Synthesis of Gold Nanoparticles from Gold Coatings Recovered from E-Waste Processors

Abstract

This work presents the synthesis of Au nanoparticles from gold coatings recovered from processor pins with minimal waste generation. The process consisted of four main steps: (1) physical recovery of pins, (2) recovery of gold coatings by acid digestion, (3) synthesis of HAuCl4 under mild conditions and, (4) synthesis of Au nanoparticles by the Turkevich method. The small dimensions of Au coatings allowed the synthesis of HAuCl4 with lower amounts of HClconc and HNO3conc than those used with aqua regia. This method has significant advantages, such as lower NO2(g) emission, easy post-treatment and purification, low synthesis cost and high yields. Gold nanoparticles synthesized from HAuCl4 were characterized by transmission electron microscopy (TEM) and UV-Vis spectroscopy. Size distribution analysis showed particles 14.23 nm in length and 12.05 nm in width, while absorption spectra showed a surface plasmon located at 523 nm; these characteristics were very similar to those observed with Au nanoparticles obtained with Aldrich’s reagent. It is suggested that recycling procedures can be improved by taking into account the size and shape of the metals to be recovered, thus introducing a new field of research known as hydronanometallurgy.

Methanol Oxidation Reaction in Alkaline Media Using Gold Nanoparticles Recovered from Electronic Waste

“…The synthesis of Au e-w /C NPs comprised four distinct stages. Initially, gold coatings from Intel Pentium 4 processor pins were recovered using the methodology proposed by Su et al [ 31 ], involving an acid digestion to selectively dissolve accompanying metals (Cu, Fe, Ni) present in the pins. Subsequently, HAuCl 4 was synthesized from the recovered gold coatings.…”

An N-Rich Polymer for the Selective Recovery of Gold from Wastewater

“…where Q e (mg/g) is the theoretical adsorption capacity; C 0 (mg/L), C e (mg/L), and C t (mg/L) are the initial, equilibrium, and moment t concentrations of the metal ions, respectively; W (g) is the mass of the adsorbent used; and V (mL) is the volume of the solution. Adsorption experiments were conducted in a water bath thermostatic oscillator at 298 K. The experiment examined the effect of pH by placing 10 mg of adsorbent into 20 mL of 100 mg/L Au(III) solution with varying pH levels (1)(2)(3)(4)(5)(6)(7)(8)(9). Similarly, 10 mg of adsorbent was added to 20 mL of a 100 mg/L Au(III) solution at the same pH.…”

“…Additionally, the accelerated iteration of current electronic products has generated a large amount of electronic waste, which contains a significant amount of gold elements. This phenomenon can cause pollution and environmental damage [6]. Therefore, the recovery and treatment of secondary gold resources are of great significance.…”