Simultaneous Recovery of Precious and Heavy Metal Ions from Waste Electrical and Electronic Equipment (WEEE) Using Polymer Films Containing Cyphos IL 101

In this article, the application of a polymer film containing the ionic liquid Cyphos IL 101 for the simultaneous recovery of precious and heavy metal ions ((Ni(II), Zn(II), Co(II), Cu(II), Sn(II), Pb(II), Ag(I), Pd(II), and Au(III)) from waste electrical and electronic equipment (WEEE) is described. The experiments were performed for solutions containing metal ions released from computer e-waste due to leaching carried out with concentrated nitric(V) acid and aqua regia. It was found that the applied polymer film allows for the efficient recovery of precious metals (98.9% of gold, 79.3% of silver, and 63.6% of palladium). The recovery of non-ferrous metals (Co, Ni, Cu, Zn, Sn, and Pb) was less efficient (25–40%). Moreover, the results of the performed sorption/desorption processes show that the polymer film with Cyphos IL 101 can be successfully used after regeneration to recover metals ions several times.

Photodegradation of Phenolic Compounds from Water in the Presence of a Pd-Containing Exhausted Adsorbent

A closed-cycle technology regarding the use of an exhausted Pd-based adsorbent as a photocatalyst in the degradation process of phenol is presented. Pd (II) represents a precious metal of great economic importance. Its obtained from natural sources become more difficult to achieve. Therefore, also considering the regulations of the “circular economy,” its recovery from secondary sources turn out to be a stringent issue in the last years. Pd(II) ions are removed from aqueous solution through adsorption onto Florisil (an inorganic solid support—magnesium silicate) impregnated with Cyphos IL 101 (trihexyl tetradecyl phosphonium chloride). It was observed that the presence of the ionic liquid (IL) in the adsorbent structure doubles the adsorption efficiency of the studied materials. The newly obtained Pd-based photocatalyst was exhaustively characterized and was used in the degradation process of phenol from aqueous solutions. The phenol degradation process was studied in terms of the nature of the photocatalyst used, time of photodegradation and solid: liquid ratio. It was observed that both the presence of IL and Pd lead to an increase in the efficiency of the phenol degradation process. The new Pd-based photocatalyst could be efficiently used in more cycles of phenol photodegradation processes. When is used as a photocatalyst the Florisil impregnated with IL and loaded with 2 mg/g of Pd, a degree of mineralization of 93.75% is obtained after 180 min of irradiation of a phenol solution having a concentration of 20 mg/L and using a solid:liquid ratio = 1:1.

Non-aqueous solvent extraction of indium from an ethylene glycol feed solution by the ionic liquid Cyphos IL 101: speciation study and continuous counter-current process in mixer–settlers

Speciation studies give insight into the mechanism of non-aqueous solvent extraction of indium from ethylene glycol solution by the ionic liquid Cyphos IL 101.

Characterization of PVC-based polymer inclusion membranes with phosphonium ionic liquids

Membrane techniques can be used to separate different compounds, i.e., toxic metal ions from waste waters. As any other method of separation, also this one, based on polymer inclusion membranes (PIMs), has certain limitations. One of them is the stability of membranes. In the present paper, the dependence of the physical and chemical properties on composition of PVC-based polymer inclusion membranes doped with phosphonium ionic liquids (CYPHOS IL 101, CYPHOS IL 104, CYPHOS IL 105 and CYPHOS IL 109) was studied. The thermal stability of investigated membranes was examined by thermogravimetry together with differential thermogravimetry analysis. Obtained results showed that studied PIMs are stable to the temperature of about 170 °C. The membrane morphology was examined by attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy, as well as scanning electron microscopy (SEM). The visibility of all characteristic bands in the ATR-FTIR spectra confirmed the presence of individual components in the membranes: a polymer, a plasticizer and the carriers. It also suggested that there were no signs of the covalent bond formation between the polymer, the plasticizer and the carrier. Only van der Waals or hydrogen bonds could be present. Moreover, in the SEM images of the investigated PIMs a rough surface without pores was observed.

Thermal stability of trihexyl(tetradecyl)phosphonium chloride

The thermal stability of the ionic liquid Cyphos IL 101 was investigated under various experimental conditions for possible high-temperature applications.