1, Liliana Giraldo1 and Juan Carlos Moreno-Pirajan2 1Facultad de Ciencias, Departamento de Quimica, Universidad Nacional de Colombia 2Facultad de Ciencias, Departamento de Quimica, Grupo de Investigacion en Solidos Porosos y Calorimetria, Universidad de Los Andes Colombia

Calorimetric: A Tecnique Useful in Characterization of Porous Solid

The adsorption of gases in porous solids such as zeolites and activated carbons, has been widely applied in cases of separation, purification and bottling of gases (Ruthven et al. 1994; Yang, 1997; Bastos-Neto et al. 2005a; Figueroa et al., 2008; Belmabkhout and Sayari, 2009). This potential is reflected not only in increasing the number of technical and scientific articles and patents, but also in the world market growth in plants for air separation and purification processes of hydrogen and natural gas and many others (Zimmermann and Keller, 2003). Due to the various applications of porous adsorbents, many research groups in various parts of the world have sought to develop and improve these materials to improve performance in these specific applications (Bastos-Neto et al. 2005b; Arou et al., 2008; Prauchner and Rodriguez-Reinoso, 2008; Rivers and Smith, 2009). In the procedures for obtaining porous solids, it is necessary to control the various process variables such as preparation, carbonization temperature and time, type and concentration of activating agents, among others, since these activation parameters determine the chemical and physical properties of adsorbents. The textural characteristics are the most important properties of the adsorbents, since it indicates the implementation and performance of the solid obtained (Giraldo and Moreno, 2005). In addition, chemical properties also determine the adsorption properties of adsorbent and solid-fluid interactions. Nature of surface groups, hydrophobic or hydrophilic character and acidic or basic behavior are some of the relevant chemical properties of the adsorbents in adsorption processes. Since the physical and chemical properties of an adsorbent determine the application and performance of the same, it is necessary to determine precisely the parameters that characterize these materials such as surface area, microporosity, pore size distribution, heats of adsorption, among others. Several experimental techniques are used to characterize porous materials, for example, mercury porosimetry, adsorption of liquid nitrogen, x-ray diffraction, etc.. The technique most commonly used to characterize the texture of carbon adsorbents (ie surface area, properties of molecular sieve, size distribution of pores, etc.). Is the physical adsorption of gases and vapors. However, immersion calorimetry, with molecular probes of various molecular dimensions, and gas adsorption microcalorimetry techniques are also applied to characterize this type of solid (Denoyel et al., 1993, Gonzalez et al. 1995; Rouquerol et al. 1999, Navarrete et al., 2004; Garcia-Cuello et al., 2009). The aim of this

Immersion Calorimetry for the Characterization of PD Catalysts Supported on Activated Carbon

Activated carbons obtained from coconut peel were oxidized using hydrogen peroxide. Superficial characteristics of these carbons were determined through N2 and CO2 isotherms and functional groups were characterized by TPD. Finally, the microcalorimetry technique was used in order to obtain the immersion enthalpies in diverse liquids and established the relation between them and the results obtained by the other characterization techniques. The results suggested that the immersion calorimetry allow establishing the difference between the supports and the catalysts.