Bench-scale injection of magnesium hydroxide encapsulated iron nanoparticles (nFe@Mg(OH)) into porous media for Cr(VI) removal from groundwater

Maamoun, I.; Falyouna, O.*; Eljamal, R.*; Idham, M. F.*; Tanaka, Kazuya  ; Eljamal, O.*

Chromium (VI) contamination in groundwater represents a significant threat to the current and future groundwater resources. Thus, in this work detailed investigation was conducted on the injection of magnesium hydroxide encapsulated iron nanoparticles (nFe@Mg(OH)) into a 3-D bench-scale groundwater treatment system for Cr(VI) removal. Cr(VI) and total iron concentration profiles were determined for the injection of both nFe and nFe@Mg(OH) into porous media. The results indicated the expected poor mobility of nFe, which caused the accumulation of the injected mass within the injection zone and the low spreading range along the length of the aquifer. The injection of nFe@Mg(OH) into the groundwater treatment system for 80 consecutive cycles resulted in a clear enhancement in preventing the rapid corrosion of the iron core and around twenty percent improvement in the final Cr(VI) removal efficiency compared with that of nFe. The injected nFe@Mg(OH) maintained the full Cr(VI) removal efficiency for 30 post-injection cycles. Such a promising potential of the nFe@Mg(OH), proposed it as one of the perfect candidates for in-situ water treatment applications, as a reactive nanomaterial with enhanced features, in terms of the prolonged reactive performance and the widespread of the injection zone to cover a larger contaminated area within the porous media.