Enhancing Removal of Cr(VI), Pb2+, and Cu2+ from Aqueous Solutions Using Amino-Functionalized Cellulose Nanocrystal

• Published in: Molecules (Basel, Switzerland) Vol. 26; no. 23; p. 7315
• Main Authors: Xu, Qinghua, Huang, Xiaodi, Guo, Lukuan, Wang, Yu, Jin, Liqiang
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 02.12.2021; MDPI
• Subjects: Adsorbents; Adsorption; Amino groups; Aqueous solutions; Atomic force microscopy; Behavior; Cellulose; cellulose nanocrystal; Chemical modification; Chromium; Copper; Diethylene triamine; diethylenetriamine; Fourier analysis; Fourier transforms; heavy metal ions; Imines; Infrared analysis; Infrared spectroscopy; Isoelectric points; Nanocrystals; Nitrogen; periodate oxidation; Spectrum analysis; X-ray diffraction; Zeta potential
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules26237315

In this work, the amino-functionalized cellulose nanocrystal (ACNC) was prepared using a green route and applied as a biosorbent for adsorption of Cr(VI), Pb2+, and Cu2+ from aqueous solutions. CNC was firstly oxidized by sodium periodate to yield the dialdehyde nanocellulose (DACNC). Then, DACNC reacted with diethylenetriamine (DETA) to obtain amino-functionalized nanocellulose (ACNC) through a Schiff base reaction. The properties of DACNC and ACNC were characterized by using elemental analysis, Fourier transform infrared spectroscopy (FT-IR), Kaiser test, atomic force microscopy (AFM), X-ray diffraction (XRD), and zeta potential measurement. The presence of free amino groups was evidenced by the FT-IR results and Kaiser test. ACNCs exhibited an amphoteric nature with isoelectric points between pH 8 and 9. After the chemical modification, the cellulose I polymorph of nanocellulose remained, while the crystallinity decreased. The adsorption behavior of ACNC was investigated for the removal of Cr(VI), Pb2+, and Cu2+ in aqueous solutions. The maximum adsorption capacities were obtained at pH 2 for Cr(VI) and pH 6 for Cu2+ and Pb2+, respectively. The adsorption all followed pseudo second-order kinetics and Sips adsorption isotherms. The estimated adsorption capacities for Cr(VI), Pb2+, and Cu2+ were 70.503, 54.115, and 49.600 mg/g, respectively.