In this paper, we consider amaranth starch extracted from the seeds of Amaranthus hypochondriacus L. An amphiphilic character is conferred to the starch by a chemical modification, which involves an esterification by lauroyl chloride at three modification levels. The degree of substitution (DS) after the modification ranged from 0.06 to 1.16. X-ray photoelectron spectroscopy analysis confirmed the presence of fatty acyl chains on the surface of the esterified starches. The hydrophobicity of starches was confirmed by their adsorption isotherms, which showed a decrease in the moisture adsorption of lauroylated as DS increased. X-ray diffraction analysis revealed a higher crystallinity, which was observed in the two samples subjected to the highest levels of modification. A higher crystallinity is related to a higher gelatinization enthalpy. These results are in agreement with the thermal characterization obtained by differential scanning calorimetry (DSC). An inhibition of the retrogradation properties of lauroylated amaranth starches was also observed.

The construction industry is a fundamental sector for the development of countries; however, it produces negative environmental impacts due to the demand for natural resources and the generation of construction and demolition waste (CDW). Therefore, the pursuit of solutions to recycle and reintegrate these wastes, which often accumulate in poorly regulated areas, becomes not only an environmental priority but also an opportunity to transform a problem into an advantage. Utilizing these residues contributes to reducing the pressure on natural resources, minimizes the environmental footprint of the construction sector, and promotes a more sustainable and responsible model that can serve as an example for future generations. The properties of recycled concrete aggregates (RCA) and recycled asphalt pavement (RAP) were determined in order to subsequently obtain the properties of different permeable recycled concrete (RPC) elaborated from a factorial design 2³ with these aggregates. The properties studied were workability, permeability, volumetric weight, compression uniaxial, and bending. Finally, they were studied and correlated with their matrix microstructure by means of TGA and SEM tests, which allowed determining the compounds contained in the various mixtures and their impact on physical–mechanical behavior. The results indicate that RCA and RAP are feasible alternatives for making porous pavements in pedestrian or light traffic areas when recycled aggregates of 3/4” size are included in their matrix, resulting in the optimum dosage of the M5 3/4” mix in this research, whose mechanical properties are: uniaxial compressive strength: 15.39 MPa; flexural strength: 3.12 MPa; permeability: 0.375 cm/s.

The need to conserve water is important, as it is predicted that in approximately 20 years there will be a global water shortage. In Mexico and the rest of the world, scientists are constantly looking for methods to help conserve and improve the processes used to treat the wastewater generated and reuse it safely. In this work, Tilapia fish scales modified with acetic acid were used for the removal of heavy metals from model water. For this experiment, the following adsorbent dose range was applied: 0.4 g to 1 g; the pH ranged from 4 to 7; and the contact time varied between 60 and 120 min. A three-factor experimental design was considered, including variables such as the adsorbent dose, contact time, and pH, each at three levels. The chemical modification produced a more porous surface on the flakes, facilitating metal adsorption, as confirmed by morphological and physicochemical analyses. The results obtained confirmed the removal of 94 and 83% of Cd(II) and Pb(II) metal ions, respectively, with an bioadsorbent dose of 1 g at a pH of 4 and a contact time of 120 min for Cd(II) and an adsorbent dose of 0.4 g, a pH of 4, and a contact time of 90 min for Pb(II), with an initial concentration of 200 mg/L for both metals. The Brunauer–Emmett–Teller (BET) analysis results provide critical insights into the textural properties of modified fish scales. The modified fish scales have great potential for removing heavy metals from industrial wastewater.

La escasez de agua impulsa la búsqueda de soluciones para asegurar su acceso, siendo la captación de agua pluvial una opción clave. Los sistemas de captación de agua de lluvia ayudan a conservar recursos hídricos al disminuir la explotación de acuíferos, pero requieren políticas públicas para su implementación. En la Ciudad de México, las iniciativas para fomentar su uso enfrentan limitaciones en edificios verticales. En este trabajo, se diseñó un captador de agua de lluvia una vivienda en un edificio vertical. Se analizaron muestras de agua pluvial en diferentes épocas del año para evaluar su calidad; durante lluvias intensas en primavera, los parámetros exceden los límites de la NOM-127- SSA1-2021: pH de 9 (por encima del rango de 6.5- 8.5), DQO de 60 mg/L, turbiedad de 55,3 NTU (límite de 4 NTU), y dureza de 100 ppm. Aunque los sólidos disueltos estaban dentro del rango permitido, el agua no era apta para consumo humano lo cual, fue considerado en el diseño del sistema de captación con un filtro de tres fases, accesible y fácil de usar, para alcanzar los estándares establecidos en la norma.