Enhancing sustainability of household water filters by mixing metallic iron with porous materials

This study conceptually discusses the feasibility of enhancing the sustainability of conventional iron/sand filter (Fe0/sand filter) for safe drinking water by partially or totally substituting sand (quartz) by porous materials. Relevant materials included activated carbon, dolomites, limestone, pumice, sandstone, and zeolites. The rational was to use the internal volume of porous additives as storage room for in situ generated iron oxyhydroxides (iron corrosion products) and thus delay time to filter clogging. Based on previous works a filter with a volumetric Fe0:quartz ratio of 51:49 was used as reference system. The reference system is clogged upon Fe0 depletion. Results showed that totally substituting quartz by pumice particles having a porosity of 80% yields to a residual porosity of 41%. This encouraging result suggested that the possibility of using Fe0/MnO2/pumice systems for a synergic promotion of Fe0 reactivity (by MnO2) and filter permeability (by pumice) should be investigated in more details.