Valorization of Eichhornia crassipes for the production of cellulose nanocrystals further investigation of plethoric biobased resource.

Chemical processing is among the significant keys to tackle agro-residues utilization field, aiming to obtain value-added materials. Extraction of cellulose nanocrystals (CNCs) is an emerging route to valorize lignocellulosic wastes into high value particles. In this investigation, effect of acidic hydrolysis duration was monitored on size and morphology of obtained crystals; namely: CNCs from Nile roses fibers (NRFs) (Eichhornia crassipes). Different acidic hydrolysis duration range or different characterization techniques set this article apart from relevant literature, including our group research articles. The grinded NRFs were firstly subjected to alkaline and bleaching pretreatments, then acid hydrolysis process was carried out with varied durations ranging from 5 to 30 min. Microcrystalline cellulose (MCC) was used as reference for comparison with NRFs based samples. The extracted CNCs samples were investigated using various techniques such as scanning electron microscopy (SEM), Atomic force microscopy (AFM), Raman spectroscopy, and thermogravimetric (TGA) analysis. The figures gotten from SEM and AFM depicted that NRFs based CNCs appeared as fibril-like shapes, with reduced average size when the NRFs underwent pulping and bleaching processes. This was indicated that the elimination of hemicellulose and lignin components got achieved successfully. This outcome was proven by chemical composition measurements and TGA/DTG curves. On the other hand, AFM-3D images indicated that CNCs topology and surface roughness were mostly affected by increasing hydrolysis durations, besides smooth and homogeneous surfaces were noticed. Moreover, Raman spectra demonstrated that the particle size and crystallinity degree of NRFs based CNCs can be affected by acidic hydrolysis durations and optimum extraction time was found to be 10 min. Thermal stability of extracted CNCs-NRFs and CNCs-MCC was measured by TGA/DTG and the kinetic models were suggested to identify the kinetic parameters of the thermal decomposition of CNCs for each acid hydrolysis duration. Increasing hydrolysis duration promoted thermal stability, particularly for NRFs based CNCs. Results showcased in this article add new perspective to Nile rose nanocellulose and pave down the way to fabricate NRFs based humidity nano-sensors.

Influence of electrospinning parameters on biopolymers nanofibers, with emphasis on cellulose & chitosan.

Background: Electrospinning is an effective method for producing high-quality biopolymer nanofibers, such as cellulose and chitosan. Cellulose nanofibers have excellent mechanical properties and biocompatibility, making them a promising material for tissue engineering. Chitosan nanofibers are biodegradable, biocompatible, and antimicrobial, making them ideal for biomedical applications. The electrospinning parameters, including solution concentration, power supply voltage, orifice diameter, temperature, humidity, and flow rate, play a crucial role in determining the nanofiber diameter, morphology, and mechanical properties, as well as their suitability for various applications. Objective: This systematic review aims to synthesize and evaluate the current evidence on the influence of electrospinning parameters on the production and properties of cellulose and chitosan nanofibers. Methods: A comprehensive search of electronic databases was conducted to identify relevant studies. The inclusion criteria were studies that investigated the effect of electrospinning parameters on cellulose and chitosan nanofibers. Results: It was found that for cellulose, the average fiber diameter increased with increasing each of solution concentration, power supply voltage, orifice diameter, temperature, and humidity. Contrary to tip - collector distance and some optimal points in temperature, where average fiber diameter decreased. For chitosan, the change in voltage and tip to collector distance did not alter the average fiber diameter except for some readings of voltage, which behaved differently. On the other hand, the average fiber diameter increased with increasing flow rate. Conclusion: The review highlights the importance of considering electrospinning parameters in the production of high-quality biopolymer nanofibers and provides insights into the optimization of these parameters for specific applications. This review also highlights the need for further research to better understand the underlying mechanisms of electrospinning and to optimize the process to produce biopolymer nanofibers with improved properties.

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

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.

Current Status of Cellulosic and Nanocellulosic Materials for Oil Spill Cleanup.

Recent developments in the application of lignocellulosic materials for oil spill removal are discussed in this review article. The types of lignocellulosic substrate material and their different chemical and physical modification strategies and basic preparation techniques are presented. The morphological features and the related separation mechanisms of the materials are summarized. The material types were classified into 3D-materials such as hydrophobic and oleophobic sponges and aerogels, or 2D-materials such as membranes, fabrics, films, and meshes. It was found that, particularly for 3D-materials, there is a clear correlation between the material properties, mainly porosity and density, and their absorption performance. Furthermore, it was shown that nanocellulosic precursors are not exclusively suitable to achieve competitive porosity and therefore absorption performance, but also bulk cellulose materials. This finding could lead to developments in cost- and energy-efficient production processes of future lignocellulosic oil spillage removal materials.

Characteristics of starch-based biodegradable composites reinforced with date palm and flax fibers.

The aim of this work is to study the behavior of completely biodegradable starch-based composites containing date palm fibers in the range from 20 to 80 wt%. Hybrid composites containing date palm and flax fibers, 25 wt% each, were also examined. The composites were preheated and then hot pressed at 5 MPa and 160°C for 30 min. SEM investigation showed strong adhesion between fibers and matrix. Density measurements showed very small void fraction (less than 0.142%) for composites containing up to 50 wt% fiber content. Increasing fiber weight fraction up to 50 wt% increased the composite static tensile and flexural mechanical properties (stiffness and strength). Composite thermal stability, water uptake and biodegradation improved with increasing fiber content. The present work shows that starch-based composites with 50 wt% fibers content have the optimum mechanical properties. The hybrid composite of flax and date palm fibers, 25 wt% each, has good properties and provides a competitive eco-friendly candidate for various applications.