Removal of methylene blue dye from aqueous solution using pink guava (Psidium Guajava) waste-based activated carbon

The feasibility of using guava waste activated carbon (GWAC) for the methylene blue (MB) adsorption has been investigated. The GWAC was prepared using simple thermochemical activation method. The comparison on adsorption performance between GWAC and commercial activated carbon (CAC) were conducted using the batch adsorption study to determine the adsorption capacity for both adsorbents. The adsorption study was carried out at different initial concentrations of MB (50-500 mg/L) at temperature of 30 °C for 5 hours. The equilibrium data were analyzed using Langmuir and Freundlich isotherm models followed by kinetics study. The experimental data for both adsorbents were fitted well with Langmuir isotherm with a maximum monolayer adsorption capacity of 250.00 mg/g and 333.33 mg/g for GWAC and CAC, respectively. The peudo-second order kinetics was the best for the adsorption of MB by GWAC and CAC with good correlation. The results demonstrated that GWAC is an effective adsorbent for removal of MB and have potential to replace the commercial activated carbon for removal of dyes from wastewater.