Precious metals recovery from aqueous solutions using a new adsorbent material

Abstract

Platinum group metals (PGMs) palladium, platinum, and ruthenium represent the key materials for automotive exhaust gas treatment. Since there are no adequate alternatives, the importance of these metals for the automotive industry is steadily rising. The high value of PGMs in spent catalysts justifies their recycling. Therefore, it is really important to recovery platinum group metals from aqueous solutions. Of the many PGMs recovery procedures, adsorption is a process with a good efficiency, but an important role is played by the adsorbent material used into the process. In order to improve the adsorption properties of materials were developed new methods for chemical modification of the solid supports, through functionalization with different extractants. In present paper a new adsorbent material (Chitosan-DB18C6) was used for PGMs recovery. The new adsorbent material was produced by impregnating Chitosan with dibenzo-18-crown-6-ether using Solvent Impregnated Resin (SIR) method. The crown ethers were chosen as extractant due to their known ability to bind metallic ions, whether they are symmetrically or unsymmetrically substituted. In order to determine the PGMs recovery efficiency for new prepared adsorbent material the equilibrium and kinetic studies were performed. Also, to study the PGMs adsorption mechanism the experimental data were modelled using pseudo-first-order and pseudo-second order kinetic models. Experimental data were fitted with three equilibrium isotherm models: Langmuir, Freundlich and Sips. The results proved that new adsorbent material (Chitosan-DB18C6) is an efficient adsorbent for PGMs recovery from aqueous solutions.

Kinetic and Thermodynamic Studies of Precious Metals Sorption on Impregnated Lewatit VP OC 1026 from Chloride Solutions

“…Similar results were found for Chitosan‐DB18 C6 sorbents. The PSO kinetic model fitted better sorption of Pt(IV), Pd(II) than PFO [30] …”

Systematic Assessment of Precious Metal Recovery to Improve Environmental and Resource Protection

“…Spectral characterization indicated that the cyano group before cross-linking was converted into an amide functional group, which can reduce and adsorb Au or gold chloride complexes well . The chitosan-DB18C6 (CH-DB18C6) material prepared by impregnation with dibenzo-18-crown ether can be used for the recovery of PGMs ions . Among them, CH-DB18C6 has the highest adsorption capacity for Ru­(III) ions, which can be described by a pseudo-second-order model.…”

“…68 The chitosan-DB18C6 (CH-DB18C6) material prepared by impregnation with dibenzo-18-crown ether can be used for the recovery of PGMs ions. 69 Among them, CH-DB18C6 has the highest adsorption capacity for Ru(III) ions, which can be described by a pseudo-second-order model. Emergence of MOF Materials.…”

An Overview of Modified Chitosan Adsorbents for the Removal of Precious Metals Species from Aqueous Media

“…Grad and coworkers developed dibenzo-18-crown-6-ether-modified chitosan sorbents to remove palladium and platinum species. These sorbents can adsorb more Pd(II) ions with increasing temperature [58]. On the other hand, the thermodynamic adsorption parameters are also dependent on temperature [59], where the uptake capacity increases with increasing temperature for such endothermic processes.…”