Synthesis of N-CQDs/cellulose solid-state fluorescence composites from peanut shell by KH-560 coupling for sensitively detecting Fe3+

Abstract

Most reported solid-state fluorescence materials utilizing carbon quantum dots (CQDs) rely on simply physical dispersing in polymer or gel matrices to suppress self-quenching, resulting in the issue of fluorescence instability. Here, we initially utilize crop waste peanut shells and add ethylenediamine (EDA) as an N element dopant to obtain strong fluorescence N-CQDs possessing a high quantum yield (QY= 18.86 %). Through simple chemical treatments, cellulose was extracted from peanut shells and used as a substrate material for the further preparing bio-based solid-state fluorescence composites named as N-CQDs/cellulose (NKC) based on the coupling reaction of γ-(2,3-epoxypropoxy) propytrimethoxysilane (KH-560). Owing to vast hydroxy groups on cellulose, excellent fluorescence detection performance for Fe3+ of N-CQDs, and the steady coupling and effective dispersion of N-CQDs on cellulose, the obtained NKC boasts not only wonderful stability in water but also highly sensitive assay ability for Fe3+ with a wide range (0–3300 µM) and a low LOD (10.56 µM). Upon being treated with L-cysteine, the NKC demonstrated a potential for recycling, as evidenced by its fluorescence intensity being restored to 93 % in comparison to the original NKC solution.