In this study, the fixed - bed adsorption of carbon dioxide and a carbon dioxide - nitrogen mixture on zeolite 13X was investigated. The adsorption equilibrium and breakthrough curves were determined at different temperatures - 301 - 306 K, 323 K, 373 K and 423 K. A model based on the LDF approximation for the mass transfer, considering the energy and momentum balances, was used to describe the adsorption kinetics of carbon dioxide and a carbon dioxide - nitrogen mixture. The model acceptably reproduced all of the breakthrough curves and can be considered as adequate for designing a PSA cycle to separate carbon dioxidenitrogen mixtures.

Iron-based nanostructures mediated by plant aqueous extract were synthesized. The nanostructures were subjected to ultraviolet radiation to degrade a difficult-to-degrade compound. Various characterization techniques were performed to analyze the morphology of the nanomaterial, including scanning electron microscopy (SEM) and transmission electron microscopy (TEM), as well as crystallinity by X-ray diffraction (XRD). The chemical composition was investigated by energy dispersive X-ray spectroscopy (EDX) and structural characteristics by Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, and thermogravimetric analysis (TGA). The results showed that the nanoparticles exhibited high photocatalytic efficiency, achieving 80% degradation of the pollutant. The study concludes that iron nanoparticles synthesized with plant aqueous extract are promising for the degradation of recalcitrant compounds, combining good efficiency with a cost-effective synthesis approach.

Pumpkin (Tetsukabuto) peel extract was utilized to synthesize nanoparticles of magnesium. The nanoparticles were characterized using scanning electron microscopy/energy dispersive X-ray spectrometry (SEM/EDS), X-ray diffraction (XRD), selected area electron diffraction (SAED), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), raman spectroscopy (RS) as well as Brunauer-Emmett-Teller (BET) analysis. The results showed that the synthesis of magnesium nanoparticles is possible by use of pumpkin peel extract. The characterization analyses indicated the presence of functional groups on the surface of the nanoparticles, which aided in the bioreduction of the metals to oxides. The nanoparticles can be applied in studies involving microbial agents due to their spherical shape, which allows for easy penetration into the cell wall of microorganisms. This work provides relevant information for the field of nanoparticles and the area of green synthesis.

This study investigates the performance of eco‐friendly geopolymers synthesized from phosphate mining waste for CO ₂ /N ₂ separation. Two distinct geopolymeric adsorbents were developed using a consistent formulation (35% metakaolin, 19% phosphate mining tailings, 11% NaOH, 11%, 13% Na ₂ SiO ₃ , 22% water, w/w) but employing different processing methods to yield granular particles (MPW) with a size of 0.112 ± 0.038 mm and spherical beads (MPWE) with a 3 mm diameter. The MPW exhibited a superior textural framework with a surface area of 298 m ² /g and a micropore volume of 0.1150 cm ³ /g, significantly outperforming the MPWE in adsorption capacity. Kinetic studies revealed that the MPW achieves a CO ₂ capacity of 2.50 mmol/g (21°C and 101 kPa), with significantly faster adsorption rates and substantially higher affinity compared to N ₂ . The Avrami model best described the CO ₂ kinetics, while N ₂ adsorption followed the intraparticle diffusion model. Breakthrough curves for single and binary mixtures (CO ₂ /N ₂ ) were successfully described by a dynamic model based on mass, energy, and momentum balances. Under the specific dry‐gas breakthrough conditions investigated here, MPW exhibited an apparent dynamic separation factor of ( = 91) at 21°C and 101 kPa. Cyclic adsorption/desorption experiments revealed a slight decrease in CO ₂ adsorption due to interactions between CO ₂ and the adsorbent, with CO ₂ desorption observed at low temperatures, although desorption is more effective at higher temperatures. These results highlight the potential of phosphate waste‐based geopolymers as sustainable, promising adsorbents for industrial carbon capture.