Abstract

Hector Ruiz¹, Monica Zambtrano¹, Liliana Giraldo², Rocio Sierra¹, Juan Carlos Moreno-Pirajan^3*

DOI : http://dx.doi.org/10.13005/ojc/310217

In this study, the recovery of volatile carboxylic acids (VCA) by adsorption onto activated carbon adsorbent (CA) was explored. The CA was synthesized from palm-oil kernel shells using H₃PO₄ at 10 and 60% w/w as activating agent. The samples produced in this manner were labeled as CA10A, CA60A respectively. Also KOH was used as activating agent at 10 and 60% w/w. In this case, the produced samples were labeled as CA10B, CA60B respectively. After activation, the surface of all four CA samples was extensively characterized both physically and chemically. The obtained CA adsorption behavior for VCA was assessed by submerging samples of CA in solutions at a fixed initial VCA concentration. Because some of the acids were adsorbed on the CA surface, the VCA concentration in solution was reduced. Carbon CA60B exhibited the greatest adsorption capacity, reaching 1300 mg of adsorbed acids/g carbon. Five adsorption isotherms models were fitted to experimental data. The Langmuir-Freundlich model described best the adsorption phenomena. Desorption behavior was assessed by placing CA after adsorption in water and was not high, which forces to reconsider either de desorption mechanism proposed in this study and/or the use CA as synthesized here for VCA recovery.

carboxylic acids; activated carbon; oil-palm kernel shell; equilibrium isotherms

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