Dragon fruit skin as a potential biosorbent for the removal of methylene blue dye from aqueous solution

摘要

Dragon fruit skin (DFS) was investigated for its potential in the removal of methylene blue (MB) from aqueous solution. Effects of contact time, initial concentration and pH medium were investigated. Adsorption isotherm studies were also carried out. Three isotherm models, namely the Langmuir, Freundlich and Tempkin models, were used to predict the behaviour of the adsorption process. Adsorption equilibrium for the removal of MB was achieved in a relatively short time and the batch experiments were done without any pH adjustment. The experimental data fitted the Langmuir Type II adsorption isotherm with a high maximum adsorption capacity (qinfmax/inf) of 640 mg gsup-1/sup, which is superior for the removal of MB compared to most reported biosorbents. Kinetics studies were found to follow the pseudo-second order model and intraparticle diffusion is involved but not as the rate-determining step. Dragon fruit skin (DFS) was investigated for its potential in the removal of methylene blue (MB) from aqueous solution. Effects of contact time, initial concentration and pH medium were investigated. Adsorption isotherm studies were also carried out. Three isotherm models, namely the Langmuir, Freundlich and Tempkin models, were used to predict the behaviour of the adsorption process. Adsorption equilibrium for the removal of MB was achieved in a relatively short time and the batch experiments were done without any pH adjustment. The experimental data fitted the Langmuir Type II adsorption isotherm with a high maximum adsorption capacity (q max ) of 640 mg g -1 , which is superior for the removal of MB compared to most reported biosorbents. Kinetics studies were found to follow the pseudo-second order model and intraparticle diffusion is involved but not as the rate-determining step.