Extraction of lanthanides by polysulfone microcapsules containing EHPNA. II. Coaxial microfluidic method

The Evaluation of Cellulose Acetate Capsules Functionalized for the Removal of Cd(II)

Cellulose acetate is derived from cellulose and has the characteristics of biodegradability and reusability. So, it has been used for the elimination of toxic compounds capable of producing different diseases, such as cadmium, that result from human and industrial activity. For this reason, capsules functionalized with Cyanex 923 were prepared and characterized by FTIR spectroscopy, Energy Dispersive X-ray Spectroscopy (EDX), and SEM. The functionalized capsules were used for removing and recovering Cd(II) by modifying variables such as HCl concentration in the extraction medium and carrier content in the capsules, among others. The extraction of cadmium from battery leachates and the three isotherm models, Langmuir, Freundlich, and Dubinin Radushkevich, were also tested to model the cadmium removal process. The results showed a favorable physical sorption with a good capacity for extraction and the possibility of reusing the capsules for up to seven cycles without a decrease in the percentage of cadmium recovery.

Functionalized Magnetic Silica Nanoparticles for Highly Efficient Adsorption of Sm3+ from a Dilute Aqueous Solution

Separation of Sm³⁺ from a dilute solution via conventional solvent extraction is often plagued by emulsion and third phase formation. These problems can be overcome with functionalized magnetic nanoparticles that can capture the target species and be separated from the raffinae phase rapidly and efficiently on application of a magnetic field. Magentic silica nanoparticles (Fe₂O₃/SiO₂) were synthesized by a modified Stöber method and functionalized with carboxylate (Fe₂O₃/SiO₂/RCOONa) and phosphonate (Fe₂O₃/SiO₂/R₁R₂PO₃Na) groups to achieve high adsorption capacity and fast adsorption kinetics. The adsorbents were characterized by X-ray diffraction analysis, transmission electron microscopy, BET measurements, magnetization property evaluation, Fourier infrared spectroscopy, and thermogravimetric analysis. Equilibrium adsorption of Sm³⁺ on Fe₂O₃/SiO₂/RCOONa particles was attained within 10 min and within 20 min on Fe₂O₃/SiO₂/R₁R₂PO₃Na nanoparticles. The kinetic data were correlated well with a pseudo-second-order model. Adsorption capacities of Fe₂O₃/SiO₂/RCOONa and Fe₂O₃/SiO₂/R₁R₂PO₃Na were 228 and 180 mg/g, respectively. The recovery of the adsorbed Sm³⁺ using 2 mol/L HCl as desorption agent was evaluated. The adsorption mechanism is discussed based on FTIR analysis, carboxylate group/Sm³⁺ molar ratio, phosphonate group/Sm³⁺ molar ratio, and pH. The adsorbents show significant potential for Sm³⁺ recovery in industrial applications.