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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]

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. [ABSTRACT FROM AUTHOR]

[Display omitted] • Gas diffusion electrode (GDE) Sigracet 39BB provides excellent performance for alkaline oxygen reduction to peroxide. • Current density of 500 mA cm−2 is achieved with 97 % Faradaic efficiency on a 20 cm2 geometric area GDE at atmospheric pressure and 293 K. • GDE operation modes with gas flow-by, flow-through and quasi flow-through are investigated. • GDE flooding threshold limit is studied and established. • Stable operation is obtained in quasi flow-through mode at 500 mA cm−2. The two-electron electrochemical O 2 reduction reaction (2e-ORR) on a gas diffusion electrode (GDE) using clean electricity is an attractive process for generating the green oxidant hydrogen peroxide (H 2 O 2). Electrolyte flooding through the porous catalyst and diffusion layers is one of the major factors inhibiting the operational stability and longevity under industrially relevant current densities (>100 mA cm−2). This study reports for the first time that optimizing the two-phase flow and the mode of reactor operation brings about a remarkable improvement in the high current density operation (up to 500 mA cm−2) on a scalable (20 cm2 geometric area) and commercially available Sigracet 39BB GDE with the microporous carbon layer (MPL) acting as the catalyst layer. The interacting effects of current density, gas and liquid flow rates and the flooding threshold limit for the differential liquid/gas pressure were determined. While high peroxide Faradaic efficiency (FE > 95 %) was attained in a gas flow-by mode during short-term experiments, long-term stability was only established when the gas was switched to the flow-through or quasi-flow-through mode of operation. Under the latter conditions, at 500 mA cm−2 operational stability of more than 20 h was demonstrated with a peak FE of 97 % in 1.0 M KOH, at 293 K, 1 atm. It was found that optimizing the reactor operation has a profound effect during scale-up, and developing novel catalytic materials for 2e-ORR to alkaline peroxide is not warranted since a low-cost microporous carbon-based GDE is sufficient for stable and efficient operation. [ABSTRACT FROM AUTHOR]

Effects of alkaline peroxide (AP) treatment on chemical compositions and characteristics of lignocellulosic nanofibrils (LCNFs) were investigated. The AP treatment was conducted on a wood powder (Liriodendron tulipifera) at 80 °C for 1 or 5 h with different hydrogen peroxide concentrations (0.2 to 12 wt%) to selectively remove hemicelluloses and lignin. The treated wood powder was then defibrillated using wet-disk milling (WDM). The hemicelluloses and lignin in the LCNFs were successfully reduced to the ranges of 6.0% to 23.6% and 13.0% to 30.0%, respectively, depending upon the AP treatment conditions. The defibrillation efficiency improved as the hemicelluloses and lignin were removed, which reduced the LCNF dimensions. The filtration time increased with decreasing lignin and hemicellulose contents. The cellulose crystallinity and surface area of the LCNFs increased with decreasing lignin and hemicellulose contents. The tensile strength and water contact angles of the nanopaper handsheets increased, and the paper's color became whiter as the lignin content decreased. [ABSTRACT FROM AUTHOR]

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. [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. [ABSTRACT FROM AUTHOR]

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/PSPH2O2 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. [ABSTRACT FROM AUTHOR]

Alkaline peroxide mechanical pulp (APMP) is a newly emerging high yield pulp (HYP) with numerous advantages. However, the drawback of the alkaline peroxide mechanical pulp from untreated plant biomass is its poor network strength. In this work, 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CHPTAC) modification was proposed to enhance pulp network strength by fiber surface modification that could enhance fiber bonding. Three factors were analyzed by response surface methodology (RSM) to optimize treatment conditions based on factorial designs. The results showed that the optimal conditions were CHPTAC dosage of 0.8% (oven-dry pulp), NaOH dosage of 0.1% (oven-dry pulp), and pulp concentration of 8%. The modified pulp fibers were characterized by elemental analysis, charge density analysis, Fourier transform infrared spectroscopy (FTIR), thermal gravity analysis (TGA), and internal bond strength analysis, as well as zero span tensile analysis. The physical strength of the modified APMP pulp was increased in terms of tensile index, tear index, and burst index. After modification, the tensile index, tear index, and burst index increased by 35.3%, 29.2%, and 16.7% respectively. The internal bonding strength increased by 144.4%; however, the increase of zero span tensile index of modified pulp fibers was insignificant. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The compositions of the organic pollutants of chemi-mechanical pulping wastewater were studied using Fourier transform infrared spectra and gas chromatography-mass spectrometry. The chemical oxygen demand (COD) was approximately 18110 mg/L, and the ratio of biological oxygen demand to COD (BOD5/COD) was approximately 0.17, due to low biodegradability. In this study, Phanerochaete chrysosporium was selected and the changes in bacterial culture time required to transform pulping wastewater and the metabolites present before and after pretreatment in the wastewater were identified. A decline in the components of the pulping wastewater was observed. Initially, 43 kinds of organic compounds were detected in the raw water. After 3 days of treatment, only 21 organic compounds were detected. Then, 7 days later, the organic pollutants in the waste amounted to only 7 organic compounds. Through the analysis of analysis of P-RC APMP pulping wastewater and that treated by Phanerochaete chrysosporium using GCMS, the relative content of organic acids was 12.4%, in which phenylpropionic acid had the highest concentration of 11.3%. So, in the culture medium, phenylpropionic acid as the single carbon source can be completely degraded within 96 h. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The molecular weight distribution and composition of organic pollutants from chemi-mechanical pulping waste liquor was studied using ultra-filtration, Fourier transform infrared spectra, and gas chromatography-mass spectrometry. The concentration of dissolved chemical organic compounds was approximately 1.81 × 104 mg·L-1. In addition, the wastewater had poor biodegradability. The chemical oxygen demand (COD) was primarily composed of small molecular organic pollutants, and the larger pollutants in the waste liquor were its primary source of color. The data indicated that there were chromophoric and auxochrome groups in the waste liquor. The waste liquor contained 38 types of organic pollutants, which were aromatic compounds, including phenols, ketones, alcohols, and fatty acids. [ABSTRACT FROM AUTHOR]

Effects of alkaline peroxide (AP) pre-treatment were investigated with respect to the extracted cellulose fibres from the vascular bundles of oil palm (Elaeis guineensis) fronds (OPF) rachis at different AP concentrations. The extracted fibres were prepared through the mechanical fibrillation resulting from the AP pre-treatment concentrations of the rachis. The cellulose fibres obtained were characterized using microscopic (SEM), spectroscopic (FTIR), thermal (TGA-DTG), and X-ray diffraction (XRD) techniques. The screen pulp yield was between 38.07% and 42.69%, which increased with the increase in the AP concentrations. The SEM showed a significant separation of the fibres after the AP pretreatment. FTIR spectroscopy and TGA showed significant dissolution of both lignin and hemicellulose molecules from the treated biomass at higher alkaline peroxide concentrations. The thermal stability of the extracted fibres ranged from 366 °C to 392 °C while the XRD results showed that the cellulose fibre extracted at H2O2/NaOH ratio of 2.5%: 2.0%,w/v AP concentrations gave the highest percentage crystallinity (35.7%). The handsheet made from the cellulose fibre showed that tensile, burst, and tear indexes increased with an increase in AP concentration. Duncan Multiple Range Test shows that mild alkaline peroxide pretreatment (medium concentrations) is best favoured for paper making pulp and bio-composite production. [ABSTRACT FROM AUTHOR]

In the mechanical pulping process, some process state and product quality variables are difficult to measure on-line. In this paper, soft sensors were used to estimate Canadian Standard Freeness (CSF) and outlet consistency (Cout) after the high consistency refining stage of the alkaline peroxide mechanical pulping (APMP) process. After the secondary variables for modeling that are readily available processed measurements in pre-treatment and the HC refining stage was selected, models based on the case-based reasoning (CBR) method were developed to estimate CSF and Cout. The ability of CBR soft sensors to predict CSF and Cout was tested using data collected from an APMP mill, and the results were satisfactory. Additionally, two typical soft sensor methods that back propagation network (BP) algorithms and support vector regression algorithms (SVR) were employed to predict CSF and Cout and evaluate the performance of the CBR soft sensor. As a result, the proposed soft sensor demonstrated a better performance than the BP method and can be regarded as of comparable quality to the SVR method. [ABSTRACT FROM AUTHOR]

An enzymatic mild acidic hydrolysis was used to separate and purify residual lignin from alkaline peroxide mechanical pulp (APMP). Using the optimum conditions for the laccase treatment (pH 4.5, temperature 50℃, lignin consistency of 1%, a reaction time of 60 min, and a laccase dosage of 8 µ/g), oven-dried lignin was treated with laccase and in a laccase mediator system (LMS) to explore the mechanism for laccase and the LMS modification of APMP. The changes of functional groups in lignin were analyzed using nuclear magnetic resonance (31P-NMR and 13C-NMR). The molecular weight distributions of the lignin samples were confirmed by gel permeation chromatography (GPC). The 31P-NMR and 13C-NMR spectra revealed that the lignin structure changed significantly with the laccase and the LMS treatments. Meanwhile, GPC demonstrated that laccase without a mediator could lead to the polymerization of lignin, while the LMS could degrade the lignin. Hence, it was concluded that laccase is an attractive enzyme for lignin modification. [ABSTRACT FROM AUTHOR]

Background: The effect of time of fecal sampling on the accuracy of acid-detergent insoluble ash (ADIA) and alkaline-peroxide lignin (APL) for the prediction of fecal output (FO) in cattle was evaluated. Eight ruminally cannulated cows (594 ± 35.5 kg) were allocated randomly to 4 bermudagrass [Cynodon dactylon (L.) Pers.] hay diets markedly different in crude protein concentration (79-164 g/kg) with 2 replicates per diet for 3 periods. Cows were offered hay individually at 20 g DM/kg of body weight daily in equal feedings at 08:00 and 16:00 h for a 10-d adaptation period followed by 5-d of total fecal collection. Fecal grab samples also were taken each day during the fecal collection period at 06:00, 12:00, 18:00, and 24:00 h either directly from the rectum or from freshly voided feces. Samples were composited within cow and time across the 5 d total fecal collection period. Additionally, forage, ort, and fecal samples were analyzed for concentrations of APL and ADIA. Results: Fecal concentrations of ADIA and APL were not affected by sampling time (P = 0.22), even though diet affected (P < 0.01) fecal ADIA and APL concentrations. There were no diet × sampling time interactions (P = 0.60). Estimates of FO and dry matter digestibility (DMD) from ADIA and APL were not affected (P = 0.16) by sampling time or the diet × sampling time interaction (P = 0.74). Estimates of FO and DMD from markers from different sampling times or all different combinations of sampling time were not different (P = 0.72) from those of total collection among internal markers. Conclusion: Little variation in concentrations of ADIA and APL in daily fecal excretion across time increases flexibility in fecal grab sampling schedules for predicting FO and DMD. [ABSTRACT FROM AUTHOR]

In China, alkaline peroxide mechanical pulping performed with refinerchemical preconditioning (P-RC APMP) is well known to produce fiber with high bulk, opacity, and light scattering coefficient but weak bonding and strength properties. In this study, the characteristics of different PRC APMP fiber fractions were investigated, and their effects on bonding strength properties were determined. The results showed that there was only 5.8% R30 fiber fraction and 14.1% P100/R200 fiber fraction, and the specific surface area increased from R30 to P100/R200. The tensile index increased by 51.85% and the bonding index increased by 15.35%, when the fibers were changed from the R30 fraction to the P100/R200 fraction. The short fiber fraction (P100/R200 fraction) had smaller fiber length and coarseness but larger specific surface area and greater surface charge density than the long fiber fraction (R30 fraction). The fiber specific surface area and surface charge density made significant contributions to the bonding capacity, whereas fiber coarseness and length were negatively correlated with the tensile index. [ABSTRACT FROM AUTHOR]

In recent years, the alkaline peroxide mechanical pulping performed with refiner-chemical preconditioning (P-RC APMP) has obtained a wide application in many paper grades in China. This is due to such desirable pulp characteristics as its high bulk, opacity, and light scattering coefficient. However, compared with its bleached chemical pulps, the poplar P-RC APMP has weak bonding strength, which limits its application in value-added products. Usually, the interfiber bonding abilities of different fiber fractions are quite different. In this study, the page bonding strength index (B) and the interfiber bonding abilities (shear bond strength per unit area (b) and relative bonding area (RBA)) of different P-RC APMP fiber fractions were extrapolated by the traditional Page Equation. The results show that the higher B could be obtained when the fiber fraction was shorter or smaller. The same trend was observed for b and RBA. Wet pressing was used to improve the bonding ability, and higher pressure of wet pressing or shorter fiber fraction can lead to obviously higher tensile strength. [ABSTRACT FROM AUTHOR]

Rice husks surround rice grains, and are known to provide them with a protective lignocellulosic cover. This biomass has many potential uses, such as biofuel production. However, the high concentrations of lignin and silica limit its use, for example, they hinder fermentation reactions. In this study, both the delignification and silica removal from husks using a combination of hydrogen peroxide and sodium hydroxide has been investigated. Response surface methodology has been used to find the optimum conditions for maximizing lignin and silica removal, and solid yield. Three independent variables, namely, NaOH concentration, H 2 O 2 concentration and reaction temperature were studied by using Box-Behnken design. The first optimization focused on maximum removal of impurity, and was found at 8% NaOH, 1% H 2 O 2 and 20 °C. Under such conditions, 71.78% lignin removal, 88.47% silica removal and 50.89% solid yield were achieved. The second optimization emphasized the reduction of chemical costs, and was found at 5.29% NaOH, 1% H 2 O 2 and 20 °C; resulting in 59.85% lignin removal, 75.13% ash removal and 59.21% solid yield. Image 1 • Alkaline peroxide was used to extract lignin and silica from rice hulls. • The treatment temperature, NaOH concentration, and H 2 O 2 concentration were varied. • With RSM, the silica ash removal, lignin removal, and solid yield were optimized. • Nearly 51% solid yield was retained, with about 71% lignin and 88% silica removal. • Nearly 60% solid yield is possible, with about 60% lignin and 75% silica removal. [ABSTRACT FROM AUTHOR]

Residual melanins have been detected in multimillion-year-old animal body fossils; however, confident identification and characterization of these natural pigments remain challenging due to loss of chemical signatures during diagenesis. Here, we simulate this post-burial process through artificial maturation experiments using three synthetic and one natural eumelanin exposed to mild (100 °C/100 bar) and harsh (250 °C/200 bar) environmental conditions, followed by chemical analysis employing alkaline hydrogen peroxide oxidation (AHPO) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Our results show that AHPO is sensitive to changes in the melanin molecular structure already during mild heat and pressure treatment (resulting, e.g., in increased C-C cross-linking), whereas harsh maturation leads to extensive loss of eumelanin-specific chemical markers. In contrast, negative-ion ToF-SIMS spectra are considerably less affected by mild maturation conditions, and eumelanin-specific features remain even after harsh treatment. Detailed analysis of ToF-SIMS spectra acquired prior to experimental treatment revealed significant differences between the investigated eumelanins. However, systematic spectral changes upon maturation reduced these dissimilarities, indicating that intense heat and pressure treatment leads to the formation of a common, partially degraded, eumelanin molecular structure. Our findings elucidate the complementary nature of AHPO and ToF-SIMS during chemical characterization of eumelanin traces in fossilized organismal remains. [ABSTRACT FROM AUTHOR]

• Novel protocol for delignification developed to intensify downstream hydrolysis. • Relationship between delignification processes and biomass structure is considered. • Delignification kinetics is explored and related parameters estimated. • Monomeric sugars are generated by enzymatic hydrolysis of delignified biomass. • Inhibition kinetics is studied using both competitive and non-competitive models. Delignification of lignocellulosic biomass by alkaline peroxide pre-treatment is a preliminary important step for an overall biomass fractionation process. In the present work, saw dusts are pre-treated by aqueous alkaline peroxide solution under different temperatures over a predetermined time. It is seen that Combined Pre-treatment (CP) removes a substantially higher quantity of lignin from biomass under a particular temperature. At elevated temperatures, the extent of delignification is observed much better. The % removal is: [PR: 19.35%(30 °C):25.26%(50 °C):33.30%(100 °C)]; [CD:14.64%(30 °C):23.64%(50 °C): 28.83%(100 °C)]. Batch kinetics is investigated with certain models and corresponding parameters are estimated. As pre-treatment severity is strongly correlated to the pre-treatment temperature, increased value of " potential degree of delignification " is observed at escalated temperatures. Kinetics of enzymatic hydrolysis of delignified biomass shows decreased product inhibition with increased substrate concentration under a particular enzyme loading. Starting with a combination of 50 g/L substrate concentration with an enzyme loading of 13.23 g/L, an optimum concentration of 17.2 g/L and 21.19 g/L of glucose are produced from Pinus roxburghii and Cedrus deodara respectively. Experimental data fit quite well with the competitive inhibition kinetics based theoretical models with r2 ≥0.95. It is inferred that enzymes are competitively inhibited by glucose. [ABSTRACT FROM AUTHOR]

Developing economical and sustainable fractionation technology of lignocellulose cell walls is the key to reaping the full benefits of lignocellulosic biomass. This study evaluated the potential of metal chloride-assisted p-toluenesulfonic acid (p-TsOH) hydrolysis at low temperatures and under acid concentration for the co-production of sugars and lignocellulosic nanofibrils (LCNF). The results indicated that three metal chlorides obviously facilitated lignin solubilization, thereby enhancing the enzymatic hydrolysis efficiency and subsequent cellulose nanofibrillation. The CuCl2-assisted hydrotropic pretreatment was most suitable for delignification, resulting in a relatively higher enzymatic hydrolysis efficiency of 53.2%. It was observed that the higher residual lignin absorbed on the fiber surface, which exerted inhibitory effects on the enzymatic hydrolysis, while the lower lignin content substrates resulted in less entangled LCNF with thinner diameters. The metal chloride-assisted rapid and low-temperature fractionation process has a significant potential in achieving the energy-efficient and cost-effective valorization of lignocellulosic biomass. [ABSTRACT FROM AUTHOR]

(1) Background: The adhesion and microbiological behaviour of thermoplastic PETG dental appliance surfaces is governed by roughness parameters. The aim of this research was to evaluate the antibiofilm activity of alkaline peroxide-based disinfectant in Candida albicans biofilms on thermoplastic PETG, related to artificial ageing and surface characteristics, on multiscale levels. (2) Methods: In the present study, two PETG materials were investigated: Crystal® (Bio Art Dental Equipment, Sao Carlos, Brazil), noted as C, and Duran® (Scheu-Dental GmbH, Iserlohn, Germany)—noted as D. Half of the specimens were thermally cycled (TC), resulting in four sample groups, as follows: C, CTC, D, and DTC. Surface roughness was evaluated on different scale topographies. The biofilms were grown on the surfaces. An alkaline peroxide-based disinfectant was used. Statistical analyses were performed. (3) Results: Related to nanoroughness, there are insignificant differences among materials or related to thermocycling. More irregular surfaces are associated with larger grain sizes. After thermocycling, micro-roughness values increase. Disinfectant activity decreases the amount of biofilm developed on the surfaces, significantly in the two groups, but is not correlated to the material and artificial ageing. (4) Conclusion: The impact of surface roughness (Ra) on biofilm constitution is controlled by different scale topographies. [ABSTRACT FROM AUTHOR]

In this study, the structural modification of Siam weed (Chromolaena odorata) was performed using NaOH-H2O2- and Ca(OH)2-H2O2-based oxidative pretreatment for the enzymatic conversion of the biomass to a biocommodity, reducing sugar (RS). Pretreatment of raw sample was evaluated at temperatures of 60°C, 70°C, 80°C, 90°C for different time intervals of 3, 6, 9, 12 h in alkaline medium (NaOH or Ca(OH)2). The effects of pretreatment time and temperature were considered in obtaining the optimum conditions. The optimum conditions for NaOH-H2O2 was obtained at 70°C and 3 h with a maximum cellulose content of 44.29%(w/w), lignin content reduced to 21.09% from the initial raw value of 24.2%. Pretreatment with Ca(OH)2-H2O2 resulted in the optimum conditions obtained to be 70°C for 3 h with a cellulose content of 47.18%. Enzymatic hydrolysis on the pretreated biomass at the optimum conditions showed NaOH-H2O2-treated sample yielded 424.35 mg equivalent glucose/g biomass of RS while Ca(OH)2-H2O2-treated sample yielded 335.81 mg equivalent glucose/g biomass of RS. The untreated raw sample yielded 68.75 mg equivalent glucose/g biomass of RS. Consequently, NaOH-H2O2 pretreatment displayed a higher efficiency than Ca(OH)2-H2O2 pretreatment. Stereomicroscopic and scanning electron microscopic imaging of the treated and untreated samples revealed morphological disruptions brought about by the treatments. [ABSTRACT FROM AUTHOR]

Lignocellulose nanofibrils (LCNFs) were prepared using Liriodendron tulipifera L. wood flour. Electrospun nanofibers were fabricated by mixing the LCNFs with poly(vinyl alcohol) (PVOH). The lignin and hemicellulose contents of the wood flour were controlled with an alkaline-peroxide treatment at a pH of 11.5 using various hydrogen peroxide concentrations. The morphological characteristics, mean diameter, and filtration time of the LCNFs subjected to wet disk milling (WDM) and high-pressure homogenization were determined. Furthermore, the spinning suspension viscosity was measured with various LCNF concentrations and PVOH/LCNF addition ratios. After the alkalineperoxide treatment, the lignin and hemicellulose contents decreased with an increasing hydrogen peroxide concentration and reaction time. As the lignin content decreased, the nanofibril diameter decreased and the filtration time increased. The diameter decreased further after the homogenization treatment following WDM. The viscosity of the mixed solution increased with an increasing PVOH and LCNF mixed solution concentration and LCNF addition ratio, and decreasing lignin content. Scanning electron micrographs revealed that the diameter of the electrospun nanofibers increased as the mixed solution concentration and LCNFs addition increased, the lignin content decreased, and with the homogenization treatment. [ABSTRACT FROM AUTHOR]

This study focuses on the extraction of nanocrystalline cellulose (NCC) from the dried stalk of Corchorus olitorius, commonly known as jute, using a combination of a microwave-assisted alkaline peroxide pulping process (AHP) and ultrasonication. Dried jute stalk powder was pretreated using sodium hydroxide under microwave irradiation for the removal of lignin. The partially delignified sample was bleached using 30% hydrogen peroxide solution. The resulting crude cellulose was hydrolyzed using ultrasonication in the presence of ionic liquid and sulfuric acid. The effect of hydrolyzing medium on the physicochemical characteristics of the extracted nanocellulose was investigated. The nanocrystalline cellulose (NCC) obtained after combined treatments was rod-like, with diameters of 10 to 15 nm and lengths of 92 to 105 nm. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction analysis (XRD) showed that some breakages of intramolecular hydrogen bonds and glycosidic bonds occurred during the hydrolysis reaction of pretreated biomass. Ultrasonication in the presence of an acid hydrolyzing medium most effectively accelerated these breakages in the long chain cellulose biopolymer, leading to the formation of nanocrystalline cellulose (NCC) with higher crystallinity. [ABSTRACT FROM AUTHOR]

Sourced from agricultural waste, hemp hurds are a low-cost renewable material with high stiffness; however, despite their potential to be used as low-cost filler in natural fiber reinforced polymer biocomposites, they are often discarded. In this study, the potential to add value to hemp hurds by incorporating them into poly(lactic acid) (PLA) biopolymer to form bio-based materials for packaging applications is investigated. However, as with many plant fibers, the inherent hydrophilicity of hemp hurds leads to inferior filler-matrix interfacial interactions, compromising the mechanical properties of the resulting biocomposites. In this study, two chemical treatments, alkaline (NaOH) and alkaline/peroxide (NaOH/H2O2) were employed to treat hemp hurds to improve their miscibility with poly(lactic acid) (PLA) for the formation of biocomposites. The effects of reinforcement content (5, 10, and 15 wt. %), chemical treatments (purely alkaline vs. alkaline/peroxide) and treatment cycles (1 and 3 cycles) on the mechanical and thermal properties of the biocomposites were investigated. The biocomposites of treated hemp hurd powder exhibited enhanced thermal stability in the temperature range commonly used to process PLA (130–180 °C). The biocomposites containing 15 wt. % hemp hurd powder prepared using a single-cycle alkaline/peroxide treatment (PLA/15APHH1) exhibited a Young's modulus of 2674 MPa, which is 70% higher than that of neat PLA and 9.3% higher than that of biocomposites comprised of PLA containing the same wt. % of untreated hemp hurd powder (PLA/15UHH). Furthermore, the tensile strength of the PLA/15APHH1 biocomposite was found to be 62.6 MPa, which was 6.5% lower than that of neat PLA and 23% higher than that of the PLA/15UHH sample. The results suggest that the fabricated PLA/hemp hurd powder biocomposites have great potential to be utilized in green and sustainable packaging applications. [ABSTRACT FROM AUTHOR]

Background: Reducing the cost of producing cellulosic ethanol is essential for the industrialization of biorefinery. Several processes are currently under investigation, but few of these techniques are entirely satisfactory in terms of competitive cost or environmental impact. In this study, a new ethanol and lactic acid (LA) coproduction is proposed. The technique involved addition of waste alkaline peroxide pretreated hydrolysate (mainly LA and hemicelluloses) to the reaction mixture after ethanol fermentation (mainly LA and xylose) to reduce the ethanol production cost. Results: The following processes were investigated to optimize LA production: no addition of hemicelluloses or hydrolysate, addition of recycled hemicelluloses, and addition of concentrated hydrolysate. The addition of concentrated hydrolysate at 48 hours, which resulted in a maximum LA concentration of 22.3 g/L, was the most environment-friendly and cost-effective process. After the improved fermentation, 361 mg LA and 132 mg ethanol were produced from 1 g of raw poplar wood. That is, the production of one gallon of ethanol produced $9 worth of LA. Conclusions: The amount of LA produced from the pretreated hydrolysate and reaction mixture after ethanol fermentation cannot be underestimated. The recovery of hydrolysate rich in LA and hemicelluloses (or xylose) significantly improved LA yield and further reduced the ethanol production cost. [ABSTRACT FROM AUTHOR]

In this study, polyploid Miscanthus lutarioriparius (PML) was introduced as a new sustainable and scalable source for cellulose nanocrystal (CNC). The agronomic traits of PML were significantly different from Miscanthus × giganteus (MG), but their chemical components and physical features were similar. Notably, a remarkable co-extraction of hemicellulose, lignin and ash and non-crystalline cellulose was observed during crude cellulose isolation from PML than it from MG by modified alkaline peroxide pretreatment. In addition, subjecting crude cellulose of PML and MG biomass to sulfuric acid hydrolysis provided high-quality CNC. The analysis of particle size distribution, zeta potential, crystalline index, the degree of polymerization, SEM and yield potential suggested that the CNC extracted from PML showed higher stability, processability and productivity than that from MG. Therefore, it provides a new theoretical basis for the applications of CNC prepared by PML and MG. The results also revealed potential genetic approaches for Miscanthus spp. to enhance biomass and CNC yield. [ABSTRACT FROM AUTHOR]

Background. Oil palm trunk (OPT) with highly cellulose content is a valuable bioresource for bioethanol production. To produce ethanol from biomass, pretreatment is an essential step in the conversion of lignocellulosic biomass to fermentable sugars such as glucose and xylose. Several pretreatment methods have been developed to overcome biomass recalcitrance. In this study, the effects of different pretreatment methods such as alkali pretreatment, microwave-alkali, and alkaline peroxide combined with autoclave on the lignocellulosic biomass structure were investigated. Moreover, ethanol production from the treated biomass was performed by simultaneous saccharification and cofermentation (SSCF) under different temperatures, fermentation times, and cell ratios of Saccharomyces cerevisiae NCYC 479 and pentose-utilizing yeast, Pichia stipitis NCYC 1541. Results. Pretreatment resulted in a significant lignin removal up to 83.26% and cellulose released up to 80.74% in treated OPT by alkaline peroxide combined with autoclave method. Enzymatic hydrolysis of treated OPT resulted in an increase in fermentable sugar up to 93.22%. Optimization of SSCF by response surface method showed that the coculture could work together to produce maximum ethanol (1.89%) and fermentation efficiency (66.14%) under the optimized condition. Conclusion. Pretreatment by alkaline peroxide combined with autoclave method and SSCF process could be expected as a promising system for ethanol production from oil palm trunk and various lignocellulosic biomass. [ABSTRACT FROM AUTHOR]

Corn stalk rind (CSR) was treated with Trametes hirsuta lg-9 and then refined into pulp. The biotreatment resulted in loss of paper strength and brightness, but energy consumption during refining (ECR) was reduced. Meanwhile, multiple linear regression was carried out, for which ECR served as the dependent variable, and the yield and infrared relative absorbance intensities at 3414 cm-1 and 1653 cm-1 of the biotreated CSR served as independent variables. Results showed that the determining parameters of the biotreated CSR may be used to predict the ECR. In this work, delignified corn stalk pith (CSP) was added to aspen alkaline hydrogen peroxide mechanical pulp (APMP). The CSP enhanced the strength properties of the aspen APMP and inhibited yellowing. The biomechanical pulping of CSR has the potential to produce a low-cost green pulp, and the delignified CSP can serve as a pulp additive. [ABSTRACT FROM AUTHOR]

Crotalaria juncea bast fibers a novel cellulose rich material is valorized by producing cellulose nanocrystals (CNCs) which gained much attention due to its unique properties. CNCs obtained during this study consisted of two steps: pretreatment of C. juncea fibers to obtain chemically purified cellulose followed by sulfuric acid hydrolysis. Efficacy of two different pretreatment methods chlor-alkali method (pre-treatment-I) and ultra sound assisted chlorine free alkaline peroxide (pre-treatment-II) methods was examined for CNC preparation. Pre-treatment-I was found to be more effective yielding higher crystallinity and higher surface sulfate ester groups containing CNCs compared to CNCs obtained using pre-treatment-II. Moreover the cellulose structure was altered with more pure cellulose-I structure obtained from pretreatment- I. The process conditions of pre-treatment – I was optimized for CNC preparation. The acid concentration of 80%(w/v) was found to be optimized to produce CNCs with~43% yield, 80.9% crystallinity index having a rod-like structure (Length −120 ± 26 nm and diameter − 25 ± 5.5 nm). The surface charge density of the optimized CNC was found to be 0.34 meqv/g and a zeta potential −27.7 mV was recorded emphasizing stable dispersion. [ABSTRACT FROM AUTHOR]

Carbon dots (CDs) are carbon-based nanomaterials with remarkable properties that can be produced from a wide variety of synthesis routes. Given that "standard" bottom-up procedures are typically associated with low synthesis yields, different authors have been trying to devise alternative high-yield fabrication strategies. However, there is a doubt if sustainability-wise, the latter should be really preferred to the former. Herein, we employed a Life Cycle Assessment (LCA) approach to compare and understand the environmental impacts of high-yield and "standard" bottom-up strategies, by applying different life cycle impact assessment (LCIA) methods. These routes were: (1) production of hydrochar, via the hydrothermal treatment of carbon precursors, and its alkaline peroxide treatment into high-yield CDs; (2) microwave treatment of carbon precursors doped with ethylenediamine; (3) and (6) thermal treatment of carbon precursor and urea; (4) hydrothermal treatment of carbon precursor and urea; (5) microwave treatment of carbon precursor and urea. For this LCA, four LCIA methods were used: ReCiPe, Greenhouse Gas Protocol, AWARE, and USEtox. Results identified CD-5 as the most sustainable synthesis in ReCiPe, Greenhouse Gas Protocol, and USEtox. On the other hand, in AWARE, the most sustainable synthesis was CD-1. It was possible to conclude that, in general, high-yield synthesis (CD-1) was not more sustainable than "standard" bottom-up synthesis, such as CD-5 and CD-6 (also with relatively high-yield). More importantly, high-yield synthesis (CD-1) did not generate much lower environmental impacts than "standard" approaches with low yields, which indicates that higher yields come with relevant environmental costs. [ABSTRACT FROM AUTHOR]

Each lignocellulosic material is a new terrain to be explored, therefore, the physical chemical characterization of these materials is a fundamental step for the biotransformation process. The lignocellulosic composition of sweet sorghum bagasse was determined, values close to values reported in the literature were found. Pretreatment technologies were explored with steam, mild acid hydrolysis, alkaline delignification, NH3 soaking, AFEX, ozonolysis and alkaline peroxide; Being that the alkaline delignification with NaOH is the best option to pre-treat this substrate. The lignin content was decreased by 52% and ethanol productivity of 0.87 g / Lh was obtained, which equates to a yield of 114 L of ethanol / Ton bagasse of pre-treated dry sweet sorghum. [ABSTRACT FROM AUTHOR]

The viability of most fermentation processes is very much dependent on the cheap fermentation medium used. Palm kernel cake (PKC) is an abundant biomass generated from the palm oil processing industry that can be used as the carbon source for the growth and production of acetone-butanolethanol fermentation (ABE) by Clostridia. In this study, ABE production from the fermentation of PKC using Clostridium acetobutylicum YM1 in a batch culture was conducted. The PKC was subjected to treatment with acids (sulphuric and hydrochloric acids), alkali (sodium hydroxide and alkaline peroxide), enzymatic hydrolysis, and hydrothermal treatment (in autoclave). The sulphuric acid-treated PKC (2% SAPKC) method produced the highest concentration of reducing sugars (30 g/L) compared with the other methods applied. The results showed that increasing the concentration of H2SO4 up to 3% decreased the amounts of generated reducing sugars to 20.4 g/L, which is about 32% less. The fermentation of 1%, 2%, and 3% SAPKC resulted in the production of ABE of 1.07, 5.72, and 3.48 g/L, respectively. This study showed that the pretreatment of PKC improved the content of fermentable sugars and subsequently enhanced the production of ABE by C. acetobutylicum YM1. This study also revealed that PKC can be regarded as a potentially low cost substrate for ABE fermentation. [ABSTRACT FROM AUTHOR]

King Grass is a fast growing, high yield, hybrid grass that grows in a variety of soil conditions and does not compete with food crops. King Grass is perennial and can be harvested several times per year. Therefore it has a high potential for ethanol production in tropical countries. The pretreatments alkaline delignification (66.6–133 °C, 30–180 min, solid to liquid ratio 1:13.3–1:20 wt and NaOH concentration 0.7–2% wt), diluted acid hydrolysis (2% wt sulfuric acid, solid to liquid ratio of 1.0 g biomass/mL solution, stirring at 90 °C for 90 min), steam explosion (at 180 °C for 5 min, i.e., severity 3.05), alkaline peroxide (2% vol. H 2 O 2 , liquid to solid ratio of 20:1 wt, pH 11.5, stirring at 35 °C for 3 h) and aqueous ammonia soaking (15% wt ammonia solution, 8 mL of ammonia solution per gram of material, at 60 °C for 6 h) were studied. The alkaline pretreatment with NaOH led to the highest concentration of reducing sugars, i.e., 58.6 g/L, and to the highest ethanol concentration, i.e., 17.9 g/L. A more detailed study of the effect of the alkaline pretreatment conditions (temperature, solid to liquid ratio, NaOH concentration and residence time) on the production of ethanol from King Grass was carried out. Under pretreatment conditions of 120 °C for 1 h with 2% wt NaOH and a solid to liquid ratio of 1:20 the highest ethanol yield reported so far was obtained, i.e., 27.7 g/L (165.9 mg ethanol/g dry biomass, 92% of theoretical yield). Furthermore, this pretreatment allowed the removal of most of lignin present in King Grass, i.e., 94%, and allowed a high recovery of the cellulosic fraction in the solid (93–99%). Under typical growing conditions of King Grass in Colombia this maximum ethanol yield corresponds to 12,616 L/ha/year which is higher than that obtained from sugar cane bagasse (4602 L/ha/year). [ABSTRACT FROM AUTHOR]

Research in the many areas of human immunodeficiency virus treatment, eradication and prevention has necessitated measurement of antiretroviral concentrations in nontraditional specimen types. For HIV infection, drug combinations are typically used as highly active antiretroviral therapy, intended to maximize viral suppression. A novel four drugs combination was used, which contains two nucleoside analog reverse transcriptase inhibitors (lamivudine and tenofovir) and two protease inhibitors (darunavir and ritonavir). A new simple, efficient, and sensitive reverse phase high performance liquid chromatographic method has been developed for simultaneous extraction and determination of the concentrations of lamivudine, tenofovir, darunavir and ritonavir in bulk and in their tablets. Four compounds were separated on a reversed-phase C18 column at 30±2.0° using a gradient mobile phase combination containing potassium dihydrogen phosphate, acetonitrile and methanol. The pH was adjusted to 3.5±0.05 by the addition of orthophosphoric acid. The samples were detected using a UV detector, 260 nm for lamivudine, tenofovir and darunavir and 240 nm for ritonavir. The procedure separated analytes and its potential degradation products such as lamivudine, tenofovir, darunavir and ritonavir eluting at about 2.385, 4.055, 11.353 and 14.010 mins, respectively. The linear range of lamivudine, tenofovir, darunavir and ritonavir was 58.32-174.96 μg/ml, 58.32-174.96 μg/ml, 72.00-216.00 μg/ml and 112.50-337.5 μg/ml, respectively. The relative standard deviation for precision was less than 2.0%. The drug was subjected to acid, alkaline peroxide and photolytic stress conditions and the performance of the method was validated according to the International Conference on Harmonization guidelines for specificity, linearity, accuracy, precision and robustness. [ABSTRACT FROM AUTHOR]

This paper aimed to investigate the reasons for improved properties of bamboo alkaline peroxide mechanical pulp (APMP), such as relatively high brightness and low post-colour number, by alkali hydrogen peroxide pre-extraction (AHPP) treatment. It was found that AHPP could affect the dissolution of 1% sodium hydroxide extractives, benzene-ethanol extractives, and acid-soluble lignin. The results of Fourier transform infrared (FTIR) and 13C-nuclear magnetic resonance spectroscopy (13CNMR) illustrated that carboxyl, syringyl, guaiacyl, acetyl, and methoxyl groups of the milled wood lignin (MWL) in bamboo were degraded slightly after AHPP treatment. However, some lignin-like structures, the links of α- O-4, β-O-4, and some carbohydrates such as xylan, α-glucose, β-glucose, α-mannose, and β-mannose in lignin-carbohydrate complexes (LCCs) were degraded noticeably. The analysis of UV spectrophotometry indicated that AHPP treatment was conductive to the degradation of some chromophores in MWL. The degradation of MWL and LCC under simulated AHPP conditions showed consistency with the above results. [ABSTRACT FROM AUTHOR]

To reduce the refining energy consumption of chemi-mechanical pulping, treatment with NaOH-thiourea-urea aqueous solution was studied in this work. By means of single-factor experiments, the effects of alkali dosage, soaking time, and freezing time were evaluated. It was found that the optimal conditions were an alkali dosage of 8%, soaking time of 45 min, and freezing time of 105 min. The results revealed that refining energy consumption could be reduced by approximately 40% under optimal conditions compared with that of alkaline peroxide mechanical pulp, while other pulping or paper-making properties were similar. There were no significant effects on the structure of the functional groups, the crystalline region of the pulp, or the whole structure of the treated wood chips. However, damage to single wood fibers on the chips treated in NaOHthiourea- urea aqueous solution was more obvious. [ABSTRACT FROM AUTHOR]

The effect of degumming pretreatment on whole cotton stalk alkaline peroxide mechanical pulp (APMP) was researched. Degumming pretreatment was used as the first stage of an APMP pulping process, replacing conventional hot water pretreatment. Two degumming agents of sodium hydroxide (NaOH) and sodium oxalate (Na2C2O4) were researched separately. The efficiency of hot water pretreatment, NaOH pretreatment, and Na2C2O4 pretreatment on pectin and metal ions removal was compared. After pretreatment of hot water, NaOH, and Na2C2O4, pectin content was reduced to 4.0%, 2.1%, 1.6%, respectively, compared to original material (4.3%), at removal rates of 7%, 51%, and 64%, respectively. For metal ions, especially transition metal ions, the removal rate was up to 20% after degumming pretreatment. The brightness of the handsheets was 64% ISO, 68% ISO, and 73% ISO, respectively. The dirt count was 2674 mm²·m-2, 533 mm²·m-2, and 132 mm²·m-2, respectively. After Na2C2O4 pretreatment, the tension index and tear index were increased to 40.5 N·m·g-1 and 4.5 mN·m²·g-1, respectively. Through degumming pretreatment, pectin, metal ions, and dirt count were reduced efficiently, and the brightness and physical strength were improved significantly. [ABSTRACT FROM AUTHOR]

The production of high-yield pulp in China has increased significantly in recent years. The well-known advantages of this type of pulp include low production cost, high opacity, and good paper formation. In the context of state-of-the-art technologies, China's high-yield pulping, which is dominated by the PRC-APMP (preconditioning refiner chemical treatment-alkaline peroxide mechanical pulping) process, has a much higher energy input but a significantly lower wood consumption in comparison with the kraft pulping process. If the saved wood in the forest or plantation is considered as an increment of carbon storage, then the carbon dioxide emission from the production of high-yield pulp can be regarded as much lower than that of kraft pulp. [ABSTRACT FROM AUTHOR]

From birch wood, it is possible to obtain both acetic acid and 2-furaldehyde as valuable value-added products. The main objective of this study was to develop a new wasteless technology for obtaining 2-furaldehyde, acetic acid, and lignocellulose (LC) residue usable as feedstock in further processing such as thermomechanical (TMP), alkaline peroxide mechanical (APMP), and sulfate pulping processes. To achieve this objective several screening tests were performed, and a further experimental plan was developed using DesignExpert11. Process yields were analyzed both in terms of total yield and at individual time increments. In addition, the obtained LC residue was also characterized. A unique bench-scale reactor system was used to obtain an LC material without pentoses and with maximum preservation of cellulose fiber for further research. Studies on the deacetylation and dehydration of birch wood hemicelluloses of pentose monosaccharides to 2-furaldehyde and acetic acid using orthophosphoric acid as a catalyst were carried out. Results showed that, depending on the used pre-treatment conditions, the 2-furaldehyde yield was from 0.04% to 10.84% oven dry mass (o.d.m.), the acetic acid yield was from 0.51% to 6.50% o.d.m., and the LC residue yield was from 68.13% to 98.07% o.d.m. with minimal content of admixtures. Process optimization using DesignExpert11 revealed that the main pre-treatment process parameters that influenced the yield of 2-furaldehyde in the pre-treatment process were process temperature (53.3%) and process duration (29.8%). [ABSTRACT FROM AUTHOR]

Lignin extraction from lignocellulosic biomass using different approaches for the intensified production of value added chemicals. • Intensification of delignification of sawdust using different ultrasonic reactors. • Comparison of different configurations in terms of efficacy and energy requirements. • Highest lignin yield is achieved using longitudinal ultrasonic horn. • Alkaline peroxide treatment is effective in cleaving carbonyl and ethylene groups. • Characterization of extracted lignin confirms presence of structural activity. Delignification of sawdust was studied using ultrasound assisted alkali peroxide approach using longitudinal horn for the first time and the efficacy compared with more commonly used configurations of ultrasonic reactors. Comparison with the conventional approach based on stirring has also been presented to establish the process intensification benefits. Effect of different operating parameters such as sodium carbonate concentration (0.1, 0.15, 0.2, 0.25 M), hydrogen peroxide concentration (0.2, 0.4, 0.6, 0.8, 1 M) and biomass loading (2, 4, 6, 8, 10 wt%), on the efficacy of lignin extraction has been investigated for different ultrasonic reactors. The optimum conditions for probe type ultrasonic horn were established as 150 W, 50% duty cycle and 80% amplitude with optimum process conditions as Na 2 CO 3 concentration as 0.2 M, H 2 O 2 concentration as 1 M, biomass loading of 10 wt% and operating time of 70 min. Longitudinal horn resulted in best efficacy (both in terms of yield and energy requirements) followed by ultrasonic horn and ultrasonic bath whereas the conventional approach was least effective. The obtained lignin was also analyzed using different characterization techniques. The presence of peaks at wavelength range of 875–817, 1123–1110, and at 1599 cm−1 for the extracted sample confirmed the presence of lignin. Increase in the crystallinity index of the processed sample (maximum for longitudinal horn) also confirmed the lignin removal as lignin is amorphous in nature. Overall it has been concluded that ultrasound can be effectively used for delignification with longitudinal horn as best configuration. [ABSTRACT FROM AUTHOR]

Bi2WO6 assembled by flower-like microspheres and nanosheets were controllably synthesized through a one-step hydrothermal approach. Multiple technologies, including X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and UV–Vis diffuse reflectance spectrum (UV–Vis), were carried out to characterize the as-synthesized samples. The photocatalytic efficiency of Bi2WO6 synthesized with a series of temperature and pH values shows different morphologies and photocatalytic properties. The photocatalyst (Bi2WO6) synthesized at 220 °C and pH of 7 exhibited the best photocatalytic performance, with the methylene blue (MB) degradation approaching 91.6% after reaction time of 60 min. Free radical capture experiments indicate that •OH is the primary reactive species in the methylene blue (MB) degradation reaction, h+ and •O2− contribute negligible influence, while the addition of H2O2 significantly improves the photocatalytic activity of Bi2WO6. Biodegraded poplar preconditioning refiner chemical alkaline peroxide mechanical pulp wastewater (PPW) was treated over Bi2WO6 under UV light (Bi2WO6/UV/H2O2); chemical oxygen demand (CODCr) and color degradation rate were 85.8% and 92.0%, respectively. These results show that Bi2WO6 semiconductors can be introduced as an efficient and stable photocatalyst for industry wastewater treatment. [ABSTRACT FROM AUTHOR]