A Comparative Study for Adsorption of Methylene Blue Dye from Wastewater on to Three Different Types of Rice Ash

Document Type : Original Article


Chemistry Department, Faculty of Science, Tanta University, 31527, Egypt.



High innuendo to organic dyes, such as methylene blue (MB) potentially has retrograde effects and can cause acute health problems leading to a number of particular diseases. Our work aimed at evaluating of three different types of heap fired ash as low-cost adsorbents for the removal of methylene blue (MB) dye from wastewater has been investigated. The effects of pH of solution, dosage adsorbent, contact time and initial concentration were investigated. The results showed that the adsorption of MB is highly influenced by the adsorbent dose, time, initial MB concentration, solution pH and slightly affected by the aqueous medium temperature. Also, the higher percentage of MB removal at lower initial dye concentrations and the equilibrium between MB in the solution and the adsorbent surface was practically achieved in 60 min. The adsorption process was found to obey second-order rate model with endothermic nature. Equilibrium adsorptive data for MB were well represented by Langmuir and Freundlich isotherm models. Additionally, the dye adsorption process was also characterized through the thermodynamic parameters such as Gibbs free energy (ΔGo), change in heat of adsorption (ΔHo) and entropy change (ΔSo). The negative value of ΔGo indicated spontaneous adsorption of MB onto RHA and ATRH. Finally, RHA show high efficiency in MB removal as low-cost and effective adsorbent.