title: Nickel removal by biosorption onto medlar male flowers coupled with photocatalysis on the spinel ZnMn2O4.
abstract: Ni2+ is a highly toxic above 0.07 mg/L and its removal is of high significance. The biosorption of Ni2+ onto medlar male flowers (MMF) was studied in relation with the physical parameters like pH, contact time, biosorbent dosage, Ni2+ concentration and temperature. The interaction biosorbent-Ni2+ was examined by the FTIR technique. The equilibrium was achieved within 40 min and the data were well fitted by the Langmuir and Redlich-Peterson (R-P) models. The maximum Ni2+ uptake capacity was 17.073 mg/g at 25°C and the Ni2+ removal follows a pseudo-second order kinetic with activation energy of 13.3 kJ/mol. The thermodynamic parameters: ΔS°, ΔH° and ΔG° showed that the biosorption was spontaneous and endothermic. MMF was used as a post treatment technique and the biosorption was coupled with the visible light driven Ni2+ reduction over the spinel ZnMn2O4. The effect of the pH, ZnMn2O4 loading and light intensity on the photoactivity was investigated. 77.5% of Ni2+ was reduced after ~140 min under optimal conditions. The Ni2+ removal reached a rate conversion of 96% of with the coupled system biosorption/photocatalysis is very promising for the water treatment.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Chergui
authors.affiliation: Laboratory of Storage and Valorization of Renewable Energies, Faculty of Chemistry, Algiers, Algeria. faridmadjene@hotmail.fr.
authors.forename: Farid
authors.initials: F
authors.lastname: Madjene
authors.forename: Mohamed
authors.initials: M
authors.lastname: Trari
authors.forename: Ali
authors.initials: A
authors.lastname: Khouider