Yarazett Hernández Castillo

Coastal ecosystems of the tropical Atlantic and the Mexican Caribbean have experienced recurrent massive influxes of pelagic brown macroalgae, Sargassum natans and Sargassum fluitans, generating severe environmental, social, and economic impacts. While the accumulation of this biomass poses a significant waste management challenge, it also represents an underexploited renewable resource aligned with circular economy and sustainability principles. This study investigated the valorisation of Sargassum spp. through comprehensive physicochemical characterisation and multiple value-added applications. The biomass collected in Tulum, Quintana Roo, Mexico, was analysed to determine its chemical composition, including lignin, holocellulose, α-cellulose, ash, and moisture content, using standardised methods of the Technical Association of the Pulp and Paper Industry (TAPPI). For mechanical testing, methods from the American Society for Testing and Materials (ASTM) were used. The biomass was subjected to controlled pretreatment and thermochemical conversion processes. Evaluated valorisation pathways included: (1) taxonomic identification and physicochemical characterisation, (2) polymer composites, (3) reinforcement in construction materials such as unfired clay bricks, and (4) biochar and activated carbon production for contaminant adsorption. The results demonstrated that Sargassum spp. biomass can be transformed from an environmental nuisance into a multifunctional, high-value biomaterial, providing scalable solutions that mitigate waste disposal challenges and contribute to climate and resource sustainability.

La evaluación del cumplimiento de los Objetivos del Desarrollo Sostenible (ODS) está a cinco años de distancia, en un contexto en el que se está llegando al límite de 1.5ºC en el calentamiento global. Este artículo revisa las investigaciones realizadas en el marco de los ODS respecto a energías limpias y almacenamiento de electricidad usando materiales abundantes y de menor impacto ambiental e incluso materiales generados a partir de residuos recuperados; materiales para temas de salud como la atenuación de radiación electromagnética y finalmente, el monitoreo de la calidad del ambiente en una zona urbana altamente industrializada, más algunas estrategias de remediación basadas en materiales avanzados. Estos trabajos se llevan a cabo por una red de investigación basada en Altamira, México entre instituciones consolidadas y de reciente creación.

The mechanical properties of polypropylene-bentonite nanocomposites were studied in this work. In this study, stearic acid was used as both a new surface modifier of the nano bentonite and a new interface modifier during the compounding of the nanocomposites with a twin-screw extruder. Three different weight concentrations (1.5 wt.%, 2.5 wt.%, and 5.0 wt.%.) were chosen for each type of nanobentonite compounds. Fourier transform infrared spectroscopy allowed us the possibility to discard any chemical interaction between the nanobentonite and stearic acid. Nevertheless, the physical interactions between both components favored the mechanical properties, resulting in around 150% improvement in the elongation of the nanocomposites containing stearic acid as surface and interface modifier. This can be due to the good intercalation of the nanobentonite platelets as found by wide angle X-ray diffraction and this was further confirmed by scanning electron microscopy, where the fracture surface analyses of these nanocomposites showed the best dispersion and wetting of the nanoplatelets by the polymer matrix. Crystallization behavior was also modified by stearic acid incorporation and the nanocomposites with better dispersion exhibited crystallization temperatures similar to pure polypropylene.