Removal of Methylene Blue Dye from Textile Wastewater Using Water Hyacinth Activated Carbon as Adsorbent: Synthesis, Characterization and Kinetic Studies

Abstract

Water hyacinth, an aquatic plant in Lake Tana, was utilized as a raw material for the synthesis of activated carbon. It was produced by chemical activation using phosphoric acid followed by carbonization at 4000C for two hours. The activated carbon has been employed for the elimination of methylene blue (MB) dye. Different physico-chemical properties of activated carbon were determined. Effects of different factors like solution temperature, pH, adsorbent dosage, contact time and initial dye concentration were studied under batch adsorption. The concentration of methylene blue dye was determined by UV-Vis spectroscopy instrument. The maximum removal of dye (98.6%) was achieved at pH 10, 1.5g adsorbent dosage and 60 min at 15 mg/L of dye concentration. The adsorption isotherms followed well to both the Langmuir and Freundlich equations. Adsorption of MB on WHAC (R2 = 0.97) followed Langmuir model and in Freundlich isotherm model (R2 = 0.9907). The pseudo second order kinetic model delivered a better fit for the adsorption data.