JOSE PARRA SILVA
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Resumo IPEN-doc 27674 Surface activation of Palygoskite nanotubes for wastewater treatment2020 - MELLO-CASTANHO, S.; PARRA SILVA, J.; YAMAGATA, C.The ion exchange / sorption method is one of the most popular and attractive methods used to treat effluents containing heavy metals. The peculiar chemical characteristics, associated to the nanoscale of the structural network with the presence of natural nanotubes, as is the case of paligorsquita, makes it a potential candidate to meet the requirements of high sensitivity and selectivity in the extraction of heavy ions in wastewater. In the process of developing materials with sorption properties for the incorporation and subsequent immobilization of heavy ions in the same matrix, the most important steps are the generation of active sites, together with increased specific surface area. The parameters and conditions for the activation process of the natural Palygorskite nanotubes aiming to the sorption and immobilization of nickel ions present in wastewater from industrial activities were determined. Paligoskite from Piaui State Brazil, was used as raw material. The characterized and the acid activation process were selected for this development. Subsequent heat treatments were carefully selected conditions by thermal analysis (ATD/TG) to avoid collapse of the nanotubes. The results obtained of maximum sorption capacity for nickel on activated natural nanotubes were very promising. Structural folding observed in the clay may surely important contribution for the heavy metal immobilization processes. Finally, the optimization of the acid activation process is fundamental to improve the sorption’s capacities in solid-liquid medium for extraction specifics metals by activated natural nanotubes.Resumo IPEN-doc 25497 Advanced processing strategies for the development of energy efficient devices with eco-friendly, natural materials2018 - MELLO-CASTANHO, S.R.; SILVA, J.P.; CARDOSO, S.The search for green technologies and the reduction of environmental impacts has become a constant in the scenario of technology options worldwide and in particular in countries with emerging economies that adapt very easily to the new paradigms of sustainability. Therefore, it is essential to develop new processing strategies for the green manufacture of ceramics to preserve natural sustainability and to generate clean and sustainable energy resources in remote areas. Therefore, the future of ceramic materials requires now to search for simple technological options that result in the use of low energy consumption and low emission of effluents to the environment and low cost. Processes involving mimicry, reuse, recovery, simple value-added products, in short, the development of the methodologies with strong ecological appeal can effectively aid to the economic turnover in manufacturing processes and it is one of the major challenges since the end of last century. This work, dials with the development and optimization of energy efficient processes to generate clean and sustainable energy sources such as the surface activation of natural nanotubes based on Palygorskite clay and the use of vegetable fiber Luffa Cylindrical as replica in porous burner technology. In the first case the green chemistry on surface activation by change Mg cations by radionuclides Ni, Sr, in stable condition shows a promisor potential using this raw material in the mitigation by immobilization of industrial nuclear rejects. In the second one, the controlled colloidal processing shows that it is possible to use silicates to fabricate burning gas light with luminescent characteristics, resistant to use in remote places that have not yet the electric energy available for lightning.Dissertação IPEN-doc 21824 Incorporação de radionuclídeos em nanotubos naturais ativados2016 - SILVA, JOSÉ P.Os nanotubos naturais da paligorsquita, por apresentarem propriedades físicas e químicas específicas, têm potencial uso como nano sorventes e matrizes para imobilização, retenção, e solidificação de radionuclídeos presentes em efluentes nucleares. No processo de desenvolvimento de materiais com propriedades de sorção visando a incorporação e imobilização de radionuclídeos, as etapas mais importantes são a geração de sítios ativos simultaneamente com o aumento da área superficial específica e tratamento térmico adequado para conduzir ao colapso estrutural. Neste estudo foram avaliados parâmetros e condições determinantes no processo de ativação dos nanotubos naturais da paligorsquita visando a sorção de radionuclídeos de interesse na estrutura dos nanotubos e a avaliação posterior dos parâmetros que afeitam ao colapso estrutural por tratamento térmico. Por este estudo constatou-se que a otimização do processo de ativação ácida é fundamental para o aumento da capacidade de sorção de níquel usando estruturas de nanotubos naturais ativados. A condição otimizada de ativação superficial, mantendo a integridade estrutural foi removido cerca de 33,3% dos cátions de magnésio, equivalente a 6,30·10-4 mol·g-1 de magnésio em massa, aumentando a área superficial específica em 42,8%. Este aspecto permitiu a incorporação de mesma concentração molar de níquel presente nos rejeitos radioativos líquidos em um tempo de processo de 80min.