Use of Sawdust- Biochar Amended Wood Pulp as A Substrate for Container Cultivation

Soilless substrates have many advantages over soil based system as they provide optimal conditions for plant growth when compared to soil-based agricultural practices. Different substrates are currently being used as support to the root system of plant. Substrates can be organic such as peat, bark, bagasse, sawdust, rice hulls, wood chips, etc. They can be inorganic mineral based such as sand, gravel, perlite, and stone wool slab. As the second phase of an earlier work by one of the authors on softboard as a novel wood fibre-based substrate for hydroponic systems, the present study was carried out to explore the effects of biochar amendment to wood pulps (or pulp wastes generated from fiberboard factories), on seed germination and seedling growth of Green gram (Phaseolus aureus) crop. The study also included a comparison of seedling growth in hardwood pulp and softwood pulp and to select the most suitable one for container cultivations. Keywords: Sawdust, biochar, wood pulp, green gram, container cultivation

Comparison of Cellulose Dissolution Behavior by Alkaline and Sulfuric Acid Solvents and Their Films’ Physical Properties

Three alkaline mixtures (NaOH/thiourea, NaOH/urea/thiourea, NaOH/urea/ZnO) and sulfuric acid were used at low temperatures as cellulose solvents, and their cellulose solubility and films’ physical properties for bleached chemical wood pulps and cotton linter were compared. Their degree of polymerization (DP) was controlled to 600–800 before dissolution. Among the alkaline solvents, NaOH/urea/ZnO gave the film the highest tensile strength and stretch. When compared to sulfuric acid, NaOH/urea/ZnO gave lower strength properties but higher crystallinity indices in the films. While alkaline solvents could not dissolve the high DP cellulose (DP ~ 2000), sulfuric acid could dissolve the high DP cellulose at below zero Celsius temperature, and the strength properties of the films were not much different from that of the low DP one. It appeared that the low-temperature sulfuric acid treatment did away with the cellulose’s DP controlling stage; it decreased cellulose DP very quickly for the high-DP cellulose at the initial stage, and as soon as the cellulose DP reached a DP low enough for dissolution, it began to dissolve the cellulose to result in stable cellulose solution.

Papermaking as Potential Use of Fibers from Mexican Opuntia ficus-indica Waste

The papermaking potential of Opuntia ficus-indica (OFI) waste fibers was studied in this research. Alpha cellulose, lignin, hollocellulose, ethanol/benzene extractives and ash content were determined as 53.7±0.1%, 2.4±0.3%, 61.6±5.7%, 7.1±0.3% and 26.4±0.1%, respectively. The average fiber length, width, lumen and cell wall thickenss were found to be 1.1±0.3 mm, 18.8±6.1µm, 12.1±5.4 µm, 4.3±1.0 µm. Soda pulping was conducted using 20 and 28% sodium hydroxide, cooking temperatures of 160 and 175 °C, cooking times of 60 and 120 min, and liquor- to fiber ratio of 9:1. Soda pulping with 28% sodium hydroxide, 175 °C and 120 min showed a lower Kappa number of 29.60±1.7 and a total yield of 32.2±1.6 %. In general, tensile strength index (36.0±5.0 Nm/g), stretch (1.7±0.3%), breaking length (3.7±0.5 km), burst index (3.2±0.4 KPa.m2/g), tear index (7.3±0.0 mN.m2/g), folding endurance (166 times) and porosity (> 120 s) of OFI pulp were comparable with wood and non-wood pulps.

WOOD PULP FOR POLYMER COMPOSITES PRODUCTION

The use of cellulosic fibers in composites is advantageous compared to inorganic materials, because they present lower density, abrasiveness and cost, besides the renewable origin. This study aimed to evaluate the influence of wood pulp obtained by the chemical (bleached and unbleached) and mechanical process, and wood-flour of Pinus taeda as reinforcement in low density polyethylene (LDPE) matrix. The composites were extruded and the specimens molded by compression. The samples were characterized by thermal analysis, density, mechanical properties and scanning electron microscopy (SEM). The incorporation of the wood pulps and the wood flour in the matrix improved the composites mechanical properties and reduced the rate of material degradation. All fibers types acted as nucleating agents because the composites had better mechanical properties than pure LDPE. There was influence of the studied parameters on tensile and flexural strength and the interactions were significant. In general, the highest values of strength and stiffness were obtained with the use of thermo-mechanical process pulp as reinforcement and the lowest values with the use of unbleached chemical process pulp. micrographs analysis showed that the coupling agent was effective for compatibilizing the wood fibers with the LDPE in the composites. It was possible to produce composite materials with good physical and mechanical properties and improved thermal stability by experimental model.

Synthesis and Application of N-methylphthalimidylazo Disperse Dyes to Cellulose Diacetate for High Wash Fastness

Cellulose diacetate fibers were prepared from cellulosic biomass with high α-cellulose contents such as purified cotton linters and wood pulps. Cellulose diacetate fibers are sensitive to alkaline solution, which causes hydrolysis of the acetate ester to hydroxyl groups, especially at high temperatures. Thus, the low alkali-resistance of cellulose acetate fibers makes it difficult to achieve high wash fastness by restricting the application of intense after-treatment, such as reduction clearing. A series of N-methylphthalimide-based high-washable azo disperse dyes were synthesized and their dyeing and fastness properties on cellulose diacetate fabrics were investigated. From the overall results obtained in this study, N-methylphthalimidylazo disperse dyes are expected to be a desirable alternative to high value-added dyes that can be used for high color fastness dyeing of cellulose diacetate with a minimal discharge of wastewater during washing process.

Physicochemical Characteristics of Fungal Xylanases and their Potential for Biobleaching of Kraft and Non-wood Pulps

Xylanases are enzymes with a wide variety of biotechnological applications, such as in the bioconversion of lignocellulosic materials, improvement of feed digestibility, and bleaching kraft pulps to increase pulp brightness. Many studies have been conducted and published over the years on cellulose pulp bleaching due to the need to search for more sustainable tools and thus reduce environmental pollution. Thus, in this review, we focus on analyzing the biochemical properties of xylanases produced by mesophilic and thermophilic fungi that have been used in the bleaching processes of kraft and non-wood pulps. Eucalyptus kraft pulp is still one of the most used raw materials in the production of pulp and paper, while straw and bagasse are alternative sources of non-wood pulps. Thermophilic fungal xylanases show optimum enzymatic activity at high temperatures and a shorter treatment period when compared to mesophilic xylanases in the bleaching step. However, mesophilic fungal xylanases exhibit a longer period of enzymatic treatment but achieve a satisfactory brightness and kappa number. Hence, these approaches will contribute to future applications of these xylanolytic enzymes in pulp and paper industries.