Adsorption of silver(I) on dithizone-immobilized coal fly ash

Adsorption of Ag(I) on dithizone-immobilized coal fly ash (Dtz-CFA) from PT Madukismo Factory, Yogyakarta, Indonesia has been investigated. Immobilization of dithizone on activated coal fly ash (Act-CFA) was done by stirring the mixture of two precursors in toluene medium at 50o C for 16 h. Parameters influencing adsorption of Ag(I) such as pH of solution, contact time and initial concentration of Ag(I) ions were optimized. FT-IR and XRD characteriztions show that the surface of fly ash has successfully immobilized by dithizone. The optimum conditions for Ag(I) adsorption are reached at pH 6, contact time of 45 min and initial concentration of 100 mg g-1 . The ability of Dtz-CFA to adsorb Ag(I) metal ions significantly increases as compared to that of Act-CFA. Kinetic and isotherm adsorption studies suggest that adsoption of Ag(I) using both Act-CFA and Dtz-CFA follows a second-order pseudo reaction and Langmuir isotherm model, respectively. These results indicate that Dtz-CFA may be used as prospective adsorbent for removing Ag(I) ion. © 2021 Trans Tech Publications Ltd, Switzerland.