Synthesis of Stable Al(0) Nanoparticles in Water in the form of Al(0)@Cu and Sequestration of Cu²⁺(aq) with Simultaneous H₂ Production

Abstract

Copper contamination is a serious ecological and human health hazard. Therefore, a multifunctional/synergistic process, which sequesters Cu2+ while also providing additional functionalities (say a high-value nanoparticle and an energy source as byproducts) would be relevant. On the other hand, although several sophisticated methods have been utilized for the synthesis of Al nanoparticles (NPs); simple chemical synthesis of Al NPs, particularly in water, has not been explored due to its instability in the aqueous medium. In this work, a coreduction based sequestration of Cu2+ (aq) is demonstrated where Al3+(aq) and Cu2+(aq) are coreduced in copper-contaminated water. The outcome of the process is the formation of stable Al(0) nanoparticles and simultaneous sequestration of Cu2+(aq); this occurs along with production of hydrogen gas as a byproduct. Nanoparticle stability is likely due to the Cu coating on Al nanoparticles, resulting in the formation of Al(0)@Cu NPs. Hydrogen is produced as a byproduct at a rate of 550 mL/min per 0.5 g of both Al3+ and Cu2+ salts, leading to three benefits (stable Al(0)@Cu NPs formation, Cu2+ sequestration, and hydrogen production) from a single approach.