Comparative Adsorption of an Acid Dye with Different Activation of Fly Ash

Adsorption technology involving use of low cost adsorbent provides an economical and eco-friendly option for treating dye wastewaters studded with different type and concentration of various organic pollutants. Present work focuses on various activation techniques of fly ash and its use as an adsorbent. An activation technique of fly ash includes heat treatment (CFA 600), Alkali treatment (CFA NaOH) and Acid treatment (CFA HCl). From experimental study it was observed that raw coal fly ash CFA and CFA HCl had superior adsorbing ability than two modified coal fly ashes (CFA-600 and CFA-NaOH) for the dye Acid Orange 7 (AO7). The adsorption capacities followed the order CFA HCl > CFA> CFA-600 > CFA-NaOH. The adsorptions of AO7 onto CFA, CFA-600, CFA HCl and CFA-NaOH all followed pseudo-second-order kinetics. The isotherm for the adsorption of AO7 onto the raw and modified coal fly ashes fits the Temkin isotherm. This study includes the application of these adsorbents in batch application by varying the parameters such as dosage of adsorbent, contact time, initial concentration, and pH.