Extra-functionalized oxidized graphenes are widely preferred for the removal of different pollutants, however, removal with pristine oxidized graphenes, i.e., graphene oxide (GO) and reduced graphene oxide (rGO) is vaguely explored. Herein, we report a comparative adsorption kinetics study of the removal of mercury(II) (Hg(II)) from water using eco-friendly prepared GO and rGO. This work consists of the synthesis protocol and the corresponding morphological and spectroscopical characterization of the obtained pristine adsorbents as well as the adsorption mechanism in terms of initial concentration, removal percentage, pseudo-first and pseudo-second-order models, intraparticle diffusion study, and pH analysis. In particular, scanning electron microscope (SEM) and transmission electron microscope (TEM) images evidence the presence of thin sheets with some defects on the GO structure, these defects substantially disappear in rGO, after reduction. Raman spectrum of rGO shows a less intense D* peak which is attributed to the diamond-like carbon phase. Most importantly, the equilibrium adsorption time in GO is 10 min with a removal percentage of ~28% while in rGO it is 20 min with a removal percentage of ~75%. The adsorption process of Hg(II) either in GO or rGO is more in line with the pseudo-second-order model, suggesting that the adsorption kinetics could be controlled by chemisorption. Our results evidence the interesting adsorbing properties of pristine oxidized graphenes and are expected to be useful for the proposal and study of non-extra functionalized graphene-based materials for water treatment.

La sostenibilidad social, económica y ambiental del aprovechamiento del potencial de los residuos de camal (rumen) para el tratamiento de aguas residuales se centró en el análisis social en torno al área de desarrollo de las descargas de agua residual de la industria quesera San José y el líquido ruminal como residuo poco aprovechado proveniente del camal municipal de la ciudad de Riobamba. El estudio se realizó en dirección de dos ejes: el primero, correspondiente al estudio de los conflictos socio ambientales derivados de la disposición final de las aguas residuales de una quesera con análisis del costo- beneficio social, el segundo eje relacionado con las pruebas de crecimiento y adaptabilidad de bacterias lipolíticas del rumen de vaca para tratamiento de aceites y grasas en aguas residuales. El estudio de los conflictos socio ambientales se realizó a través de un diagnóstico línea base entorno de la quesera empleando las herramientas de análisis de conflictos desde diferentes perspectivas formando una plataforma para el diseño de estrategias de transformación. Se analizó la eficiencia de las bacterias lipolíticas del líquido ruminal de vaca aislándolas en agar tributirina. La concentración de aceites y grasas de las aguas residuales de la quesera disminuyó en un 52% cumpliendo con la normativa ambiental vigente para descargas de agua, resultado que determinó que el tratamiento empleado de bajo costo aprovechó la potencialidad de un residuo municipal generado en grandes volúmenes e impulsó las prácticas de producción limpia dentro de la microempresa.

The expansion of agricultural activities has led to growing concerns about the contamination of groundwater resources, especially the intensive use of fertilizers and pesticides. This study evaluates the impact of these practices on groundwater quality from a hydrogeochemical approach. Sampling was carried out in intensive agricultural areas and physical-chemical parameters such as nitrates, phosphates, electrical conductivity and pH were analyzed. The results show elevated concentrations of nitrates, above the limits established by the WHO, as well as alterations in the natural ionic balance of water. The hydrogeochemical analysis allowed the identification of the predominant pollution processes related to agricultural activity. It is concluded that there is a direct influence of intensive agriculture on the degradation of groundwater quality, with significant implications for public health and the sustainability of the resource.

In the present reserch, two methods for the extraction of starch from seeds of Amaranthus quitensis L. (Ataco) were analyzed in order to determine the procedure with the best performance and then to determine its main physical-chemical and functional characteristics. Initially, the inflorescences of the Ataco plants were collected, where their seeds are found, to later extract them, dry them to the environment and finally reduce them to fine dust. Then, simultaneous extractions of the starch contained in the flour were carried out by testing with two independent methods; the first wet method with bidistilled water and the second with an aqueous solution of sodium hydroxide (NaOH, 0.25 M); the starch extracted by both methods was washed and dried to the environment, to later calculate its yield, establishing that the highest yield is achieved with the method of extraction with NaOH solution. The results of the proximal analysis of the extracted products showed that there are significant differences (p≤ 0.05) in all properties analyzed since they vary depending on the method. Regarding the functional properties analyzed, it was found that as regards the Water Absorption Index (IAA) and the Water Solubility Index (ISA) there are significant differences between the values measured by each method. Regarding the temperature of gelatinization, there is no significant difference because this property does not depend on the extraction method of the starches but it varies depending on the plant.

This article reviews the didactic units in biology and environmental education in the context of Latin America, analyzing their design, implementation, and effectiveness in the teaching of environmental and biological topics. Through a literature review and case analysis, the most commonly used teaching strategies are identified and their impact on student learning is evaluated. It highlights best practices and proposes recommendations to improve the quality of biology and environmental education in the region.

Food security, environmental sustainability and technological innovation in agriculture have become fundamental axes to face the global challenges derived from climate change, urbanization and population growth. This article explores the intersection between food preservation technologies, advances in agricultural biotechnology, and sustainable approaches that seek to transform agrifood systems. Through a theoretical review and comparative analysis of recent studies, integrated practices that improve supply chain efficiency, reduce food waste, and promote ecological resilience are examined. The results show that the synergistic implementation of these strategies favours the transition towards more sustainable and resilient agri-food models.