Abstract:
In this study, banana peel (BP) and its derivatives after sequential extraction of biochemical components
were evaluated for selective recovery of gold. In-depth instrumental characterizations including XPS,
FTIR, XRD and HR-TEM were performed to understand the adsorption mechanisms. The biomass after
lipid extraction, BP-L, demonstrated very good affinity and selectivity towards gold. In multi-metal systems
containing 100 mg/L of Pt(IV), Au(III), Pd(II), Zn(II), Co(II), Ni(II) and Li(I), the selectivity coefficient
increased from 978.45 in BP to 2034.70 in BP-L. Moreover, the equilibrium gold uptake was improved and
reached 475.48 ± 3.08 mg/g owing to reduction-coupled adsorption mechanisms. The BP-L also showed
improved gold nanoparticle formation properties that were pH-dependent. In a strategic adsorptioncombined
incineration process, metallic gold reaching 99.96% in purity was obtained. The BP and its
derivative, BP-L have thus shown potentials for multiple applications in the areas of precious metal
recovery and nanoscience.