Optimising the Design of Fe⁰-Based Filtration Systems for Water Treatment: The Suitability of Porous Iron Composites
Pages 165-177
Mohammad Azizur Rahman, ShyamalKarmakar, Heba Salama, Nadège Gactha-Bandjun, Brice DonaldBtatkeu K. and ChicgouaNoubactep

DOI: http://dx.doi.org/10.6000/1929-5030.2013.02.03.2

Published: 31 August 2013

Abstract: This study assessed the functionality of metallic iron (Fe⁰) filtration systems using porous iron composite (PIC) as an alternative to granular Fe⁰/aggregate mixtures. The usage of PIC for water treatment has many challenges which are related to the well-drained nature of highly porous filters and the corresponding increase in hydraulic conductivity (shorter contact time). In this article, the extent of (i) iron exhaustion and (ii) porosity loss in four filtration systems are critically discussed. The considered filtration systems are: (i) Fe⁰ alone, (ii) PIC alone, (iii) Fe⁰/sand and (iv) Fe⁰/pumice. In all four systems, mono-sized granular spherical particles are assumed. Sand and Fe⁰ are compact (f = 0 %) whereas PIC and pumice are porous (e.g. f = 40 %). Results demonstrated that under anoxic conditions (Fe₃O₄ as major corrosion products) Fe⁰ depletion is possible in all systems except Fe⁰ alone. Under oxic conditions (e.g. formation of Fe(OH)₃), the PIC system exhibited the highest level of Fe⁰ depletion (58 %). The increasing order of sustainability was: Fe⁰ < Fe⁰/sand < Fe⁰/PM < PIC. These results suggested that manufacturing PIC with defined porosity and intrinsic reactivity is the key for more efficient usage of Fe⁰ for environmental remediation and water treatment.