Cellulose nanocrystals from agricultural residues (Eichhornia crassipes): Extraction and characterization

Mohamed H Hemida; Hesham Moustafa; Sherif Mehanny; Mohamed Morsy; Alain Dufresne; Eid N Abd El Rahman; M M Ibrahim

doi:10.1016/j.heliyon.2023.e16436

Cellulose nanocrystals from agricultural residues (Eichhornia crassipes): Extraction and characterization

Heliyon. 2023 May 25;9(6):e16436. doi: 10.1016/j.heliyon.2023.e16436. eCollection 2023 Jun.

Authors

Mohamed H Hemida¹, Hesham Moustafa^{2

3}, Sherif Mehanny⁴, Mohamed Morsy^{5

6}, Alain Dufresne⁷, Eid N Abd El Rahman¹, M M Ibrahim¹

Affiliations

¹ Agricultural Engineering Department, Faculty of Agriculture, Cairo University, Egypt.
² Department of Polymer Metrology & Technology, National Institute of Standards (NIS), Tersa Street, El Haram, P.O Box 136, Giza, 12211, Giza, Egypt.
³ Bioanalysis Laboratory, National Institute of Standards (NIS), Tersa Street, El Haram, P.O Box 136, Giza, 12211, Giza, Egypt.
⁴ Department of Mechanical Design and Production, Faculty of Engineering, Cairo University, Egypt.
⁵ Building Physics and Environment Institute, Housing and Building National Research Center (HBRC), Dokki, Giza, Egypt.
⁶ Nanotechnology Research Center (NTRC), The British University in Egypt (BUE), El Sherouk City, Suez Desert Road, Cairo, 11837, Egypt.
⁷ Université Grenoble Alpes, CNRS, Grenoble INP, LGP2, F-38000, Grenoble, France.

Abstract

Extraction of cellulose nanocrystals (CNCs) from agro-residues has received much attention, not only for their unique properties supporting a wide range of potential applications, but also their limited risk to global climate change. This research was conducted to assess Nile roses (Eichhornia crassipes) fibers as a natural biomass to extract CNCs through an acid hydrolysis approach. Nile roses fibers (NRFs) were initially subjected to alkaline (pulping) and bleaching pretreatments. Microcrystalline cellulose (MCC) was used as control in comparison to Nile rose based samples. All samples underwent acid hydrolysis process at a mild temperature (45 °C). The impact of extraction durations ranging from 5 to 30 min on the morphology structure and crystallinity index of the prepared CNCs was investigated. The prepared CNCs were subjected to various characterization techniques, namely: X-ray diffraction (XRD), FT-IR analysis, Transmission electron microscopy (TEM), and X-ray Photoelectron spectroscopy (XPS). The outcomes obtained by XRD showed that the crystallinity index increased as the duration of acid hydrolysis was prolonged up to 10 min, and then decreased, indicating optimal conditions for the dissolution of amorphous zones of cellulose before eroding the crystallized domains. These data were confirmed by FT-IR spectroscopy. However, a minor effect of hydrolysis duration on the degree of crystallinity was noticed for MCC based samples. TEM images illustrated that a spherical morphology of CNCs was formed as a result of 30 min acid hydrolysis, highlighting the optimal 20 min acid hydrolysis to obtain a fibrillar structure. The XPS study demonstrated that the main constituents of extracted CNCs were carbon and oxygen.

Keywords: Acid hydrolysis; Agricultural residues; Cellulose nanocrystals extraction; Nile rose; Transmission electron microscopy; XPS analysis.