Photocatalytic Oxidative Degradation of Diclofenac in Water Using Iron-Containing Metal-Ceramic Composites Under Irradiation and Ozonation Conditions

The photocatalytic activity of iron-containing silicon nitride-based metal-ceramic composites in the process of oxidative degradation of the pharmaceutical pollutant diclofenac (DCF) has been investigated. The composites were obtained by nitriding ferrosilicon without additives and ferrosilicon with shungite (modifier for SiC production) in combustion mode. It is noted that the use of urea allows to additionally modify the ceramic matrix of composites with semiconducting phases (FeO, CN) capable of absorption in the region of near-UV and visible light. The phase composition has been established, morphological features and optical properties of the composites have been studied. The acid-base properties of the surface have been evaluated. Adsorption and catalytic activity of composites in the absence and with HO addition under UV irradiation (Fenton photochemical process), under ozonation conditions under UV and visible light irradiation were studied. The highest degree of DCF degradation was found when heterogeneous photocatalysis and Fenton process were combined (84%) and under photocatalytic ozonation conditions (88%). The kinetics of photocatalytic degradation of DCF was investigated using a pseudo-first-order model. The degradation products of DCF were determined GC—MS.