Straw Pulp Research Articles

Alterations in Energy Partitioning and Methane Emissions in Murciano-Granadina Goats Fed Orange Leaves and Rice Straw as a Replacement for Beet Pulp and Barley Straw.

Simple SummaryReducing methane emissions in ruminants with the recycling of agro-industrial by-products is of great importance today. Pruning waste from citrus trees is currently burned or incorporated into soil. Regarding rice straw, this waste is traditionally eliminated through controlled burning, releasing into the atmosphere large amounts of greenhouse gases as well. The aim of this study was to convert this recovered waste into a new animal feed capable of reducing methane emissions in ruminants. The interest in use waste by-products for ruminant nutrition is increasing. Therefore, we replace the beet pulp and cereal straw from dry-non-pregnant goats’ diet with orange leaves and rice straw with the objective of studying their effect upon intake, digestibility, energy efficiency, carbon and nitrogen balance, and methane emissions.Considering the huge quantities of crops by-products and pruning waste such as rice straw and citrus leaves produced annually worldwide, and their potential pollution capacity, recycling as feed for livestock is an alternative. The objective was to study these by-products effect on energy balance and methane emissions in 10 Murciano-Granadina goats at maintenance. The control diet (CTR) included barley straw and beet pulp while the experimental diet (ORG) consisted of rice straw and orange leaves. Differences were found for energy intake (248 kJ/kg of BW0.75 greater for CTR than ORG). The intake of metabolizable energy was 199 kJ/kg of BW0.75 lower in ORG than CTR, and the energy efficiency was higher with CTR (0.61) than ORG (0.48). Protein retained in the body was 9 g/goat greater with CTR than ORG, and fat retention in the body was approximately 108 g/goat greater with CTR than ORG. Despite more unfavorable energy balance in response to feeding ORG than CTR, the retention of body energy was always positive. Reductions in CH4 emissions were detected when goats were fed ORG diet (from 22.3 to 20.0 g/d). Overall results suggested that feeding orange leaves and rice straw was effective in reducing CH4 emissions without adversely affecting energy balance.

Immobilization of enzyme cocktails on dopamine functionalized magnetic cellulose nanocrystals to enhance sugar bioconversion: A biomass reusing loop

A combined enzymatic treatment/acid hydrolysis technique was utilized to synthesize cellulose nanocrystals (CNCs) from sugar beet pulp. CNCs were functionalized with magnetite nanoparticles and dopamine making a versatile nano-carrier (DA/Fe3O4NPs@CNCs) for covalent enzyme immobilization. Oxygene/amine functionalities, high magnetization value, and specific surface area of DA/Fe3O4NPs@CNCs made it a reusable and green candidate for conjugation to hydrolytic enzyme cocktails (three cellulases, two hemicellulases, and their combinations) to prepare an innovative and practical nano-biocatalyst for biomass conversion. The conjugated enzymes showed an enhanced optimum temperature (∼ 10 °C), improved thermal stability, and shifted optimum pH toward alkaline pHs. Covalent attachment could successfully suppress the enzyme leaching and provide easy recovery/reuse of the nano-biocatalyst up to 10 cycles, with > 50% of initial activity. Application of the nano-biocatalyst in hydrolysis of rice straw and sugar beet pulp showed an increase (20-76%) in the yield of fermentable sugars compared to the free enzyme cocktails.

The potential of anaerobic-constructed wetland system for wastewater treatment of rice straw pulping

Wastewater of cooking rice straw in the manufacture of pulp contains high levels of pollutants that must be treated first before being discharged into the environment. The purpose of this research is to study the potential of anaerobic and constructed wetland systems in treating pulp-making wastewater from rice straws. Anaerobic reactor with a volume of 30 L was filled with 5 L domestic sludge as sludge seed. Wastewater with COD of 762 - 17,900 mg/L, BOD5 of 354 – 8,000 mg/L, and TSS of 123 - 350 mg/L was fed into the anaerobic reactor. The organic loading rate was varied from 0.15 to 2.13 kg COD/m3 day, during the residence of wastewater for 5-8 days. Anaerobic reactor effluent was further processed in a constructed wetland reactor that varies in height from a mixture of sandy soil of 10-30 cm. The hydraulic residence time of wastewater in the constructed wetland reactor was 6.7 - 11.6 days. Influent and effluent of anaerobic and constructed wetland reactors were analysed for COD, BOD5, TSS, and pH parameters. The result indicated that wastewater treatment with anaerobic system could reduce COD of 63-72% and BOD5 of 65-75%, and the constructed wetland system could reduce COD and BOD5 of 96.5% and 96.1%, respectively.

Thermodynamic Functions and Kinetic Models for Methelyne Blue Adsorption on Corn Straw Pulp (Dept.P)

Methylene Blue (MB) in aqueous solutions was subjected to color removal by the adsorption technique onto corn straw pulp (CSP) as a biosorbent waste agricultural material. Results obtained indicate that the removal efficiency of Methylene Blue at 25°C exceeds 91% and that the adsorption process is highly pH-dependent. The optimum pH lies between 5 and 9. The amount of Methylene Blue adsorbed from the aqueous solution increases with the increase of the initial Methylene Blue concentration and temperature. Smaller adsorbent particles help in increasing the percentage removal of Methylene Blue. The results fit the BET model for adsorption of Methylene Blue on corn straws pulp, verify the assumption molecules could be adsorbed in more than one layer thick on the surface of the adsorbent. A comparison of kinetic models (pseudo first-order, the pseudo second order, Elovich and intraparticle diffusion kinetic models) at different conditions showed that the pseudo second-order kinetic model correlates the experimental data well. Van't Hoff equation was used to evaluate the thermodynamic parameters (AH, AS and AG) for the interpretation of the adsorption process. The values of the thermodynamic parameters indicate that all adsorption processes are endothermic, and this is in agreement with the increasing adsorption capacity with temperature. The process of removal of MB by Corn straw pulp is a spontaneous one.

Valorization of Wheat Straw for the Paper Industry: Pre-extraction of Reducing Sugars and Its Effect on Pulping and Papermaking Properties.

Cleaner production of sugars and pulp from renewable feedstocks has captured significant scientific attention in the recent past because they can be used for various end applications. In the papermaking industry, a major fraction of hemicellulosic sugars is lost during the pulping. The present study aims at retrieving these hemicellulosic sugars through alkali-, hot-water-, and acid-mediated extraction prior to pulping, which otherwise would have been lost during pulping and washing of pulp. These retrieved sugars can be used as feedstocks for renewable energy and value-added products. Different pretreatments were applied, aided with varying temperature, chemical concentrations, and time. Substantial amounts of total reducing sugars (TRSs) up to 21.98, 13.2, and 15.01% were extracted prior to pulping by acid, alkali, and hot-water pretreatments. Compositions of mono sugars present in the treated liquor were also characterized and confirmed by high-performance liquid chromatography analysis. The morphological changes in the wheat straw after pre-extraction were studied using the field emission gun scanning electron microscopy technique. Pulping of untreated and pretreated wheat straw was carried out at different alkali charges (12, 14, and 16% NaOH). Among all, acid-pretreated straw showed an increase in pulp yield by 10.9% at a 16% alkali charge. Physical strength properties of different pulps were further examined. Alkali- and hot-water-pretreated straw pulp retained 94.26 and 83.16% tensile indices and 92.43 and 87.02% burst indices, respectively. An increase in tear index up to 4.32, 2.01, and 2.30% for alkali-, hot-water-, and acid-pretreated straw pulp was achieved, respectively. Hot-water- and alkali-pretreated wheat straw was observed to be conducive for paper production. The integrated use of wheat straw for extraction of underutilized sugars and pulp production in this way may serve as a key stepping stone for future biorefinery designs in pulp and paper mills.

Optimization of xylanase production by Bacillus tequilensis strain UD-3 using economical agricultural substrate and its application in rice straw pulp bleaching

Thermo-alkali-stable xylanase producing Bacillus tequilensis strain UD-3 was isolated from the hot spring, and the biobleaching effect on rice straw pulp was evaluated. Bacillus tequilensis strain UD-3 produced xylanase (8.54 IU mL−1) employing on wheat bran. The xylanase production was increased about 2 fold after optimization of media via central composite design. The maximum xylanase activity was achieved at 8.0 pH, 50 °C temperature, and boosted at 1.0 mM concentration of metal ions such as Mn+2, Fe+3, Cu+4, and Zn+4. Furthermore, Zn+4 concoction with xylanase was evaluated for pre-bleaching of rice straw pulp in which xylanase significantly reduce the Kappa number (17.24 ± 0.02) after Xyl + Zn bleaching. A significant reduction was also observed in the reducing sugars (50%), phenolic (29.19%), hydrophobic (33.20%), and lignin compounds (35.86 and 40.48%) during the Xyl + Zn treatment of pulp samples in comparison to the only xylanase.

Synergistic approach using ultrafiltered xylano-pectinolytic enzymes for reducing bleaching chemical dose in manufacturing rice straw paper.

In this study, action of ultrafiltered xylano-pectinolytic enzymes from a bacterial strain has been evaluated for bleaching of rice straw soda-anthraquinone pulp. Maximum bio-bleaching effect and release of non-cellulosic impurities were noticed with xylano:pectinolytic enzymes dose of 6.0:2.1-IU/g pulp, treatment time of 180min at 10% pulp consistency, pH8.5, and temperature 55°C. Microscopic images of bio-bleached rice straw pulp also confirmed the efficacy of ultrafiltered enzymes, as bleaching agent. This bio-bleaching treatment resulted in 15.38% and 32% reduction in kappa number and active chlorine dioxide dose, respectively, along with increase in various physical properties, burst index (12.50%), tear index (19.07%), breaking length (14.30%), double fold number (26.31%), Gurley porosity (45.32%) and viscosity (16.17%). This bio-bleaching approach not only improved the pulp quality but also reduced environmental pollution load by decreasing effluent parameters values of BOD and COD by 23.67% and 27.44%, respectively. This study indicates that use of ultrafiltered xylano-pectinolytic synergism for rice straw pulp bleaching will ultimately help in making the process eco-friendly, along with better quality pulp. This is the first report on use of ultrafiltered xylanase and pectinase, produced from a bacterial isolate, for bleaching of rice straw pulp.

Effect of introducing ozone in elemental chlorine free bleaching of pulp on generation of chlorophenolic compounds

Abstract Effect of using ozone before elemental chlorine free (ECF) bleaching of oxygen delignified wheat straw pulp produced following soda-anthraquinone pulping on bleaching effluent and pulp properties was studied. The effluent generated during bleaching of pulp contains high amount of adsorbable organic halogens (AOX), chemical oxygen demand (COD), biochemical oxygen demand (BOD) and highly toxic chlorophenolic compounds. This study is aimed to utilise green chemistry approach during bleaching of one of the abundantly used agro residue wheat straw for improving the quality of bleaching effluent and pulp properties. Introducing ozone stage before ECF bleaching resulted in significant reduction of chloriphenolic compounds like chlorocatechols by 48.9 %, chloroguaiacols by 33.3 %, chlorovanillins by 28.4 % and chlorophenols by 26.7 % in the effluent compared to those of control. Incorporation of ozone before ECF bleaching BOD, COD, AOX and colour were reduced by 40.0 %, 41.1 %, 46.7 % and 57.8 %, respectively, as compared to control. Optical properties like brightness and whiteness of the pulp bleached using ozone were also improved by 2.5 units and 4.0 units, respectively as compared to that with control.

Chlorine dioxide bleaching of nineteen non-wood plant pulps

AbstractBleaching of unbleached and oxygen delignified pulps from nineteen non-wood plants has been evaluated in elemental chlorine free bleaching. Chlorine dioxide charge (kappa factor 0.15, 0.20 and 0.25) and temperature (70 and 85 °C) in the delignification stage (D) were varied. Chlorine dioxide (ClO2) charge and temperature exhibited lower kappa number and higher brightness after alkaline extraction (EP) stage. High temperature ClO2delignification (DHT) exhibited higher final pulp brightness. The final brightness of wheat straw pulp reached to 90 % after D0/DHT(EP)D1bleaching, while banana pseudo stem pulp showed the worst bleachability. Residual hexeneuronic acid contents in final pulp from most of the non-wood plants were lower and exhibited 1–2 % higher pulp brightness in DHTprocess than D0process. Oxygen delignified pulp and DHTprocess discharged lower COD load.

An eco-friendly approach to preparing cellulose nanocrystals by precisely controlling the dissolution of natural cellulose in TBAH/H2O solvent

Applications of cellulose nanocrystals (CNCs) in various fields of high value have been and are being widely studied. However, research about the fundamental preparation method has come to a standstill. This work aims to introduce a concept of progressive dissolution of cellulosic fibers and an eco-friendly way of preparing CNCs. By controlling TBAH concentration, the amphiphilicity and dissolving capability of TBAH/H2O can be regulated. Through a controlled partial dissolution of cellulose in the solvent, aqueous tetra-butylammonium hydroxide (TBAH), the fiber can be dissolved to make nanoscale particles (CNC suspensions). Polarized light microscopy provides a quantitative evaluation of the progress of dissolution, by which a processing window (43% TBAH/H2O, 30 min dissolution at room temperature) for preparing CNCs from cotton pulp has been determined. The multiscale cellulose products, including micron-scale, nanoscale, and well-dissolved products of cellulose, have been separated with the assistance of the derivatization process. There are interestingly homogeneous materials of cellulose I with a needle-like shape in the nanoscale products extracted. Furthermore, the cellulose raw materials can be extended from cotton pulp to wood pulp, bamboo pulp, straw pulp, and microcrystalline cellulose, indicating it to be a universal method. Analysis of XRD patterns of the raw and CNCs indicates that amorphous and less-crystalline cellulose can be precisely and controllably dissolved by the solvent, leaving CNCs.

Screening of Organic Substrates for Solid-State Fermentation, Viability and Bioefficacy of Trichoderma harzianum AS12-2, a Biocontrol Strain Against Rice Sheath Blight Disease

The present study was undertaken to find the most suitable organic substrates for the biomass production, viability and efficacy of the biocontrol strain Trichoderma harzianum AS12-2 in the solid-state fermentation system. In total, 13 inexpensive, locally available substrates (agricultural wastes or by-products) were inoculated with the antagonist, and following one month of incubation at room temperature, all colonized substrates were air dried and ground to powder. The shelf life and viability of the Trichoderma strain were assessed as colony-forming units per gram (CFUs g−1) of each substrate on a monthly basis for up to one year at room temperature (25 ± 2 °C) and in the refrigerator (4 °C). In order to find out the effect of the substrate on the bioefficacy of T. harzianum AS12-2, the biocontrol potential of the formulations was evaluated against rice sheath blight disease caused by Rhizoctonia solani. The results showed that the fungus colonized more or less all substrates after one month, although the degree of colonization and conidiation was different among the substrates, being especially high in broom sorghum grain, rice husk, rice straw, rice bran and sugar beet pulp. Analysis of variance (ANOVA) of the population in the substrates in “Month 0” showed that the effect of treatment was significant, and the means were significantly different. The maximum population was recorded for broom sorghum grain and rice straw (6.4 × 1010 and 5.3 × 1010 CFUs g−1, respectively). The population declined in all substrates after one year of incubation at room temperature. This decline was relatively smaller in broom sorghum grain, rice straw and rice husk. On the other hand, the population in the same substrate incubated in the refrigerator was decreased in a mild slope, and the final population was high. In addition, the results of greenhouse assay showed that all bioformulations were effective in controlling the disease, and there were no significant differences among the substrates. According to the results of this study, broom sorghum grain, rice husk, rice straw, sugar beet pulp and cow dung could be recommended as suitable fermentation media for the industrial-scale production of T. harzianum strains.

Characterization of residues from non-woody pulping process and its function as fertilizer

Pulping and paper industries using non-woody feedstocks face the challenge of its notorious waste disposal problem. To resolve this problem, in this study, we evaluated a variety of properties of solid residues reclaimed from the effluents of both wheat straw ammonium sulfate and Kraft pulping processes as organic fertilizers. The results show that both residues from the ammonium sulfate (RAS) and Kraft pulping (RKP) processes possess desirable C/N ratios, appropriate nutritional compositions, and low levels of harmful heavy metals. The high solubilities (>35 g/L) of both residues allow their use for fertigation or foliar applications. The salt index (30–50) is within the range of commercial chemical fertilizers such as potassium sulfate (42.6) and magnum sulfate (44). The E3/E5 ratios of residues suggest that the residues have small molecular sizes, which are similar to fulvic acids. Overall, wheat straw pulping residues demonstrate the potential as the sustainable organic fertilizers and the beneficial soil amendments. This work has the potential to resolve the severer effluent disposal problem faced by the non-woody pulping and papermaking industries, open a door to effectively utilize residues as value-added byproducts, and lead to both environmental sustainability and economic benefits.

Eco-friendly pulping of wheat straw using crude xylano-pectinolytic concoction for manufacturing good quality paper.

In this study, suitability of xylano-pectinolytic enzymes in pulping of wheat straw has been explored. The suitable biopulping conditions were optimized, with xylanase dose of 400 and pectinase dose of 120IU/g wheat straw, 1:10 (g/ml) material to liquid ratio, 55°C temperature, 3h treatment time, 0.75% Tween 80 and pH8.5. Enzymatic pretreatment efficiently increased the pulpability of wheat straw, generated pulp with higher yield, lower kappa number (15.67%) and rejections (59.65%) in comparison with chemical pulp. The brightness of pretreated wheat straw pulp with enzyme was 16.04% higher than that of the non-enzyme treated wheat straw pulp. The biopulping resulted in 12% reduction of pulping chemicals along with more residual alkali content, in order to achieve similar optical and chemical properties as obtained by 100% chemically treated pulp. Physical properties of pulp also improved after enzymatic pretreatment, increasing burst index (26.50%), tear index (18.22%) and breaking length (5.56%). The enzyme plus chemical (88% pulping chemicals) treated pulp showed improvement in brightness and whiteness, with reduction in yellowness at all bleaching stages. In comparison with chemically bleached pulp, biopulp with reduced alkali dose (88%) had higher breaking length (6.63%), double fold number (51.28%), tear index (2.83%), burst index (24.31%), along with increased viscosity (6.12%) and Gurley porosity (27.50%). These results clearly suggest that biopulping of wheat straw with xylano-pectinolytic enzymes can reduce chemical loading during soda-anthraquinone pulping and also improve the quality of paper. This is the first report demonstrating the biopulping of wheat straw using crude xylano-pectinolytic enzymes.

Water purification ultrafiltration membranes using nanofibers from unbleached and bleached rice straw

There has been an increasing interest in recent years in isolating cellulose nanofibers from unbleached cellulose pulps for economic, environmental, and functional reasons. In the current work, cellulose nanofibers isolated from high-lignin unbleached neutral sulfite pulp were compared to those isolated from bleached rice straw pulp in making thin-film ultrafiltration membranes by vacuum filtration on hardened filter paper. The prepared membranes were characterized in terms of their microscopic structure, hydrophilicity, pure water flux, protein fouling, and ability to remove lime nanoparticles and purify papermaking wastewater effluent. Using cellulose nanofibers isolated from unbleached pulp facilitated the formation of a thin-film membrane (with a shorter filtration time for thin-film formation) and resulted in higher water flux than that obtained using nanofibers isolated from bleached fibers, without sacrificing its ability to remove the different pollutants.

On the Design of Novel Biofoams Using Lignin, Wheat Straw, and Sugar Beet Pulp as Precursor Material.

In this paper, we report the synthesis and characterization of pyrolyzed lignin compacts reinforced with 50 wt % wheat straw (WS) or sugar beet pulp (SBP) fibers. The compacts were pyrolyzed at 300, 500, 700, and 900 °C in an Ar atmosphere. Detailed thermogravimetric analysis (TGA), thermomechanical analysis (TMA), Fourier transform infrared (FTIR) spectroscopy, and microstructure analysis were performed on these samples. FTIR analysis showed that pyrolysis of lignin–WS and lignin–SBP resulted in aromatic char. Scanning electron microscope (SEM) studies showed that foams obtained by pyrolyzing both lignin–50 wt % SBP and lignin–50 wt % WS composites have a cellular structure. X-ray tomography and energy-dispersive spectrometry (EDS) studies showed that pyrolysis of wheat straw caused the formation of mineral-rich nodules in the pyrolyzed lignin matrix, which was responsible for the denser and uniform microstructure of the lignin–WS composites. Due to this reason, the lignin–WS composites were denser and had a better mechanical strength as compared to the lignin–SBP composites. Both the compositions also showed temperature-dependent wettability behavior.

A Dynamic Comparison Sustainability Study of Standard Wastewater Treatment System in the Straw Pulp Papermaking Process and Printing & Dyeing Papermaking Process Based on the Hybrid Neural Network and Emergy Framework

Sustainability study of the standard wastewater treatment system is the pivotal procedure in the water protection field. In order to better study the sustainability of sewage treatment systems, wastewater treatment system of straw pulp papermaking (WTSPP) and wastewater treatment system of printing and dyeing and papermaking (WTPDP) have been selected to assess the sustainable level in China. Based on the hybrid neural network and emergy framework, WTSPP and WTPDP were considered and analyzed in this paper. Therein, three types of indicators were used to evaluate these two systems, including basic structure emergy indicators (BEI), functional emergy indicators (FEI), and eco-efficiency emergy indicators (EEI). Through the basic neural network model and detailed neural network model design, the iteration paths and algorithm operation diagram of WTSPP and WTPDP were designed and realized in this article. Primary contents include: (1) For WTSPP and WTPDP, nonrenewable resources emergy are both the primary contributor and account for roughly 62.5% and 53.7%, respectively. (2) As the important indicator group, the environmental loading ratio (ELR) is 176 in the WTSPP and 323 in the WTPDP, respectively. Emergy sustainability indicators (ESIs) in the WTSPP and WTPDP, are 0.015 and 0.014, respectively. (3) Depending on fluctuation degrees, WTSPP is better than WTPDP. The maximum fluctuation ranges of WTSPP and WTPDP are (3%, −27%) and (28%, 61%), respectively. (4) All neural network analysis results manifest that the emergy sustainability indicators (ESIs) of WTSPP and WTPDP are [0.0151, 0.011] and [0.0179, 0.0055] in view of a long-term predictive view, respectively.

Enhancement of Versatile Extracellular Cellulolytic and Hemicellulolytic Enzyme Productions by Lactobacillus plantarum RI 11 Isolated from Malaysian Food Using Renewable Natural Polymers.

Lactobacillus plantarum RI 11 was reported recently to be a potential lignocellulosic biomass degrader since it has the capability of producing versatile extracellular cellulolytic and hemicellulolytic enzymes. Thus, this study was conducted to evaluate further the effects of various renewable natural polymers on the growth and production of extracellular cellulolytic and hemicellulolytic enzymes by this novel isolate. Basal medium supplemented with molasses and yeast extract produced the highest cell biomass (log 10.51 CFU/mL) and extracellular endoglucanase (11.70 µg/min/mg), exoglucanase (9.99 µg/min/mg), β-glucosidase (10.43 nmol/min/mg), and mannanase (8.03 µg/min/mg), respectively. Subsequently, a statistical optimization approach was employed for the enhancement of cell biomass, and cellulolytic and hemicellulolytic enzyme productions. Basal medium that supplemented with glucose, molasses and soybean pulp (F5 medium) or with rice straw, yeast extract and soybean pulp (F6 medium) produced the highest cell population of log 11.76 CFU/mL, respectively. However, formulated F12 medium supplemented with glucose, molasses and palm kernel cake enhanced extracellular endoglucanase (4 folds), exoglucanase (2.6 folds) and mannanase (2.6 folds) specific activities significantly, indicating that the F12 medium could induce the highest production of extracellular cellulolytic and hemicellulolytic enzymes concomitantly. In conclusion, L. plantarum RI 11 is a promising and versatile bio-transformation agent for lignocellulolytic biomass.

Development of Rice Straw Paper Coated with Pomelo Peel Extract for Bio-Based and Antibacterial Packaging

This study aimed to develop paper packaging from rice straw fibers with its function as antibacterial activity obtained from pomelo (Citrus maxima) peels. Paper with ca. 106.42 g/m2 basis weight, 0.34 mm thickness, 34.15 % brightness and 78.7 N.m/g tensile index was prepared from rice straw fibers and pulps. Bioactive compounds of crude pomelo peels extracted using maceration technique with 75% (v/v) ethanol were coated onto rice straw papers at concentration of 10, 15 and 20 % (w/v). The coated papers had similar thickness, and slightly lower tensile index and brightness as compared to those of control papers. Scanning electron microscopy confirmed the changes of surface and cross-section structures of coated and uncoated papers. The rice straw coated papers had relatively greater barrier property to prevent water absorption. In addition, the coated papers with pomelo peel extract showed significant antibacterial activity against food pathogenic bacteria, including Staphylococcus aureus, Bacillus cereus and Escherichia coli. This study reveals the benefits of natural by-products as a potential material for active packaging.

Mild potassium hydroxide pulping of straw

This research focused on the pre-extraction of rice and wheat straws by potassium hydroxide (KOH) at 90 ​°C prior to alkaline pulping to remove silica and some of the lignin and hemicelluloses. Pre-extraction removed 76 and 73% lignin, 50.5 and 26.8% pentosans and 81 and 87% silica from the rice and wheat straws, respectively. Pre-extracted rice and wheat straws were subjected to KOH pulping at varying KOH charges (8.4, 11.2, 14, and 16.8% as KOH on straw), cooking times (60, 90, and 120 ​min), and cooking temperatures (70 and 90 ​°C). Pulp yields of 43.6 and 51.0% with kappa numbers16.2 and 20.2, for rice straw and wheat straw, respectively, were obtained at the conditions of 12% alkali for 120 ​min of cooking at 90 ​°C. KOH rice straw and wheat straw pulps were bleached. The ISO brightness was 76.8 and 80.1%, respectively, by the D0(EP)D1bleaching sequence on using a fixed total ClO2 consumption of 25 ​kg ClO2/tonne pulp. The strength properties of the pulps at the lower cooking temperature were inferior to that of corresponding pulps produced at a higher cooking temperature. Dissolved silica, lignin, and hemicelluloses were separated from the spent black liquor. The potassium-rich spent liquor was used as a soil amendment (fertilizer).

Research of Physical and Chemical Properties of Powder Cellulose from Various Type of Raw Materials

The features of obtaining powder cellulose from non-woody plant materials, excluding the stages of acid and / or enzymatic hydrolysis using the original technological approach at atmospheric pressure and temperature, were studied 90-100 degree of Celsius. The feedstock after alkaline treatment, according to the proposed technology, is subjected to physico-chemical activation using a modified extrusion unit, providing intensive grinding and defibrillation of the fibers, washing, drying, grinding on a hammer mill. Physicochemical and structural studies of the obtained powder pulp from lucerne, oat straw and cotton powder pulp were carried out. The efficiency and prospects of the proposed process are shown.