Platinum (IV) Recovery from Waste Solutions by Adsorption onto Dibenzo-30-crown-10 Ether Immobilized on Amberlite XAD7 Resin–Factorial Design Analysis

Abstract

Platinum is a precious metal with many applications, such as: catalytic converters, laboratory equipment, electrical contacts and electrodes, digital thermometers, dentistry, and jewellery. Due to its broad usage, it is essential to recover it from waste solutions resulted out of different technological processes in which it is used. Over the years, several recovery techniques were developed, adsorption being one of the simplest, effective and economical method used for platinum recovery. In the present paper a new adsorbent material (XAD7-DB30C10) for Pt (IV) recovery was used. Produced adsorbent material was characterized by X-ray dispersion (EDX), scanning electron microscopy (SEM) analysis, Fourier Transform Infrared Spectroscopy and Brunauer-Emmett-Teller (BET) surface area analysis. Adsorption isotherms, kinetic models, thermodynamic parameters and adsorption mechanism are presented in this paper. Experimental data were fitted using three non-linear adsorption isotherms: Langmuir, Freundlich and Sips, being better fitted by Sips adsorption isotherm. Obtained kinetic data were correlated well with the pseudo-second-order kinetic model, indicating that the chemical sorption was the rate-limiting step. Thermodynamic parameters (ΔG°, ΔH°, ΔS°) showed that the adsorption process was endothermic and spontaneous. After adsorption, metallic platinum was recovered from the exhausted adsorbent material by thermal treatment. Adsorption process optimisation by design of experiments was also performed, using as input obtained experimental data, and taking into account that initial platinum concentration and contact time have a significant effect on the adsorption capacity. From the optimisation process, it has been found that the maximum adsorption capacity is obtained at the maximum variation domains of the factors. By optimizing the process, a maximum adsorption capacity of 15.03 mg g−1 was achieved at a contact time of 190 min, initial concentration of 141.06 mg L−1 and the temperature of 45 °C.

Scandium Recovery from Aqueous Solution by Adsorption Processes in Low-Temperature-Activated Alumina Products

“…By graphing the linear dependence between ln k 2 and 1/T, the activation energy of the adsorbent was calculated using the slope of the line obtained. To explain the adsorption mechanism, the Gibbs free energy (ΔG°) value was calculated using the Gibbs–Helmholtz equation [ 78 ]: where ΔG° is the Gibbs free energy variation (kJ/mol); ΔH° is enthalpy standard variation (kJ/mol) ΔS° is entropy standard variation (J/mol·k); T is absolute temperature (K).…”

Synthesis, Characterization and Antimicrobial Activity of Multiple Morphologies of Gold/Platinum Doped Bismuth Oxide Nanostructures

“…In order to improve the antimicrobial activity of materials, all samples were doped with metal ions (at concentration of 50 mg/L) known for their antimicrobial properties, namely Au(III) and Pt(IV) [73]. Doping was carried out in such a way that the metal ion:material ratio (v/w) is 10:1, at pH < 3, according to previous studies by the authors [74,75]. The samples were left in contact for 24 h at room temperature, then dried in the oven (Pol-eko model SLW 53, SDT, Wodzisław Śl ąski, Poland) for 24 h at 323 K.…”

Synthetic Modifications of a Pb2+-Sensor Acridono-Crown Ether for Covalent Attachment and Their Effects on Selectivity

“…However, current sustainability requirements encourage chemists to regenerate these host molecules, even if they are easily obtainable. In practice, this requires the covalent immobilization of the host molecules on various solid carriers, such as a stationary phase [ 7 , 8 ], a nanoparticle [ 9 ], a resin [ 10 ], a polymer [ 11 ], etc. Also, the chemical incorporation of the host molecules into solid carriers prevents the contamination of the samples with ionophores during analysis.…”