Gold recycling at laboratory scale: from nanowaste to nanospheres

GARCÍA, CAROLINA S.; SOLER-ILLIA, GALO; OESTREICHER, VÍCTOR; ANGELOMÉ, PAULA C

CHEMSUSCHEM

WILEY-V C H VERLAG GMBH

Año: 2019 vol. 12 p. 4882 - 4888

1864-5631

The market for products based on nanotechnology increases day by day, and with itthe use of nanomaterials and the generation of waste that containnanowaste. Among thevast variety of nanomaterials available, gold nanoparticles (AuNPs) are within the moststudied and applied ones in commercial products. This current situation requires both,the development of recovery methods to reduce the amount of produced nanowaste andnew synthetic methods that allow the reuse of recovered gold for new nanomaterial pro-duction; in both cases keeping in mind economical and ecological reasons. In this work, amethodology to recover gold from aqueous laboratory nanowaste and to transform it intoan aqueous HAuCl4solution was developed, using extremely simple procedures and easilyavailable chemical reagents (NaCl, HCl, H2O2), allowing the recovery of more than 99%of the original gold. The experiments were performed using both simulated and real lab-oratory nanowastes obtaining practically the same results. Moreover, the subsequent useof the obtained aqueous HAuCl4 solution, from the recovered gold, to produce sphericalAuNPs through a seed-mediated approach was demonstrated. Thus, this work presents,for the first time to the best of our knowledge, a complete recycling cycle from nanowaste,to the reagent and back to the nanomaterial.