Abstract This work reports the preparation of magnetic polymeric microspheres based on poly(methyl methacrylate) and the investigation of these materials as catalysts in heterogeneous Fenton processes for the decolorization of methyl orange (MO). The microspheres were prepared by polymerization of the magnetic material together with the monomers by aqueous suspension polymerization. The microspheres had specific surface area of 48.2 m2 g-1. Mossbauer data indicated that the magnetic material was a mixture of magnetite (31%), maghemite (21%), and goethite (48%). Fenton reactions were performed by varying the concentration of H2O2, pH, composite mass, and contact time. The highest color removal rates (around 80%) were reached at pH 3.0, 20% w/v of composite, 20 minutes contact time, and 10 ppm of H2O2. The composite could be reused during four cycles with removal efficiency above 50%. The results indicated that the adsorption and oxidation mechanisms act together determining the variation of the MO dye removal.

Abstract The literature reports several potential applications of polymers prepared with high internal phase emulsions (HIPEs). However, the evaluation of these materials as supports for antimicrobial agents has not been explored. In this work, silver composites based on polyHIPEs were prepared. Initial studies indicated that these materials can be efficient to prevent biofilm formation. The silver composites were prepared in three steps. First, HIPEs based on styrene-divinylbenzene were polymerized by aqueous suspension polymerization. These particles showed surface areas of 18 and 48 m2/g. These polyHIPEs were sulfonated with concentrated sulfuric acid or acetyl sulfate and showed cation exchange capacities of 4.03 and 5.07 meq/g respectively. The sulfonated material was impregnated with silver ions, followed by reduction of the ions to prepare silver composites. These composites showed inhibition halos against E. coli and P. aeruginosa. and did not present adhesion of bacterial cells of K. variicola and S. aureus on their surface.

Abstract This article reports the evaluation of the antimicrobial activity of a silver composite based on sulfonic resin. The antimicrobial action of the composite was evaluated against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus through plate, batch and colunm experiments. In batch studies, the efficiency of the composite was evaluated as a function of composite mass, bacterial concentration and contact time. We also developed a method to evaluate the antimicrobial activity of this composite using column tests. The antimicrobial activity of the composite was similar against the three bacteria in halo inhibition and batch experiments. The antibacterial activity was 100% against all bacteria above 0.20 g of composite and for all concentrations of bacteria studied. Column studies showed that the composite (1 g) had 100% action against 48 cm3 of S. aureus and 55 cm3 of E. coli and P. aeruginosa suspensions (105 cells mL-1, 50 cm3 min-1).

Magnetic composites have a wide range of potential technological applications; however the evaluation of this material for extraction of phenolic compounds has not been sufficiently studied. Due to its high toxicity and solubility the removal of phenolic compounds from the aquatic environments has critical importance. In this work polymeric composites were prepared by anchoring Ni and Co particles on sulfonatedpoly(styrene-co-divinylbenzene) PS-DVB. The PS-DVB beads were synthesized by suspension polymerization and reacted with acetyl sulfate, aiming to obtain sulfonated copolymers. All materials were capable of removing phenol from aqueous solutions. The phenol adsorption kinetics was influenced by the polymer porosity and swelling capacity in water. The composite derivative of the more porous copolymer impregnated with nickel (C1SNi) was the most efficient in phenol removal, with the sorption equilibrium being established more rapidly than for the other composites. The pseudo second-order model was more adequate to describe the phenol adsorption process for the composite C1SNi. The Langmuir model describes successfully the phenol removal by this composite.