Removal Of Non-cellulosic Components Research Articles

Production and Characterization of Nanocellulose from Maguey (Agave cantala) Fiber.

Plant fibers have been studied as sources of nanocellulose due to their sustainable features. This study investigated the effects of acid hydrolysis parameters, reaction temperature, and acid concentration on nanocellulose yield from maguey (Agave cantala) fiber. Nanocellulose was produced from the fibers via the removal of non-cellulosic components through alkali treatment and bleaching, followed by strong acid hydrolysis for 45 min using sulfuric acid (H2SO4). The temperature during acid hydrolysis was 30, 40, 50, and 60 °C, and the H2SO4 concentration was 40, 50, and 60 wt. % H2SO4. Results showed that 53.56% of raw maguey fibers were isolated as cellulose, that is, 89.45% was α-cellulose. The highest nanocellulose yield of 81.58 ± 0.36% was achieved from acid hydrolysis at 50 °C using 50 wt. % H2SO4, producing nanocellulose measuring 8-75 nm in diameter and 72-866 nm in length, as confirmed via field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) analysis. Fourier-transform infrared spectroscopy (FTIR) analysis indicated the chemical transformation of fibers throughout the nanocellulose production process. The zeta potential analysis showed that the nanocellulose had excellent colloidal stability with a highly negative surface charge of -37.3 mV. Meanwhile, X-ray diffraction (XRD) analysis validated the crystallinity of nanocellulose with a crystallinity index of 74.80%. Lastly, thermogravimetric analysis (TGA) demonstrated that the inflection point attributed to the cellulose degradation of the produced nanocellulose is 311.41 °C.

Plasma Treatment as a Sustainable Method for Enhancing the Wettability of Jute Fabrics

In this paper, raw jute fabric was subjected to atmospheric pressure dielectric barrier discharge (at 150 or 300 Hz) to enhance its wettability, i.e., capillarity and wetting time. Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy and Field Emission Scanning Electron Microscopy (FE-SEM) were used to assess the changes in the fabrics’ surface chemistry and morphology induced by plasma treatments. The obtained results revealed that both plasma treatments enhanced the wettability of jute fabrics, which could be ascribed to the changes in the fibers’ surface chemistry (the removal of non-cellulosic components, exposure of the cellulose molecules, and oxidation) and morphology (increased roughness due to etching of the surface layers and partial fibrillation). Capillary rise heights increased by approximately 1.8 and 1.9 times, and wetting times were 35 and 34 times shorter 24 h after the plasma treatment at 150 and 300 Hz, respectively. Special attention was given to the aging effect of plasma treatment indicated no significant changes in the fabrics’ capillarity and wetting time after 28 and 7 days, respectively, proving the durability of the effects of plasma treatment. Plasma-treated raw jute fabrics could be used as water-binding geo-prebiotic polysaccharide supports to provide the necessary water for the initial growth of cyanobacterial biocrusts. The lack of moisture is the main constraint in biocrust development after cyanobacterial inoculation. The combination of such water-supportive fabrics and cyanobacterial strains could be used for the rehabilitation of various degraded lands, sediments, and substrates, as well as for air and water pollution control.

Comparative Characteristics of Hemp Nanocellulose Extracted by Different Methods

Abstract: The study describes the extraction of nanocellulose from organosolv hemp pulp (OHP) by different methods: acid hydrolysis, oxidation in the medium of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) and in deep eutectic solvent (DES). OHP was obtained from renewable plant material - hemp fibers by extraction with NaOH solution and cooking using a mixture of acetic acid and hydrogen peroxide. SEM and FTIR data confirmed the reduction of cellulosic fibers and the removal of non-cellulosic components from hemp samples during their sequential thermochemical treatment. The data of X-ray structural and thermogravimetric analyzes confirmed that with increasing crystallinity index and resistance of cellulose-containing hemp samples to the influence of temperature, the obtained nanocelluloses are arranged in the following order: OHP – NCD – NCT – NCH. The values of physical and mechanical parameters of hemp nanocelluloses obtained by different methods are compared. It was established that with approximately the same values of the transverse size of hemp nanoparticles, nanocellulose obtained in the process of acid hydrolysis (NСH) has higher values of physical and mechanical parameters than nanocellulose obtained in TEMPO-medium (NCT) and in the DES (NCD).

The effects of alkaline treatment on the oil residue, thermal properties and surface morphology of oil palm Mesocarp fiber

AbstractOil palm mesocarp fiber (MF) holds the potential to be used as a filler in polymeric biocomposite systems. To further improve the dispersion and interfacial adhesion between the fiber and polymer matrix, MF was treated with sodium hydroxide (NaOH) at different concentrations (1%, 3%, 5%, 8% and 10%) and soaking times(1 h, 4 h, 8 h, 24 h and 48 h). The effects of NaOH solution and soaking duration on the oil residue, thermal stability and surface morphology of the MF were investigated. It was found that the soaking time had a prominent effect on the oil residue content compared to the NaOH concentration. Fourier transform infrared spectra demonstrated that alkaline treatment decreased the peak intensities of the carboxyl group and alkene of the fatty acid (oil) at 1630–1700 cm–1. Meanwhile, the clean and smooth surface of MF was revealed by scanning electron microscopy, indicating the removal of noncellulosic components. The treatment also reduced the degree of crystallinity of MF, as reflected by its melting temperature (Tm) and heat of melting (ΔHm), as measured by using differential scanning calorimetry. MF with oil residue is envisioned to improve the fiber dispersion across the polymer matrix during polymer processing.

Cellulose fibers extracted from sesame hull using subcritical water as a pretreatment

Sesame processing facilities typically discard sesame seed hulls (SH) as waste or animal feed. However, these hulls are rich in cellulose and make them potentially valuable to the food industry. This study for the first time studied the effect of subcritical water (SW) and alkali (AT) pretreatment on extraction of purified cellulose from SH. The results indicated that the yield of SWCs (cellulose obtained by subcritical water pretreatment, 9.2–11.6%) was close to that of ATC (cellulose obtained by alkali pretreatment, 10.1%). Crystallinity of SWCs (68.7–75.8%) was significantly higher than ATC (60.9%). Subcritical water pretreatments interfered more significantly than alkali with the removal of non-cellulosic components according to Fourier transform infrared spectrometry and scanning electron microscope photographs. In addition, the diameter of the SWC was smaller than ATC, and the obtained SWC was comparable to ATC in terms of thermal stability. This study shows that subcritical water, as an environmentally friendly solvent, can be used to extract good quality cellulose from SH. In addition, subcritical water is more effective than alkali, suggesting it could be used more widely in the food industry for producing cellulose from other sources.

Non-Acidic Method for Isolation of Microcrystalline Cellulose From Oil Palm Empty Fruit Bunch Fiber

In this study, the microcrystalline cellulose (MCC) was extracted via a non-acidic method from the oil palm empty fruit bunch (EFB) cellulose. The extraction was conducted through Ammonium Persulfate (APS) oxidation treatment, which was followed by the ball milling process. The effects of varied temperature levels from APS oxidation treatment (60, 80 and 90oC) and different milling time (1, 4 hours) were investigated. APS oxidation treatment at 90oC was found to produce the most optimum results. The size of the MCC was less than 20μm and had demonstrated the highest degree of crystallinity index and thermal stability. The high crystallinity index is associated with the removal of non-cellulosic components as seen from FTIR analysis, where a decrease was observed in the characteristic peak intensity of 1735 and 1510 cm-1. The milling time had also affected the formation of MCC. Although a relatively longer milling time had produced smaller MCC with narrow size distribution, it had, however, given rise to a slight adverse effect on the crystallinity index and thermal stability.

Environmentally-Friendly Extraction of Cellulose Nanofibers from Steam-Explosion Pretreated Sugar Beet Pulp.

Cellulose nanofibers (CNFs) with an average diameter of 22 nm were prepared from sugar beet pulp (SBP) via an environmentally-friendly method. Steam-explosion pretreated SBP was treated with hydrogen peroxide (H2O2) bleaching, high-speed blending, and ultrasonic treatment. Thermogravimetric analysis showed that hemicellulose was partially hydrolyzed in the steam-cooking stage, pectin was removed in the explosion stage, and lignin was removed by H2O2 bleaching. The removal of non-cellulosic components was confirmed by Fourier-transform infrared (FT-IR) spectroscopy. Morphological analysis showed that steam-explosion pretreatment largely extracted the binder materials of hemicellulose and pectin. This exposed the microfibrillated cellulosic fibers, which promoted subsequent nanofibrillation. X-ray diffraction showed that the CNFs had a crystallinity index of 62.3%. The CNFs had good thermal stability, and thus have potential for use as fillers in polymer matrices. The only chemical reagent used in this green method was H2O2. Combining H2O2 bleaching with steam explosion, high-speed blending, and ultrasonic treatment reduced the overall energy consumption and increased the efficiency of the CNFs extraction. The method, therefore, has potential application in industrial processes.

Isolating cellulose nanofibers from steam-explosion pretreated corncobs using mild mechanochemical treatments

Cellulose nanofibers (CNFs) with an average diameter 8 nm were isolated from corncobs using a stepwise method that included steam-explosion pretreatment, alkaline treatment, sodium hypochlorite bleaching, high-speed blending, and ultrasonic treatment. This mechanochemical method used only two chemical reagents in low concentrations to remove non-cellulosic components. The removal of non-cellulosic components was confirmed by Fourier-transform infrared spectroscopy. X-ray diffraction revealed an increase in crystallinity during steam explosion and subsequent mechanochemical treatments. Pretreatment by steam explosion caused the partial hydrolysis of hemicellulose and loosened the structure of raw materials, which facilitated the subsequent chemical processes. The thermal stability and morphology of samples at different stages were also investigated. Steam explosion increased the thermal stability of hemicellulose and cellulose components, as it removed a fraction of hemicellulose. High-speed blending reduced the entanglement of cellulosic fibers and created uniform size. Ultrasonic treatment was used in the final step of nanoscale fibrillation. The method used in this study is environmentally friendly and has the potential to be applied at industrial scale.

Extraction and structural characterization of cellulose from milkweed floss

ABSTRACTThe aim of this study was to investigate the utilization of milkweed fruit floss residues as a source for the isolation of cellulose. Cellulose was extracted by acidified sodium chlorite and sodium hydroxide treatments. Characterization of the pristine milkweed floss and extracted cellulose was performed by chemical composition analysis, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The extracted cellulose had mainly α-cellulose as the other components hemicellulose and lignin were significantly removed during cellulose extraction process. The FTIR spectra also indicated that the chemical treatments extensively removed hemicellulose and lignin from the pristine milkweed floss. SEM technique was used to investigate the surface morphology of the pristine milkweed floss and extracted cellulose. The intensity of the crystalline peak in the X-ray diffractograms of the extracted cellulose was higher than that of pristine milkweed. Further, the XRD results indicated a structural transformation of cellulose I (pristine milkweed) to cellulose II (extracted cellulose) because of the chemical treatments. The extracted cellulose, which is a high biomass, had better thermal stability than the pristine milkweed floss owing to removal of non-cellulosic components.

Individual cotton cellulose nanofibers: pretreatment and fibrillation technique

We report a method to fibrillate raw dried cotton fibers into individual cellulose nanofibers (CNFs) by chemical purification (removal of non-cellulosic components) and pretreatment by a high-speed blender (breaking down the fiber structures) combined with high-pressure homogenization (nanofibrillation). The resultant CNFs were found to have a width of approximately 10–30 nm and high aspect ratios. The high light transmittance of the CNF/acrylic resin composite indicated that our treatment successfully disintegrated the raw cotton fibers into uniform CNFs. The cotton CNFs were found to have the advantages of high crystallinity and thermal stability.

Morphology and Structure of Modified Oil Palm Empty Fruit Bunch Cellulose Fibre

Oil palm empty fruit bunch (OPEFB) cellulose fibre has been widely used as a reinforcing filler in polymer composites. Surface modification of OPEFB fibre was aimed enhancing inter-phase adhesion with a poly(lactic acid) matrix. In this study, the OPEFB fibres were pre-treated in a sodium hydroxide solution. Surface compositions and thermal stability of the fibres were studied using ATR-FTIR and TGA techniques, respectively. The pre-treatment resulted in the removal of non-cellulosic components leaving purer fibres. In addition, an acetylation of OPEFB cellulose fibres by acetic anhydride was conducted under solvent free condition at room temperature (30 °C). The acetylation reaction was catalyzed by iodine. The degree of substitution monitored by solid state 13C NMR depended upon reaction time and molar ratio of OPEFB cellulose and acetic anhydride. Crystalline structure and morphology of the partial acetylated fibres were investigated using WAXD and SEM, respectively.

Effect of processing route on the composition and properties of hemp fibre

There is great interest in the plant Cannabis sativa (hemp) as a source of technical fibres for the reinforcement of polymers in composite materials due to its high mechanical properties. In this work, the effect of enzymatic, hydrothermal and alkaline treatments on the composition and mechanical properties of hemp fibre are compared. The influence of enzyme concentration and treatment time was examined (2.5–80 % Pectinex® Ultra SP-L, 6–48 hrs). Additionally, hydrothermal (170 °C, 10 bars) and alkaline treatments (18 wt. % NaOH, 40 °C) were used as pre-treatments to observe their effect on subsequent enzymatic treatment. The composition of hemp fibre was analysed by wet chemistry and Fourier transform infrared spectroscopy, while microstructure and mechanical properties were examined by scanning electron microscopy and tensile testing, respectively. Enzymatic treatment resulted in extensive fibrillation and removal of non-cellulosic components, especially when combined with hydrothermal treatment. However, a lengthy enzymatic treatment or combinative enzymatic-alkaline treatment led to extensive fibre breakdown that was accompanied by a pronounced reduction in the mechanical properties. Enzymatic treatment decreased Young’s modulus and tensile strength by 77 and 73 % respectively, and alkaline treatment by 83 and 36 %. The hydrothermal treatment resulted in only minor changes in these properties.