Carla da Silva Meireles

Avaliação das características de transporte em membranas de poliamida 66 preparadas com diferentes solventes

In the present study, polyamide 66 (PA 66) membranes were prepared by phase inversion method and characterized in order to verify their potential application in ultrafiltration processes. PA 66 membranes were prepared using two different solvents, formic acid (FA) and hydrochloric acid (HCl), and water as a non-solvent. Fourier-transform infrared spectroscopy (FT-IR) showed that the chemical structure of PA 66 was not altered by the use of solvents in the preparation of membranes. The compaction experiment with pure water performed at a pressure of 1500 kPa revealed that membranes prepared with FA undergo greater compaction of its structure and had a permeate flux value of approximately 17 L.m-2.h-1 whereas the membrane prepared with HCl had a permeate flux of 22.2 L.m-2.h-1. In the ultrafiltration experiment, both membranes had retention values around 70% for egg albumin and 80% for bovine serum albumin. Based on this result, one concludes that both membranes had nominal cut off values for application in ultrafiltration processes.

Utilização do acetato de celulose produzido a partir da celulose extraída do caroço de manga como matriz para produção de sistemas microparticulados

Cellulose acetate produced from mango seed fibers cellulose was used as a matrix for preparation of microparticles empty and load with acetaminophen (Paracetamol) in order to evaluate the incorporation of an active agent during the formation of microparticles. The microparticles are characterized by Fourier Transformed Infrared spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and Scanning Electron Microscopy (SEM). The incorporation of paracetamol can be confirmed by the change in value of glass transition temperature (Tg). The formation of microparticles spherical was observed by SEM and showed an average diameter of 1.010 and 0.950 mm for empty and load microparticles respectively.

Síntese de poliestireno sulfonado para aplicações no tratamento de água produzido a partir de copos e bandejas descartadas de poliestireno

In the present paper, the use of poly(styrene sulfonate) (PSS), produced from discarded polystyrene materials through heterogeneous and homogeneous processes, was investigated. The use of PSS for water treatment, using a kaolin suspension as wastewater model, reduced water turbidity for all the employed materials when compared to the blank analysis, without PSS. The most efficient polyelectrolyte was PSS cups obtained by homogeneous route. The same behavior was observed for real system. The homogeneous PSS cups showed a balance between a moderate molecular weight and high anionic character that improved flocks formation and water removal turbidity.

Effect of cellulose fibers on morphology and pure water permeation of PSf membranes

Chemical and physical changes are necessary to improve the transport properties of polymeric membranes. Cellulose fiber pulp from Pinus taeda was processed in knives and balls mills in order to reduce the dimensions of the fibers for later application in polysulfone (PSf) membranes. By adding cellulosic fibers in PSf membranes, a composite membrane with improved morphological properties, permeate flux and good resistance to pressure was obtained. The fibers as well as the PSf and PSf/cellulose fibers membranes were morphologically characterized by scanning electron microscopy. Tests of pure water permeate flux were performed with pressure up to 20 bar. The addition of 0.2% (wt) of cellulose fibers in the formation of composite membranes resulted in the elimination of macrovoids, causing an increase in pure water flux (50% ±10) when pressure was risen.