Adsorção de ácido naftênico pelo carvão ativado de casca de Orbignya phalerata

Abstract

The petrochemical industry involves a process chain with great potential for pollution.The presence of naphthenic acids in oily wastewater causes environmental damage, harming various organisms. The objective of this study was to evaluate the adsorptive capacity of activated carbon derived from Orbignya phalerata (babaçu coconut) shells for the removal of a model naphthenic acid, 1,4-cyclohexanedicarboxylic acid. To do this, kinetics and adsorption isotherms were determined in a batch system. Acid adsorption kinetics in the adsorbent were relatively fast, reaching equilibrium after 60 minutes of contact. Kinetic data was better adjusted to the pseudo-second order model, revealing the chemisorption character of the contaminant adsorption process. Equilibrium data was adjusted according to the Langmuir and Freundlich models, and bothpresented good fit. Based on the equilibrium constant analysis, activated carbon has higher affinity as an adsorbate and the maximum retained amount ofacid obtained experimentally was 417.0 mg g-1. Thus, the equilibrium data obtained for the system suggest that the adsorbent tested has promising outcomes in the removal of acid contaminants present in wastewater from oil refining processes.