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The ability of ultrasound-catalyst hybrid system in degradation of HA, and survey the effective parameters in degradation is the objectives of the present study. The characteristics of the synthesised catalyst was investigated by SEM, XRD and UV-DRS. The performance of the system in pollutant removal was investigated using the OFAT (One Factor at a Time Method) method. The kinetics of the process, mechanism and the reusability of the catalyst were determined in optimised conditions. The results indicated that pH = 3, catalyst dosage = 400 mg/l, HA concentration = 5 mg/l have best efficiency (74%). Superoxide and hydroxyl radicals were considered as the main cause of HA degradation. Catalyst stability was investigated in 5 replicates and verified. The reduction in TOC obtained 45%. The overall results show that the ultrasound Fe–doped TiO2 hybrid system has partial promising performance in degradation of HA. [ABSTRACT FROM AUTHOR]

Disinfection is one of the most important stages of water and wastewater treatment. Today, the use of photocatalytic processes by sunlight as a sustainable way of water disinfection has been noted. The purpose of this study was to remove coliform and fecal coliform from the effluent of a hospital sewage treatment plant using the solar/N-doped titanium dioxide (TiO2 ) process. In order to conduct the experiments, the raw samples (effluent of secondary sedimentation) were taken from the Ali Ibn Abi Talib hospital wastewater treatment plant in Zahedan City, Iran. N-doped TiO2 nanoparticles and the samples were poured into the reactor and then exposed to direct sunlight in summer. The results indicated that the photocatalytic process efficiency was enhanced by increasing reaction time and nanoparticles dosage. Furthermore, it was found that N-doped TiO2 nanoparticles and sunlight had a synergistic effect on the deactivation of coliform and fecal coliform. The number of coliforms and fecal coliforms bacteria cells decreased from 5 × 105 to 7 × 10³ MPN/100 mL and 4 × 10³ to 2 × 102 MPN/100 mL in the solar/N-doped TiO2 process after 150 min, respectively. It has been generally concluded that the solar/N-doped TiO2 process can effectively deactivate a wide range of real effluent microorganisms on a laboratory scale. [ABSTRACT FROM AUTHOR]

TiO2 and Fe-doped TiO2 nanoparticles were synthesised by sol-gel method. To determine the properties of nanoparticles, scanning electron microscopy, X-ray diffraction and diffuse reflectance spectroscopy were used. The results of the analysis showed that the synthesised nanoparticles are almost uniform and agglomerated as well as the Fe-TiO2 band gap has decreased from 3.1 to 2.84 and the absorption spectrum has changed towards the visible region. The final concentration of 2,6-dichlorophenol and degradation products were measured with gas chromatography-flame ionisation detector and gas chromatography-mass spectrometry. The maximum efficiency and reaction rate constant of 2,6-dichlorophenol were determined at pH 4 and k0 = 2.11 × 10−2, initial concentration of 2,6-dichlorophenol 20 mg L−1 and k0 = 8.01*10−2, and nanoparticles dosage of 500 mgL−1 and k0 = 5.07*10−2 at 90 min time. The degradation reaction followed the first-order kinetic model. The efficiency of degradation and mineralisation of 2,6-dichlorophenol were in order of sonophotocatalytic > photocatalytic > sonocatalytic. [ABSTRACT FROM AUTHOR]