Valorization of coal fired-fly ash for potential heavy metal removal from the single and multi-contaminated system

In this study, adsorption of three different heavy metals i.e. cadmium (Cd (II)), copper (Cu (II)) and nickel (Ni (II)) was carried out in single and multi-contaminated system using coal-fired fly ash (CFFA). Initially, for the single contaminated system, various physical process parameters were selected for optimization by deploying Box-Behnken design of experiments. Further, the evaluation of CFFA for removal of heavy metals in a multicomponent system from aqueous solution was performed by employing Plackett-Burman design of experiments with all the three heavy metals at two different levels by varying their initial concentration (10-50 mg L-1). In both the aforementioned cases, CFFA showed its great potential for heavy metal removal, i.e. single and multicomponent system and followed the order: Cu (II) > Ni (II) > Cd (II). Further, FTIR study confirmed the involvement of amide, aldehyde, alkoxy, alkanes, and alkene groups for heavy metal adsorption by CFFA.