Removal of Methylene Blue by Activated Carbon from Jackfruit: Kinetic, Isothermal Evaluation and Optimization Using by Response Surface Methodology

Activated carbons derived from the byproducts of jackfruit processing, specifically the skin (peel) and pulp, were prepared using the chemical assisted microwave irradiation method. The structural and physical properties were evaluated based on the results of scanning electron microscope, X-ray diffraction patterns, Fourier-transform infrared spectroscopy, Brunauer–Emmett–Teller theory analysis. The results have shown that activated carbon from jackfruit skin and activated carbon from jackfruit pulp have a honeycomb shape with a surface area of 268 m2 g-1 and 309 m2 g-1, respectively. Both samples showed the presence of specific functional groups such as C=C, C=O, O–H and C–H. It can be seen that the material structure was semi-crystalline and clearly shown in the 2θ value ranges which are 2θ = 20-35º and 40-45º. Specifically, 2θ = 20-35º represents the structural characteristics of the carbon or graphite lattice. Factors that influence the removal of methylene blue that have been evaluated which include adsorption time, solution pH, ambient temperature, activated carbon dosage, dye concentration and optimization by the response surface methodology model. The parameters for the adsorption process are optimized from the response surface methodology model with activated carbon from jackfruit pulp (pH 8.97, concentration of 50.5 mg L-1, dosage of 0.57 g L-1, time 120 min, temperature 30 ºC, the adsorption capacity of 90.82 mg g-1, adsorption efficiency 100%) and activated carbon from Jackfruit skin (pH 8.61, concentration 52 mg L-1, dosage 0.57 g L-1, time 120 min, temperature 30 ºC, adsorption capacity 94.04 mg g-1, adsorption efficiency 100%), respectively. The adsorption process shows that activated carbon from jackfruit pulp (ACJP) follows the pseudo-second order and Langmuir model and activated carbon from jackfruit skin (peel) (ACJS) follows the model of Bangham and Langmuir. The adsorption process is predicted with many mechanisms, including chemical interactions, multilayer adsorption and diffusion. The materials showed application potential as the reusability was three times.