This study shows the energy optimization and stabilization in the time of solutions composed of H₂O + TX-100 + Multi-Wall Carbon Nanotubes (MWCNTs), used to improve the mechanical properties of Portland cement pastes. For developing this research, sonication energies at 90, 190, 290, 340, 390, 440, 490 and 590 J/g are applied to a colloidal substance (MWCNTs/TX-100 + H₂O) with a molarity of 10 mM. Raman spectroscopy analyses showed that, for energies greater than 440 J/g, there are ruptures and fragmentation of the MWCNTs; meanwhile at energies below 390 J/g, better dispersions are obtained. The stability of the dispersion over time was evaluated over 13 weeks using UV-vis spectroscopy and Zeta Potential. With the most relevant data collected, sonication energies of 190, 390 and 490 J/g, at 10 mM were selected at the first and the fourth week of storage to obtain Portland cement specimens. Finally, we found an improvement of the mechanical properties of the samples built with Portland cement and solutions stored for one and four weeks; it can be concluded that the MWCNTs improved the hydration period.

In this article, the study of the influence of the calcination temperature on the crystallographic, compositional, and morphological properties of the natural hydroxyapatite taken from sheep bones was carried out. The obtained samples were characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy, with elemental analysis (SEM-EDS) in order to obtain structural information, compositional and morphological properties. In the thermogravimetric curves, the decomposition temperatures of the organic phases present in the sheep bones powder were identified. In the X-ray diffraction analyzes, it was found that the diffraction patterns presented characteristic peaks of hydroxyapatite and, it was observed that the increase in temperature favors the growth crystallite size. Likewise, in the morphological analysis, changes in the samples were verified, finding greater agglomeration of the particles, while the EDS analyzes revealed the different Ca/P relationships for the calcination temperatures used. In the FTIR spectra, the characteristic vibrational bands of the phosphate and hydroxyl functional groups present in the samples were observed. Moreover, due to the temperature changes, the vibrational bands corresponding to water and proteins disappeared, and a decrease in the carbonate bands was also identified.

La contaminación del agua por metales pesados y otros iones metálicos es un problema ambiental global que requiere soluciones efectivas. En este artículo de revisión bibliográfica se analiza el uso de compuestos de carbón activado e hidroxiapatita para la remoción de iones metálicos en aguas contaminadas. Se examinan aspectos clave como los métodos de síntesis de estos compuestos, su capacidad de adsorción y los mecanismos de remoción de iones metálicos. Además, se discuten las ventajas y limitaciones de estos compuestos, así como su potencial para su aplicación a gran escala en la purificación del agua. Se concluye que los compuestos de carbón activado e hidroxiapatita son prometedores para la eliminación de iones metálicos y se sugieren áreas de investigación futura para optimizar su eficiencia y aplicabilidad. Este artículo proporciona una visión general actualizada del tema y es relevante tanto para investigadores como para profesionales involucrados en la gestión del agua y la protección del medio ambiente.