Multi-functional magnesium hydroxide coating for iron nanoparticles towards prolonged reactivity in Cr(VI) removal from aqueous solutions

In this study, the reactive performance of magnesium hydroxide-coated iron nanoparticles (Fe-0 @Mg(OH)(2)) was investigated for the removal of hexavalent chromium (Cr(VI)) from aqueous solutions. Short-and long-term progressive-release of Fe-0 @Mg(OH)(2) reactivity was evaluated through several batch tests. The Multifunctional effect of the environmentally-friendly Mg(OH)(2) coating shell was represented by the progressive shell-dissolution in water and preventing the rapid corrosion of Fe-0-core, which resulted in a controlled release of Fe0 reactivity towards Cr(VI). Fe-0 @Mg(OH)(2) showed good performance in preserving Fe-0 long-term reactivity within a wide range of pH (3.0 - 9.0) and temperature (15-55 ?). The long-term investigation of Fe-0 @Mg(OH)(2) performance towards Cr(VI) removal confirmed the progressive and maintained reactivity, represented by the continuous release of Fe(0 )electrons, to achieve 100% removal efficiency of 40 mg/L initial Cr(VI) concentration over 50 days reaction time, to be reported for the first time in the literature. Fe-0 @Mg(OH)(2) showed high regeneration abilities up to 5 cycles with 1.36 times average enhancement in Cr(VI) removal efficiency compared to that of Fe-0. Moreover, Fe-0 @Mg(OH)(2 )achieved an increase in the shelf-live longevity performance up to 30 days without any storing solution with 90% final Cr(VI) removal efficiency after 180 min reaction time.

Automated summary

In this study, the reactive performance of magnesium hydroxide-coated iron nanoparticles was investigated for the removal of hexavalent chromium from aqueous solutions. The results showed that the coated nanoparticles exhibited good reactivity and regeneration abilities, achieving high removal efficiency of hexavalent chromium under different pH and temperature conditions.