Membranes made of carbon nanotubes and cellulose acetate with polyacrylic acid were designed in order to study their properties and their applicability for chromium removal. The membranes were prepared by phase inversion method using cellulose acetate and polyacrylic acid. Carbon nanotubes were added to the membrane during their process of synthesis in proportions of 1% by weight. The pores in the material are formed in layers, giving the effect of depth and forming a network. Both the carbon nanotubes and membranes were characterized by IR, Raman, and SEM spectroscopy. In addition, the concentration of acidic and basic sites and the surface charge in the materials were determined. The concentration of acid sites for oxidized nanotubes was 4.0 meq/g. The removal of Cr(VI) was studied as a function of contact time and of initial concentration of Cr(VI). The removal of Cr(VI) (~90%) mainly occurs in a contact time from 32 to 64 h when the initial concentration of Cr(VI) is 1 mg/L.

La oxidación de los nanotubos de carbono, ha generado gran interés porque además de eliminar impurezas, aumenta el grado de dispersión de los agregados y logra nuevas in­teracciones entre los materiales. En este trabajo, nanotubos de carbono (NTC) fueron tra­tados con diferentes métodos de oxidación para conocer la modificación superficial que cada tratamiento efectúa en la estructura del material. Los métodos contrastados fueron el tratamiento químico tradicional (mediante ácidos fuertes) y el tratamiento asistido por microondas. Los resultados mostraron que ambos tratamientos disminuyen el área super­ficial (NTC tradicional < NTC microondas < NTC sin tratamiento). Utilizando microondas, se redujo el tiempo de oxidación, se obtuvo una mayor concentración de grupos funcionales carboxílicos y se disminuyó el daño en la estructura con lo que se obtienen nanotubos oxi­dados con mejores características estructurales.

This work focused on the synthesis and characterization of composites, obtained based on polyacrylic acid and cellulose acetate, which incorporated graphite oxide and graphene oxide as structural reinforcement. The composites were obtained using the phase inversion method and the incorporation of the reinforcement, during the synthesis process, was carried out in proportions of 1% by weight. The characterization of the composites was carried out using IR, Raman, BET, SEM spectroscopy techniques and methods for determining acidic and basic sites. The results obtained showed that it is possible to synthesize composites that present a network configuration, made up of layers that give the material the effect of depth. Furthermore, it was possible to observe that both graphite oxide and graphene oxide were deposited on the outer edge of the hexagonal pores present in the material. Finally, the concentration values of acidic and basic sites were obtained. The presence of these sites could be associated with carboxylic groups inserted during the oxidation of graphitic materials and with non-reactive sites present in cellulose.

Within the automotive industry one of the most used materials for user comfort is animal skin, this material is used to coat pieces that will have contact with the consumer. One of the most important problems that arise with the handling of the skin in operations of coating and assembly within plants of the automotive sector is the lack of resistance. A treatment that must be applied to the skin to improve its conditions of resistance to mechanical tension, is in function of two factors: percentage of moisture in the skin and amount of surfactant applied. In the present investigation, optimal operating conditions are established for the handling of the skin used in processes of the automotive sector based on a 3k factorial experimental design. The application case was carried out in a company dedicated to manufacture armrests for high-end cars. The results of the investigation show an improvement of 97% in operations where the resistance of the skin is required to meet the quality standards established in the automotive industry.

This work focused on the study of the hexavalent chromium removal process from graphene oxide supported on a cross-linked cellulose acetate and polyacrylic acid polymeric membrane. The membranes were synthesized by the phase inversion method and Graphene oxide was added in proportions of 1% by weight to the polymeric material. Graphene oxide was obtained from crystalline graphite (Electron Microscope Science, No. 70230). The graphite was oxidized using the improved method of Hummers. The characterization of polymer and graphene oxide was made by Raman spectroscopy. The surface charge and point of zero charge of the materials were evaluated using a potentiometric titration method proposed by Loskutov and Kuzin. The removal of Cr (VI) was studied as a function of contact time and of initial concentration of Cr (VI). The removal of Cr (VI) (~90%) mainly occurs in a contact time from 32 to 64 h when the initial concentration of Cr (VI) is 1 mg/L.