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In this study, allelochemicals were extracted from pulping effluents rather than from the raw material of plants. Herein, five organic solvents (ethyl acetate (EAC), methyl tert-butyl ether (MTBE), dichloromethane (DCM), carbon tetrachloride (CTC), and petroleum (PE)) were applied to separately extracting the allelochemicals from alkaline peroxide mechanical pulp (APMP) effluents. The results from the algal density, inhibition ratio, and optical density of 446 nm (OD446nm) concluded that the extractives from the APMP effluents can act as effective allelochemicals and showed noticeable allelopathic inhibition effects on Microcystis aeruginosa growth. The results indicated that organic solvent extraction could be a practical approach to isolate the allelochemicals from the APMP effluents, which would broaden the potential application of the APMP effluents in the production of antimicrobial agents and other value-added materials.

The necessity for the reduction in greenhouse gas emissions, the growing demand for the improvement of biorefinery technologies, and the development of new biorefining concepts oblige us as a society, and particularly us, as scientists, to develop novel biorefinery approaches. The purpose of this study is to thoroughly evaluate the leftover lignocellulosic (LC) biomass obtained after the manufacture of 2-furaldehyde, with the intention of further valorizing this resource. This study demonstrates that by using thermomechanical and alkaline peroxide mechanical pulping techniques, birch wood chips can be used in the new biorefinery processing chain for the production of 2-furaraldehyde, acetic acid, and cellulose pulp. In addition, the obtained lignocellulosic residue is also characterized. To produce a lignocellulosic material without pentoses and with the greatest amount of cellulose fiber preserved for future use, a novel bench-scale reactor technology is used. Studies were conducted utilizing orthophosphoric acid as a catalyst to deacetylate and dehydrate pentose monosaccharides found in birch wood, converting them to 2-furaldehyde and acetic acid. The results showed that, with the least amount of admixtures, the yields of the initial feedstock’s oven-dried mass (o.d.m.) of 2-furaldehyde, acetic acid, and lignocellulose residue ranged from 0.04 to 10.84%, 0.51 to 6.50%, and 68.13 to 98.07%, respectively, depending on the pretreatment conditions utilized. The ideal 2-furaldehyde production conditions with reference to the purity and usability of cellulose in residual lignocellulosic material were also discovered through experimental testing. The experiment that produced the best results in terms of 2-furaldehyde yield and purity of residual lignocellulose used a catalyst concentration of 70%, a catalyst quantity of 4%, a reaction temperature of 175 °C, and a treatment period of 60 min. It was possible to create pulp with a tensile index similar to standard printing paper by mechanically pulping the necessary LC residue with alkaline peroxide, proving that stepwise 2-furaldehyde production may be carried out with subsequent pulping to provide a variety of value-added goods.

Lignocellulose materials, essentially consisting of lignin, cellulose and hemicelluloses, are abundant sources of fermentable sugars. The bast fiber of Crotalaria juncea (Sunn hemp), a native cover crop of India, was used as feedstock for this study. The primary objective of this study was to add value to the waste C. juncea bast fiber. The same was achieved by pretreating the waste fiber using alkaline peroxide solution at various process conditions. The optimal process condition for alkaline peroxide pretreatment was identified for the fiber to pretreatment solution (S/S) ratio of 1/40 at 50°C for 5h with respect to all response variables (lignin removal, hemicellulose recovery, recovery of solid pretreated material, and crystallinity of lignocellulose). Three-way ANOVA results revealed that S/S ratio had no significant effect; whereas, both temperature and time, and the combination of parameters, exhibited significant effect on response variables. The characteristic peaks associated with lignin and cellulose demonstrated a higher amount of lignin removal and increased cellulose content with elevated treatment time. Autoclave assisted pretreatment proved to be inefficient due to removal of lower amount of lignin in addition to higher hemicellulose degradation. On the other hand, pretreatment using ultrasound was found to be most effective in removing lignin, liberating hemicelluloses along with diminition in cellulose crystallinity.

Production of high value-added products from lignocelluloses is an economically sustainable alternative to decreasing dependence on fossil fuels and making the chemical processes environmentally friendly. In this study, different methodologies of alkaline (Ca(OH)2 and NaOH), dilute acid (10%w/w H2SO4), hydrogen peroxide (H2O2), alkaline peroxide oxidation (H2O2/Ca(OH)2 and H2O2/NaOH), and molten hydrated salt (MHS) mediated (ZnCl2.4H2O) pretreatments were employed in the hydrolysis of corncob amenable to enzymatic hydrolysis. Optimal enzyme hydrolysis temperature (considering 45 and 50 ℃) and time (2, 24, 72, and 96 h) were investigated for each pretreatment procedure to ascertain the concentrations of glucose, xylose, and total sugar present in the corncob. At 45 ℃ and 96 h, NaOH alkaline pretreatment achieved the best optimum total sugar production of 75.54 mg/mL (about 54% and 88% increments compared to dilute acid pretreatment (35.06 mg/mL total sugars) and MHS (9.32 mg/mL total sugar) pretreatment respectively). In this study, total sugars production increased appreciably at 45 ℃ and longer hydrolysis period (96 h) compared to hydrolysis at 50 ℃ (with maximum total sugars production of 18.00 mg/mL at 96 h). Scanning electron microscopic imaging of the untreated and treated samples displayed cell wall distortion and surface disruptions.

Flax is a commercial crop grown in many parts of the world both for its seeds and for its fibers. The seed-based flax variety (linseed) is considered less for its fiber after the seed is extracted. In this study, linseed straw was utilized and processed to extract fiber and cellulose through optimization of retting time and a multi-step alkaline peroxide extraction process using the Taguchi design of experiment (DOE). Effects of retting duration on fiber properties as well as effects of solvent concentration, reaction temperature, and time on removal of non-cellulosic fiber components were studied using the gravimetric technique, Fourier transform infrared (FTIR) spectroscopy and thermal studies. Based on these findings, retting for 216 h at room temperature should offer adequate retting efficiency and fiber characteristics; 70% cellulose yield was extracted successfully from linseed straw fiber using 75% ethanol–toluene at 98 °C for 4 h, 6% NaOH at 75 °C for 30 min, and 6% H2O2 at 90 °C for 120 min.

Lignocellulosic biomass has great potential as a low-cost source of fermentable sugar for the production of biofuels and high value organic acids. One potential biomass is oil palm empty fruit bunch, since it has high cellulose and hemicellulose content. However, its lignin content can hinder the access of cellulose and hemicellulose during the hydrolysis process. Therefore, an effective pretreatment for the delignification of lignocellulose biomass should be considered to reduce the lignin content. In this study, delignification of oil palm empty fruit bunch using peracetic acid and alkaline peroxide solution combined with the ultrasound method is investigated as a novel combination method of biomass pretreatment. The effect of pretreatment time was observed by using a peracetic acid solution for 1, 3, 5, 7 and 9 hours, followed by an alkaline peroxide solution for 4, 6, 8 and 10 hours. Based on the results, the best delignification was achieved by pretreatment using peracetic acid pretreatment for 3 hours, followed by alkaline peroxide pretreatment for 10 hours. Both pretreatments were assisted by the ultrasound method. The results show hemicellulose, cellulose and lignin content of 14.13%, 77.27% and 8.6% respectively. The lignin content was reduced by 68.73% and the cellulose content increased by 121.85%, relative to the untreated EFB. This result was considered as the best pretreatment, since the pretreatment time was shorter and high cellulose content together with low lignin content was achieved, which will improve the hydrolysis process.

The exploration of sustainable lignocellulosic nanomaterials with unique properties and applicable functions is receiving growing interest. In this work, holocellulose nanofibrils (HCNFs) were prepared from moso bamboo using mild alkaline peroxide bleaching method (MAPB) followed by mechanical nanofibrillation. MAPB was proved to effectively remove lignin and retain hemicellulose. Meanwhile, partial allomorphic changes from cellulose I to cellulose II were revealed together with varying degrees of crystallinity. Thermogravimetric analysis (TGA) experiment showed an increasing thermal stability trend due to more allomorphic changes into anti-parallel cellulose II. Well-dispersed HCNFs suspensions were successfully prepared by homogenization and HCNFs films with high transparency and flexibility were fabricated. The films reached the maximum tensile strength of 55.8 MPa and tensile strain of 1.55 % along with a calculated toughness of 25 MJ/m3. Moreover, the prepared materials are biocompatible and completely non-toxic, which will theoretically support the application of HCNFs materials in fields of biology, medicine and food industry. [Display omitted] [ABSTRACT FROM AUTHOR]

The necessity for the reduction in greenhouse gas emissions, the growing demand for the improvement of biorefinery technologies, and the development of new biorefining concepts oblige us as a society, and particularly us, as scientists, to develop novel biorefinery approaches. The purpose of this study is to thoroughly evaluate the leftover lignocellulosic (LC) biomass obtained after the manufacture of 2-furaldehyde, with the intention of further valorizing this resource. This study demonstrates that by using thermomechanical and alkaline peroxide mechanical pulping techniques, birch wood chips can be used in the new biorefinery processing chain for the production of 2-furaraldehyde, acetic acid, and cellulose pulp. In addition, the obtained lignocellulosic residue is also characterized. To produce a lignocellulosic material without pentoses and with the greatest amount of cellulose fiber preserved for future use, a novel bench-scale reactor technology is used. Studies were conducted utilizing orthophosphoric acid as a catalyst to deacetylate and dehydrate pentose monosaccharides found in birch wood, converting them to 2-furaldehyde and acetic acid. The results showed that, with the least amount of admixtures, the yields of the initial feedstock's oven-dried mass (o.d.m.) of 2-furaldehyde, acetic acid, and lignocellulose residue ranged from 0.04 to 10.84%, 0.51 to 6.50%, and 68.13 to 98.07%, respectively, depending on the pretreatment conditions utilized. The ideal 2-furaldehyde production conditions with reference to the purity and usability of cellulose in residual lignocellulosic material were also discovered through experimental testing. The experiment that produced the best results in terms of 2-furaldehyde yield and purity of residual lignocellulose used a catalyst concentration of 70%, a catalyst quantity of 4%, a reaction temperature of 175 °C, and a treatment period of 60 min. It was possible to create pulp with a tensile index similar to standard printing paper by mechanically pulping the necessary LC residue with alkaline peroxide, proving that stepwise 2-furaldehyde production may be carried out with subsequent pulping to provide a variety of value-added goods. [ABSTRACT FROM AUTHOR]

Primary refined coarse softwood thermomechanical pulp was treated with alkaline peroxide prior to low-consistency (LC) refining. The effects of the pre-treatments on pulp quality, refinability, and electrical energy consumption were assessed. Four pre-treatments were conducted with alkali charges of 2.5 and 6% and peroxide charges of 3 and 4%. The pulps were refined to specific energies up to 600 kWh/t by multiple passes through an LC refiner at intensities of 90 and 150 kWh/t. It was found that alkaline peroxide treatments increased tear strength and protected the fibre from cutting, especially during high intensity refining below a specific energy of 300 kWh/t. Treatment with 6% NaOH and 4% or 3% H2O2 led to lower brightness gains and scattering coefficients but increased the tensile strength index by 31%, potentially lowering the total electrical energy required to achieve strong pulp. The enhancement of tensile strength caused by the highly alkaline peroxide mostly resulted from increased bonding, which was attributable to acid group generation rather than the promotion of further fibrillation during LC refining.

This study investigated the performance of recycled polypropylene (RPP)/peanut shell powder (PSP) composites with untreated PSP and treated PSP with alkaline peroxide. The RPP/PSP and RPP/PSP-H2O2 composites were prepared by melt mixing and compression molding at different PSP loadings (10 wt.% to 40 wt.%). The samples were characterized by processing properties, tensile properties, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and water absorption behavior. The treated PSP enhanced the stabilization torque, tensile strength, elongation at break, tensile modulus, and water absorption of RPP/PSP-H2O2 composites. FTIR spectra and SEM showed that the elimination of lignin content strongly influenced the fractured surface and chemical characteristics of the RPP/PSP-H2O2 composites.

In this work, the surface of oil palm mesocarp fiber (OPMF) was modified via alkaline-peroxide treatment with hydrogen peroxide under alkaline conditions. The effect of the treatment on the chemical composition and microstructure of the fiber was examined using chemical analysis, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD) analysis. The treatment resulted in the removal of lignin, hemicellulose, and waxy substances from the fiber and increased its surface roughness and crystallinity. The eco-friendly biocomposite was made from poly(butylene succinate) (PBS) and chemically treated fiber at a weight ratio of 30:70, and was fabricated via a melt-blending technique followed by hot-pressed moulding. The results indicated that alkaline-peroxide treatment of the fiber improved the tensile strength, tensile modulus, and elongation at break of the OPMF/PBS biocomposite by 54, 830, and 43%, respectively. The SEM analysis revealed improvement of the interfacial adhesion between the chemically treated fiber and the PBS. This work demonstrates that alkaline-peroxide treatment of fiber is beneficial prior to its use in fabricating biocomposites.

Effects of dual-treatment on cellulose fiber quality, micro-structure appearance, crystalline structure, hydrogen bonds, and surface elements were analyzed using a fiber quality analyzer (FQA), scanning electron microscope (SEM), wide-angle X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS), respectively. In comparison to the untreated pulp, the brightness of pulp increased by 51.71%, whereas the apparent density and burst strength index of the pulpboard decreased by 11.76% and 48.18%, respectively. The absorption time, absorbability, and bulk of the fiber obtained by defibering the pulpboard decreased by 47.40%, 8.33%, and 5.32%, respectively, when it had been subjected to supplementary alkali. With the analysis of FQA and SEM, fiber swelled and curled, its surface was relatively smooth, and filaments of its partial surface area were exposed as a result of the supplementary alkali. Additionally, XRD analysis, FT-IR analysis, and XPS scanning spectra all showed that the crystallinity degree of fiber decreased by 45.10%, indicating more crystal structures were converted into amorphous structures. The proportion of total intra-molecular hydrogen bond intensity to total hydrogen bonds increased. The –OH content on fiber surface only decreased by 4.15%, compared with those of the untreated pulp, when the fiber was subjected to the two-step chemical treatment.

Low-pressure steam explosion (LPSE) combined with alkaline peroxide (AP) pretreatment was first employed to separate hemicellulose from Lespedeza stalks. The monosaccharide composition and molecular weight distribution of the obtained hemicellulose fractions were characterized in this study. The results show that the hemicellulose extracted from Lespedeza stalks consisted of xylose, glucose, galactose, and mannose, which was a mixture of arabinoxylans and xyloglucans or β-glucans. The yield of hemicellulose fractions after AP pretreatment ranged from 11.2% (2.5% hydrogen peroxide (H2O2), w/v for 12 h) to 12.2% (3.3% H2O2, w/v for 72 h). The molecular weight of hemicellulose decreased from 2,458 g/mol to 1,984 g/mol after AP pretreatment, indicating its degradation reaction. The structure of hemicellulose was analyzed by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, and heteronuclear single quantum coherence. The AP pretreatment partially cleaved the backbone and the ether linkage between lignin and hemicelluloses. Also, branched-chain α-D-arabinofuranosyl in which β-D-xylose substituted at the C-3 position (monosubstituted) was removed, illustrating a partial debranching reaction. Therefore, the combination of low-pressure steam explosion and alkaline peroxide pretreatment (LPSE-AP) is an effective pretreatment method to separate hemicellulose from Lespedeza stalk.

Abstract This study evaluated the effects of three chemical pretreatments of biomass sorghum (BS): dilute alkaline (PTA1 and PTA2), dilute acid (PTB1 and PTB2) and alkaline hydrogen peroxide (PTC1 and PTC2) in the enzymatic hydrolysis and ethanol production. Among the six investigated conditions, the pretreatment with 7.36% H2O2 (PTC2) was the most efficient in the lignin removal and preservation of the polysaccharide fraction. After the enzymatic hydrolysis, increases in the glucose and xylose concentrations were observed in the pretreated BS hydrolysates, mainly in PTB1 and PTC1. All the hydrolysates obtained low concentrations of inhibitors. In the alcoholic fermentations with Pichia stiptis, the greatest ethanol yield was obtained in PTB1 hydrolysate (3.84 g L-1), corresponding to 16.15% of yield. The highest ethanol yield in PTB1 hydrolysate can be justified by the maximum concentration of xylose obtained in this hydrolysate, demonstrating the potential of P. stiptis in the fermentation of pentose to ethanol. The results indicated that biomass sorghum is an alternative lignocellulose source with potential for the production of second generation ethanol, opening up prospects for additional studies.

Flax is a commercial crop grown in many parts of the world both for its seeds and for its fibers. The seed-based flax variety (linseed) is considered less for its fiber after the seed is extracted. In this study, linseed straw was utilized and processed to extract fiber and cellulose through optimization of retting time and a multi-step alkaline peroxide extraction process using the Taguchi design of experiment (DOE). Effects of retting duration on fiber properties as well as effects of solvent concentration, reaction temperature, and time on removal of non-cellulosic fiber components were studied using the gravimetric technique, Fourier transform infrared (FTIR) spectroscopy and thermal studies. Based on these findings, retting for 216 h at room temperature should offer adequate retting efficiency and fiber characteristics; 70% cellulose yield was extracted successfully from linseed straw fiber using 75% ethanol-toluene at 98 °C for 4 h, 6% NaOH at 75 °C for 30 min, and 6% H 2 O 2 at 90 °C for 120 min.

In a paper mill’s water circuit, normal runnability of the paper machine is often disturbed due to buildup of hydrophobic dissolved and colloidal substances (DCS), such as wood pitch, white pitch, and stickies. General cationic fixing agents such as hydrophilic polymers do not always work to minimize these problems. In the present study, two kinds of novel hydrophobically associating polyethylenimine (PEI) coagulants grafted by acetic anhydride and 1,2-epoxydodecane, named PEI-Ac and PEI-Ed, respectively, were synthesized to remove hydrophobic DCS. The performances of the modified PEI samples were evaluated using a model suspension containing alkaline peroxide mechanical pulp (APMP) and styrene-butadiene latex. The results showed that the modified PEI was more inclined to interact with hydrophobic substances than was non-modified PEI. The relationship between DCS removal and non-modified or modified PEI content was not linear, but there was a maximum. The turbidity and particle counts of model suspensions decreased 30% and 80%, respectively, when the dosage of PEI-Ed(a) was 0.025%. Compared with the 72.8% decrease in the case of non-modified PEI, cationic demand decreased by 67.7% when the PEI-Ed(a) concentration was 0.2%. It was also found that PEI-Ed had a better affinity for DCS than PEI-Ac, which may be because the PEI-Ed had a long hydrophobic chain.

A double pretreatment was developed to improve the efficiency of enzymatic hydrolysis and to increase the sugars production from palm fibre in batch and fed-batch systems. After alkaline peroxide pretreatment using NaOH-H2O2 solution, rigid structure of palm fibre was broken and partial of the hemicelluloses and lignin were removed. Compared with cellulase Accellerase® 1500, when using the conjunction of Accellerase® 1500 and Optimash BG, the conversion ratio increased from 35.9% to 45.0% and the reducing sugar yield increased from 245 mg/g substrate to 307 mg/g substrate. To further increase the hydrolysis efficiency, double pretreatment with NaOH-H2O2 solution was used to treat the hydrolysized residues. Then, the hydrolysis ratio reached 93% and reducing sugar yield was 752 mg/g substrate. Fed-batch enzymatic hydrolysis was carried out with 7% (w/v) solids loading and 0.3 mL/g substrate. Then, 7% solids were fed consecutively at 12 h, 24 h, 36 h and 48 h. After 144 h, the final concentration of reducing sugar reached 214.0 g/L and total biomass conversion ratio was 75.23%. Keywords: Cellulase, Palm fibre, Reducing sugar, Lignin, Alkaline peroxide pretreatment

Eucalyptus wood is among the most important biomass resource in the world. Wood mechanical defibration and fibrillation are energy-intensive processes utilized not only to produce pulp for papermaking, but also to produce reinforcement fibers for biocomposites, nanocellulose, or pretreat lignocellulosic material for biofuels production. The structural features of different Eucalyptus hybrids affecting the refining energy consumption and produced fiber furnish properties were evaluated. The defibration and fiber development were performed using an alkaline peroxide mechanical pulping (APMP) process, which included chelation followed by an alkaline peroxide treatment prior to wood chip defibration. Despite the similar wood densities and chemical compositions of different Eucalyptus hybrids, there was a clear difference in the extent of defibration and fibrillation among the hybrids. The high energy consumption was related to a high amount of guaiacyl lignin. This observation is of major importance when considering the optimal wood hybrids for mechanical wood defibration and for understanding the fundamental phenomena taking place in chemi-mechanical defibration of wood.

As part of a program to reduce electrical energy consumption in the refining process, the effects of the ozone and alkaline peroxide treatments on fibre and handsheet properties, prior and subsequent to low consistency (LC) refining, were assessed and compared by applying different levels of ozone and a range of peroxide and alkali charges to a primary stage hemlock thermomechanical pulp (TMP). Both highly alkaline peroxide treatments and ozone treatments decreased the specific energy required for strong mechanical pulp. The improvement in pulp strength through alkaline peroxide treatment mainly resulted from pulp surface changes caused by generation of acid groups. The highly alkaline peroxide treatments significantly increased pulp brightness but did not promote the further fibrillation during the subsequent LC refining. On the other hand, ozone treatments provided tensile strength increases, along with small brightness enhancements for the dark hemlock TMP, and increased the tensile gains obtained through LC refining. The effects of ozone treatments on tensile strength before and after LC refining were the result of pulp surface modifications, fibre swelling, and loss of fibre wall integrity due to non-selective chemical attack. High levels of ozone treatment caused tear strength to decrease during subsequent LC refining.

Using a multi-effect evaporation system to concentrate the effluent from alkaline peroxide mechanical pulping (APMP) plants is known to require a high energy consumption. In order to improve the situation, a polyethersulfone membrane was used to concentrate the effluent of APMP plants beforehand. An orthogonal experimental design was applied and a mathematical model was established to optimize the filtration parameters. An estimation of potential energy and water savings from this new concentration process was developed. The optimal filtration conditions obtained were: molecular weight cut-off at 10,000 Dalton, trans-membrane pressure at 3 bar, feed temperature at 50oC, cross-flow velocity at 420 rpm, and volume reduction factor at 0.93. The average permeate flux under these conditions was 45.31 l/m2.h. The total solids content was increased from 14.74 g/l in the feed to 95.04 g/l in the concentrate. The permeate had low total solid contents of 8.75 g/l, Chemical Oxygen Demand of 6696 mg/l, and Biochemical Oxygen Demand of 4383 mg/l. Such qualities would allow the permeate to be reused in the alkaline peroxide mechanical pulping process. With this new concentration process, about 4840.6 kwh energy can be saved and 23.3 m3 effluent discharge can be reduced for each ton of pulp produced.