Extraction of Lignin from Empty Fruit Bunch Fiber via Microwave-Assisted Deep-Eutectic Solvent Heating

Deep Eutectic Solvent (DES) are eutectic mixes of hydrogen bond acceptors (HBA) and donors (HBD) with melting points significantly lower than their constituents. Choline chloride (ChCl) and glycerol were chosen as HBA and HBD because they are simple to prepare, have low toxicity, are biodegradable, and are environmentally friendly. As a result, the study aims to determine the feasibility of extracting lignin from oil palm fronds (OPF) and empty fruit bunches (EFB) using DES. The molar ratios of DESs were investigated to determine their effect on OPF solubility and lignin yield. The reaction is carried out at a solid loading ratio of 1:10, 150°C, and 6 hours. Because the DES medium induces homogeneous swelling and breakdown of small fibre fragments but not dissolution, both OPF and EFB are insoluble in DES. Small fragment disintegration suggests rapid dissolution, which will be easily dissolved in the DESs. The lignin yield and solubility of EFB and OPF in DESs are significantly reduced when the molar concentration of glycerol is increased. The highest lignin yields, 27.6% (EFB) and 16.1% (OPF) were obtained with a ChCl/glycerol molar ratio of 1:3. The comparatively low lignin yield achieved for both OPF and EFB is ascribed to the poor hydrogen bonding between the chloride ion and the hydroxyl group of the DES due to the low acidity of the DES. Despite this, lignin is extracted successfully due to the presence of chloride ions in ChCl, which target β-O-4 bonds and successfully cleave the ether bonds present in the lignin-carbohydrate linkage.

A new developed of polymer materials made up of polypropylene (PP), recycled nitrile gloves (NBRr) and empty fruit bunch (EFB) fiber was fabricated. Recycled nitrile glove was blended together with PP plastic to reduce the use of petroleum based and to solve the issue of waste discarded at the landfill. EFB fiber was incorporated to lower the production cost of composite. Due to incompatibility of different phases, stearic acid treatment was used to improve the EFB fiber polarity. Thus, the effect of different EFB loading for untreated and treated stearic acid of PP/NBRr/EFB composite was studied. In this work, all the materials were mixed well using a heated two roll mill with temperature 180 °C within 9 minutes. The EFB loading were varied from 0 to 30 phr. The analysis of tensile properties was tested followed the ASTM D638, Type IV, testing procedure, to analyze tensile strength, Young’s modulus and elongation at break. The structural properties of the fracture sample surfaces were observed using Scanning Electron Microscope (SEM) and the chemical properties was analyzed using Fourier Transform Infra-Red (FTIR). Composites with stearic acid treatment have shown higher tensile strength compared to untreated EFB fiber. Besides, the micrograph structure surface from scanning electron microscopy analysis showed better fiber and matrix interaction, as the treated-EFB fiber is well encapsulated with the PP matrix. From the FTIR analysis, the intensity peak of OH for PP/NBRr/EFB/SA was reduced due to the removal O-H bond of cellulose from fibers during the surface modification of fibers.

The objective of this study was to compare the properties of green composites based on tapioca starch (TS) and celluloses isolated from empty fruit bunches (EFB) and commercial celluloses from cotton linter (supplied by Sigma). Empty fruit bunches (EFB) acted as the main source to obtain the cellulose by using a chemical approach whereas the commercial cellulose from Sigma was used as reference. The TS/cellulose composite films were prepared using cellulose in varying proportions as filler into TS matrix by a casting method. The amount of celluloses added into the tapioca starch were 5, 10, 15, 20 and 25 phr (as per dry mass of TS). The celluloses were characterized using Fourier transform infrared (FTTR) spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). While the green composite films were analyzed in terms of thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), SEM and tensile properties. FTTR analysis confirmed the removal of non-cellulosic materials such as hemicelluloses and lignin from raw EFB after the chemical treatment. XRD diffractograms revealed that the crystallinity of celluloses EFB increased from 43.1 % of raw EFB to 52.1 %. SEM images showed the fibrillar structure of cellulose isolated from EFB. The TGA and derivative thermogravimetric (DTG) curves of green composite films showed no significant effect on the thermal stability. Melting temperature of TS/cellulose EFB higher than neat TS while TS/cellulose Sigma lower than neat TS. The green composite films with 15 phr cellulose from EFB filler loading provided the best tensile properties in term of its strength and modulus. However, in term of elongation at break, the percentage elongation decreased with the increased of the amount of filler loading. SEM images of the films demonstrated a good interaction between cellulose filler and TS matrix especially with the addition of 15 phr of cellulose from EFB.

Enzymatic hydrolysis of treated palm oil empty fruit bunches fibre (EFB) using combination alkali-microwave techniques

A total of 37.5 million tons of palm empty fruit bunches (EFBs) produced in Indonesia in 2018 have the potential to be used as an alternative eco-friendly solid fuel. However, a pretreatment process is necessary to increase the heating value and reduce the potassium content of EFBs. Several methods can be employed to improve the characteristics of EFBs as a solid fuel, such as drying and torrefaction to increase the heating value and the leaching process for reducing the potassium content of EFBs. The main concept of increasing the heating value is to increase the fuel content, which is carbon. Through drying, the carbon ratio can be increased by reducing the moisture content and, through torrefaction, the carbon ratio could be increased due to the decomposition of lignocellulose. A simple way to reduce the potassium content of EFBs is the leaching process. Two types of leaching treatment have been studied before: soaking and stirring treatment. This study reviews those methods to make EFBs more suitable as a solid fuel with a high heating value and less potassium content. Increasing the carbon content in EFBs is crucial for enhancing their heating value as a fuel. Drying and torrefaction decrease the moisture content and modify the chemical structure, resulting in higher carbon ratios. The leaching process effectively reduces the potassium content of EFBs and stirring treatment is more effective than immersion treatment. Torrefaction positively affects leaching by decreasing the potassium content, while hydrophobicity may hinder leaching by repelling water. The high moisture content of leached EFBs requires additional energy for evaporation during torrefaction, resulting in a lower energy density yield compared with raw EFBs. Adjustments may also be required to account for the decreased mineral content, which functions as a torrefaction catalyst in EFBs that have not been leached.

The production of biogas from solid wastes in addition to palm oil mill effluents is necessary due to the shortage of the effluents, operation of biogas plants at low to moderate capacities, and large amount of solid wastes, particularly oil-palm empty fruit bunches (EFB). However, the biogas production from raw EFB gives low yield. This study therefore aims to investigate the effect of EFB pretreatment methods on the improvement of biogas production. The pretreatment of EFB was carried out through chemical (NaOH solutions), physical (size reduction) and biological (activated sludge and bio-scrubber effluent) processes. The experimental data was tested against corrected Gompertz model. The results showed that size reduction and pretreatments of EFB with 7% w/v NaOH, activated sludge and bio-scrubber effluent could improve biogas yield significantly and differently. The highest yield of methane was 429.9 ml/g.VS, obtained from EFB with size reduction. For the pretreatments of EFB with 7% w/v NaOH, bio-scrubber effluent and activated sludge, the methane yields were 345.5, 326.4 and 297.3 ml/g.VS, respectively. Without pretreatment, the methane yield was only 226.0 ml/g.VS. The change in cellulose and lignin compositions of EFB after pretreatment is attributed to the improvement of biogas yield. It is economically interesting that the bio-scrubber effluent from palm oil mills can be recycled to treat EFB. In the modeling study, the corrected Gompertz model could fit all data sets reasonably well.

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.

Lactic acid (LA) is a potential platform chemical that can be produced from lignocellulosic biomass. The development of a cost-competitive, catalytic-based LA production system is gaining significant attention in modern biorefineries. A series of experimental study was carried out to investigate the chemocatalytic effect of the conversion of oil palm empty fruit bunch (EFB) fibers into lactic acid under hydrothermal conditions. Synthesis of chemicals from lignocellulosic biomass involves complex mechanisms because of the complex composition of the biomass. Therefore, experimental parameters, i.e., temperature, Pb(II) concentration, and reaction time were studied. It was found that production of LA is highly dependent on the experimental conditions. In this study, the highest LA yield obtained from EFB fibers was > 46% (230 °C, 2 mM Pb(II) after 4 h of reaction). However, a similar yield can be achieved either using higher Pb(II) and shorter reactions time or vice versa. The selective production of chemical compounds (glucose, 5-hydroxymethyl furfural (5-HMF), furfural, levulinic acid, and lactic acid) from EFB fibers is highly dependent on the availability of Pb(II) ions.

The lignins from dewaxed oil palm trunk and empty fruit bunch (EFB) fibers were fractionated into 95% ethanol soluble, cold and hot water soluble, and 1% NaOH soluble lignins, respectively. The chemical and structural composition of the lignin preparations was determined by using UV, GPC, FT-IR, 13C-NMR spectroscopy and nitrobenzene oxidation. The alkali soluble and 95% ethanol soluble lignin fractions were found to contain low amounts of chemically linked polysaccharides, 2.9-3.9% and 7.5-8.0%, respectively, while the water soluble lignin fractions showed significant amounts of bound polysaccharides (16.2-23.3%). All of the lignin fractions contained a high proportion of non-condensed syringyl units, together with small amounts of non-condensed guaiacyl and fewer p-hydroxyphenyl units. The lignin from oil palm EFB fiber contained a significant amount of esterified p-hydroxybenzoic acid and a minor quantity of esterified glucuronic acid. Trace of ferulic acids was both esterified and etherified to lignin side chains in the EFB fiber cell walls.

Converting empty fruit bunch (EFB) fibers into a solid fuel through briquetting process has been actively explored due to its potential as renewable energy fuel. However, briquetting process required the addition of a binder as a solution in upgrading the briquette properties. In this study, carbonized EFB fibers was blended with different type of organic and inorganic binders at composition of EFB fibers to binders solution (water/binder) with ratio of 100:110/20. Organic binders used are tapioca starch and corn starch, while calcium hydroxide and sodium hydroxide represent inorganic binders. Blended materials were then manually compressed in a cylindrical mould for 10 minutes. The compressive strength, proximate properties and combustion characteristics were investigated to evaluate the effects of different types of binder on the briquette properties. Results showed that carbonized EFB briquette blended with tapioca starch had the best physical and chemical properties compared to others. Furthermore, the combustion rate of these briquette generate heating value up to 23.62 MJ/kg which indicate it has potential to be applied as good solid fuel and later to produce gas with less tar content. It was also observed that the type of binder influenced the combustion characteristics of the carbonized EFB briquette.

BACKGROUNDHigher‐value products, such as cellulose and carboxymethylcellulose (CMC), may be produced from lignocellulosic agroindustrial residues, such as oil palm empty fruit bunch (EFB) fibers that are presently underutilized or discarded. Recovery of cellulose from EFB and its conversion of CMC are discussed as methods of creating value and reducing the environmental impact of EFB.RESULTSCellulose was recovered from EFB fibers and converted to water soluble CMC. Cellulose isolation used a two‐step sequential treatment involving peracetic acid (PA) (50 g dry EFB L−1 PA, 35 °C, 9 h) for initial delignification, and then alkaline peroxide (AP) (50 g delignified‐EFB L−1 AP, 45 °C, 12 h). This treatment removed 91.5% of lignin in the original EFB fiber. The recovered solids, designated as cellulose‐EFB, were comprised of 83.7 ± 3.4% cellulose, 5.6 ± 0.3% hemicellulose, 1.7 ± 0.0% lignin, and 1.7 ± 0.1% ash. A two‐step process with an initial alkalization {3 g cellulose‐EFB in 99 mL solvent [10:1 by vol mixture of ethanol (95%) and 35% NaOH], 30 °C, 2 h} followed by etherification was used to convert cellulose‐EFB to CMC sodium salt. The conversion yield was 50% of the theoretical maximum.CONCLUSIONThe best conditions for preparing CMC from cellulose‐EFB were a 2 h treatment with 35% (wt/vol) NaOH during alkalization at 30 °C, followed by etherification at 55 °C. The CMC had a degree of substitution of 0.16 and a water solubility of 6.8 g L−1 at 30 °C. © 2021 Society of Chemical Industry

Chemical composition of empty fruit bunch (EFB) is an important chemical property that determines its utilization performance in bioconversion process. Various chemical compositions of EFB have been reported, and these differences in composition affects EFB utilization in terms of conversion and product yield. Complex structure and recalcitrant characteristic of lignocellulosic biomass (LCB) also affects its utilization that leads to pretreatment system requirement. Pretreatment using deep eutectic solvent (DES), a group of ionic liquid (IL), has attracted scientific interest due to its exceptional ability in hemicellulose and lignin removal. This research determined the chemical composition of six native EFB sample collected in Malaysia, and identified composition difference among samples using t-test. The work further determined the influence of DES01 pretreatment on selected pretreated samples using enzymatic hydrolysis process. Chemical compositions of six native EFB samples, collected in Perak, Selangor and Negeri Sembilan in dry and wet seasons, were determined using National Renewable Laboratory Analysis (NREL) protocol. Enzymatic hydrolysis of pretreated EFB samples were conducted following NREL protocol using Cellic CTec2 and Cellic HTec2 enzymes for 72 hours. The t-test analysis on structural carbohydrate (SC) content of native EFB showed Sg. Siput sample (SSD) in dry season and Bahau sample (BW) in wet season had statistically significant difference where native SSD contained the highest SC while native BW had the lowest. Enzymatic hydrolysis results of DES01 SSD and DES01 BW samples indicated the influence of DES01 pretreatment. DES01 SSD substrate produced higher glucan and xylan conversion after 72 hours of hydrolysis with 92.40% and 68.71% respectively compared to the DES01 BW sample with 75.82% and 18.78% only. This could be correlated with higher glucan and lower lignin contents in However, the different composition of native EFB also affected the hydrolysis of pretreated EFB. The variable pressure scanning electron microscopy (VPSEM) analysis showed that EFB structures were destroyed by the hemicellulose and lignin removal after the pretreatment and enzymatic hydrolysis. Â

The usage of renewable energy is a mitigation phenomenon majorly impacting the power sectors, with biomass being one of the sources directly replacing coal in various applications. This leads to the portrayal of biomass having the potential to be a carbonaceous material, namely the Empty Fruit Bunch (EFB) of oil palm. To increase the characteristics of EFB, it can be converted into carbon-based products through thermochemical processes, such as hydrothermal carbonization. Therefore, this study aimed to compare the characteristics of feedstock and biochar EFB using the TGA method. The heating rate used in this study is 10 – 30°C/min at five °C/min intervals. The effect of heating rate on kinetic parameters and thermal (DTG, TGA) and combustion (T ignition, T burn out) characteristics was also determined. This study carried out the HTC process at temperatures of 210ᵒC and 230ᵒC. The results showed that biochar EFB had a higher ignition, burnout temperature, and activation energy than raw EFB. Ignition temperatures for EFB-HT210°C and EFB-HT230°C were 297°C and 298°C; burnout temperatures for EFB-HT210°C, EFB-HT230°C were 407°C and 450°C; and the activation energy for EFB-HT210°C, EFB-HT230°C were 58.84 kJ/mol and 62.16 kJ/mol. Besides the characteristics of biomass, the heating rate also affects combustion. This proved that increased heating rate caused higher ignition and burnout temperature and decreased activation energy. The results also indicated that the difference in heating rate influenced the peak temperature in DTG.

Isobutanol production from empty fruit bunches

The urgent need to decarbonize the construction sector has increased interest in circular approaches that convert biomass waste into high‐performance building materials. Unmanaged agricultural residues pose environmental risks, highlighting the importance of valorizing such waste through sustainable material innovations. This study explores the characterization and fabrication of composite thermal insulation panels using two lignocellulosic wastes: empty fruit bunch (EFB) fibers and spent mushroom substrate (SMS) fibers. Empty fruit bunch fibers were physically treated using a refining process at disk gap settings of 1.75 mm, 1.50 mm, and 1.25 mm. Panels were fabricated using a hot‐pressing technique with a 60% SMS and 40% EFB fiber blend. Morphological analysis, flexural strength, thermal diffusivity, atomic force microscopy (AFM), and heat flux simulations were conducted. Refining improved EFB fiber morphology by increasing fibrillation, which enhanced interfiber bonding and distribution. The panel that used EFB refined at 1.50 mm showed optimal performance, combining thermal properties with adequate mechanical strength. It achieved a specific flexural strength of 21.00 MPa, thermal conductivity of 0.246 W m −1 K −1 , and thermal diffusivity of 0.235 mm 2 s −1 . A peak specific heat capacity of 1.049 J kg −1 K −1 indicated effective thermal buffering. Atomic force microscopy confirmed fewer voids and better surface uniformity. Heat flux simulation revealed a reduction from 287 to 68.88 W m −2 as panel thickness increased from 6 mm to 25 mm. This study demonstrates a viable pathway to convert biomass waste into sustainable insulation materials, offering a low‐carbon alternative that supports energy efficiency and sustainable building practices.