The Valorization of Luffa cylindrica as an Etheramine Biosorbent in Wastewater Treatment
2022
Evangelista, Jessica C. S. | Rocha, Sônia Denise F.
The water reuse in mineral processing as well as the quality of hydric bodies that receive the effluents can be benefited with the removal of etheramines. In this study, synthetic effluents with etheramines (EDA) were treated by adsorption, in batch and in a fixed bed column, using Luffa cylindrica. The biosorbent was washed in three cross-current steps of 60 min. The increase in pH from 7.5 to 9.5 provided a small increase in the EDA amount adsorbed, but a subsequent rise to 10.5 slightly impacted the adsorption. At equilibrium, the adsorption capacity in TOC (total organic carbon) was 7.98 mg/g (Cᵢ = 50 mg/l) and 22.47 mg/g (Cᵢ = 200 mg/l) and the kinetics was represented by a pseudo-second-order model. Based on determination coefficients, the Freundlich, Redlich-Peterson, and Sips isotherms were similar with adequate fits. In a column of d = 13 mm and h = 25 cm, the breakthrough curves were represented by the Yan model. At pH 7.5 and 26 °C, the effects of bed height (5, 10, 15, and 20 cm), feed flow rates (3.2; 8.9; 14.5; and 22.8 ml/min), and initial EDA concentrations of 50 and 150 mg/l on adsorption were evaluated. The column tends to a fast exhaustion at higher application rates (17.177 ml/cm².min); however, there was a greater stability using a lower one (6.705 ml/cm².min). The shortest exhaustion time was 60 min for hL = 10 cm and superficial application rate of 17.177 ml/min.cm² and the longest time was 360 min for the lowest superficial application rate (2.411 ml/min.cm²). From the results, it can be inferred that the column adsorption of etheramines by Luffa cylindrica presents high potential for use in the treatment of liquid effluents containing residual concentrations of EDA.
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