Calcination-hydrothermal treament of fly ash for methylene blue adsorption

Abstract

Due to its high surface area, porous structure, small particle size and rich in mineral composition, fly ash has been widely studied as a potential adsorbent material (AM), which exhibits a significant capacity to adsorb pollutants from the environment and can be effectively used in wastewater treatment. However, current researches on the use of fly ash for methylene blue (MB) removal from wastewater are still limited. Therefore, this study aims to evaluate the MB adsorption capacity of modified fly ash (MFA) with 96% solid NaOH at 600oC for 1 hour. The static adsorption study has been conducted on the adsorption of MB solution of different concentrations on MFA at varying pH, contact time and initial concentration of dye solution. Research results show that the adsorption capacity of MFA is much greater than that of the original raw fly ash sample (FA); the equilibrium time of MFA is about 90 minutes; the optimal pH value is 7 with the adsorption efficiency of 98.53% and MB concentration is 100 mg/l. The highest adsorption capacity is 16.87 mg/g. Therefore, using MFA for MB adsorption can not only solve environmental problems, utilizing waste resources but also bring many technical and economic benefits, contributing to the sustainable development of related industries.