sodium-hypochlorite and titanium-dioxide

Anthracyclines are a class of pharmaceuticals used in cancer treatment have the potential to negatively impact the environment. To study the possibilities of anthracyclines (represented by pirarubicin and valrubicin) removal, chemical inactivation using NaOH (0.01 M) and NaClO (5%) as decontamination agents and adsorption to powdered nanocrystalline titanium dioxide (TiO2) were compared. The titanium dioxide (TiO2) nanoparticles were prepared via homogeneous precipitation of an aqueous solution of titanium (IV) oxy-sulfate (TiOSO4) at different amount (5-120 g) with urea. The as-prepared TiO2 samples were characterized by XRD, HRSEM and nitrogen physisorption. The adsorption process of anthracycline cytostatics was determined followed by high-performance liquid chromatography coupled with mass spectrometry (LC-MS) and an in-situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) technique. It was found that NaClO decomposes anthracyclines to form various transformation products (TPs). No TPs were identified after the reaction of valrubicin with a NaOH solution as well as in the presence of TiO2 nanoparticles. The best degree of removal, 100% of pirarubicin and 85% of valrubicin, has been achieved in a sample with 120 grams of TiOSO4 (TIT120) and TiO2 with 60 grams (TIT60), respectively.

Topics: Adsorption; Crystallization; Cytostatic Agents; Decontamination; Doxorubicin; Hydrolysis; Nanostructures; Particle Size; Sodium Hydroxide; Sodium Hypochlorite; Surface Properties; Titanium; Water Pollutants, Chemical

Decomposition of urea in aqueous solution was carried out using a microwave discharge electrodeless lamp (MDEL) consisting of two photoreactors with a triple tube structure that generate vacuum-UV/UV light and reactive oxygen species (ROS) using microwaves (MW) as an energy source. The rate of decomposition of urea was highest under acidic conditions (pH 4) compared with those at pH 7 and 10. When used in combination with dispersed TiO

Topics: Catalysis; Hydrogen-Ion Concentration; Microwaves; Oxidation-Reduction; Ozone; Photolysis; Reactive Oxygen Species; Sodium Hypochlorite; Solutions; Titanium; Urea; Water

Multidrug-resistant Acinetobacter baumannii is a well-documented pathogen associated with hospital-acquired infections. In addition to multidrug resistance, A. baumannii can also become resistant to colistin, the antibiotic treatment of last resort, by the loss of the lipopolysaccharide from its outer membrane. Here, we demonstrate that the development of colistin resistance also increases the resistance of A. baumannii to titanium dioxide (TiO2) photocatalysis. Both colistin-sensitive A. baumannii (CSAB) and colistin-resistant A. baumannii (CRAB) were inactivated by TiO2 when irradiated by ultraviolet A (UV-A). The resistance of CRAB to TiO2 photocatalysis was 1.5 times higher than that of CSAB, as determined by either culture assay or quantification of leaked proteins after photocatalysis (p < 0.05). The results of two-dimensional gel electrophoresis led to the speculation that the high resistance of CRAB may be associated with a lack of sensitive targets and oxidative enzymes. This hypothesis was confirmed by antimicrobial assays with 25 mM hydrogen peroxide (H2O2) and 1.07 mM sodium hypochlorite (NaClO). CRAB was significantly more resistant to H2O2 and NaClO treatment than CSAB (p < 0.01), consistent with the results of the TiO2 inactivation experiment. Therefore, the antibiotic resistance profiles of bacterial strains should be considered before the use of strains as indicators to represent sanitary quality after TiO2 photocatalysis.

Topics: Acinetobacter baumannii; Anti-Bacterial Agents; Colistin; Drug Resistance, Bacterial; Hydrogen Peroxide; Oxidation-Reduction; Sodium Chloride; Sodium Hypochlorite; Titanium

The photocatalytic degradation of Reactive Red 195 (RR195) has been investigated in aqueous suspensions by using ultraviolet (UV), sodium hypochlorite (NaOCl) and TiO(2)/Sep nanoparticles together. To get the TiO(2)/Sep nanoparticle, the nanocrystalline TiO(2) anatase phase on sepiolite was obtained using a sufficient thermal treatment by gradually increasing the temperature from 300, 400 and 500 degrees C for 3h. Then, TiO(2)/Sep materials were characterized using different spectral and technical structural analyses with scanning electron microscopy (SEM) and X-ray diffraction (XRD). The influence of pH, catalyst amount, oxidant and initial dye concentration was investigated in all the experiments. Maximum colour and chemical oxygen demand (COD) removal were 99.9% and 78% respectively, at a dye concentration of 250 mg L(-1), NaOCl dosage of 50.37 mM, 0.1 g L(-1) weight of TiO(2)/Sep and pH of 5.45 in 3h. In addition, the pseudo-first order model was applied and r(2) values were noted from 0.92 to 0.99.

Topics: Azo Compounds; Catalysis; Hydrogen-Ion Concentration; Microscopy, Electron, Scanning; Nanostructures; Naphthalenesulfonates; Photochemistry; Sodium Hypochlorite; Titanium; Ultraviolet Rays; X-Ray Diffraction

The photocatalytic degradation of lignin obtained from wheat straw kraft digestion has been investigated by using TiO(2) and ZnO semiconductors. ZnO has been found to be a better photocatalyst than TiO(2). The different variables studied, include catalyst dose, solution pH, oxidant concentration and initial concentration of the substrate. The degradation of lignin was favorable at pH 11. Optimum values of catalyst dose and oxidant concentration were found to be 1g/l and 12.2 x 10(-6) M, respectively. The degradation of the organic compound was also evaluated as COD removal and increase in the COD removal was observed with increase in degradation rate. An attempt has also been made to explore the applicability of ZnO in immobilized mode for the degradation of lignin under solar light for industrial scale application. Further the comparative evaluation of ZnO in slurry/immobilized mode has been carried out.

Topics: Catalysis; Industrial Waste; Lignin; Oxidants; Paper; Photochemistry; Sodium Hypochlorite; Sunlight; Titanium; Waste Disposal, Fluid; Water Pollutants, Chemical; Water Purification; Zinc Oxide