CETMIC   05378
CENTRO DE TECNOLOGIA DE RECURSOS MINERALES Y CERAMICA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
UPFLOW AND DOWNFLOW CLAYBIOMASS COLUMNS FOR THE REMOVAL OF U(VI)
Autor/es:
OLIVELLI, MELISA SOLEDAD; CURUTCHET, GUSTAVO; TORRES SÁNCHEZ, ROSA MARÍA
Lugar:
Río de Janeiro
Reunión:
Congreso; XV International Clay Conference; 2013
Resumen:
In previous studies was demonstrated that biopolymers generated from fungal biomass and amontmorillonite (BMMTs) were efficient as biosorbentes in batch uranium removal systems.BMMTs showed high adsorption efficiency even at low concentrations. Also, using very lowconcentrations BMMT reached their saturation only after several cycles during U(VI)progressive adsorption experiments.The objective of this work is to evaluate their metal exchange capacity by potentiometrictitration and evaluate the U(VI) sorption capacity of BMMT systems for its removal fromeffluents.Downflow and upflow BMMT columns were performed in order to compare and optimize thesystem for continuous sorption techniques. Also, elution of downflow columns with dilutedH2SO4 was performed. Both columns were fixedbed columns with a volume of 0,8 ml. In thecontinuous removal experiences, both type of columns were loaded with a solution of 25 ppmU(VI). For upflow columns a peristaltic pump was used at a flow rate of 0.65 ml/min.The total proton consumption of the studied materials indicated that there were more availablesites to exchange protons in BMMTs than in MMT.Downflow columns presented a non constant flow, resulting in an inefficient method for thesesorbents. The saturation of the column was reached with a very low volume, making thecalculation of a breakthrough point not possible to. A possible explanation for this behaviourcould be that during the load of the column a hydration process of the material could takeplace generating an increase in the adsorption specific surface of the biopolymer components.Data from U(VI) extraction after saturation of downflow BMMT columns indicatedthe possibility of recycling the BMMT after processes of U(VI) sorption, because U(VI) elutionfrom the column was complete.For upflow columns, the U(VI) removal percentage was around of 83.3% from 150 ml ofloading, 75% from 150 to 300 ml and near 58% from 300 to 400 ml. The total amount of U(VI)retained during the first 500 bed volumes, was near 20 mg U(VI) / g BMMT; leading to a yieldten times higher than that of downflow columns. Also, neither the montmorillonite nor thefungal biomass alone allowed the development of a column experiment due to the mechanicalinstability of the material when the solution passed trough the column. On the otherhand, BMMTs presented a suitable stability of the biomaterial for the development ofadsorption columns. These results indicated that upflow columns presented an advantageousperformance for being applied in a greater scale and that they could be used in thedevelopment of economic and efficient biofilters