Fluorescent carbon dots crosslinked cellulose Nanofibril/Chitosan interpenetrating hydrogel system for sensitive detection and efficient adsorption of Cu (II) and Cr (VI)

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 430; p. 133154
• Main Authors: Chen, Xueqi, Song, Zihui, Yuan, Bingnan, Li, Xiaojuan, Li, Shaopeng, Thang Nguyen, Tat, Guo, Minghui, Guo, Zhanhu
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-02-2022
• Subjects: Biomass-based Hydrogel; Cellulose Nanofibril (CNF); Interpenetrating Polymer Network (IPN); Nitrogen-doped Carbon Dots; Simultaneous Detection and Adsorption; Biomass-based Hydrogel; Cellulose Nanofibril (CNF); Interpenetrating Polymer Network (IPN); Simultaneous Detection and Adsorption; Nitrogen-doped Carbon Dots
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2021.133154

•One-pot synthesis of carbon dots cross-linked cellulose nanofibril hydrogel.•The introduction of chitosan by solvent displacement forms IPN hydrogel.•Carbon dots provide visual detection during Cu (II) and Cr (VI) adsorption.•Amphoteric biomass and carbon dots provide adsorption sites for Cu (II) and Cr (VI).•The mechanism of Cu (II) and Cr (VI) sorption and sensing was determined.
To address the pollution of heavy metal ions in water resources, a novel self-assembled nitrogen-doped carbon dots (NCDs) crosslinked, cellulose nanofibril (CNF) and chitosan (CS) based interpenetrating polymer network (IPN) hydrogel (NCDs-CNF/CSgel) was prepared for simultaneous fluorescent detection and adsorption of Cu (II) cation and Cr (VI) anion. The NCDs cross-linked CNF hydrogel network was synthesized by an environmentally friendly low-temperature hydrothermal process and subsequently, solvent replacement was used to form the second layer of CS network. The morphology, chemical structure, fluorescent properties, and adsorption behaviors of NCDs-CNF/CSgel were analyzed. The results showed that NCDs-CNF/CSgel exhibited a wide linear range of fluorescence response for Cu (II) (50–1000 mg/L, detection limit of 40.3398 mg/L) and superior sensitivity and selectivity of fluorescence response for Cr (VI) (linear range of 1–50 mg/L, detection limit of 0.7093 mg/L). NCDs-CNF/CSgel showed high adsorption capacities of 148.30 mg/g and 294.46 mg/g for Cu (II) and Cr (VI), respectively, and fitted well to the pseudo-second-order model and the Langmuir model. The detection of Cu (II) and Cr (VI) and their adsorption mechanisms onto NCDs-CNF/CSgel were further determined. Hence, this work provides a green and sustainable approach for the synthesis of a functional material which can be applied for the detection and adsorption of heavy metal ions.