Efficient activation of peroxymonosulfate by porous Co-doped LaFeO3 for organic pollutants degradation in water

Sulfate radical-based advanced oxidation technology has been considered one of the most effective methods to remove organic pollutants from water. In this study, porous Co-doped LaFeO3 catalysts were synthesized by the sol-gel method and applied in peroxymonosulfate (PMS) activation for organic pollutants degradation. The effects of catalyst dosage, PMS concentration, initial pH of the solution and radical scavenger on the degradation of Acid Red G (ARG) were systematically studied. The porous LaFeO3 showed higher specific surface area (27.62 m(2)/g) and pore volume (0.15 cm(3)/g) than the traditional LaFeO3 (7.83 m(2)/g and 0.11 cm(3)/g), resulting in higher activity. After doping Co, more oxygen vacancies generated. The catalytic activity of LaFe1-xCoxO3 was remarkably enhanced. ARG could be completely degraded in LaFe0.90Co0.10O3/PMS system within 10 min. The degradation rate was 51 times higher than that in the porous LaFeO3/PMS system. The superior activity can be attributed to the oxygen vacancies and synergistic effect of Co and Fe, which facilitated the activation of PMS and generated SO4 center dot- and HO center dot. It was SO4 center dot- that mainly contributed to the degradation of ARG. The detailed degradation pathway was proposed, according to the intermediate products of ARG degradation. Besides, the degradation rate of ARG by the as-prepared catalyst exceeded 80% even after using for 5 times.