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The current investigation introduces a novel diatomite-TiO2/ZnS photocatalyst tailored to address the challenges posed by organic dye pollution while concurrently providing antibacterial activity. The methodology commences with diatomite purification, followed by the deposition of nanoparticles forming a heterojunction system between ZnS and TiO2 on the diatomite surface, culminating in the development of the nanocomposite. Notably, the optical absorption edge of the diatomite-TiO2/ZnS nanocomposite resides within the UV light spectrum. Subsequent heat treatment at 500 °C heightens the system's responsiveness to UV radiation. The nanocomposite exhibits exceptional efficacy in the photocatalytic degradation of rhodamine B dye. The optimal catalyst, DTZS 500, achieves a remarkable 98% degradation of rhodamine B within 180 min, boasting a pseudo-first-order constant of 0.03299 min−1, which is twice that of P25. Furthermore, nearly complete mineralization of organic matter is evidenced by chemical oxygen demand (COD) measurements. These superior performances are ascribed to the well-dispersed TiO2 and ZnS on the diatomite surface, the adsorption properties of diatomite, and the effective separation of photo-generated electron–hole pairs facilitated by the formation of a heterojunction system between TiO2 and ZnS. Moreover, the nanocomposite exhibits notable antibacterial effects against S. aureus, as evidenced by substantial inhibition zones measuring 38 mm in diameter. This study thus presents a promising avenue towards the provision of highly efficient and economical solutions for water treatment, encompassing both photocatalysis and bacterial disinfection. [ABSTRACT FROM AUTHOR]

This study introduces a cost-effective methodology to synthesize Ag@MCM-41 composites, utilizing petroleum sludge ash as a precursor. These nanomaterials exhibit well-structured arrangements and hold tremendous promise for applications in both photocatalysis and antimicrobial activities within the context of water treatment. The catalysts were subjected to thorough characterization using techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS), and scanning electron microscopy (SEM) to assess their structural and optical properties. The XRD analysis corroborated the successful synthesis of orderly nanomaterials, while reflections corresponding to metallic silver planes convincingly demonstrated the effective integration of silver nanoparticles onto the MCM-41 surface, while simultaneously preserving its refined and ordered mesostructure. Subsequently, the photocatalytic performance of the composites was meticulously evaluated, and the results indicated exceptional degradation rates for MB, RhB, and MO dyes, by 15Ag@MCM-41. This degradation kinetic adhered to a pseudo-first-order model. Furthermore, the nanocomposite displayed remarkable photocatalytic stability across three reuse cycles, with a slight reduction in degradation efficiency observed during the third cycle. In addition to their notable photocatalytic attributes, all Ag@MCM-41 ratios demonstrated notable antibacterial activity against S. aureus and E. coli, as substantiated by the presence of an inhibition zone with a diameter of approximately 14 mm and 12 mm respectively. The nanocomposites we have developed in our current study hold significant promise within the realm of water treatment. They have the potential to serve as a low-cost tool for addressing two crucial aspects: the degradation of pollutants, such as dyes, from water effluents, and the inhibition of microorganisms in water systems. [ABSTRACT FROM AUTHOR]