title: Effects of operating conditions on the removal of heavy metals by zeolite in fixed bed reactors.
abstract: This work investigates the effects of flow rate (5-15 Bed Volumes/h), particle size (0.8-1.7 mm), concentration (0.005-0.02 N) and Na(+)-enrichment of natural clinoptilolite on the removal efficiency of Pb2+, Cu2+, Fe3+ and Cr3+ in aqueous solutions. Ion exchange is performed in an upflow fixed bed reactor. The removal efficiency is increased with decreasing flow rate, particle size and concentration and is improved by a factor of 2-10, depending on the specific metal. The modification of the natural sample is favorable, leading to an increase of removal efficiency by 32-100%. For the experimental conditions examined, removal efficiency order is the following: Pb2+ > Cr3+ > Fe3+ > or = Cu2+. Finally, the operation is influenced by the studied parameters, following the order: concentration > volumetric flow > rate > particle size > modification of the material.
authors.affiliation: Department of Chemical Engineering, Section II: Process Analysis and Plant Design, Laboratory of Chemical Process Engineering, Zografou Campus, GR-15780 Athens, Greece.
authors.forename: V J
authors.initials: VJ
authors.lastname: Inglezakis
authors.forename: Helen
authors.initials: H
authors.lastname: Grigoropoulou
mesh_terms: D007220:Industrial Waste / Q000517:prevention & control*; D019216:Metals, Heavy / Q000302:isolation & purification*; D009994:Osmolar Concentration; D010316:Particle Size; D012996:Solutions; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D014877:Water Pollution, Chemical / Q000517:prevention & control*; D017641:Zeolites / Q000737:chemistry*
chemical_list: D007220:Industrial Waste; D019216:Metals, Heavy; D012996:Solutions; D014874:Water Pollutants, Chemical; C083175:clinoptilolite; D017641:Zeolites