Adsorption of methylene blue from aqueous solution using different types of activated carbon

In this study, four types of adsorbents were examined for their ability to remove methylene blue MB from aqueous solution by adsorption in a fixed bed system. The adsorbents used were activated carbon (AC), manufactured activated carbon (ACPP1), chemically activated carbon with nitric acid (10% wt) (ACPP2), and with nitric acid and H2SO4 (ratio 1:1) (ACPP3). 28 experiments were conducted to test the effect of MB concentrations, adsorbent bed depth, and solution flow rate. Langmuir and Freundlich as isotherm models were analyzed by nonlinear regression. For AC and ACPP1 the adsorption occurred under heterogeneous and multilayer surfaces. Conversely, for ACPP2 and ACPP3 adsorbent, homogeneous and monolayer control adsorption of MB on this adsorbent and maximum adsorption capacity was 33.149 and 38.508 mg/g for MB onto ACPP2 and ACPP3, respectively. The effect of the flow rate (132,200 and 250 cc/min), bed height (0.05, 0.1, and 0.15 m), and initial MB concentration (150, 300, and 500 mg/l) on the performance of the breakthrough curves were clarified. The Bohart-Adams and Thomas-BDST models have a better correlation in relation to the analysis of fixed bed data.