title: Enhanced chromium (VI) removal using activated carbon modified by zero valent iron and silver bimetallic nanoparticles.
abstract: Recently, adsorption process has been introduced as a favorable and effective technique for the removal of metal ions from aqueous solutions. In the present study, bimetallic nanoparticles consisting of zero valent iron and silver were loaded on the activated carbon powder for the preparation of a new adsorbent (PAC-Fe(o)/Ag). The above adsorbent was characterized by using XRD, SEM and TEM techniqes. Experimental data were exploited for kinetic, equilibrium and thermodynamic evaluations related to the adsorption processes. The Cr(VI) adsorption process was found to be favorable at pH 3 and it reached equilibrium state within 60 min. The stirring rate did not have a significant effect on the adsorption efficiency. Furthermore, the monolayer adsorption capacity of Cr(VI) based on the Langmuir model was measured to be 100 mg/g. The experimental equilibrium data were fitted to the Freundlich adsorption and pseudo second-order models. According to the thermodynamic study, the adsorption process was spontaneous and endothermic in nature, indicating the adsorption capacity increases with increasing the temperature. The results also revealed that the synthesized composite can be potentially applied as a magnetic adsorbent to remove Cr(VI) contaminants from aqueous solutions.
authors.affiliation: Department of Environmental Health Engineering, School of Public Health, Ahvaz, Jundishapur University of Medical Sciences, Ahvaz, Iran.
authors.forename: Babak
authors.initials: B
authors.lastname: Kakavandi
authors.affiliation: Department of Environmental Health Engineering, School of Public Health, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Roshanak Rezaei
authors.initials: RR
authors.lastname: Kalantary
authors.affiliation: Department of Environmental Health Engineering, School of Public Health, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Mahdi
authors.initials: M
authors.lastname: Farzadkia
authors.affiliation: Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran ; Center for Solid Waste Research, Institute for Environmental Research, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Amir Hossein
authors.initials: AH
authors.lastname: Mahvi
authors.affiliation: Department of Environmental Health Engineering, School of Public Health, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Ali
authors.initials: A
authors.lastname: Esrafili
authors.affiliation: Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Ali
authors.initials: A
authors.lastname: Azari
authors.affiliation: Department of Environmental Health Engineering, School of Public Health, Qom University of Medical Sciences, Qom, Iran.
authors.forename: Ahmad Reza
authors.initials: AR
authors.lastname: Yari
authors.affiliation: Department of Environmental Health Engineering, School of Public Health, Shahrood University of Medical Sciences, Semnan, Iran.
authors.forename: Allah Bakhsh
authors.initials: AB
authors.lastname: Javid
keywords: Activated carbon; Adsorption; Bimetallic; Chromium; nZVI