Ultrasonic Powered Hydrothermal Modification of Coal Fly Ash to Cost-Effective Zeolites

Coal fly ash (CFA) waste is one of the anthropogenic materials having detrimental impact as particulate and leachate contaminant. Dumping of such solid waste into landfills and other improper waste management conduct can be lethal for environment. In this work CFA waste was attempted to modify into zeolites using ultrasonic assisted hydrothermal and conventional heating approaches. The conventional and ultrasonic assisted synthesized zeolites showed entirely different cation exchange capacity (CEC) and morphology. However, FTIR and XRD patterns of zeolites synthesized by both of techniques were almost similar. However, a better crystalline structure, functionality and morphology of Na-X, NaP1 and hydroxy sodalite (SOD) classes of zeolites synthesized in ultrasonic (USZ-8) and hydrothermal (HT-48) curing modes were observed. Hydrothermally treated (HT-8) material was found with a lower porosity and low CEC (109 meq/100g) in contrast to USZ-8 with high porosity and CEC (390 meq/100g) for the same reaction time. ICP-OES analysis demonstrated that ultrasonic cavitation was more appropriate way to convert coal fly ash based aluminosilicates into active zeolites, economically. It can be concluded reasonably that ultrasonic modification of coal fly ash into valuable zeolites is a constructive approach and a step to gear up greener innovation.