Enhanced removal of basic violet 10 by heterogeneous sono-Fenton process using magnetite nanoparticles.

The removal of basic violet 10 (BV10), which is known as a cationic dye, from aqueous solution was studied by employing a heterogeneous sono-Fenton process over the nano-sized magnetite (Fe3O4) which had been prepared by the milling of magnetite mineral using a high-energy planetary ball milling process. The magnetite samples were characterized using the X-ray diffraction (XRD), high resolution scanning electron microscopy (HR-SEM), energy-dispersive X-ray spectroscopy (EDX), Brunauer-Emmett-Teller (BET), Fourier transform infrared spectroscopy (FTIR), and inductively couple plasma mass spectrometer (ICP-MS). It was found that the catalytic activity of the ball-milled magnetite sample was enhanced along with the improvement in its physicochemical properties; also, the ball-milled magnetite of 6 h displayed the highest catalytic activity in BV10 removal by the heterogeneous sono-Fenton process as compared with that for 4 h (66.12% after 120 min) and 2 h (48% after 120 min).The effect of operational parameters, namely, pH solution, catalyst dosage, the initial H2O2 concentration, ultrasonic power and the initial BV10 concentration, on the removal efficiency (RE%) of BV10 was investigated. The optimum conditions for the BV10 RE% were: the pH value of 3, the catalyst dosage of 1.5 g L-1, the initial H2O2 concentration of 36 mM, the ultrasonic power of 450 W L-1, and the initial BV10 concentration of 30 mg L-1. The RE% of BV10 was 75.94% at these conditions after the reaction time of 120 min. The trapping experiments revealed that OH radicals were the dominant oxidative species, but O2-/HO2 radicals also had a partial role in the removal of BV10.The reusability of the magnetite nanoparticles revealed about 28% decrease in the removal efficiency within five consecutive runs. The results obtained through GC-MS analysis also confirmed the efficient removal of BV10 molecules in the aqueous solution during the process.

Sonocatalytic degradation of ciprofloxacin using synthesized TiO2 nanoparticles on montmorillonite.

TiO2/Montmorillonite (TiO2/MMT) nanocomposite as sonocatalyst was produced by immobilizing synthesized TiO2 on the surface of montmorillonite. The characteristics of produced nanocomposite were investigated using XRD, XRF, FTIR, TEM, SEM, EDX, UV-vis DRS and nitrogen adsorption-desorption analyses. The synthesized TiO2 and TiO2/MMT samples were applied as catalysts for sonocatalytic degradation of ciprofloxacin (CIP). The performance of the TiO2/MMT was greater than pure TiO2 sample in treatment of CIP solution. The degradation efficiency of the CIP by sonocatalytic process was affected by solution pH, catalyst dosage, initial CIP concentrations and ultrasonic power. Degradation efficiency of 65.01% was obtained at the pH of 6, catalyst dosage of 0.2gL-1, initial CIP concentration of 10mgL-1 and ultrasonic power of 650WL-1. It was observed that the presence of inorganic and organic scavengers suppressed the performance of sonocatalytic process. The stability of the nanocomposite was studied in several successive experiments, and the degradation efficiency declined only 61.48% after 4 repeated experiments. The main degradation by-products were recognized by GC-MS method to propose the possible sonocatalytic mechanism for the degradation of CIP.