Environmentally friendly synthesized and magnetically recoverable designed ferrite photo-catalysts for wastewater treatment applications

Fenton processes are promising wastewater treatment alternatives for bio-recalcitrant compounds. Three different methods (i.e., reverse microemulsion, sol-gel, and combustion) were designed to synthesize environmentally friendly ferrites as magnetically recoverable catalysts to be applied for the decomposition of two pharmaceuticals (ciprofloxacin and carbamazepine) that are frequently detected in water bodies. The catalysts were used in a heterogeneous solar photo-Fenton treatment to save the cost of applying high-energy UV radiation sources, and was performed under a slightly basic pH to avoid metal leaching and adding salts for pH adjustment. All the developed catalysts resulted in the effective treatment of ciprofloxacin and carbamazepine in both synthetic and real domestic wastewater. In particular, the sol-gel synthesized ferrite was more magnetic and more suitable for reuse. The degradation pathways of both compounds were elucidated for this treatment. The degradation of ciprofloxacin involved attacks to the quinolone and piperazine rings. The degradation pathway of carbamazepine involved the formation of hydroxyl carbamazepine and dihydroxy carbamazepine before yielding acridine by hydrogen abstraction, decarboxylation, and amine cleavage, which would be further oxidized.