Preparation of activated carbon from rice husk by microwave irradiation for adsorption of methylene blue dye
Loading...
Date
2017-06
Authors
Siti Khairunnisa Binti Ishak
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
In this study, rice husk based activated carbon (RHAC) was prepared for the
removal of methylene blue (MB) dye. Rice husk was used to prepare RHAC through
physical activation process which involved microwave irradiation and carbon dioxide
(CO2) gasification. The effect of initial dye concentration (25-500 mg/L), contact time
(1-24 h) and solution temperature (30-60°C) were evaluated. The optimum preparation
conditions were obtained from response surface methodology (RSM) at radiation
power of 440 W and activation time of 4.28 minutes which have resulted in 83.93%
MB removal and 32.55% RHAC yield. Optimized RHAC sample has surface area of 668.30 m2
/g, pore volume of 0.348 cm3 /g and fixed carbon content of 70.34. The pore
of RHAC was mesoporous type with average pore diameter of 4.42 nm. The adsorption
equilibrium data is to be fitted into three isotherm models which are Langmuir,
Freundlich and Temkin. Adsorption equilibrium and kinetic of MB on RHAC were
best fitted by Freundlich isotherm and pseudo-second order kinetic models. From
thermodynamic study, the adsorption process of MB onto RHAC was endothermic in
nature and spontaneous process