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Diverse renewable resources, especially those obtained from residual agricultural wastes, are being exploited to reduce the impact of environmental damage. This study presents a method to produce purified cellulose extracted from locally planted pineapple leaves (Ananas comosus). The cellulose was extracted by maceration pretreatment. The heating times were varied. This method is a simpler and more effective approach to delignify the pineapple leaf fibers compared with conventional chemical pulping and bleaching processes. The chemical composition of the cellulose was investigated according to TAPPI standards and by structural analyses, namely Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). The results indicated that the hemicellulose and lignin were partially removed from the cellulose. Chemical analysis confirmed that the cellulose content increased from 25.8% (pineapple leaf fibers) to 70.9% (macerated cellulose). The optimum heating time was 3 h. However, XRD showed that the extracted cellulose had a higher crystallinity index than the initial pineapple leaf fibers. These results indicated that pretreatment via maceration has good potential applications in the production of macerated cellulose. [ABSTRACT FROM AUTHOR]

In this study, soda alkali lignin from oil palm empty fruit bunch (EFB-AL) and kenaf core (KC-AL) are esterified with maleic anhydride under two different conditions, namely i) pyridine at temperature of 120°C for 3h and ii) aqueous alkaline solution at room temperature for 4h. As a result, the weight percentage gain (WPG) of the esterified EFB-AL (EFB-EL) and esterified KC-AL (KC-EL) in pyridine demonstrated a higher compared to aqueous alkaline solution. The FT-IR results of EFB-EL and KC-EL in both solvents exhibited some changes at the carbonyl and hydroxyl groups. Furthermore, the esterification process induced the carboxylic peak to appear in both alkali lignin samples. The outcome is confirmed by conducting H-NMR analysis, which demonstrated ester and carboxylic acid peaks within the spectral analysis. Finally, the TGA results showed both EFB-EL and KC-EL that are exposed to aqueous alkaline actually possessed better thermal stability and higher activation energy (Ea) compared to the esterified samples in pyridine. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) was used as a catalyst support and for regeneration of a homogeneous catalyst in the catalytic conversion of glucose to lactic acid (LA). First, a solid base catalyst was prepared through the adsorption of Pb2+ ions by GO through ionic interaction with oxygenated groups of GO. The collected GO-Pb catalyst was characterized, demonstrating the successful loading of Pb2+ onto GO sheets using FTIR and XPS. The GOPb catalyst was subsequently used for the conversion of glucose into LA. A maximum LA yield of approximately 30% was achieved in 30 min. The catalyst demonstrated the ability to be used for at least five cycles. In contrast, the leached Pb2+ ions during the hydrothermal process were regenerated through adsorption with fresh GO. The regenerated catalyst demonstrated the possibility of the regenerated Pb2+ ions for further catalytic conversions of lactic acid. This study could be essential to produce valuable chemicals through the use of heterogeneous catalysts that are produced via a simple and environmental benign process. [ABSTRACT FROM AUTHOR]

Kenaf core pulp has been successfully autohydrolysed using an autoclave heated in oil bath at various reaction temperature at 100, 120 and 140 °C. Membranes, hydrogels and aerogels were then prepared from autohydrolysed kenaf in urea/alkaline medium by casting on the glass plate, by using epichlorohydrin (ECH) as cross-linker via stirring and freeze-drying method, respectively. The autohydrolysis process reduced the molecular weight of cellulose and enhanced cellulose solubility and viscosity. Structure and properties of the regenerated products were measured with Field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), Ultraviolet–visible (UV–Vis) spectrophotometer and swelling testing. As the autohydrolysis temperature increased, the porosity of cellulose membranes (as seen from the morphology) increased. The autohydrolysis process improved the swelling porperties and transparency of regenerated cellulose hydrogels. This finding is expected to be useful in reducing molecular weight of cellulose in order to produce regenerated bio-based cellulose materials. [ABSTRACT FROM AUTHOR]

As the demand towards nanocellulose increases day by day due to its excellent characteristics such as biodegradability, thermal stability and biocompatibility, Elaeis guineensis frond (oil palm frond, OPF) serves as a new promising renewable sources for sustainable nanocellulose production. Synthesis of nanocellulose from OPF was performed through three different chemical treatments including alkaline, bleaching and acid hydrolysis processes. Acid hydrolysis on commercialized Sigma cellulose was also performed in order to compare it with OPF nanocellulose. The chemical structure, crystallinity, suspension stability, particle size and morphology of the synthesized nanocellulose were characterized using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), particle size analyser with zeta potential, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM). FTIR spectra after the chemical treatments showed the elimination of certain chemical groups of lignin and hemicellulose from raw OPF. XRD diffractograms revealed that OPF nanocellulose showed crystallinity improvement compared to OPF cellulose, while Sigma nanocellulose showed crystallinity deterioration against chemical treatments. From physical appearance, both nanocellulose specimens were stable in suspension form. OPF nanocellulose specimens were smaller in size compared to Sigma nanocellulose as shown in the results of particle size analyser, FESEM, TEM and AFM. All these results confirmed the production of nanocellulose, which was synthesized from OPF that have potential for sustainable development, includes ecology and economics. [ABSTRACT FROM AUTHOR]