Estimation on Fixed-Bed Column Parameters of Breakthrough Behaviors for Gold Recovery by Adsorption onto Modified/Functionalized Amberlite XAD7

Abstract

The objective of this paper was to evaluate the potential of a new adsorbent material to recover Au (III) from real wastewater, in a column with a fixed bed in a dynamic regime. The material was obtained through functionalization, by impregnation of the commercial resin, Amberlite XAD 7 type, with L-glutamic acid, which has active groups –NH2 and –COOH. The goal of the experiments was to follow the correlation of fixed-bed column specific adsorption parameters (the effluent volume, the amounts of adsorbent, heights of the adsorbent layer in column) with the time necessary to cross the column. The experimental data obtained were modeled, using the Bohart–Adams, Yoon–Nelson Thomas and Clark models, to establish the mechanism of the Au (III) recovery process, in a dynamic regime. Also, we established the number of cycles for adsorption–desorption for which the new material can be used. We used 5% HNO3 (5%) as desorption agent in five adsorption–desorption cycles, until the process was no longer efficient. The degree of desorption varied between 84% and 34% from cycle 1 to cycle 5.

Full Factorial Design for Gold Recovery from Industrial Solutions

“…The residual solutions resulting after the gold-plating procedure utilized in our research contained 2 g/L gold ions, 0.7-1 g/L Ni (II), 1 mg/L Cu (II), and 2 mg/L Fe (III), which were determined in these solutions before the experiments [44].…”

“…The experiments were carried out in triplicate, with standard deviations of the obtained values under 1%. In previous studies [44,50], the authors revealed more details of the experiments.…”

“…The L-Glutamic acid content of the impregnated resin, Amberlite XAD 7, was determined after washing with H 2 O (which completely eluted the extractant) followed by subsequent titration with 0.1 M NaOH [49]. The extractant content of the L-Glutamic acid impregnated XAD-7 material was 0.32 g L-Glutamic acid impregnated resin [44,50]. Notice that in this procedure adsorption is mainly a physical process.…”

“…In this context, the goal of this research was to optimize the gold extraction from industrial waste diluted solutions using a new adsorbent material, synthesized by us [44], which is a commercial Amberlite XAD-type resin functionalized by chemical modification with L-glutamic acid (Am-L-GA), using the dry solvent-impregnated resin (SIR) method. At the first stage, the material's morphology was analyzed by AFM to emphasize the roughness parameters, which are important for the adsorption capacity.…”

Purification of Wastewater from Biomass-Derived Syngas Scrubber Using Biochar and Activated Carbons

“…One of the main weaknesses of the Thomas model is that its derivation assumes that the adsorption process is limited by kinetics, while it is often controlled by interphase mass transfer. Nevertheless, Thomas is widely used to describe the adsorption process in packed bed columns [37][38][39][40][41]. Furthermore, experimental data were also modelled with the Modified Dose Response (MDR) model [42]:…”