Optimization of OPEFB lignocellulose transformation process through ionic liquid [TEA][HSO4] based pretreatment

Abstract

Research on the transformation of Oil Palm Empty Fruit Bunches (OPEFB) through pretreatment process using ionic liquid triethylammonium hydrogen sulphate (IL [TEA][HSO4]) was completed. The stages of the transformation process carried out were the synthesis of IL with the one-spot method, optimization of IL composition and pretreatment temperature, and IL recovery. The success of the IL synthesis stage was analyzed by FTIR, H-NMR and TGA. Based on the results obtained, it showed that IL [TEA][HSO4] was successfully synthesized. This was indicated by the presence of IR absorption at 1/λ = 2814.97 cm−1, 1401.07 cm−1, 1233.30 cm−1 and 847.92 cm−1 which were functional groups for NH, CH3, CN and SO2, respectively. These results were supported by H-NMR data at δ (ppm) = 1.217–1.236 (N–CH2–CH3), 3.005–3.023 (–H), 3.427–3.445 (N–H+) and 3.867 (N+H3). The TGA results showed that the melting point and decomposition temperature of the IL were 49 °C and 274.3 °C, respectively. Based on pretreatment optimization, it showed that the best IL composition for cellulose production was 85 wt%. Meanwhile, temperature optimization showed that the best temperature was 120 °C. In these two optimum conditions, the cellulose content was obtained at 45.84 wt%. Testing of IL [TEA][HSO4] recovery performance for reuse has shown promising results. During the pretreatment process, IL [TEA][HSO4] recovery effectively increased the cellulose content of OPEFB to 29.13 wt% and decreased the lignin content to 32.57%. The success of the recovery process is indicated by the increasing density properties of IL [TEA][HSO4]. This increase occurs when using a temperature of 80–100 °C. The overall conditions obtained from this work suggest that IL [TEA][HSO4] was effective during the transformation process of OPEFB into cellulose. This shows the potential of IL [TEA][HSO4] in the future in the renewable energy sector.

Rapid fractionation of corn stover by microwave-assisted protic ionic liquid [TEA][HSO4] for fermentative acetone–butanol–ethanol production

“…This is attributed to the dissolution effect of [TEA][HSO 4 ] on cellulose, particularly the [HSO 4 ] − anion, which acts as a hydrogen bond acceptor for cellulose dissolution, disrupting both intra and intermolecular hydrogen bonds in cellulose molecules. This process leads to the generation of amorphous portions of cellulose, which dissolve under acidic conditions [ 27 , 28 ].…”

“…In contrast, the absorption peak at 890 cm −1 in the pulp fractionated by MI-230 W/3 min was enhanced, signifying the transformation of cellulose I to the amorphous form [ 35 ]. As it is illustrated in literature, attribute to the broken down of the intramolecular hydrogen bonds by protic ILs, especially [HSO 4 ] − anion acts as a hydrogen bond acceptor for cellulose dissolution, cellulose which regenerates after pretreatment tends to be more amorphous [ 27 ]. All these statements coincided with the results shown in Table 2 .…”

The Practical Utility of Imidazolium Hydrogen Sulfate Ionic Liquid in Fabrication of Lignin-Based Spheres: Structure Characteristic and Antibacterial Activity

“…Moreover, there is a wide band that is responsible for stretching vibrations of -CH from 2,970 cm −1 to 2,900 cm −1 and of N-CH 3 at the maximum of wavenumber at 2800 cm −1 . There is also a presence of characteristic functional groups which are related to the anion, including HOSO 3 − (1250 cm −1 ) and O=S=O (1164 cm −1 ) ( Gupta et al, 2017 ; Nurdin et al, 2021 ).…”

Cellulose Nanocrystals and Lignin Nanoparticles Extraction from Lemna minor L.: Acid Hydrolysis of Bleached and Ionic Liquid-Treated Biomass

“…In particular, the hydrogen sulfate anion is very effective in fiber decomposition, thereby reducing the recalcitrant nature of the biomass to fiber separation. Cellulose, which regenerates after IL treatment, tends to be more amorphous in its macrostructure, making it easier for it to undergo further hydrolysis [57]. Based on this assumption, the pulps originating from the [TEA][HSO 4 ] treatment of pristine duckweed (see Section 3.3.2) were subjected to sulfuric acid hydrolysis for further recovery of cellulose nanocrystals (CNC IL ) [58,59].…”