Study of catalytic ozonation for tetracycline hydrochloride degradation in water by silicate ore supported Co3O4

Tetracycline hydrochloride (TCH) degradation by cobalt modified silicate ore (CoSO) catalytic ozonation in aqueous solution was investigated. CoSO catalyst was synthesized by an impregnation method using Co(NO3)(2) as the precursor and natural silicon ore (SO) as the support. The key catalyst preparation conditions (i.e., impregnation concentration, calcination temperature and time) were optimized. The activity and stability of CoSO catalyst and its catalytic ozonation mechanism for TCH degradation were studied. The results showed that Co3O4 was successfully coated on the silicon ore and the CoSO catalyst was highly efficient in catalytic ozonation for TCH degradation. The TCH removal by CoSO/O-3 could reach 93.2%, while only 69.3% by SO/O-3 and only 46.0% by O-3 alone at 25min. The reaction of TCH degradation followed pseudo-first order kinetics. TOC removal rate by CoSO/O-3 was 2.0 times higher than that by SO/O-3, and 3.5 times higher than that by O-3 alone. The reaction conditions (TCH initial concentration, catalyst concentration, pH and temperature) for catalytic ozonation were systematically investigated. The possible mechanism for the CoSO catalytic ozonation process was proposed, where hydroxyl radical oxidation mainly accounted for the substantial TCH degradation. Furthermore, CoSO showed great durability and stability after seven reaction cycles.