RESUMO
In an actual economic context, the demand for scandium has grown due to its applications in top technologies. However, further development of new technologies will lead to an increase in the market for Sc related to such technologies. The present study aims to improve and upgrade existing technology in terms of efficient scandium recovery, proposing a new material with selective adsorptive properties for scandium recovery. To highlight the impregnation of Amberlite XAD7HP resin with tri-n-octylphosphine oxide extractant by the solvent-impregnated resin method, the obtained adsorbent material was characterized by physico-chemical techniques. Further, the specific surface of the adsorbent and the zero-point charge of the adsorbent surface have been determined. Different parameters, such as initial concentration, adsorbent amount, contact time, or temperature, have been studied. The initial pH effect was investigated when a maximum adsorption capacity of 31.84 mg g-1 was obtained at pH > 3, using 0.1 g of adsorbent and a contact time of 90 min and 298 K. An attempt was made to discuss and provide a clear representation of the studied adsorption process, proposing a specific mechanism for Sc(III) recovery from aqueous solutions through kinetic, thermodynamic, and equilibrium studies. Adsorption/desorption studies reveal that the prepared adsorbent material can be reused five times.
RESUMO
Given the ever-increasing demand for gallium(III) as a crucial precursor in the fabrication of advanced materials, there arises an imperative to devise efficient recovery processes from primary and secondary sources. In the present investigation, the retrieval of gallium(III) from aqueous solutions through the mechanism of adsorption was investigated. Materials with superior adsorbent properties play an important role in the dynamics of the adsorption process. To enhance these properties, select materials, such as Amberlite-type polymeric resins, are amenable to functionalization through impregnation with extractants featuring specialized active groups, designed for the selective recovery of metal ions-specifically, Ga(III). The impregnation method employed in this study is the Solvent-Impregnated Resin (SIR) method, utilizing the amino acid DL-valine as the extractant. The new material was characterized through Scanning Electron Microscopy (SEM), Elemental Analysis via X-ray energy-dispersive spectroscopy (EDX), and Fourier transform infrared spectroscopy (FTIR) to elucidate the presence of the extractant on the resin's surface. Concurrently, the material's pHPZC was determined. The adsorptive prowess of the synthesized material was investigated through kinetic, thermodynamic, and equilibrium studies. The influence of specific parameters in the adsorption process-namely, pH, contact time, temperature, and Ga(III) initial concentration-on the maximal adsorption capacity was determined. The optimal adsorption conditions were established using the Taguchi method.
RESUMO
The need to develop advanced wastewater treatment techniques and their use has become a priority, the main goal being the efficient removal of pollutants, especially those of organic origin. This study presents the photo-degradation of a pharmaceutical wastewater containing Kabi cytarabine, using ultraviolet (UV) radiation, and a synthesized catalyst, a composite based on bismuth and iron oxides (BFO). The size of the bandgap was determined by UV spectroscopy, having a value of 2.27 eV. The specific surface was determined using the BET method, having a value of 0.7 m2 g-1. The material studied for the photo-degradation of cytarabine presents a remarkable photo-degradation efficiency of 97.9% for an initial concentration 0f 10 mg/L cytarabine Kabi when 0.15 g of material was used, during 120 min of interaction with UV radiation at 3 cm from the irradiation source. The material withstands five photo-degradation cycles with good results. At the same time, through this study, it was possible to establish that pyrimidine derivatives could be able to combat infections caused by Escherichia coli and Candida parapsilosis.