Synthesis of activated carbon from Kenaf core fibre for removal of Methylene Blue

Abstract

Kenaf core fiber (KF) which is an agricultural biomass was synthesized into activated carbon and used as an adsorbent for removal of methylene blue (MB) dye. Kenaf Activated Fiber Carbon (KAFC) was produced using pre-treatment process and activation process with phosphoric acid (H3PO4). The KAFC that have been synthesized were characterized using fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The FTIR results shows the functional groups such as carboxylic acid, phenol, ether and ester that contained in the KAFC. The SEM results shows the number of pores formed was higher on KAFC surface area as compared to raw KF. The optimum adsorbent dosage is 0.10 g and the adsorption process reach equilibrium within 180 minutes with 98 % for percentage removal of MB dye. Apart from that, at low concentration which is 20 ppm, the percentage removal of MB was high which is above 90 % because there were many available active sites on the adsorbent surface. By using pH 10 of the methylene blue solution, it indicated the higher value on removal of methylene blue due to the effect of electrostatic forces attraction. For adsorption isotherm, Langmuir isotherm is more preferable as compared to Freundlich isotherm since the value of R2 is 0.9964 which is nearer to 1 which indicated the interaction between the adsorbate and adsorbent. Since the KAFC followed Langmuir isotherm model, it was assumed that the adsorption happened at homogeneous sites on adsorbent surface. Besides that, for adsorption kinetic, pseudo-second order is more preferable than pseudo-first order model since the value of R2 > 0.99 is nearer to 1 interpreted that the amount of adsorbate can be adsorbed is constant as time is increased.