Optimization of methylene blue biosorption and mass transfer resistance on Gardenia carinata activated carbon

Abstract

This study evaluated Methylene blue (MB) adsorption from dye effluent using a new activated carbon derived from Gardenia carinata. The derived Gardenia carinata activated carbon (GCAC) has a large surface area of 1,187.33 m2/g. Experiments were designed with the central composite design model of the response surface methodology. The interaction between independent variables (adsorbent mass, pH and initial MB concentration) was evaluated at pre-determined contact time of 30 min. Results show that MB adsorption decreased with increasing pH from 4 to 10 but increased with increasing adsorbent mass and initial concentration. MB adsorption exceeded 89% at optimum conditions. Kinetic examination indicated no mass transfer resistance with increasing MB concentration. The driving force (B) of MB transport increased from 3.621 to 4.906 mg/g with increasing MB concentration. Furthermore, the adsorbate/adsorbent attraction increased from 10.570 to 17.064 g/h/mg with increasing MB concentration. This study demonstrates that activated carbon derived from abundant waste materials such as Gardenia carinata can be useful in many significant ways.