Abstract
The main purpose of this paper was to obtain a material with efficient adsorbing properties and selectivity, to recover the gold (III) from residual diluted solutions resulted from the electroplating process. In this regard, a material was obtained by physico-chemical functionalization of a chemically inert support with functional groups of nitrogen and carboxyl. As a source of functional groups glutamic acid was used, and Amberlite XAD7 type acrylic resin was used as solid support. In order to establish the mechanism of the adsorption process, kinetic, thermodynamic and equilibrium studies were performed. The maximum adsorption capacity of the material has been established, and a gold (III) recovery process has been proposed using thermal decomposition of the exhausted adsorbed material. Main objective of this study was to evaluate an environmental friendly adsorbent material to recover gold from secondary industrial sources.
Highlights
It is known that historically, precious metals were and have remained important in the manufacture of coins, being known worldwide as currency forms, according to ISO 42172
To prove that the polymeric support was functionalized with extractant molecules, was evidenced the presence of nitrogen atoms from glutamic acid into the functionalized material by recording the X-ray dispersion (EDX) spectra for the new produced adsorbent material
It is observed that the studied material has a maximum experimental absorption capacity of 14.23 mg Au (III)/g and the theoretically established capacity after the experimental data were modelled using Sips isotherm, is 14.9, a value very close to the experimental one, being a confirmation that this model best describes the adsorption process of Au (III) on the studied material. These results reveal that the adhesion of Au (III) to Amberlite XAD7-glutamic acid is a heterogeneous process because the coefficient ns > 142
Summary
It is known that historically, precious metals were and have remained important in the manufacture of coins, being known worldwide as currency forms, according to ISO 42172. Gold was mainly recovered from ores through the cyanide process[14,15,16,17], a pollutants generating method with a significant negative impact on the environment; a worldwide controversial; other gold recovery agents are: ammonium thiosulphate[18], royal water[19], thiourea[20], tiosulfates[21], ammonia, iodine, natural organic acids, bromine, sodium sulphide[22], and so on. Processes employing these chemical reagents are separation and purification processes (such as cementations, reduction, adsorption, coagulation, solvent extraction, ion exchange, gravity separation, ionic flotation, and so on[6]). The obtained material has selective, relatively inexpensive, environmental friendly adsorbent properties and can be used with good results for recovering gold from dilute solutions which resulted as www.nature.com/scientificreports/
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
