Publicação
New eco-efficient polymers for phosphorus recovery
| Resumo: | In the last 50 years a considerably decline on quality of superficial natural waters, in special for aquatic environments, where the water residence time is higher (more than one year), has been witnessed. Discharge of wastewaters without appropriate treatment, leaching of fertilisers and slurry from agricultural land resulted in a massive input of nutrients to superficial waters, especially phosphorus and nitrogen. As a consequence of this nutrient enrichment, aquatic plants start to overgrow impairing the waters, a process describe as eutrophication. The eutrophication prevents the use of water for recreational proposes, increases the cost of water purification for human and animal consumption and has severe consequences for biodiversity. Therefore, the main of this thesis was to develop a new polymeric material able to remove phosphorus from eutrophic waters without any environmental contamination. Hybrid nanocomposites containing aluminium nanoparticles were prepared by sol-gel reaction in the melt in an internal mixer. Polypropylene (PP), polypropylene grafted with maleic anhydride (PP-g- MA) and poly(ethylene vinyl acetate) (EVA) were used as organic components to prepared the nanocomposites. Two different aluminium precursors, aluminium isopropoxide (Al(Pr-i-O)3) and aluminium acetylacetonate (Al(acac)3) were used to produce the aluminium nanoparticles. Several analytical techniques were used to characterize the nanocomposites produced. The results shows that aluminium precursor with short organic chain (Al(Pr-i-O)3) allow faster and extensive reactions without a post step treatment. The nanoparticles are smaller and well dispersed. Regarding to phosphorus removal efficiency, the nanocomposite based of PP was the one that exhibited better performance. Therefore, this material was also produced in a twin-screw to evaluate the scale-up production. The results in a pilot scale, where real eutrophic water was treated using this material, confirm that it is able to remove phosphorus from natural waters. Moreover, it can be used several times and the phosphorus can be recovery. |
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| Autores principais: | Oliveira, Manuel António Sousa Cortez Gonçalves |
| Ano: | 2012 |
| País: | Portugal |
| Tipo de documento: | tese de doutoramento |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | In the last 50 years a considerably decline on quality of superficial natural waters, in special for aquatic environments, where the water residence time is higher (more than one year), has been witnessed. Discharge of wastewaters without appropriate treatment, leaching of fertilisers and slurry from agricultural land resulted in a massive input of nutrients to superficial waters, especially phosphorus and nitrogen. As a consequence of this nutrient enrichment, aquatic plants start to overgrow impairing the waters, a process describe as eutrophication. The eutrophication prevents the use of water for recreational proposes, increases the cost of water purification for human and animal consumption and has severe consequences for biodiversity. Therefore, the main of this thesis was to develop a new polymeric material able to remove phosphorus from eutrophic waters without any environmental contamination. Hybrid nanocomposites containing aluminium nanoparticles were prepared by sol-gel reaction in the melt in an internal mixer. Polypropylene (PP), polypropylene grafted with maleic anhydride (PP-g- MA) and poly(ethylene vinyl acetate) (EVA) were used as organic components to prepared the nanocomposites. Two different aluminium precursors, aluminium isopropoxide (Al(Pr-i-O)3) and aluminium acetylacetonate (Al(acac)3) were used to produce the aluminium nanoparticles. Several analytical techniques were used to characterize the nanocomposites produced. The results shows that aluminium precursor with short organic chain (Al(Pr-i-O)3) allow faster and extensive reactions without a post step treatment. The nanoparticles are smaller and well dispersed. Regarding to phosphorus removal efficiency, the nanocomposite based of PP was the one that exhibited better performance. Therefore, this material was also produced in a twin-screw to evaluate the scale-up production. The results in a pilot scale, where real eutrophic water was treated using this material, confirm that it is able to remove phosphorus from natural waters. Moreover, it can be used several times and the phosphorus can be recovery. |
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