Examinando por Materia "OXIDO DE HIERRO"

Mostrando1 - 3 de 3
  • Artículo de Publicación Periódica
    Enhancement of the fouling resistance of zwitterion coated ceramic membranes
    (2020-08) Storms, Max; Kadhem, Abbas J.; Xiang, Shuting; Bernards, Matthew; Gentile, Guillermina José; Fidalgo de Cortalezzi, María Marta
    "Ceramic membranes suffer from rapid permeability loss during filtration of organic matter due to their fouling propensity. To address this problem, iron oxide ultrafiltration membranes were coated with poly(sulfobetaine methacrylate) (polySBMA), a superhydrophilic zwitterionic polymer. The ceramic-organic hybrid membrane was characterized by scanning electron microscopy (SEM) and optical profilometry (OP). Membranes with and without polySBMA coating were subjected to fouling with bovine serum albumin solution. Hydraulic cleaning was significantly more effective for the coated membrane than for the non-coated one, as 56%, 66%, and 100% of the fouling was removed for the first, second, and third filtration cycle, respectively. Therefore, we can highlight the improved cleaning due to an increased fouling reversibility. Although some loss of polymer during operation was detected, it did not affect the improved behavior of the tested membranes."
  • Artículo de Publicación Periódica
    Fabrication and characterization of iron oxide ceramic membranes for arsenic removal
    (2010-11) Sabbatini, Paola; Yrazu, Fernando M.; Rossi, F.; Thern, G; Marajofsky, A.; Fidalgo de Cortalezzi, María Marta
    "Nanoscale iron oxide particles were synthesized and deposited on porous alumina tubes to develop tubular ceramic adsorbers for the removal of arsenic, which is an extremely toxic contaminant even in very low concentrations. Its natural presence affects rural and low-income populations in developing countries in Latin America and around the world, which makes it essential to develop a user-friendly, low energy demanding and low cost treatment technology. The fabricated ceramic membranes can be operated with minimal trans-membrane pressure difference and do not require pumping. The support tubes and final membrane have been characterized by surface area and porosity measurements, permeability tests and scanning electron microscopy (SEM) imaging. Arsenic concentrations were determined by inductively coupled plasmaeoptical emission spectroscopy (ICP-OES). Due to its low cost and simple operation, the system can be applied as a point of use device for the treatment of arsenic contaminated groundwaters in developing countries."
  • Artículo de Publicación Periódica
    Virus removal by iron oxide ceramic membranes
    (2014-09) Fidalgo de Cortalezzi, María Marta; Gallardo, María V.; Yrazu, Fernando M.; Gentile, Guillermina José; Opezzo, Oscar; Pizarro, Ramón A.; Poma, Hugo R.; Rajal, Verónica Beatriz
    "Nanoporous iron oxide ceramics were studied for the removal of virus contamination from water. Supported and unsupported iron oxide nanostructured hematite was fabricated by a green chemistry route from ferroxane nanoparticles. The material had a surface area of approximately 30 m2/g and a mean pore size of 65 nm. Bacteriophage P22 was chosen as a model for human virus. The kinetics and equilibrium of the attachment process was investigated. P22 adsorption isotherms on iron oxide were described by the Freundlich equation. Batch experiments resulted in 1.5 LRVs. Removal proceeded rapidly for the first 7 h; next, a diffusion-limited stage occurred. Dynamic attachment experiments demanded extensive recirculation to achieve significant reduction levels. Up to 3 LRV were observed. The enhanced performance can be explained by the higher iron oxide area available and the facilitated access to inner porosity sites that were previously unavailable due to slow diffusion. The role of electrostatic interactions in the attachment mechanisms was confirmed by the dependence of the isotherm on the ionic strength of the suspension medium. P22 bacteriophage is expected to attach to the iron oxide by electrostatic forces up to a pH of 6.5. DLVO theory predicts moderately well the interaction energies between P22 particles themselves and between the phage and the ceramic. However, a slight underestimation of the P22–P22 repulsive forces was evident by comparison to the experimental data."