Sawdust as an Adsorbent for the Removal of Methylene Blue from Aqueous Solution: Adsorption and Equilibrium Studies

Abstract

The present research indicated that activated carbon prepared from saw dust has been used to adsorb methylene blue (MB) from aqueous solution using NaOH as an activating agent at initial concentration of 10-50 mg/L. Percentage carbon yield decrease with increase in activation burn off time since more volatiles are release from the char. The pH range of 7.81±0.01 to 7.83±0.02 obtained by activated carbons prepared from saw dust is suitable for MB removal from aqueous solution since for most application, activated carbon pH of 6-8 is acceptable. Adsorption capacity at equilibrium (qe) tend to increases with increases in initial concentration from 10 – 50 mg/L with higher MB removal of 99.67 % recorded. Adsorption isotherm which include Langmuir, Freundlich, Temkin and Harkin’s – Jura were used to analysed the equilibrium data. Langmuir isotherm best described the adsorption data with higher correlation coefficient R2 values (R2 = 0.982, R2 = 0.996 and R2 = 0.995) and RL values less than one (RL= 0.009, RL = 0.001 and RL= 0.001) for SD/NaOH/5, SD/NaOH/10 and SD/NaOH/15 activated carbon respectively.