Herein, the catalytic properties of a carbonaceous nanocomposite in the catalytic ozonation process (COP) of 2, 4-dinitrophenol (2, 4-DNP) were investigated and the results were compared with those obtained from single ozonation process (SOP). Magnetic carbonaceous nanocomposite, as a novel catalyst, was applied to optimize the condition for the removal of 2, 4-DNP in the COP, and the influential parameters such as pH, catalyst dosage, addition of radical scavengers, and durability were all evaluated. The results showed that the degradation efficiency of 2, 4-DNP and COD in the COP (98.2, 92%) was higher compared to the SOP (75, 61%) and the highest catalytic potential was achieved at an optimal pH of 6. The first-order modeling demonstrated that the reactions were dependent on the concentration of the catalyst, with the kinetic constants varying from 0.022 (1/min) in the SOP to 1.377 (1/min) in the COP at the catalyst dosage of 4 g/L and the optimum concentration of catalyst (2 g/L). The addition of radical scavenger noticeably diminished the removal efficiency of 2, 4-DNP in the SOP from 75% down to 54%, while the corresponding values for the COP dropped from 98.2 to 93%. Furthermore, a negligible reduction in the catalytic properties of the catalyst was observed (~5%) after five-time reuse. The results also revealed that the applied method is effectively suitable for the removal of 2, 4-DNP contaminant from industrial wastewaters.

Magnetic bentonite (MBt) and Ti/TiO2 nanotube/PbO2, for the first time, were investigated as particle electrodes and anode of three dimensional electro-Fenton process (3DEF) for the degradation of diclofenac (DCF) and naproxen (NPX). The characteristics of the electrodes were determined by X-ray diffraction(XRD), scanning electron microscope(SEM) and energydispersive X-ray spectroscopy(EDS) analyses and the effects of operating parameters on degradation were studied. The results showed that adsorption and electrochemical processes have lower removal efficiency than the 3DEF process at neutral pH. This efficiency was due to the greater production of hydroxyl radical (•OH) through the anode and MBt surface. The results of the scavenging experiments confirmed an increase in the amount of production of •OH. The maximum removal efficiency of DCF and NPX was obtained at pH of 6, MBt dosage of 500 mg/L, current density of 25 mA/cm²and electrolysis time of 120 min. The electrodes reusability was confirmed by consecutive reaction cycle and the Fourier-transform infrared spectroscopy (FTIR) and SEM-mapping analysis explained their stability. The results of continuous electro-oxidation reactor showed proper removal of the chemical oxygen demand(COD) from real wastewater. The degradation by-products were identified by gas chromatography mass-spectrometry (GC-MS) analysis coupled with dispersive liquid–liquid microextraction (DLLME). Based on comparative tests and products identification, the possible mechanism and pathway of drugs degradation were suggested.