Water contamination is a worldwide concerning problem. Emerging contaminants have made conventional water treatment processes ineffective. This makes the search for new materials with improved physical-chemical properties for water treatment an urgent necessity. Doping metal oxides nanostructures can improve the photocatalytic degradation of contaminants and the antimicrobial activity of the material. During this process, water treatment not only involves the degradation of toxic pollutants, but also the elimination of virus and bacteria. Then, it is important to study not only the effect of a dopant in a material as photocatalyst but also the effect in its antimicrobial properties. In this work ZnO nanorods, Ga doped ZnO nanorods and Ag doped ZnO nanorods are synthesized and supported in polyethylene by a fast-hydrothermal microwave heating synthesis. Their photocatalytic performance and antimicrobial properties for water treatment were evaluated. Experiments show that Ag and Ga can improve the photocatalytic and antimicrobial properties of ZnO nanorods; the relationship between doping concentrations, with both the toxicity effect of the nanorods toward bacteria and the nanorods photocatalytic performance, is shown.

Low concentrations of hazardous gases are difficult to detect with common gas sensors. Using semiconductor nanostructures as a sensor element is an alternative. Single ZnO nanowire gas sensor devices were fabricated by manipulation and connection of a single nanowire into a four-electrode aluminum probe in situ in a dual-beam scanning electron microscope-focused ion beam with a manipulator and a gas injection system in/column. The electrical response of the manufactured devices shows response times up to 29 s for a 121 ppm of H₂ pulse, with a variation in the nanowire resistance appreciable at room temperature and at 373.15 K of approximately 8% and 14% respectively, showing that ZnO nanowires are good candidates to detect low concentrations of H₂.

In this study, we synthesized and characterized pH-responsive Chitosan–AgCl-doped ZnO hybrid hydrogels and evaluated their potential for loading aquaculture bioactive compounds, and assessed their antimicrobial properties against a threatening pathogen associated with disease across a broad spectrum of warm water fish and invertebrates. Hydrogel characterization consisted of assessing morphology via SEM, composition via EDS, hydrogels’ network components interactions via FT-IR and pH response through swelling behavior determinations. The swelling characterization of the synthesized hydrogels demonstrated a pH-responsive behavior, showing that low pH values caused the hydrogel polymeric network to expand and capture more of the aqueous solution. These characteristics make the synthesized hydrogels suitable for the encapsulation and controlled release of drugs and bioactive compounds in aquaculture. Chitosan_ZnO hybrid hydrogels showed great antimicrobial activity against Vibrio harveyi, even better than that of loaded PB hydrogels. Here, we provide evidence for the potential capacity of Chitosan_ZnO hybrid hydrogels for the preventive and curative treatment of diseases that impact aquaculture animal health and prevent drug resistance by bacteria.

The aim of the present study is to analyze the synergy of antimicrobial elements, such as Ga, Ag and Cl by incorporating them in ZnO nanorods and measuring their antimicrobial and photocatalytic activity under visible light irradiation for water treatment. AgGa-doped ZnO nanorods and AgGaCl-doped ZnO nanorods on polyethylene substrate were prepared by a simple and fast microwave assisted synthesis. HCl was used in order to lower the pH of the precursor solution and favor Ga and Cl incorporation in the ZnO nanorods. The synthesized undoped and doped ZnO nanorods were analyzed with SEM, EDX, XRD and CL. The photocatalytic properties of the nanorods were evaluated via methylene blue degradation under visible light irradiation. Antimicrobial activity of the nanorods was measured via growth kinetics of Vibrio parahaemolyticus. It was found that AgGaCl-doped ZnO nanorods improve the methylene blue photo-degradation and above all, the antimicrobial activity of the AgGaCl tri-doped ZnO nanorods showed a lethal effect on the bacteria’s growth. This work shows that AgGaCl NRs are an excellent alternative for the development of sustainable water treatment devices and antimicrobial applications.

Las comunidades microbianas en ambientes hipersalinos son clave en los ciclos biogeoquímicos y la productividad ecológica. Este es el primer estudio que caracteriza la composición, estructura y potencial metabólico de la comunidad procariota en la columna de agua de la Laguna Ojo de Liebre (Baja California Sur, México), un ecosistema hipersalino con relevancia ecológica y socioeconómica. A partir de la información obtenida de 4 campañas de muestreo (2021-2022) en 18 estaciones, analizamos variables físicoquímicas (salinidad, temperatura y densidad) y secuenciamos la región V4-V5 del gen 16S ARNr. Los datos se procesaron con QIIME2, y se infirió el metabolismo mediante PICRUSt2. La comunidad estuvo dominada por Actinobacteriota, Bacteroidota, Cyanobacteriota, Pseudomonadota y Verrucomicrobiota, con diferencias espaciotemporales vinculadas a gradientes de temperatura (r² = 0.77, P = 0.001) y salinidad (r² = 0.39, P = 0.01). Los taxones raros (<1% de abundancia relativa), como Thermoanaerobaculales y Desulfobacterota, contribuyeron a la diversidad, especialmente en noviembre. La inferencia metabólica reveló rutas significativas (P < 0.05), como la biosíntesis de vitamina B6, la degradación de quitina y la reducción de nitrato, lo que sugiere roles en los ciclos biogeoquímicos y la adaptación a condiciones extremas. La estructura de la comunidad procariota en la laguna respondió a variaciones fisicoquímicas, con un núcleo taxonómico estable y taxones raros que incrementaron la diversidad bajo condiciones específicas. El potencial metabólico inferido resaltó su participación en procesos biogeoquímicos y su capacidad para degradar compuestos orgánicos complejos. Estos resultados establecen una línea base para entender la dinámica microbiana en sistemas hipersalinos y su impacto en la funcionalidad ecosistémica.