resumo
In this work, alkali-activated fly ash-derived foams were produced at room temperature by direct foaming using aluminum powder. The 1 cm(3) foams (cubes) were then evaluated as adsorbents to extract heavy metals from aqueous solutions. The foams' selectivity towards lead, cadmium, zinc, and copper ions was evaluated in single, binary, and multicomponent ionic solutions. In the single ion assays, the foams showed much higher affinity towards lead, compared to the other heavy metals; at 10 ppm, the removal efficiency reached 91.9% for lead, 83.2% for cadmium, 74.6% for copper, and 64.6% for zinc. The greater selectivity for lead was also seen in the binary tests. The results showed that the presence of zinc is detrimental to cadmium and copper sorption, while for lead it mainly affects the sorption rate, but not the ultimate removal efficiency. In the multicomponent assays, the removal efficiency for all the heavy metals was lower than the values seen in the single ion tests. However, the superior affinity for lead was preserved. This study decreases the existing knowledge gap regarding the potential of alkali-activated materials to act as heavy metals adsorbents under different scenarios.
palavras-chave
METAKAOLIN BASED GEOPOLYMER; INORGANIC POLYMER; FACILE FABRICATION; EFFICIENT REMOVAL; ADSORPTION; SPHERES; GREEN; MONOLITHS; ADSORBENT; MICROSTRUCTURE
categoria
Chemistry; Materials Science; Metallurgy & Metallurgical Engineering; Physics
autores
Caetano, APF; Carvalheiras, J; Senff, L; Seabra, MP; Pullar, RC; Labrincha, JA; Novais, RM
nossos autores
Ana Caetano
Estudante de doutoramento
João António de Sousa Carvalheiras
Estudante de doutoramento
João António Labrincha Baptista
Professor Catedrático
Maria Paula Seabra
Professor Auxiliar
Rob Pullar
Colaborador