Optimization of Parameters for Adsorption of Methylene Blue on a Low-Cost Activated Carbon

We prepared activated carbon by pyrolyzing an agro-waste, rice husk, in the presence of ZnCl 2 . The activated carbon displayed both microporous and mesoporous nature with a significant surface area of 180.50 m 2 ·g −1 . Fourier transform infrared (FTIR) spectrograms of the activated carbon were recorded to determine the number and positions of the functional groups available on its surface. The adsorption of methylene blue (MB) from its aqueous solutions by rice husk activated carbon (RHAC) was studied. The removal of dye increased from (82.75 to 93.20) % with decreasing initial concentration of MB from (100 to 60) mg·L −1 . The time of equilibrium was found to be 100 min. Higher removal was obtained at higher dose of adsorbent, and the removal increased from (86.75 to 99.83) % with increasing adsorbent dose from (0.40 to 0.60) g. The removal of methylene blue increased from (93.20 to 99.16) % with increasing temperature from (30 to 50) °C at 60 mg·L −1 MB concentration, 150 rpm, and 100 μm particle size. Isotherm studies were conducted to know the capacity of the activated carbon. Langmuir and Freundlich isotherm equations were applied for the equilibrium data.