Dye residues from the textile industry constitute a critical wastewater problem. This study aimed to evaluate the removal capacity of methylene blue (MB) in aqueous media, using an adsorbent formulated from activated and sonicated nanoclay (NC) and microatomized Nostoc sphaericum (ANS). NC was obtained by acid treatment, followed by activation with 1 M NaCl and sonication, while ANS was obtained by microatomization in an aqueous medium. NC/ANS was mixed in a 4:1 weight ratio. The NC/ANS synergistic adsorbent was characterized by the point of zero charge (PZC), zeta potential (ζ), particle size, FTIR spectroscopy, and scanning electron microscopy (SEM). NC/ANS exhibited good colloidal stability, as determined by pH_PZC, particle size in the nanometer range, and heterogeneous morphology with functional groups (hydroxyl, carboxyl, and amide), removing between 72.59 and 97.98% from an initial concentration of 10 ppm of MB, for doses of 20 to 30 mg/L of NC/ANS and pH of 5 to 8. Optimal adsorption conditions are achieved at pH 6.8 and 32.9 mg/L of adsorbent NC/ANS. It was observed that the pseudo-first-order (PFO) and pseudo-second-order (PSO) kinetic models best described the adsorption kinetics, indicating a predominance of the physisorption process, with adsorption capacity around 20 mg/g. Isotherm models and thermodynamic parameters of adsorption, ΔS, ΔH, and ΔG, revealed that the adsorption process is spontaneous, favorable, thermodynamically stable, and occurs at the monolayer level, with a regeneration capacity of 90.35 to 37.54% at the fifth cycle. The application of physical activation methods, such as sonication of the clay and microatomization of the algae, allows proposing a novel and alternative synergistic material from organic and inorganic sources that is environmentally friendly and promotes sustainability, with a high capacity to remove cationic dyes in wastewater.

Growing concern about the environmental impact of traditional packaging has driven the development of biodegradable edible films made from natural and functional biopolymers. Various by-products generated during harvesting can be subjected to valorization. Potato, a tuber with high starch content, and carrot, rich in β-carotene, represent important sources of polymeric matrix and bioactive compounds, respectively. Similarly, the use of biodegradable plasticizers such as pectin and polysaccharides derived from nopal mucilage is a viable alternative. This study assessed the physical and chemical properties of edible films composed of potato starch (PS), cactus mucilage (NM), carrot extract (CJ), citrus pectin (P), and glycerin (G). The films were produced by means of casting, with three mixtures prepared that had different proportions of CJ, P, and PS. The experiments were adjusted to a simple mixture design, and the data were analyzed in triplicate, using Pareto and Tukey diagrams at 5% significance. Results showed that adding CJ (between 5 to 6%), P (between 42 to 44%) and PS (between 43 to 45%) significantly affects all of the evaluated physical and chemical properties, resulting in films with luminosity values greater than 88.65, opacity ranging from 0.20 to 0.54 abs/mm, β-carotene content up to 26.11 μg/100 g, acidity between 0.22 and 0.31% and high solubility with a significant difference between treatments (p-value < 0.05) and low water activity (around of 0.47) (p-value > 0.05). These characteristics provide tensile strength up to 5.7 MPa and a suitable permeability of 1.6 × 10⁻² g·mm/h·m²·Pa (p-value < 0.05), which ensures low diffusivity through the film. Similarly, increasing the CJ addition enables the functional groups of the other components to interact. Using carrot extract and potato starch is a promising approach for producing edible films with good functional qualities but with high permeability.

The buildup of non-biodegradable plastic waste and poor management of agro-industrial by-products have caused a major environmental crisis. The present research addresses the development of novel materials supporting the circular bioeconomy. This study aimed to develop and characterize bio-composite films derived from native Oxalis tuberosa starch and keratin microparticles (KMPs) extracted from cattle horn waste. The experimental methodology employed a 2³ factorial design and involved the characterization of the films included the evaluation of physical and optical properties and the identification of functional groups via spectroscopy, mechanical tests, and thermogravimetric analysis (TGA). The results revealed significant interactions (p ≤ 0.05). Higher processing temperatures were the main reason for the drop in water activity (a_w) and moisture content (MC) levels. Concurrently, the incorporation of KMPs reduced water solubility, increased opacity, and enhanced thermal stability. FTIR analysis confirmed the existence of intermolecular interactions between the hydroxyl and amide functional groups. In conclusion, bio-composites composed based on Oxalis tuberosa starch and keratin microparticles represent a sustainable alternative to mitigate the use of conventional plastics in the industry.

Objective: The objective of this study was to evaluate the removal of Pb and As in aqueous media by activated clay (AC). Theoretical Framework: Heavy metals in water represent a risk to health and ecosystems, their removal through new materials is a challenge for the industry. Method: The methodology adopted for this research comprises in that natural clay (NC) was activated with sodium chloride and phosphoric acid followed by sonication. A synthetic solution of Pb and As was prepared at different pH. Results and Discussion: The zero charge point was found to be 7.10 for AC and 8.02 for NC, the ζ potential was found to be between - 41.15 and - 45.43 mV in the pH range of 4 to 12, with degree of crystallinity of 97.24% and crystal size of 2.85 nm determined by XRD. FTIR analysis allowed the identification of functional groups with chelating capacity. Was observed As removal of 75.51% (110.40 mg/g) and 23.23% (58.13 mg/g) and 97.75% (106.41 mg/g) and 100.0% (206.53 mg/g) for Pb with AC and NC respectively at pH 6 and 8. Research Implications: Los reaultadoe encontrados sugieren que la arcilla activada se convierte en un material alta capacidad de adsorción de metales pesados en sistemas multimetal. Esta cualidad se debe al incremtno de grupos funionales en su superficie y al tamaño nanométrico que incrementa el área de contacto. Originality/Value: Activation of the clay with sodium chloride and weak acid followed by sonication is an environmentally friendly process that produces a material with high heavy metal removal capacity in aqueous media.