Resumo

ALBIS A., Alberto; LOPEZ, Alexandra J.  e  ROMERO, María C.. Removal of methylene blue from aqueous solutions using cassava peel (Manihot esculenta) modified with phosphoric acid. Prospect. [online]. 2017, vol.15, n.2, pp.60-73. ISSN 1692-8261.  https://doi.org/10.15665/rp.v15i2.777.

This work reports the modification of cassava peel using phosphoric acid for the removal of methylene blue from aqueous solutions. A central composite design 3^2+star was employed using as manipulated variables the temperature of modification (113 ° C to 127 ° C), the biomass- phosphoric acid ratio (1: 0.5 to 1: 1,5) and the initial concentration of dye (100 to 800 mg/L); the response variables of the experiment were the percentage of removal and the adsorption capacity. It was found that for the percentage of removal of dye, the most important variable is the temperature, and that the adsorption capacity is favored at high concentrations of dye. The cassava peel modified at the highest temperature (127 ° C) and biomass:acid mass ratio 1:1 showed higher values for both the removal percentage and the adsorption capacity, which were 99.984% and 79.975 mg/g, respectively. The adsorption kinetics was best adjusted to a pseudo second order kinetic model, which indicates that the process is carried out by chemisorption, also, the process was adjusted to Freundlich isotherms, indicating that the adsorption is carried out in multiple layers.

Palavras-chave : Cassava peel; Methylene blue; Removal; Adsorption; Kinetics; Equilibrium isotherms.

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