Lignin-Derived Oil Palm Biomass Using Deep Eutectic Solvent

The effects of a hydrogen bond acceptor and hydrogen bond donor on carbon dioxide absorption via natural deep eutectic solvents were studied in this work. Naturally occurring non-toxic deep eutectic solvent constituents were considered; choline chloride, b-alanine, and betaine were selected as hydrogen bond acceptors; lactic acid, malic acid, and fructose were selected as hydrogen bond donors. Experimental gas absorption data were collected via experimental methods that uses gravimetric principles. Carbon dioxide capture data for an isolated hydrogen bond donor and hydrogen bond acceptor, as well as natural deep eutectic solvents, were collected. In addition to experimental data, a theoretical study using Density Functional Theory was carried out to analyze the properties of these fluids from the nanoscopic viewpoint and their relationship with the macroscopic behavior of the system, and its ability for carbon dioxide absorption. The combined experimental and theoretical reported approach work leads to valuable discussions on what is the effect of each hydrogen bond donor or acceptor, as well as how they influence the strength and stability of the carbon dioxide absorption in deep eutectic solvents. Theoretical calculations explained the experimental findings, and combined results showed the superiority of the hydrogen bond acceptor role in the gas absorption process, with deep eutectic solvents. Specifically, the cases in which choline chloride was used as hydrogen bond acceptor showed the highest absorption performance. Furthermore, it was observed that when malic acid was used as a hydrogen bond donor, it led to low carbon dioxide solubility performance in comparison to other studied deep eutectic solvents. The cases in which lactic acid was used as a hydrogen bond donor showed great absorption performance. In light of this work, more targeted, specific, deep eutectic solvents can be designed for effective and alternative carbon dioxide capture and management.

The expansion of the oil palm industry has affected the environment and the poor handling of oil palm waste has greatly endangered the habitat surrounds it. The oil palm natural fibre waste can be put to good use and used as a sound absorber for its amazing acoustic properties. At the same time, the demand for natural fibre sound-absorbing panels is increasing due to its low-cost fabrication and its healthier than synthetic fibre. This research has studied the acoustic properties of mixing Empty Fruit Bunch (EFB) and Oil Palm Frond (OPF) in a thickness of 12 mm, 14 mm, 16 mm, and 18 mm. The fibreboard has been fabricated at a density of 120 kg/m3. The Sound Absorption Coefficient, SAC, and morphologies of all the samples were examined using the Impedance Tube Method (ITM) and Scanning Electron Microscope, (SEM). The sample’s SAC value increased with thickness. It is noteworthy that this combination percentage of natural fibres of EFB and OPF show good acoustic performance where the SAC values above 0.8 at wide frequency 3000 - 6400 Hz. Sample thickness 14 mm, 18 mm achieved unity (1.0) at frequency 4000 - 5500 Hz. In addition, all the samples were found to exceed 90 % of the absorption rate in the range of 4500 - 6400 Hz. The morphology content of EFB and OPF helps in enhancing the absorption rate.

This work study about the extraction of lignin from Empty Fruit Bunch (EFB). It is a type of lignocellulosic waste produced during the palm oil extraction process. There are three main components of lignocellulosic, which is one of them is lignin. A deep eutectic solvent (DES) with microwave-assisted heating has been used as a process to extract the lignin from EFB and turn it into a value-product. This convenient method was started with the mixing of EFB and DES. After that, the mixture was heated via microwave synthesis reactor at different temperature and time parameters. The extracted lignin yield was dried and ground into a powder form. The highest lignin yield recovered is 30 % by the highest time and temperature. Interestingly, the purity of all lignin yields are above than 80 %. The highest yield of lignin was characterized. According to Fourier-Transform Infrared (FTIR) spectra, there was a significant functional group of phenolic and aliphatic hydroxyl in lignin. Besides, the methoxy group was also configured in lignin spectra. The presence of conjugated alkene also conveyed the characteristic of lignin. The FTIR spectra were intensified with 1H Nuclear Magnetic Resonance (NMR) spectra where there was a chemical shift in lignin and raw EFB which was designated to aliphatic and aromatic protons bonded to a carbon atom. Three regions of decomposition occur in the Thermogravimetric Analysis (TGA) spectra. The initial decompose temperature of lignin was lower compare to raw EFB. Next, second-stage lignin decomposed at 434.14 ℃ with weight loss of 36.21 %. Lastly, for the final stage, lignin decomposes at 552.54 ℃. Moreover, Differential Scanning Calorimetry (DSC) spectra demonstrate that the Tg value of lignin managed to be identified. However, the Tg value of raw EFB cannot be well defined. As for the characterization in residual fractions of EFB, the lowest crystallinity index (CrI) value of raw EFB has proven the presence of lignocellulosic in its structure. The residual fractions that reacted at higher temperatures have an inflated value of CrI as they contain abundant left out cellulose.

Lignocelluloses complexity has led to poor dissolution efficiency in solvents. This study was conducted to concentrate hemicellulose content in oil palm empty fruit bunches (EFB) using green solvent, choline chloride (ChCl)-based deep eutectic solvent (DES). Results showed that ChCl: formic acid (FA) is the most effective among the DES in concentrating hemicellulose content in treated EFB and exhibits the highest dissolution power of lignin. The toxicity test showed that all the synthesized DES had negligible effect against Escherichia coli and Salmonella typhimurium. Nevertheless, all of them possessed comparable cell proliferation to their individual counterparts, ChCl, glycerol, lactic acid (LA) and FA, which implied that these DES could be used in the intended industries.

Investigating the effect of systematically modifying the molar ratio of hydrogen bond donor and acceptor on solvation characteristics of deep eutectic solvents formed using choline chloride salt and polyalcohols

Composites polyvinyl alcohol filled with nanocellulose from oil palm empty fruit bunch (OPEFB) and oil palm fronds (OPF) have investigated. Nanocellulose prepared by formic acid 50 wt%. Functional groups and degree of crystalline of nanocellulose were analyzed by FTIR and XRD. The degree of crystalline nanocellulose presented at 2θ at intensity of 22.26 and 21.86 for OPEFB and OPF. Amorphous part of nanocellulose at intensity of 14.68 and 15.86 for OPEFB and OPF. Functional group of nanocellulose give the same pattern for OPEFB and OPF. Nanocellulose reinforce in polyvinyl alcohol as many as 1, 5, 10 and 20% and as a comparison with polyvinyl alcohol without filler. Eight of composite films and one of vinyl alcohol film have studied mechanical properties such as tensile strength and elongation at break, and also functional groups. The tensile strength of OPF 5% and 10% increased than polyvinyl alcohol matrix. Tensile strength OPEFB 10% slightly increase from polyvinyl alcohol. The elongation of composites both OPEFB and OPF decreased with increased of nanocellulose loading.

Redox and emission characteristics of Eu3+ in deep eutectic solvent: Unraveling the hidden potential of DES as luminescent media

An oil palm empty fruit bunch (EFB) sample was sequentially treated with ozone, 5 % NaOH, and ozone again under environmentally friendly and mild conditions to prepare cellulose-rich materials from agricultural EFB wastes. The ozonated, 5 % NaOH-treated, and re-ozonated products (O 3 -EFB, Ex-O 3 -EFB, and O 3 -Ex-O 3 -EFB, respectively) were obtained at mass recovery ratios of 83 %, 65 %, and 50 %, respectively, based on the dry mass of the raw EFB. The O 3 -EFB and Ex-O 3 -EFB samples maintained their original stick-like fiber bundle morphologies. In contrast, the O 3 -Ex-O 3 -EFB sample exhibited mostly individualized fibers. The relative glucose unit content increased from 39 % EFB to 79 % in O 3 -Ex-O 3 -EFB after removal of non-cellulosic components. The O 3 -Ex-O 3 -EFB contained a carboxy-group content of 0.37 mmol/g, which could be used as electrostatic adsorption sites of cationic compounds, nanoparticles, and metals by ion-exchange in aqueous systems. Ozonation remarkably depolymerized the cellulose molecules. However, this sample exhibited a broad molar-mass-distribution characteristic of the EFB sample, which are advantageous for better mechanical properties. The solid-state 13 C NMR spectra of the EFB samples showed the removal of acetyl ester groups in hemicelluloses and lignin during sequential treatment. Based on the results obtained in this study, suitable and unique application fields of EFB samples, different from wood chemical pulps, are provided. • Sequential O 3 -5 % NaOH-O 3 treatment increases cellulose content of EFB from 39 to 79 %. • O 3 -Ex-O 3 -treated EFB exhibits mostly individualized fibers by delignification. • O 3 -Ex-O 3 -treated EFB contains a high weak acid-group content of 0.37 mmol/g. • Degree of polymerization drops from ∼2000 for EFB to ∼330 for O 3 -Ex-O 3 -treated EFB. • 13 C NMR spectra show efficient removal of acetyl groups and lignin during treatment.

Gallic acid (GA) (3,4,5-trihydroxybenzoic acid), which is a natural secondary metabolite and widely isolated from various plants, is for the first time employed as a hydrogen bond donor (HBD) for preparing a deep eutectic solvent (DES) with choline chloride (ChCl) as a hydrogen bond acceptor (HBA). This DES has been applied as an extractant to separate gycerol from biodiesel. The finding indicates that a DES could be formed at a molar ratio of ChCl to GA of 5 : 1, 6 : 1, and 7 : 1. The characterization of the synthesized DES shows its acidic polar property with a pH of lower than its constituents, density of lower than biodiesel, and the viscosity within the range reported for previously prepared DES. Functional groups analysis using FTIR indicated the presence of all functional groups from GA and ChCl in the DES structure, along with the absence of any new spectral peaks, suggesting that there was no chemical reaction involved in the DES formation. Its ability to reduce the glycerol concentration in the biodiesel in the range of 74.6 to 99.8 % denotes its capability as a potential extractant for separation of glycerol from biodiesel.

Study of the pseudo-ternary aqueous two-phase systems of deep eutectic solvent (choline chloride:sugars) + K2HPO4 + water

This study investigates the effect of using water as a low-viscosity component in ternary amine-based deep eutectic solvents (DESs) on the physicochemical properties, thermal stability, and CO2 absorption capacity of the resulting DESs. It should be emphasized that water is a component of the ternary DES. The effect of water content in the DES, type of hydrogen bond acceptors (HBAs), hydrogen bond donors (HBDs), and HBA:HBD ratio on the above parameters was investigated. Moreover, the effect of temperature and pressure on the CO2 absorption capacity of DESs was predicted using the predictive model COSMO-RS. This model was also used to predict the CO2 solubility in the DESs and the results were compared with the experimental values. The results showed that the addition of small amounts of water, e.g., 5 and 10 wt% during preparation, can significantly decrease the viscosity of the resulting DESs, up to 25% at room temperature, while maintaining the high CO2 absorption capacity and high thermal stability. The ternary DESs based on MEA exhibited a high CO2 absorption capacity of 0.155–0.170 g CO2 / g DES. The ternary DESs were found to be thermally stable with a decomposition temperature of 125°C, which promotes the use of such solvents in post-combustion capture processes. Finally, COSMO-RS proved to be a suitable tool for qualitative prediction of CO2 solubility in DESs and demonstration of trends related to the effects of temperature, pressure, molar ratio, water content, HBD and HBA on CO2 solubility.

Deep eutectic solvents (DESs) have gained popularity in various applications due to their improved environmental sustainability and biodegradability. For the present study, several polyhydric alcohols, including ethylene glycol (EG), diethylene glycol (DEG), triethylene glycol (TEG), and glycerol (Gly), have been used as hydrogen bond donors (HBDs) and choline chloride (ChCl) as a hydrogen bond acceptor (HBA) in a fixed molar ratio to form a homogenous and stable DES. Controlled water mixing into such neat DESs has always been thought to be a quick and efficient method to tune the chemical and thermodynamic properties of DESs. The structural solvation and dynamics of the prepared DESs with the inclusion of water vary from low to high water concentrations that have been examined employing Fourier transform infrared (FT-IR), and proton nuclear magnetic resonance (1H-NMR) spectroscopy. Herein, the micellization behavior of a cationic surfactant, dodecyltrimethylammonium bromide (DTAB), in neat DESs and DES-water mixtures has been demonstrated by using tensiometry, dynamic light scattering (DLS), and small-angle X-ray scattering (SAXS) techniques. Furthermore, it has been observed that DESs exhibit an ample thermodynamic driving force for creating micelles, since they contain an H-bonded nanostructure. However, such self-assembly appears to be very much dependent on DESs, the amount of water, and the surfactant used. A computational simulation approach using a semiempirical method is put forth employing the Gaussian 09 W calculation window in the Gauss View 5.0.9 software package. In addition, this study includes the determination of several optimized descriptors that intend to offer an in-depth examination of the surfactant-DES interactions.

Deep eutectic solvents (DESs) have emerged as an alternative to both common organic solvents and ionic liquids (ILs). DESs share physicochemical properties with ILs such as low vapor pressure, high thermal stability, high viscosity while offering advantages such as low toxicity, lower cost, and ease of preparation. Moreover, DESs are attractive candidates for electrochemical applications due to their large voltage windows and solubility properties. DESs as a solvent class share a general composition of a hydrogen bond donor (HBD), typically a polyol, amide, or acid, and a hydrogen box acceptor (HBA), usually a quaternary ammonium or phosphonium salt. At a specific molar composition of a HBD and HBD, the DES forms a eutectic mixture resulting in a large melting point depression due to extensive hydrogen bonding between the components.Despite being widely studied, the microscopic structures of DESs have remained largely uncharacterized. Herein, we present a multitechnique NMR study of two DESs: glyceline (glycerol + choline chloride) and ethaline (ethylene glycol + choline chloride). Fast-field cycling 1H relaxometry, pulsed field gradient diffusion, nuclear Overhauser effect spectroscopy (NOESY), 13C NMR relaxation, and pressure-dependent NMR experiments are deployed to sample a range of frequencies and modes of motion of the polyol and choline components of the DES. Generally, translational and rotational diffusion of polyols are more rapid than those of choline while short-range rotational motions observed from 13C relaxation indicate slow local motion of glycerol at low choline chloride (ChCl) content. We show how the additional hydroxyl group present in glycerol contributes to not only higher viscosities, but a larger perturbation of the hydrogen bonding network by the addition of ChCl.Additionally, we have investigated the solubility properties of several lithium salts (LiTFSI, LiFSI, LiPF6, LiBF4, and LiOAc) in these DESs and utilized the same suite of NMR techniques to understand how they act as solvents. We observe that due to anion effects, the heterogeneities present in DES result in differential solvation for some species where there is a distinction of lithium salts co-existing in these holes as well as the bulk. The large changes in the structural organization of DESs that result from the presence of lithium salts will serve as a guide to the design of a new class of electrolytes for lithium-ion batteries.

Molecularly designed deep eutectic solvents based on choline for site-specific delivery of luteolin in the oral cavity.

New chloroacetic acid-based deep eutectic solvents for solubilizing metal oxides