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Hybrid Cotton-AgCl were prepared and found to be efficient antimicrobial agents for water disinfection under sunlight irradiation. AgCl was grafted on cotton by alternate immersion in AgNO3/KCl solutions, followed by a mild hydrothermal treatment. The as-prepared samples were characterized using a field emission scanning electron microscope (FE-SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Raman, FTIRS and UV–vis ground state diffusion reflection (GSDR) spectroscopy, TGA, ICP and XRF. The microbial inactivation efficiency was tested using Escherichia coli (E. colis) and Staphylococcus aureus (S. aureus) as model strains of Gram negative and Gram positive bacteria, respectively. The as-prepared composites exhibit stronger antibacterial activity against both strains, with complete inactivation (107 cfu mL−1) of Escherichia coli within 15 min. The preparation method is environmentally friendly, facile to scale up and the AgCl/Ag junction is effectively bonded to the cotton fabric materials. These results show that cotton-AgCl is a promising plasmonic biocidal material for water disinfection under sunlight illumination as well as under indoor illumination.

Cotton fabrics decorated with Cu

In this study, cotton fabrics decorated with Ag/AgCl and Ag/AgBr NPs were produced by a simple hydrothermal treatment using AgCl and AgBr as precursors. Their morphological features as well as, chemical composition and structural and luminescence properties were compared. Their water disinfection aptitude against E. coli and S. aureus was also investigated under solar illumination in batch as well asin dynamic conditions. The highest activity was observed for Cot-Ag/AgCl with a quasi-complete inactivation of E. coli and S. aureus(1.5 × 107cfu mL−1) within 15 min illumination. Disinfection efficiency under continuous flow was also tested using a home-made photoreactor and the cotton fabrics with the most efficient photocatalyst (Ag/AgCl). It has shown to be efficient at least for 10 cycles revealing the robustness of the functionalization. The mechanism of photocatalytic disinfection was explained in terms of the surface plasmon resonance (SPR) induced by the presence of Ag NPs, the resulting holes, h+, being one of the most intervenient species in the disinfection mechanism. The difference in the photocatalytic efficiency between AgCl and AgBr functionalized cotton was attributed to differences in the carriers (h+and e-) lifetime. This work provides a proof of concept for the potential applicability of Cot-Ag/AgCl or Cot-Ag/AgBr for in-flow potabilization of water under solar illumination.

Cotton fabrics decorated with Cu2O-Ag and Cu2O-Ag-AgBr NPs have been prepared using chemically immobilized Cu2O NPs as sacrificial templates. The objective is to prepare Cu2O-Ag heterostructures with Ag being intimately in contact with Cu2O NPs by galvanic replacement reactions without addition of any external reducing agent. Field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analysis were used to study the morphology and the chemical composition of the nanocomposites formed on the fabrics. The morphology of the ensuing nanostructures was shown to be dependent on the Ag precursor, AgNO3, concentration. The antimicrobial activity of the treated fabrics was evaluated against Staphylococcus aureus and Escherichia coli as model strains of gram-negative and gram-positive, respectively. The results showed that the fabrics loaded with Cu2O-Ag and Cu2O-Ag-AgBr nanocomposites exhibited enhanced sterilization activity compared to the Cu2O treated fabric.