Low Cost Removal of Reactive Orange 16 Dye using Cross-linked Chitosan/oil Palm Ash Composite Beads

Quercetin Recovery from Onion Solid Waste via Solid-Phase Extraction Using Molecularly Imprinted Polymer Nanoparticles

The present study deals with the valorization of the onion solid waste (i. e. peel) by extracting quercetin (Qu) compound, as a natural antioxidant food ingredient. It is used as a raw material for cosmetic, fine chemical and pharmaceutical industries. The onion peel, as a solid waste, is a highly rich source of Qu that is a valuable source of many useful biological properties, including antioxidant, anti-inflammatory, antiviral, antibacterial and antimicrobial properties. For this purpose, Qu molecular-imprinted polymer nanoparticles (Qu–MIP NPs) and its corresponding non-imprinted polymer (NIP) were prepared using precipitation/polymerization method. The prepared Qu–MIP NPs and its corresponding NIP were characterized using Fourier transform infrared spectrometer, scanning electron microscopy and high-resolution transmission electron microscope. The prepared Qu–MIP NPs and its corresponding NIP could successfully rebind Qu at binding capacities of 60 and 10.0 mM/g, respectively. Thus, the prepared Qu–MIP NPs could successfully recover 260 mg Qu from 1 kg onion peel.