RESUMEN
Biofuels offer significant potential for reducing carbon emissions and enhancing energy sustainability, but their efficient purification remains a significant challenge. In this study, the performance of a hydrophobic zeolitic imidazolate framework, ZIF-71(ClBr)-SE, in the adsorptive separation of butanol from single- and ternary-component systems (acetone, butanol, and ethanol) was investigated and compared with ZIF-8 and ZIF-71. Physicochemical characterization techniques, including XRD, SEM, BET, TGA, and DVS, confirmed that the modified ZIF-71 is hydrophobic, isostructural with ZIF-71, and has a higher surface area. Adsorption tests in aqueous solutions revealed that ZIF-71(ClBr)-SE unexpectedly showed a higher affinity for acetone over butanol. DFT molecular simulations provided insights into solute-ZIF interactions, highlighting preferential sites for ZIF interaction.
RESUMEN
trans-Cinnamic acid was synthesized under microwave irradiation, and it was used for the removal of copper, a toxic metal found in industrial wastewater, from synthetic polluted aqueous solutions. Copper removal is more favorable at pH 5 and was enhanced by increasing the copper initial concentration, reaching a maximum uptake capacity of 389.5 mg/g, which is higher than those reported in the literature. Temperature exhibited a negligible effect on the removal of copper by trans-cinnamic acid. The isotherm equilibrium uptake data were found to be described by the Langmuir model. In addition, the study of the removal kinetics shows that the uptake of copper by trans-cinnamic acid follows pseudo-first order kinetics, and equilibrium is attained at approximately 30 min. Based on the X-ray photoelectron spectroscopy, X-ray diffraction, scanning transmission electron microscopy, and Fourier-transform infrared spectroscopy studies, a copper-cinnamic acid complex [Cu(CA)2] is formed during the removal process. The reusability of this coordination compound was investigated using HCl, HNO3, and NaOH 0.1 M as desorption eluents; HCl was capable of completely desorbing copper from [Cu(CA)2], and trans-cinnamic acid was recovered as the trans-isomer. Alternatively, the [Cu(CA)2] was used to remove octamethylcyclotetrasiloxane from gaseous streams for biogas purification, obtaining an adsorption capacity of 3.37 mg/g. These promising results demonstrate the feasibility of copper removal by trans-cinnamic acid because of its high uptake capacity and potential reusability.
RESUMEN
In this study, amberlite XAD-16 (XAD-16) bed column system was used to remove ferulic acid (FA) from aqueous solutions. Laboratory-scale column experiments were conducted in downflow fixed bed at initial FA concentration of 1â g/L, initial pH 3, and 25°C. The performance of the adsorbent bed under different flow rates (1.3-7.7â mL/min) was studied. The bed utilization efficiency was in the range of 64.64-72.21% at the studied flow rates. A mass transfer model considering both axial dispersion and intraparticle diffusion was developed to predict the breakthrough curves of FA adsorption on XAD-16. This model predicted the experimental data better than Bohart-Adams model and Thomas model, based on the low deviation between predicted and experimental data. The axial dispersion coefficient value varied from 6.45 × 10(-6) to 1.10 × 10(-6)â m(2)/s at flow rate from 1.3 to 7.7â mL/min, whereas the intraparticle diffusion coefficient was 1.04 × 10(-10)â m(2)/s, being this last resistance the rate-limiting step. In conclusion, axial dispersion and intraparticle diffusion phenomena play the major role in predicting the adsorption of FA onto XAD-16 in fixed-bed columns.