Salmonella spp. is a zoonotic bacterium responsible for salmonellosis in humans (Aljuwayd et al., 2025; Carrascal-Camacho et al., 2023; Mathew et al., 2024). Salmonella spp. is also a natural inhabitant of the gastrointestinal tract of several animal species, including birds, reptiles and mammals (Carrascal-Camacho et al., 2023; Rincon-Gamboa et al., 2021). The vehicle for human transmission is the consumption of contaminated food, which is traditionally associated with animal-origin food (Benson et al., 2023; Fajardo-Guerrero et al., 2020). However, some reports have shown an increase in the occurrence of foodborne outbreaks caused by the consumption of fresh fruits and vegetables, e.g. tomatoes in the USA and in the UK (Europian Centre for Disease Prevention and Control and European Food Safety Authority, 2024), cucumbers imported from Mexico to the US (Food and Drug Administratio F, 2024) and onions among others (Center for Disease Control and Preventión, 2023; McCormic et al., 2022; Mitchell et al., 2024).

In several of these outbreaks, contamination has occurred in the field during the cultivation of these foods (McCormic et al., 2022; Mitchell et al., 2024). Some of the practices that contribute to the contamination of these products are the use of organic fertilisers (chicken manure, pork manure, among others) with poor microbiological quality (Bonanomi et al., 2025; Kiani et al., 2025; Matiz-Villamil et al., 2021) and water (contaminated with bacteria) reutilised for crop irrigation (Rabiu et al., 2025), as well as the presence of animals near the crops. Likewise, the increase in world population has forced intensive crop production, where it is necessary to use available water that does not always meet the microbiological quality for irrigation (Environmental Protection Agency E, 2012; Heyde et al., 2025; International Standard Organization I, 2020; Ministerio de Ambiente y Desarrollo Sostenible, 2014).

Recent studies have shown that these changes in the management of agricultural practices have an impact on the increase of Salmonellosis, in which water has played a key role (Dietrich et al., 2023; Semenza and Ko, 2023), because high concentrations of the bacterium have been detected in untreated wastewater and persist even in effluents treated with conventional systems (Abubakari, 2018; Fiorentino et al., 2017; Rabiu et al., 2025; Santiago et al., 2018). In addition, another problem with this bacterium in domestic and agro-industrial wastewater is the increase in the content of antibiotic-resistant strains to antibiotics (MDR), and from the sanitary viewpoint, it is a challenge related to the implementation of efficient technologies for the inactivation of this bacterium and in short periods, to avoid multiplication and dissemination (Cañón-Tafur et al., 2024b; Drauch et al., 2025; Mohammed et al., 2021; Ramirez-Hernandez et al., 2021; Santiago et al., 2018; Zhang et al., 2019).

On the other hand, some enteric bacteria (Salmonella spp., Shigella sonnei, Proteus sp., Enterobacter cloacae, and Citrobacter freundii) together with sulphate-reducing bacteria release unpleasant odours in wastewater treatment plants because they produce hydrogen sulfide (H2S), methyl mercaptans, and dimethyl disulphide, among others (Awawou et al., 2021; Salim et al., 2021; Salim et al., 2022). The H2S gas removal is crucial for environmental and public health because it is a highly toxic and corrosive gas, acting as a precursor of acid rain, directly affecting people by increasing the perception of unpleasant odours and causing respiratory and skin irritation (Alonso-Tellez et al., 2012; Fonseca-Bermúdez et al., 2022), most frequently in operators working in treatment plants and the maintenance of sewage systems in cities (Alonso-Tellez et al., 2012; Du et al., 2024; Felfoldi, 2024; Fonseca-Bermúdez et al., 2022).

To treat domestic and agro-industrial wastewater, achieving the reduction of antibiotic-resistant enteric bacteria such as some strains of Salmonella Typhimurium and the removal of H2S, emerging technologies such as advanced oxidation processes can be used, among which we can highlight photolysis-UV (Oladipo et al., 2021), photo Fenton (Pino-Sandoval et al., 2020) and photocatalysis with semiconductor materials (Bae et al., 2021; Cañón-Tafur et al., 2024b; Custódio et al., 2020; He et al., 2021; Lelis et al., 2023; Oluoch et al., 2024; Rincón-Barón et al., 2025a; Sekar et al., 2022; Thangam et al., 2020; Uyguner Demirel et al., 2018). In the photocatalysis process, one of the most widely used semiconductors is titanium dioxide (TiO2) in the anatase phase due to its chemical stability, low toxicity, and oxidising capacity, both under ultraviolet and visible light, the latter as long as its band gap is below 2.8 eV (Oluoch et al., 2024; Uyguner Demirel et al., 2018; Yan et al., 2025).

TiO2 used to be (by chemical or physical methods) deposited on inorganic and organic substrates to obtain films with photocatalytic activity (UV–VIS) (Cañón-Tafur et al., 2024b; Garg et al., 2024). Among the chemical methods, the Peroxo sol-gel technique stands out, a variant of the conventional Sol-gel method carried out in solution (Rincón-Barón et al., 2025a). In this technique, titanium precursors such as Titanium Isopropoxide (Ti(OC3H7)4), known as TTIP, are use, to which is supplied hydrogen peroxide (H2O2) to induce the hydrolysis reactions and condensation typical of the Sol-gel process (Rincón et al., 2023; Yaemsunthorn et al., 2023). In this technique variant, the H2O2 acts as an oxidising or peptizing agent, promoting the formation of Ti-peroxo species with a yellow colouration (Rincón et al., 2023; Woignier et al., 2005; Yaemsunthorn et al., 2023). The addition of H2O2 improves the dispersion and homogeneity of the colloidal TiO2 particles. Once the solution (sol) is ready, it is deposited on the substrate (usually glass) to form a thin film (Rincón-Barón et al., 2025b). Among the most widely used deposition methods is spin coating, commonly studied for its ability to perform homogeneous thin films on substrates, especially glass (Priyalakshmi et al., 2022). This technique is considered a simple, inexpensive, and fast alternative for obtaining TiO2 films.

This method involves a stable colloidal solution of Peroxo sol-gel containing TiO2 nanoparticles; the solution is applied on the surface of the substrate by rotation to ensure proper adhesion, and rigorous cleaning of the substrate is essential (Lukong et al., 2022; Rincón et al., 2023). The final film thickness depends on several parameters, such as rotation speed, rotation time, the amount of solution applied, and viscosity (Lukong et al., 2022). The surface optical and electrical properties of the films depend on the type of precursor, synthesis conditions, the number of coating cycles, and the sintering temperature (Sankapal et al., 2023). Reports by Phuinthiang et al. (2021), who deposited TiO2 on a polymeric substrate using a combination of Sol-gel and photonic assistance, to obtain crystalline films with UV-A photocatalytic activity, which allowed them to inactivate 90 % of the S. Typhimurium population after 60 min of treatment (Phuinthiang et al., 2021). Other authors have worked on titanium deposition by spin coating (SC) to improve its photoelectrocatalytic and photocatalytic properties as alternatives to inactivate Salmonella spp., demonstrating that the type of semiconductor, its concentration, the initial concentration of the microorganism and the source of irradiation are key factors to favour inactivation in aqueous matrices or wet surfaces (Espinoza et al., 2023; Socha et al., 2025).

The magnetron sputtering (MS) technique falls into the category of Physical Vapor Deposition (PVD) (Delkhosh et al., 2025; Garg et al., 2024) and has been widely used due to its ability to produce thin coatings with controlled properties, both in composition and structure (Aissani et al., 2022; Lelis et al., 2023). Magnetron sputtering is the bombardment of a metal target (currently titanium) by energetic ions generated in plasma in the presence of an inert gas such as argon (Benetti et al., 2020; Varnagiris et al., 2021). During this process, the metal target serves as the cathode, and upon impact by plasma ions, the titanium atoms are sprayed into the gas phase. These atoms travel through the deposition chamber until they reach the substrate surface, where they condense to form a thin film (Hu et al., 2023).

The thin films produced by magnetron sputtering stand out for their high purity, substrate adhesion, and control over key parameters, as thickness, surface morphology, and crystalline structure (Delkhosh et al., 2025; Garg et al., 2024). Concerning the use of this technique to inactivate Salmonella spp., Varnagiris et al. (2021) deposited carbon-doped titanium on high-density polyethylene (HDPE) by physical vapor deposition, demonstrating that this method yields TiO2 films on thermosensitive substrates with which they inactivated 95 % of the Salmonella Typhimurium population (Varnagiris et al., 2021). Lelis et al. (2023) developed a reactive magnetron sputtering magnetic photocatalysts based on C-TiO2 + Ni and ZnO + Ni with photocatalytic activity against Salmonella Typhimurium, with acceptable bacterial reduction and increased antibiotic susceptibility (Lelis et al., 2023).

During H2S removal via UV-photolysis and photocatalysis, the principal frequent intermediates are sulphite, sulphate, hydrogen, and elemental sulphur (Delkhosh et al., 2025; Oladipo et al., 2021; Sekar et al., 2022). Additionally, H2 can be produced from H2S present in wastewater by photocatalytic means, as reported by Thangam et al. (2020), who used Sol-gel-produced ZnO-TiO2 powders for photocatalytic H2 production and obtained 5189 μmol h−1 of this gas from 200 mg L−1 of H2S. These results are promising for the generation of alternative fuels and the elimination of unpleasant odours (Thangam et al., 2020). Other authors evaluated different concentrations of a composite based on cement fibres coated with TiO2 for the photocatalytic degradation of H2S, reaching 72 % of degradation as the concentration of the composite increased, as well as the surface area exposed to ultraviolet light (Custódio et al., 2020).

Although many scientific publications related to the reduction of antibiotic-resistant Salmonella spp. and the removal of H2S has been separately investigated, no recent publications evaluated (to wit) the two pollutants' simultaneous removal (biological and chemical) in wastewater. For this reason, the present research assayed a photocatalysis process involving TiO2 films deposited by spin coating and magnetron sputtering for simultaneous reduction of Salmonella Typhimurium and H2S from domestic wastewater.