Preparation of high intensity transparent fluorescent corn husk and its detection of Fe3+

Abstract

Iron is one of the most critical elements in the human body and has a close relationship with human life. Hence, it is imperative to conduct tests for iron ions. Corn husk, being a biomass material that is widely available, is abundant in cellulose. Consequently, in this study, a fluorescent probe (COHS) was devised and synthesized, utilizing a flavonoid backbone. Then, fluorescent corn husks (ACH-COHS) with hydrophobicity and transparency were prepared by bonding COHS with cellulose in corn husks through physical adsorption and hydrogen bonding. The tensile strengths of natural corn husk (NCH), delignified corn husk (ACH), and ACH-COHS were 6.98 MPa, 23.2 MPa, and 22.2 MPa, respectively. The tensile strength of ACH-COHS is approximately 3.2 times that of NCH. The elongation at break of NCH, ACH, and ACH-COHS was 1.84 %, 7.30 %, and 6.82 %, respectively. Compared to NCH, the elongation at break of ACH-COHS increased by 4.98 %. The results showed that the mechanical properties of ACH-COHS were better than those of NCH, and ACH-loaded COHS had less effect on its mechanical properties. Fe3+ had a quenching effect on ACH-COHS with a response time of 90 s and a detection limit of 0.08 μM. The detection mechanism of ACH-COHS was verified by Nuclear Magnetic Resonance (NMR), Fourier Transform Infrared Spectroscopy (FTIR), and Mass spectrometry. This study presents a new and sustainable method to visualize and detect Fe3+.