Uncovering the mesoporous secrets of Ti/γAl2O3 3-D gels: Fine-tuning morphology engineering for enhancing catalytic ozonation efficacy of environmental contaminants

Abstract

Herein, we optimized the catalytic ozonation process (COP) by engineering the morphology of versatile mesoporous Ti-doped γAl2O3 materials. Ti/γAl2O3 catalysts were synthesized as xerogels, ambigels, and aerogels for p-chlorobenzoic acid (pCBA) degradation by catalytic ozonation. The roles of Lewis acids and basic sites in Ti/γAl2O3 were investigated along with the synthesis parameters affecting the morphology, structure, and surface acidity. The incorporation of Ti4+ increased the surface acidity, resulting in an effective COP. Full characterization confirmed the uniform Ti distribution and well-defined acidic properties. The sole ozonation process was insufficient, while 0.5 g/L catalyst addition rapidly degraded 50 mg/L pCBA (xerogel: 30 min, ambigel/aerogel: 60 min) while showing excellent reusability and robustness under ions’ presence. EPR analysis suggested that pCBA removal occurs via bulk HO• and less by O3 and O2•--mediated reactions, without 1O2 generation. Based on the above findings, we proposed an integrated pCBA degradation pathway, providing insights into enhancing the COP for organic pollutant degradation via novel, cheap, and sustainable mesoporous materials.