Removal of Methyl Red Dye by Adsorption Process using Modified Fly Ash with Ultrasound Process

In objective of this study, the removal of azo dye (methyl red) commonly used the textile industry was investigated using raw fly ash and modified fly ash with ultrasound process. The effect of removal methyl red under various parameters such as adsorbent dose (1–12 g), adsorption time (10–240 min), pH (2–10), temperature (10–50 °C) and initial methyl red concentration (25–125 mg/L) were examined during adsorption experiments in detail. The adsorption capacities of unmodified and modified fly ash were found to be 13.78 mg/g and 14.52 mg/g under optimum conditions at acidic pH, respectively. The change of surface characteristics for unmodified and modified fly ash using ultrasound were determined using BET, SEM-EDS, XRF, XRD, and particle size analysis. According to obtained result, modification of fly ash by mechanical effect of ultrasound increased surface area and decreased particle size. Using modified fly ash provided successful results for methyl red removal in a shorter reaction time and with smaller fly ash dosage. The kinetics of adsorption followed by second- order kinetic model and adsorption of methyl red onto fly ash was well fitted with the Freundlich isotherm model both adsorbents. Thermodynamic parameters such as ？G°, ？H° and ？S° indicated that the adsorption of methly red onto fly ash was exothermal in the temperature range of 10–50 °C