title: Regeneration of natural zeolite polluted by lead and zinc in wastewater treatment systems.
abstract: The aim of this work was to investigate the potential regeneration of natural zeolite which had been contaminated with lead and zinc contained in aqueous solutions, treated secondary effluent and primary treated wastewater. Several desorbing solutions were examined for the removal of Pb(II) and Zn(II) from zeolite and the highest desorption efficiency was obtained for 3M KCl and 1M KCl, respectively. The desorption process depended on the type and concentration of the desorbing solution, the metal being desorbed, the mineral selectivity towards the metal and the composition of the liquid medium where the adsorption process had taken place. Successive regeneration cycles resulted in the reduction of desorption efficiency by more than 50% after 9 and 4 cycles for lead and zinc, respectively. Kinetics examination showed that desorption was slower than adsorption, while metal ions which had been easily adsorbed were difficult to be desorbed. Adsorption was characterized by a three-stage diffusion process, while desorption followed a two-stage diffusion process.
authors.affiliation: School of Chemical Engineering, National Technical University of Athens, 9 Iroon Polytechniou St., Zographou Campus, PC 157 73, Athens, Greece. ekatsou@yahoo.gr
authors.forename: Evina
authors.initials: E
authors.lastname: Katsou
authors.forename: Simos
authors.initials: S
authors.lastname: Malamis
authors.forename: Myrto
authors.initials: M
authors.lastname: Tzanoudaki
authors.forename: Katherine J
authors.initials: KJ
authors.lastname: Haralambous
authors.forename: Maria
authors.initials: M
authors.lastname: Loizidou
mesh_terms: D000327:Adsorption; D004058:Diffusion; D007700:Kinetics; D007854:Lead / Q000032:analysis; D008670:Metals / Q000737:chemistry; D015233:Models, Statistical; D011189:Potassium Chloride / Q000032:analysis; D015203:Reproducibility of Results; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000379:methods*; D017641:Zeolites / Q000737:chemistry*; D015032:Zinc / Q000032:analysis / Q000737:chemistry
chemical_list: D008670:Metals; D014874:Water Pollutants, Chemical; D017641:Zeolites; D007854:Lead; D011189:Potassium Chloride; D015032:Zinc