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This work aims to produce activated carbon from the endocarp of Syagrus oleracea by vacuum pyrolysis and evaluate its potential as an adsorbent. The effects of pyrolysis temperature (400 °C, 500 °C, 600 °C, and 700 °C), particle diameter (0.467 mm, 0.267 mm, and lower than 0.234 mm), and activation agent (H 2 SO 4 , H 2 PO 3 , and KOH) on the potential for methylene blue adsorption were investigated. In addition, kinetics and adsorption equilibrium were evaluated. The best condition found was particle diameter < 0.234 mm, final pyrolysis temperature of 700 °C, and using KOH. Adsorption kinetics followed pseudo-second order, with equilibrium reached within 20 min. Isotherms followed the Freundlich model. Values of adsorption capacity were in the order of 30 mg/g. Thermodynamic parameters indicated that adsorption occurred spontaneously with a reduction in the heterogeneity of the solid interface/solution. The results obtained demonstrate the great adsorption capacity of the activated carbon prepared from endocarp of Syagrus oleracea via vacuum pyrolysis for the removal of up to 98% methylene blue from aqueous solutions. more...

In this work, the potential of ouricuri (Syagrus coronata) fiber as a novel biosorbent to remove methylene blue (MB) from aqueous solutions was investigated. The fiber was prepared and characterized according to the fundamental features for adsorption. A 2 3 experimental design was used to evaluate the effects of adsorbent dosage (M), fiber diameter (D) and agitation (A) on the adsorption capacity. In the more adequate conditions, kinetic and equilibrium studies were performed. The experimental design results showed that M = 10 g L -1 ), D = 0.595 mm and A = 200 rpm were the more adequate conditions for MB adsorption. Based on the kinetic study, it was found that the adsorption process was fast, being the equilibrium was attained at about 5 min, with 90% of color removal. The isotherm was properly represented by the Sips model, and the maximum adsorption capacity was 31.7 mg g -1 . In brief, it was demonstrated that ouricuri fiber is an alternative biosorbent to remove MB from aqueous media, taking into account the process efficiency and economic viewpoint. more...