Kinetics and Equilibrium Studies of the Detoxification of Aqueous Solutions of Phenolic Derivatives using Activated Carbon
Nkwocha Stephen Tochi *
Department of Chemistry and Biochemistry, University of Wisconsin Milwaukee, USA.
Isaac Adebayo Akinbulu
Chemistry Department, University of Lagos, Yaba, Lagos, Nigeria.
Oke Temidayo Joseph
Department of Chemistry and Biochemistry, University of Wisconsin Milwaukee, USA.
Medubi Kayode Michelle
Department of Chemistry and Biochemistry, University of Wisconsin Milwaukee, USA.
*Author to whom correspondence should be addressed.
Abstract
This study investigates the kinetics and equilibrium of phenolic derivative detoxification from aqueous solutions using activated carbon derived from coconut husk (CHAC). Phenolic compounds, prevalent in industrial wastewater, are highly toxic to humans and aquatic life. The removal efficiency of 4-Nitrophenol (PNP) and 4-Chlorophenol (PCP) was examined using batch adsorption experiments under varying conditions including adsorbent dose, contact time, initial concentration, and temperature. Coconut husk was chemically activated and characterized for its adsorption properties. The optimal adsorbent dose for PNP removal was determined to be 0.2 g, achieving a maximum adsorption capacity of 64.65 mg/g after 120 minutes. Adsorption data were fitted to pseudo-first-order and pseudo-second-order kinetic models to understand the adsorption mechanism. The results indicated that the adsorption of PNP onto CHAC followed the pseudo-second-order kinetic model, suggesting chemisorption as the dominant process. The findings demonstrate that activated carbon from coconut husk can be an effective and sustainable adsorbent for removing phenolic derivatives from wastewater, offering a potential solution for environmental detoxification. Further studies on isotherm models and thermodynamics are recommended to optimize the adsorption process for large-scale applications.
Keywords: Activated carbon, p-nitrophenol, p-chlorophenol, kinetic measurements, chemical activation