Porous Mn<sub>2</sub>O<sub>3</sub>/<i>p</i>SiO<sub>2</sub> Nanocomposites on Bio-scaffolds for Tetracycline Degradation
Qi Zhang, Minghao Yu, Ning Wang, Junchao Qian, Yu Gu, Feng Du, Yan Lin, Feng Chen, Zhigang Chen, Zhengying Wu, Lin‐Bing Sun
Abstract
In this study, manganese sesquioxide (Mn2O3) nanoparticles (NPs) were inserted into porous silica (pSiO2) and thus a mosaic-like porous composite of Mn2O3/pSiO2 was constructed by a bio-templating route. Structure and morphology analyses reveal the successful assembly and high dispersion of Mn2O3 NPs on the matrix of porous SiO2. Because of the presence of a porous structure and high number of accessible active sites, the resulting Mn2O3/pSiO2 exhibits both large adsorption capacity and remarkable catalytic activity for the removal of tetracycline (TC, 80 mg·L–1) from aqueous solutions. With the assistance of H2O2, Mn2O3/pSiO2 could synergistically degrade TC with a total removal efficiency (RE) of 80%, which is much greater than those of pSiO2 (13%) and nMn2O3 (63%). Meanwhile, Mn2O3/pSiO2 possesses a wide pH application range (3.0–11.0, RE > 83%), quite good efficiency (64%) for highly concentrated TC (240 mg·L–1), and excellent reusability (RE = 70% after four cycles). Radical-trapping tests and electrochemical measurements reveal that a direct electron transfer pathway plays the dominant role in this TC–Mn2O3/pSiO2–H2O2 catalytic system. This study provides a convenient and effective strategy to design porous composite adsorbents/catalysts for the remediation of antibiotic wastewater.