Ranges and Fitting Ratios of Natural Aggregates for a Sustainable and Effective Fe°/Sand/Pozzolan Ternary Device Using Orange Methyl

Abstract

The remediation effectiveness of a Fe°/Sand/Pozzolan (Fe°/S/Pz) ternary device using an azo-dye for characterization is demonstrated herein. Optimal operating conditions, which specify the proportions of solid materials, such as iron (Fe°), sand (S), and pozzolan (Pz), in the reactive zone (RZ), are essential factors for the performance of such heterogeneous devices. Thus, the operative indicator orange methyl (OM) of 2 mg/L was used. Performance parameters such as pH, released iron of the collected water, flow rate, and fading power were measured using filter devices containing (1) 100% Fe°, (2) 25%/75% Fe°/S, (3) 25%/75% Fe°/Pz, (4) 25%/0%/75% Fe°/S/Pz, (5) 25%/25%/50% Fe°/S/Pz and (6) 25%/50%/25% Fe°/S/Pz for a correlation of proportions, reactivity, and performance. The experiments lasted thirty (30) days per device. It turns out that ranges of 25% ≤ % Fe° ≤ 60%, 25% ≤ %S ≤ 50%, and 25% ≤ %Pz ≤ 50% are quite enough. The ternary device, in ratios of 25%/50%/25% Fe°/S/P<SUB>Z</SUB>, is an excellent decontaminant of orange methyl OM, with regulation of pH and residual iron levels, for acceptable flows. There are therefore beneficial effects of the association of a non-expansive porous material with Fe°-based filters to delay clogging by collecting corrosion products (CPs). 25%/50%/25% Fe°/S/P<SUB>Z</SUB> device allow to reduce greatly the proportion of iron in the reactive zone (RZ) since pure iron devices are not recommended due to clogging. 25% ≤ % Fe° ≤ 60%, 25% ≤ %S ≤ 50%, and 25% ≤ %Pz ≤ 50% could provide a necessary framework for all Fe°-bed filters.