Recebido em 16/11/07; aceito em 30/6/08; publicado na web em 10/11/08 SYNTHESIS OF POLY(STYRENE SULFONATE) FROM DISCARDED POLYSTYRENE CUPS AND EXPANDED TRAYS FOR APPLICATION ON WATER TREATMENT. 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.

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Hemicelluloses were extracted from corn husk and converted into cationic hemicelluloses using 2,3-epoxypropyltrimethylammonium chloride. The degree of substitution was determined as 0.43 from results of elemental analysis. The cationic derivative was also characterized by Fourier transform infrared spectroscopy and Carbon-13 magnetic nuclear ressonance. The produced polymer was employed as coagulant aid in a sewage treatment station (STS) of the municipal department of water and sewer (Departamento Municipal de Água e Esgoto -DMAE) in Uberlândia-Minas Gerais, Brazil, using Jar test experiments. Its performance was compared to ACRIPOL C10  , a commercial cationic polyacrylamide regularly used as a coagulant at the STS. The best result of the jar-test essays was obtained when using cationic hemicelluloses (10 mg L -1 ) as coagulant aid and ferric chloride as coagulante (200 mg L -1 ). The resultsof color and turbidity reduction, 37 and 39%, respectively, were better than when using only ferric chloride. These results were also higher than those of commercial polyacrylamide, on the order of 32.4 and 38.7%, respectively. The results showed that the cationic hemicelluloses presented similar or even superior performance when compared to ACRIPOL C10  , demonstrating that the polyelectrolytes produced from recycled corn husks can replace commercial polymers in sewage treatment stations.

Aos meus pais: Pedro e Maria, por me darem a vida e os meios para que eu pudesse estudar... Quero dividir com todos amigos e companheiros de serviço pela ajuda e incentivo! Meus amigos, se para o mundo meus passos são curtos, inventarei um veículo. Conclusões Concluímos que o P.E.S. apresentou bons resultados de coagulação, floculação, podendo ser futuramente, uma alternativa ecológica de reutilização de plásticos descartáveis de poliestireno. Agradecimentos Os autores agradecem ao D M A E ; a Fapemigconvênio CEX/803/98.