| dc.description.abstract | In this study, microparticles carboxymethylcellulose (CMC) and calcium carbonate (CaCO3) were produced and the material surface was characterized by determining the total acidity and alkalinity, it was observed an amount 4.7 mEg g-1 basic groups and 0.8 mEg g-1 acid groups, and the zero charge point (pHPZC), the value found for pHPZC 8.77. The microparticles were also characterized by infrared spectroscopy, Xray diffraction and electron microscopy scanning, confirming the interaction between the CMC and the CaCO3. In this material was immobilized the diclofenac sodium drug (DS) using three different methodologys, named ADS, IDS2 and IDS3. The methodology ADS, show the adsorption of DS in the microparticles at pH 4, 5.5 and 7, and IDS2 and IDS3 methodology, the drug was incorporated simultaneously with the microparticles production. It was observed in the ADS methodology, that the pH is great influences on the DS adsorption, and the higher value obtained was 0.88 mg g-1 at pH 4. The IDS2 and IDS3 methodology the quantity of released DS was 3.65 mg L-1 e 2.84 mg L-1, respectively. For the DS adsorbed in the microparticles, infrared analysis shows the presence of a peak at 2900 cm-1 may indicate the presence of drug and the diffraction X-ray and SEM analysis it was not possible to verify the interaction between the microparticles and DS. Due to the low DS values immobilization and for comparing the adsorption capacity of the microparticles with different compounds, adsorption studies were realized with methylene blue dye (MB).
The adsorption of MB was done at pH 7 and 9.5, and it was observed that adsorption is highest at pH 9.5 and the maximum adsorbed quantity was 0.29 mg g-1. The mathematical models of Langmuir, Freundlich and Dubinin- Radushkevich isotherms well represented the MB adsorption behavior, with R2 larger than 0,9. However the experimental value for the maximum adsorption capacity (0.2517 mg g-1) is found closer to the Langmuir isotherm (0.3055 mg g-1). The MB adsorption kinetics follows the model of pseudo-second order with R2 of 0.9975 and adsorption capacity of 0.3889 mg g-1, value close to that obtained experimentally that was 0.3840 mg g-1. | |
