For the synthesis of polymeric resins, it is of great importance to review the raw materials and the equipment to be used to avoid the presence of compounds that may affect the effectiveness of the polymerization and the characteristics of the plastic to be obtained. Iron oxide is a compound that can be present in reactors after maintenance due to the techniques used and the cleaning of this equipment, and it can affect the characteristics of the resins, reducing their quality. In this study, the presence of FeO in different concentrations was evaluated to determine its effects on the properties and pyrolysis of polypropylene resins by using X-ray refraction to determine the elements of the samples, evaluating thermal degradation by TGA, the variation in molecular weight by measuring the MFI, and the compounds obtained from pyrolysis by chromatography. The results showed that the thermal degradation decreased as the FeO concentration increased, while for the MFI, the relationship was directly proportional. The evaluation of the compounds obtained from pyrolysis showed an increase in the production of alcohols, alkynes, ketones, and acids, and a decrease in alkanes and alkenes, showing that FeO affects the properties of polypropylene and the compounds that are produced during pyrolysis.

During the production of polymer-grade propylene, different processes are used to purify this compound and ensure that it is of the highest quality. However, some impurities such as acetylene and methyl acetylene are difficult to remove, and some of these impurities may be present in the propylene used to obtain polypropylene, which may have repercussions on the process. This study evaluates the impact of these acetylene and methyl acetylene impurities on the productivity of the polypropylene synthesis process and on the mechanical and thermal properties of the material obtained through the synthesis of eight samples with different concentrations of acetylene and eight samples with different concentrations of acetylene. We discovered that for the first concentrations of both acetylene (2 and 3 ppm) and methyl acetylene (0.03 and 0.1), the MFI, thermal recording, and mechanical properties of the resin were unaffected by the variation of the fluidity index, thermal degradation by TGA, and mechanical properties such as resistance to tension, bending, and impact. However, when the concentration exceeded 14 ppm for methyl acetylene and 12 ppm for acetylene, the resistance of this resin began to decrease linearly. Regarding production, this was affected by the first traces of acetylene and methyl acetylene progressively decreasing.

Heavy metal contamination of water is a critical environmental problem due to its toxicity and persistence in ecosystems. In this study, magnetic hydrogel spheres composed of carboxymethylated starch modified with poly(1-vinylimidazole) (CMS-g-PVI) and polyvinyl alcohol (PVA), combined with Fe₃O₄ nanoparticles, were synthesized and characterized to evaluate their efficiency in adsorbing metal ions such as Cu²⁺, Pb²⁺, and Cd²⁺. Structural characterization by FT-IR spectroscopy confirmed the successful integration of all functional components into the hydrogel matrix. Additionally, scanning electron microscopy (SEM) revealed a rough and porous surface morphology favorable for adsorption and an average bead diameter of 3.2 mm, influenced by the stirring rate during synthesis. Adsorption studies demonstrated maximum capacities of 82.4 mg·g⁻¹ for Cu²⁺, 66.5 mg·g⁻¹ for Pb²⁺, and 51.8 mg·g⁻¹ for Cd²⁺, with optimal removal efficiencies at pH 6.2 and 5.7. From a theoretical perspective, density functional theory (DFT) calculations using the B3LYP/6-311+G(d,p) method allowed the optimization of molecular structures and analysis of electronic properties. The total dipole moment (TDM) of the CMS-g-PVI/PVA system reached 20.81 Debye. A significant reduction in the HOMO-LUMO energy gap was observed upon metal adsorption, with values of 0.0308 eV for Cu²⁺, 0.0175 eV for Pb²⁺, and 0.0235 eV for Cd²⁺, confirming strong interactions between the hydrogel matrix and the metal ions. The combined experimental and computational approach provides a comprehensive understanding of the adsorption mechanisms and supports the development of efficient materials for water decontamination.

The influence of zirconia incorporation and template type on the physicochemical properties of NiMo/Al₂O₃-ZrO₂ catalysts was investigated for the hydrodesulfurization (HDS) of 4,6-dimethyldibenzothiophene (4,6-DMDBT) and the hydrogenation (HYD) of naphthalene (N). Catalysts were prepared by co-impregnation on supports synthesized via a sol-gel method using starch (A) and activated carbon (C) as structure-directing templates, followed by zirconium incorporation through a grafting procedure. The resulting materials were characterized by SEM–EDX, N₂ physisorption, H₂-TPR, XPS, HRTEM, and pyridine-FTIR. SEM-EDX confirmed homogeneous metal distributions and compositions close to nominal values (Mo = 20 wt%, Ni = 5 wt%, Zr = 11 wt%) with Ni/(Ni + Mo) = 0.30. N₂ adsorption–desorption isotherms correspond to type IV(a) with H3-H4 hysteresis loops, characteristic of mesoporous structures. After metal incorporation, surface areas decreased to 96 m² g⁻¹ for NiMo/Al₂O₃ and 81 m² g⁻¹ for Zr-modified catalysts, while the activated carbon-templated sample preserved a larger mesoporous volume (0.335 cm³ g⁻¹) and higher macroporosity (72%). H₂-TPR profiles indicated improved reducibility for Zr-containing catalysts. XPS revealed an increase of MoS₂ species from 45% in NiMo/Al₂O₃ to 75% in NiMo/Al₂O₃-ZrO₂(C), accompanied by a higher degree of sulfidation index (DSI) from 47.1% to 73.9%. HRTEM analysis of Zr-modified catalysts revealed longer MoS₂ slabs (11.8–12.1 nm) and higher edge-to-corner ratios (17–17.4) compared with NiMo/Al₂O₃ (6.2 nm; fe/fc = 8.2). Pyridine-FTIR showed a substantial increase in total acidity from 91 to 421 μmol g⁻¹ upon Zr addition. Catalytically, NiMo/Al₂O₃-ZrO₂(C) exhibited the highest HDS conversion (40%), reaction rate (10.5 × 10⁻⁹ mol s⁻¹ g⁻¹), and TOF (4.69 × 10⁻⁵ s⁻¹), whereas NiMo/Al₂O₃-ZrO₂(A) reached the highest naphthalene conversion (97.18%), with a reaction rate of 27.4 × 10⁻⁷ mol s⁻¹ g⁻¹ and TOF of 12.9 × 10⁻³ s⁻¹. These results demonstrate that Zr incorporation and the activated carbon template favored hydrodesulfurization, whereas the starch template promoted hydrogenation performance.