Defective Copper-Based Metal-Organic Frameworks for the Efficient Extraction of Organosulfur Compounds from Garlic-Processing Wastewater

Abstract

Organosulfur compounds (OSCs) in garlic-processing wastewater decompose under anaerobic conditions to generate toxic and harmful substances with unpleasant odors. Herein, were report the successful development of novel copper-based metal organic framework (Cu-MOF) adsorbents with high adsorption capacities for OSCs in aqueous media. Defect-rich Cu-MOF-X samples, with particle sizes between 360-750 nm, were hydrothermally synthesized in the presence of acetic acid (where X denotes the molar ratio of acetic acid relative to the pentadentate MOF linker H4PPYD). OSC adsorption experiments using allicin, ajoene and 2-ethenyl-4H-1,3-dithiine (2-VDT) showed that Cu-MOF-200 delivered fast adsorption kinetics and very high OSC adsorption capacities (149.02-171.33 mg g-1) owing to the pore accessibility and range of adsorption sites in the MOF. FT-IR, Raman, and XPS analyses, together with density functional theory (DFT) calculations, verified the strong yet reversible adsorption of OSCs in Cu-MOF-200. Results guide the development of improved adsorbents for OSC capture from garlic-processing wastewater.

Keywords: Organo sulfur compounds (OSCs), Adsorbents, Metal-organic frameworks (MOFs), Defect-rich, Cu-MOF, DFT calculations