Defect engineering of NH2-MIL-88B(Fe) using different monodentate ligands for enhancement of photo-Fenton catalytic performance of acetamiprid degradation

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2020-10, Vol.398, p.125684, Article 125684
• Main Authors: Wang, Yuexin, Zhong, Zhen, Muhammad, Yaseen, He, Hui, Zhao, Zhongxing, Nie, Shuangxi, Zhao, Zhenxia
• Format: Article
• Language: English
• Subjects: Acetamiprid degradation; Coordination mode; Lewis acid site; Ligand vacancy; Monodentate ligand strategy; photo-Fenton catalysis
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2020.125684

[Display omitted] •Ligand defects were engineered in MIL88(Fe) via different coordinations.•Ligand defects intensified adsorption ability of MIL88(Fe) towards acetamiprid.•Ligand defects improved light absorption and charge separation for MOF photocatalysis.•Ligand vacancy strengthened Fe Lewis acidity and improved Fe2+/Fe3 + redox reaction.•Pca-MIL88(Fe) greatly enhanced ACTM mineralization rate under visible light. Engineering of monodentate ligands induced defects was proposed to modify NH2-MIL-88B(Fe) in order to promote its synergetic photo-Fenton catalytic degradation performance for acetamiprid (ACTM) as model neonicotinoid insecticides. Three monodentate ligands with different coordination groups (benzoic acid, pyrrole and pyrrole-2-carboxylic acid) were applied to in-situ induce ligand vacancies on NH2-MIL-88B(Fe). Effect of defect coordination mode on its photo-Fenton catalytic performance was investigated through the ACTM degradation reaction. Ligand defects on NH2-MIL-88B(Fe) would generate three merits: (1) it can modulate surface properties to enhance adsorption affinity towards ACTM; (2) it can introduce large amount of monodentate ligands and ligand vacancies in MOFs to promote light absorption and electron-hole separation capacity for photo-catalysis; (3) it can increase the amount of Fe Lewis acid sites to improve redox capacity of Fe2+/Fe3+ for Fenton-catalysis. In this work, Pyrrole-2-carboxylic acid (Pac) was proved to introduce more monodentate ligands in MOFs and generate more ligand vacancies as well. As a result, ACTM can be easily captured by defective NH2-MIL-88B(Fe) and degraded by in-situ triggered oxidative reaction through the synergistic “photo-Fenton catalysis”. Performance measurements showed that Pac-MIL88(Fe) achieved 7.3 times higher adsorption rate and 5.5 times higher catalytic rate for ACTM than that of pristine MIL88(Fe). Moreover, total organic carbon (TOC) conversion reached 97.0% within only 90 min using Pac-MIL88(Fe) as photo-Fenton catalyst, showing 1.7 times higher than pristine MIL88(Fe). Thus, the in-situ fabrication of ligand defect-containing MIL88(Fe) can be foreseen of potential for designing new MOFs for wider practical applications.