Autor: |
Bezerra RDS; Federal Institute of Education, Science and Technology of Piauí (IFPI), Campus Teresina-Central, 64000-040 Teresina, Piauí, Brazil. rooseveltdsb@ifpi.edu.br., Silva MMF; Interdisciplinary Laboratory for Advanced Materials, Federal University of Piauí (UFPI), 64049-550 Teresina, Piauí, Brazil. mrita@ufpi.edu.br., Morais AIS; Interdisciplinary Laboratory for Advanced Materials, Federal University of Piauí (UFPI), 64049-550 Teresina, Piauí, Brazil. bredyalan@gmail.com., Osajima JA; Interdisciplinary Laboratory for Advanced Materials, Federal University of Piauí (UFPI), 64049-550 Teresina, Piauí, Brazil. josyosajima@ufpi.edu.br., Santos MRMC; Interdisciplinary Laboratory for Advanced Materials, Federal University of Piauí (UFPI), 64049-550 Teresina, Piauí, Brazil. mrita@ufpi.edu.br., Airoldi C; Institute of Chemistry, University of Campinas, Unicamp, P.O. Box 6154, 13083-971 Campinas, São Paulo, Brazil. airoldi@iqm.unicamp.br., Filho ECS; Interdisciplinary Laboratory for Advanced Materials, Federal University of Piauí (UFPI), 64049-550 Teresina, Piauí, Brazil. edsonfilho@ufpi.edu.br. |
Abstrakt: |
Crystalline cellulose chemically modified through a reaction with sodium trimetaphosphate (STMP) in an acidic or basic condition yielded Cel-P4 and Cel-P10. These phosphated solids were characterized by elemental analysis, X-ray diffraction (XRD), infrared (IR) spectroscopy, scanning electron microscopy (SEM), nuclear magnetic resonance (NMR) at the solid state for phosphorus nucleus and dispersive X-ray energy. The elemental results demonstrated that the phosphorylation reaction was more efficient in the basic medium, as supported by the amount of phosphorous content. The synthesized biomaterials decreased in crystallinity in comparison to the precursor cellulose, with an increase in roughness and present two distinct phosphorus environments in the formed structure. The phosphated cellulose in an alkaline condition was applied to sorb the drug ranitidine. This process was applied in varying pH, time, temperature and concentration. The best sorption kinetic model to fit the experimental data was the pseudo-second-order with a coefficient correlation of 0.8976, and the Langmuir isotherm model was the most adjusted to the variation in concentration. The efficient drug sorption has a low dependence on temperature, with maximum values of 85.0, 82.0 mg and 85.7 mg·g -1 for Cel-P10 at 298, 308 and 318 K, respectively. The best sorption occurred at pH = 6 with a saturation time of 210 min. |