Facile microwave assisted one-pot solid-state construction of Co-Fe spinel oxide/porous biochar for highly efficient 4-nitrophenol degradation: Effect of chemical blowing and surface vulcanization

Herein, microwave assisted one-pot solid-state construction method was developed for cellulose carbonization and Co-Fe spinel oxide loading to prepare Co-Fe spinel oxide/porous biochar for highly efficient 4-nitrophenol (4-NP) oxidation degradation through peroxymonosulfate (PMS) activation. With just 3 min domestic microwave heating of a solid mixture of cobalt nitrate, iron nitrate, alpha-cellulose, ammonium bicarbonate and thiourea, Co-Fe spinel and metal sulfides well dispersed, oxygen vacancies and pyrrole N enriched as well as BET increased porous Sx-CF@PC catalytic materials could be prepared with NH4HCO3 aided chemical blowing and thiourea assisted surface vulcanization. The optimal catalyst S-1-CF@PC could achieve 99.0 % 4-NP removal in 10 min with rate constant as high as 0.564 min(-1). Well dispersed spinel and metal sulfides could activate PMS to generate more SO4 center dot- and (OH)-O-center dot for 4-NP degradation; Meanwhile, oxygen vacancies and pyrrole nitrogen could promote O-1(2) based non-free radical 4-NP degradation pathways. This study provided the simplest microwave assisted solid-state metal oxide/porous biochar construction for energetic organic pollutants degradation.