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The cellulose-based textiles currently used in hospitals are good conducive materials for cross-infection or transmission of diseases caused by microorganisms. Thus, great interest has been recently found in the antibacterial finishing of fabrics for practical applications to prevent the infection incidence. In this work, we developed novel SnO2/ZnO/chitosan bionanocomposites by one-step simultaneous sonochemical/sol–gel deposition to prepare an antibacterial textile as a model for combating bacterial infections. The different prepared samples were characterized using transmission electron microscope, X-ray diffraction, and scanning electron microscopy (SEM) indicating the embedded SnO2 and ZnO nanoparticles in treated fabrics. The treated fabrics were used to evaluate antibacterial activities against Escherichia coli and Streptococcus aureus as a model for Gram-negative and Gram-positive bacteria, respectively, using disk diffusion method in dark conditions as an in vitro model for treatment of bacterial wound infection. The procedure was more developed in terms of SnO2/ZnO molar ratio and using chitosan and citric acid to improve the antibacterial properties of the fabrics and their wash durability, respectively. The highest antibacterial activity of the fabrics was attained in a 50 min sonochemical coating process using SnO2/ZnO 1:2 molar ratio in initial sol and simultaneously deposited chitosan and citric acid. The presence of chitosan as complexing agent, citric acid as crosslink agent, and SnO2–ZnO heterojunction as important influencing parameters synergistically enhanced both the antimicrobial efficiency and maintenance of modified cotton durability after performing several washing cycles.

Protection against bacterial contamination remains a demand for healthcare textiles such as wound dressings to reduce or eliminate hospital-acquired infections related to antibiotic-resistant bacteria. We report herein a simple and straightforward in situ approach to deposit copper oxide and titanium oxide nanoparticles onto cotton fabric using a sonochemical-mediated sol–gel method. Modification of the cotton surface was achieved by incorporation of citric acid (CA) and polyethylene glycol (PEG) to improve the attachment of the nanoparticles and reduce the attachment of bacteria to the cotton surface, respectively. The resultant cotton fabric was used against Escherichia coli as a Gram-negative bacterium and Staphylococcus aureus as a Gram-positive bacterium in dark condition as an in vitro model for treatment of bacterial wound infection. The effects of different treatment parameters including duration and frequency of ultrasonic irradiation, surface modification with PEG and/or CA, and cotton chemical composition with different metal oxide molar ratios on the antibacterial activity of the treated cotton fabric were studied. All treated cotton fabrics showed antibacterial activity, with higher efficiency for those coated with CuO or CuO/TiO2 (1:1 molar ratio) among the single metal oxide and composite-modified cotton fibers, respectively. Our results show that such functionalized cotton fibers could actively fight the spread of bacterial infections by preventing bacterial adhesion, enabling more efficient bonding, and ultrasonically promoting generation of nanoparticles and their strong adhesion to the fabric surface.

The textile industry is characterized by high consumption of water, fuel, and chemicals. The wastewater treatment and recycling possibilities in the textile industry are environmentally of the highest importance. The most common chemical pollutants present in textile industry wastewater are the azo-dyes. The solution based sol–gel method was used to synthesize ZnO thin films using different solvents to evaluate the morphology-dependent photocatalytic activity toward the degradation of two azo dyes including sodium [3-[(4,5-dihydro- 3-methyl-5-oxo-1-phenyl-1H-pyrazol-4-yl)azo]-2-hydroxy-5-nitrobenzenesulp-honato (3-)] hydroxychromate (1-) and sodium (5-((4′-((2,6-dihydroxy-3-((2-hydroxy-5-sulfophenyl)azo)phenyl)azo)-4-biphenylylazo) salicylato (4-)) cuprate (2-) in water. 2-Propanol, methanol, ethanol, and 1,4-butanediol were used as solvents. The photocatalytic degradation rates depend on the dye structure and concentration, solvent-dependent ZnO film morphologies, pH of the medium and excitation light source. The observed rate constants of ZnO film prepared using 2-propanol and of ZnO film prepared using methanol were enhanced approximately by a factor of 3 under UV light and under visible light, respectively. The obtained results were discussed according to the structure and morphology of ZnO films as key parameters in photocatalytic activity.

The nano-sized coupled oxides ZnO/SnO2 thin films in a molar ratio of 2:1 (Z2S), 1:1 (ZS) and 1:2 (ZS2) were prepared using sol–gel dip coating method and characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV–vis spectroscopy. Escherichia coli (E. coli, ATCC 25922) was selected as a model for the Gram-negative bacteria to evaluate antibacterial property of composite samples compared with single ZnO (Z) and single SnO2 (S) films. The antibacterial activity has been studied applying the so-called antibacterial drop test under UV illumination. The bactericidal activity was estimated by relative number of bacteria survived calculated from the number of viable cells which form colonies on the nutrient agar plates. The influence of the SnO2–ZnO nanocomposite composition on the structural features and on the antibacterial properties of the thin films are reported and discussed. It is found that all coatings exhibited a high antibacterial activity. The coupled oxide photocatalyst Z2S has better photocatalytic activity to bacteria inactivation than ZS, ZS2, Z and S films. Furthermore, nanostructured films were active even in the absence of irradiation.

Indium oxide (In 2 O 3 ), zinc oxide (ZnO), stannic oxide (SnO 2 ), and titanium dioxide (TiO 2 ) thin films were prepared on glass substrates using electron beam evaporation. The samples characterized by UV–vis spectroscopy, diffraction ray-X and scanning electron microscopy techniques. The photocatalytic degradation of methylene blue in an aqueous solution, as a model compound, was investigated using different metal oxides in an attempt to compare the decomposition reaction rate. The progress of degradation was monitored using UV–vis spectrophotometry. The effects of various experimental parameters such as initial concentration of methylene blue (5–10 mg/l), pH of the solution (2–8), annealing temperature (250–550 °C), and catalyst nature and its microstructure were systematically studied in order to achieve maximum degradation efficiency. The results obtained were fitted with the Langmuir–Hinshelwood model to study the degradation kinetics and discussed in detail. Nearly complete degradation was obtained at optimal operational parameters including the higher annealing temperature of thin film and the increase in MB solution pH. The degradation with In 2 O 3 was more efficient than with SnO 2 , ZnO and TiO 2 films.

Photocatalytically active indium tin oxide thin film electrodes were prepared by electron beam evaporation technique onto a glass substrate having thickness 120 nm. Degradation of reactive dye yellow direct 42 has been performed using photoeletrocatalysis. A biased potential is applied across indium tin oxide photoelectrode illuminated by UV light. The best experimental conditions were found to be dye concentration 1.0 × 10− 5 mol L− 1, pH 5.25 and 0.5 mol L− 1 NaCl as supporting electrolyte when the photoelectrode was biased at + 0.5 V versus saturated calomel electrode. The effects of other electrolytes, dye concentration, pH solution, electrode annealing temperature and applied potentials have been also investigated and are discussed. Several common inorganic salts Na2SO4, Na2CO3, NaNO3 and NaCl were chosen to act as supporting electrolytes, which was added into the dye solution. It is shown that the charge-transfer resistance of photoanode can be calculated by the analysis of its electrochemical impedance spectroscopy, and the photoelectrocatalytic degradation rate of yellow direct 42 was inversely proportional to the value of charge-transfer resistance of photoelectrodes at different pH. The value of charge-transfer resistance is smaller, the higher its photoelectro-activity is.