Effect of Pumice and Sand on the Sustainability of Granular Iron Beds for the Aqueous Removal of Cu super(II), Ni super(II), and Zn super(II)

• Published in: Clean : soil, air, water Vol. 41; no. 9; pp. 835 - 843
• Main Authors: Bilardi, Stefania, Calabro, Paolo S, Care, Sabine, Moraci, Nicola, Noubactep, Chicgoua
• Format: Journal Article
• Language: English
• Published: 01-09-2013
• ISSN: 1863-0650; 1863-0669
• DOI: 10.1002/clen.201100472

Current knowledge of the basic principles underlying the design of Fe super(0) beds is weak. The volumetric expansive nature of iron corrosion was identified as the major factor determining the sustainability of Fe super(0) beds. This work attempts to systematically verify developed concepts. Pumice and sand were admixed to 200g of Fe super(0) in column studies (50:50 volumetric proportion). Reference systems containing 100% of each material have been also investigated. The mean grain size of the used materials (in mm) were 0.28 (sand), 0.30 (pumice), and 0.50 (Fe super(0)). The five studied systems were characterized (i) by the time dependent evolution of their hydraulic conductivity (permeability) and (ii) for their efficiency for aqueous removal of Cu super(II), Ni super(II), and Zn super(II) (about 0.3mM of each). Results showed unequivocally that (i) quantitative contaminant removal was coupled to the presence of Fe super(0), (ii) additive admixture lengthened the service life of Fe super(0) beds, and (iii) pumice was the best admixing agent for sustaining permeability while the Fe super(0)/sand column was the most efficient for contaminant removal. The evolution of the permeability was well-fitted by the approach that the inflowing solution contained dissolved O sub(2). The achieved results are regarded as starting point for a systematic research to optimize/support Fe super(0) filter design. The present work is an attempt to improve the design of Fe super(0) filtration systems based on recent theoretical studies. The efficiency of five different systems for aqueous contaminant removal is tested in column studies. The volumetric expansive nature of iron corrosion as the most important clogging factor in water treatment could be shown.