AppliedChem, Volume 5, Issue 2 (June 2025) – 3 articles

In this study, copper ferrite nanoparticles, a type of ferrimagnetic spinel ferrite, were synthesized using the sol-gel auto-combustion method with three different fuels: citric acid, urea, and ethylene glycol. The crystal structures of the synthesized samples were analyzed using X-ray diffraction (XRD), and the growth of secondary phases like Fe₂O₃ and CuO for samples prepared with urea and ethylene glycol indicated the presence of impurities. Additionally, we observed that the particle size varied significantly with the type of fuel, being the smallest for citric acid and the largest for urea. The electrical and magnetic properties showed strong correlations with the particle size and the presence of impurities. In particular, the optical band gap values, derived from UV-Vis spectroscopy, varied significantly with the choice of fuel, ranging from 2.06 to 3.75 eV. The highest band gap of 3.75 eV was observed in samples synthesized with citric acid. Magnetic properties were measured using a vibrating sample magnetometer (VSM), and it was found that the copper ferrite synthesized with citric acid exhibited the highest values of magnetic saturation and coercivity. These findings demonstrate that the choice of fuel during the synthesis process has substantial impacts on the structural, optical, and magnetic properties of CuFe₂O₄ nanoparticles. Full article

This study investigated the effectiveness of a ligand known as (2-Mercapyo-phenylimino)-1,3-dihydro-indol-2-one-based ligand, in removing stable/radioactive cesium and cobalt from contaminated wastewater. Several parameters, such as contact duration, temperature, adsorbent quantity, pH of the medium, and concentration of adsorbate, have been investigated as primary active parameters impacting the adsorption process. Regarding the stable isotopes, the concentrations of Co²⁺ and Cs⁺ were measured before and after the treatment processes using the Optical Emissions Spectroscopy with Inductively Coupled Plasma (ICP-OES) technique. Additionally, kinetic and equilibrium isotherm models were applied to understand the equilibrium data. Both Cs⁺ and Co²⁺ were ideally eliminated after 120 and 60 min, respectively. The optimal pH for Cs⁺ was 6.3, while that for Co²⁺ was 5. The results indicate that the adsorption process is endothermic for Co²⁺ and exothermic for Cs⁺. Three thermodynamic parameters (∆G°, ∆H°, and ∆S°) were calculated. The reported R² values for the Freundlich and Langmuir models showed that the adsorption process for Cs⁺ and Co²⁺ always followed these isotherms, regardless of the temperature used. For Cs⁺, the maximum single-layer capacity (q_max) was 15.10 mg g⁻¹, while for Co²⁺, it was 62.11 mg g⁻¹. When the aqueous medium was spiked with both radioisotopes individually, the elimination of ⁶⁰Co and ¹³⁴Cs achieved maximum values of 99 and 86%, respectively, within 120 min. It can be concluded that the ligand effectively removed cobalt and cesium from wastewater, with higher adsorption for cobalt. Full article

Capsaicinoids obtained from lyophilized serrano chili by sorbitan monooleate solutions were investigated. Sorbitan monooleate was as effective as methanol in extracting capsaicin and dihydrocapsaicin (DHC). Subsequently, a Box–Behnken design was used to optimize capsaicin, DHC, and polyphenol extraction, as well as to evaluate the antioxidant capacity of dehydrated serrano chili. Particle size (PS) (20–60 mesh), processing temperature (55–75 °C), and sorbitan concentration (1.5–2.5%) were selected as independent variables. The statistical analysis showed that the quadratic models adequately describe the response of the concentration of capsaicin and DHC, but not with polyphenols and antioxidant capacity. The highest extraction of capsaicin (~620 mg/100 g dw) and DHC (~520 mg/100 g dw) was achieved with the combination of sorbitan at 2%, temperature at 65 °C, and PS from 40 mesh. Experimental and predicted values were closely consistent. Meanwhile, extracts with the highest antioxidant potential (~7510 and ~5820 µM of Trolox Eq/100 g dw for ABTS and FRAP, respectively) were those extracted in sorbitan and PS from 40 mesh. In contrast, the highest values of polyphenols (~171 mg gallic acid Eq/100 g dw) were found in the extracts prepared at 75 °C. These results suggest that sorbitan monooleate solutions can be an effective, non-toxic, and environmentally responsible way to obtain capsaicinoids and bioactive compounds from dehydrated serrano chili. Full article