PREPARAÇÃO DE COMPÓSITOS DE POLIANILINA EM MATRIZES DE COPOLÍMEROS ESTIRENO-DIVINILBENZENO E ESTUDOS DE ADSORÇÃO POR TROCA IÔNICA DE ÂNIONS COMPLEXOS DE [FeCl4]- E [CuCl4]2-
Carregando...
Data
2008-06-30
Autores
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Federal de Goiás
Resumo
In this work, composites of dispersed polyaniline in beads of styrenedivinybenzene
copolymer (Pani/Sty-DVB copopolymer) with different porosities
were prepared through in situ polymerization. Materials with high surface areas
and high porosities were obtained what explain their properties to adsorve
transition metals. SD29 and SD84 copolymers were prepared through suspension
polymerization in the presence of inert diluents as toluene/heptane with different
DVB ratios to obtain macroporous beads. SD29/Pani and SD84/Pani composites
were obtained by swelling the copolymers with aniline/ethanol mixtures (20/80%)
before polymerization. Oxidative polymerization of aniline was carried out with
ammonium persulfate in the presence of nitric acid at pH extremely acid and
temperature range from 0 to 3 oC for 5 hours. All materials were characterized by
infrared spectroscopy, porosity measurements, optical microscopy and adsorption
capacity. The composite surface areas and pore volumes diminished in relation to
original
xv
copolymers, while apparent density increased due polyaniline incorporation. Pore
size distributions did not suffer large variations and all were typical of macroporous
structures. Due the high DVB content, SD84/Pani composite and SD84 copolymer
presented higher porosity and specific surface area when compared to systems
with low reticulation degree. From acid solutions, [FeCl4]- and [CuCl4]2-, complex
anions were adsorbed on SD29/Pani and SD84/Pani composites through ion
exchange batch process. The amounts of complex anions adsorbed were
determined by atomic absorption spectrophotometry. Complex anions adsorption
increased with chloridric acid and metal concentration for both composites.
Maximum adsorption capacity (mg of anion/g of composite) of [FeCl4]- were higher
than [CuCl4]2-
for both composites. Kinetic data showed a time of 12h for
adsorption equilibrium of [FeCl4]- anions, while for [CuCl4]2- anions the equilibrium
was not reached in 24 h for both composites. Infrared spectra showed vibrational
bands of characteristic functional groups in the materials and band shifts were
observed after [FeCl4]- and [CuCl4]2- complex anions adsorptions on the
composites. Morphology evaluation showed that aniline polymerized
homogeneously in the presence of nitric acid for all porous structures of the
copolymers. Therefore, it can be concluded that complex anions adsorption
depend as so the amount of adsorption sites of polyaniline as the porous structures
of the composites.
Descrição
Palavras-chave
copolímeros , polimerização , polianilina , compósitos
macroporosos , adsorção , ânions complexos , ferro , cobre , troca iônica , copolymers , polimerization , polianilyne , composites , macroporous , complex anions , adsorption , iron , copper , exchange ionic , 1. Copolímeros 2. Polimerização 3. Polianilina 4. Compósitos macroporosos 5. Adsorcao 6. Ânions complexos 7. Ferro 8. COBRE 9. Troca ionica
Citação
SILVA, Robson Benedito. PREPARATION FOR SUPPORTING COMPOSITE POLIANYLINE IN
MATRIZES OF COPOLYMERS ESTYRENE-DIVINYLBENZENE AND STUDIES
OF ADSORPTION BY EXCHANGE IONIC OF COMPLEX ANIONS OF [FeCl4]-
AND [CuCl4] 2-. 2008. 146 f. Dissertação (Mestrado em Educação em Química) - Universidade Federal de Goiás, Goiânia, 2008.