Franco Dani Rico Amado

High-impact polystyrene/polyaniline membranes for acid solution treatment by electrodialysis : Preparation, evaluation, and chemical calculation

In this study different membranes were produced, aiming to evaluate their use in electrodialysis. These membranes were produced using conventional polymer (high-impact polystyrene) and polyaniline. The membrane characterization was done by FTIR spectroscopy, scanning electron microscopy (SEM), and thermogravimetry (TGA). The studies of the zinc and proton extraction ionic transport through the membranes were evaluated using a three-compartment cell. The results obtained using the produced membranes were compared to the results obtained with the commercial membrane Nafion 450. It was found that a synthesized membrane can be used to recover zinc in acid media. In addition, a preliminary computational essay about the structures of PAni and CSA is presented.

Study of Chromium Removal by the Electrodialysis of Tannery and Metal-Finishing Effluents

The metal-finishing and tannery industries have been under strong pressure to replace their current wastewater treatment based on a physicochemical process. The electrodialysis process is becoming an interesting alternative for wastewater treatment. Electrodialysis is a membrane separation technique, in which ions are transported from one solution to another through ion-exchange membranes, using an electric field as the driving force. Blends of polystyrene and polyaniline were obtained in order to produce membranes for electrodialysis. The produced membranes were applied in the recovery of baths from the metal-finishing and tannery industries. The parameter for electrodialysis evaluation was the percentage of chromium extraction. The results obtained using these membranes were compared to those obtained with the commercial membrane Nafion 450.

Desenvolvimento de membranas e filmes auto-suportados a partir de polianilina: síntese, caracterização e aplicação

Polimeros condutores sao uma nova classe de polimeros que tem recebido especial interesse para a producao de membranas e filmes. A polianilina (PANI) destaca-se entre eles por sua elevada estabilidade quimica, facil polimerizacao e baixo custo. O objetivo deste trabalho foi desenvolver uma blenda de polimero convencional (HIPS) com polimero condutor (PANI-CSA) e um filme de polianilina auto-suportado, usando acido canforsulfonico (CSA) como dopante primario e 4-cloro-3-metil fenol (CMC) como dopante secundario. Estes dois materiais foram empregados como membranas ion-seletivas em um sistema de eletrodialise para remocao de niquel de solucoes. A membrana e o filme foram caracterizados por condutividade eletrica, MEV, espectroscopia FTIR, Raman e TGA. Os resultados obtidos apontam para a possibilidade de aplicacao da membrana seletiva para eletrodialise. A extracao de niquel para a membrana sintetizada se mostrou semelhante a extracao para a membrana comercial. O filme auto-suportado apesar de exibir boa resistencia mecânica no estado solido apresentou comportamento pouco satisfatorio quando colocado em imersao com a solucao de trabalho para eletrodialise, devido ao seu estado quebradico.

Estudo da obtenção através de síntese eletroquímica de poliaminonaftalenos e poliaminoantracenos

The polyaromatics are a group of polymers composed by polyaminonaphthalenes, polyaminoanthracenes and polynaphthoquinones that have aromatic systems with two or three rings. In this work, films of polyaminoanthracene (PAA) and 1,5 polydiaminonaphthalene (PDAN-1,5) have been electropolymerized on Pt electrodes in a single compartment cell with three electrodes. Fourier transform infra-red (FTIR) and Raman spectroscopies have been used to confirm that the PAA structure is similar to that of polyaniline (PAni). Electrochemical studies have shown that the PAA and the PDAN-1,5 present only one redox pair. However, the PAA did not show a good electrochemical stability, in contrast to PDAN-1,5. The micrographs showed homogeneous and compact films, with globular structure and for both polymers, although PAA showed cracks produced during drying with cold air flow.