Volume 11 Issue 3

Cellulose-based flocculants have shown excellent performance for wastewater flocculation, being low-cost and eco-friendly. However, they are still disturbed by the problems of incomplete biodegradability and unstable chemical structure. In the present study, 2,3,6-tricarboxylate cellulose (TCC) was developed as a novel fully biodegradable flocculant to deal with the preceding problems. The key carboxymethylation of cellulose was first carried out to make the subsequent NaIO4 oxidation occur under homogeneous conditions, which greatly enhanced the carboxylate content of the final TCC products. The chemical structure and solution properties of the TCCs were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffractometer system (XRD), field emission scanning electron microscopy (FESEM), charge density, particle size, and zeta potential. The flocculation performance of the TCCs was evaluated preliminarily by the turbidity removal of kaolin suspension. The positive results showed that all the TCC products had high carboxylate contents (more than 10 mmol/g) and zeta potentials. They exhibited excellent flocculation performance for the kaolin suspensions, in which the residual turbidities decreased from 610 to 14.9 NTU. Considering the degradation of cellulose caused by excessive NaIO4 oxidation, the TCC IV, together with its synthesis technology, could be used for practical applications in wastewater flocculation.

To help protect the environment and reduce energy consumption in the wood industry, air-drying has been used to pre-dry lumber to about 30% moisture content. An air-drying model based on the principle of diffusivity was developed to help estimate air-drying times more accurately. Because the moisture movement rate considerably differs from that which occurs during kiln drying, the effective diffusion coefficients were experimentally determined at different temperatures. A user-friendly computer program predicting air-drying times was developed using the control volume method. The model was experimentally confirmed by air-drying practices. This program is a powerful tool used to estimate the air-drying times for any final moisture content for larch lumber, at any time of the year, at any location where the historical meteorological data, such as temperature, relative humidity, and wind speed, is available. This tool enables mill managers to generate an optimal operation plan based on their kiln capacity, yard availability, inventory requirements, and weather conditions.

Acoustic properties such as specific dynamic Young’s modulus (Ed/γ), internal friction (Q-1), and acoustic conversion efficiency (ACE) of wood are important properties frequently examined using free-free flexural vibration. This study determined the suitability for making musical instrument soundboards and frameboards from four tropical wood species; namely Syzygium, Dialium, Gymnostoma, and Sindora. The results show that (Ed/γ), (Q-1), and ACE were in the range of 20.0 to 28.9 GPa, 0.0031 to 0.0085, and 3.41×107 to 10.83×107, respectively. Based on the results, Syzygium was preferred for making the frameboard of violins and guitars. The outer sapwood (outer part) of Syzygium was the most suitable for making frameboard by considering the lowest ACE and highest Q-1. Based on Ed/γ, the inner sapwood (middle part) in Dialium was the most suitable for making soundboard, but based on Q-1 and ACE, heartwood (inner part) was the most preferred for making soundboard. Gymnostoma was also preferred for making soundboard of violins and guitars (inner sapwood) because it yields the highest mean value of Q-1 and ACE. Considering ACE and Q-1, the outer sapwood in Sindora was the best for making frameboard. When considering Ed/γ and Q-1, the heartwood is the most suitable for making the frameboard of violins and guitars.

Laminated composite is a wood panel constructed from timber pieces then are laminated together. Bio-adhesives such as tannin adhesive are a potential alternative to synthetic adhesives. The purposes of this study were to characterize the chemical makeup of tannin from mangium (Acacia mangium) bark extract and to determine the physical-mechanical properties of the panels made from jabon (Anthocephalus cadamba) and sengon (Falcataria moluccana), and adhesives based on either mangium tannin or methylene diphenyl diisocyanate (MDI). The panels made from five layers of lamina were 5 cm × 24 cm × 120 cm in thickness, width, and length, respectively. Based on results from gas chromatography–mass spectrometry, mangium tannin had 34.04% phenolic compounds. Both wood species were low density, 0.31 g/cm3 for sengon and 0.44 g/cm3 for jabon, with an average moisture content of 12.4%. The panels had better width shrinkage than solid wood, with an anti-shrink efficiency of 72.5%. With regard to mechanical properties, none of the panels met the standard for the MOE or shear strength; however, sengon panel with MDI met the standard for MOR. In the delamination test, sengon panel was resistant to cold water immersion. All panels had low formaldehyde emission and met the standard requirements.

In this laboratory study, the initial phase of a single-stage sodium bisulfite cook was observed and analyzed. The experiments were carried out using either a lab- or a mill-prepared cooking acid, and the cooking temperature used in these experiments was 154 °C. Investigated parameters were the chemical consumption, the pH profile, and the pulp yield with respect to cellulose, lignin, glucomannan, xylan, and finally extractives. Cooking was extended down to approximately 60% pulp yield and the pulp composition during the cook, with respect to carbohydrates and lignin, was summarized in a kinetic model. The mill-prepared cooking acid had a higher COD (Chemical Oxygen Demand) and TOC (Total Organic Carbon) content than the lab-prepared cooking acid and this influenced the pH and the formation of thiosulfate during the cook. It was found that the presence of dissolved carbohydrates and lignin in the bisulfite cooking liquor affected the extractives removal and the thiosulfate formation.

Mechanical properties of wood composites made from multiple wood species (50% Crimean pine, 30% Eastern Black Sea oak, 15% quaking aspen, and 5% wood machining residues) were evaluated using various amount of glass wool (GW) and stone wool (SW) additives. A total of 70 experimental panels were produced with a target density of 640 kg/m3. The bending strength, modulus of elasticity, tensile strength parallel to the surface of boards, tensile strength perpendicular to the surface of boards (internal bond), and cutting (shear) strength parallel to the surface of boards were determined. After statistical analysis, the results indicated that the SW and GW additives decreased the bending strength and modulus of elasticity by 49% in almost all boards. The addition of SW resulted in a 6% reduction in the tensile strength parallel to the surface. Relative to SW, GW resulted in an additional 8% reduction in shear strength, a 3% reduction in the screw tensile strength perpendicular to the surface, and a 6% reduction in the tensile strength parallel to the surface. Thus, the SW and GW additives decreased all the selected mechanical properties of wood composites.

Optimization of process parameters in oriented strand board (OSB) manufacturing is a vital issue for improving product quality. In this study, the Taguchi method (TM) was applied to determine the effects of production factors such as adhesive ratio, press pressure, and pressing time on the thermal conductivity of OSB. Obtained results showed that adhesive ratio is the main factor affecting thermal conductivity. Press pressure and pressing time are the second and third most important factors influencing thermal conductivity, respectively. The study also identified the optimal values of factors that minimize thermal conductivity.

The objective of this study was to evaluate the mechanical and optical properties of paper made from alkaline sulfite anthraquinone and methanol (ASAM) unbleached pulp from bamboo (Gigantochloa scortechinii). The bamboo pulps were beaten using a PFI mill at 10,000 revolutions. To determine the properties of unbleached bamboo ASAM paper, handsheets with a density of 60 g/m2 were formed with 14 to 18% NaOH, 80/20 Na2SO3/ NaOH, 0.1% AQ, 0.5% EDTA, and 15% methanol pulping conditions. Pulping at 18% NaOH for 120 min cooking time produced paper with properties of 24.8 Nm/g and 43.02% for the tensile index and ISO brightness, respectively. Cooking at 16% sodium hydroxide for 90 min rendered the best results for mechanical and optical properties, with results of 20.86 Nm/g, 22.64 mN.m2/g, and 39.32% ISO value for the tensile, tear indices, and brightness, respectively. High quality bamboo paper produced by the ASAM pulping process was beneficial for producing highly durable paper and paperboard.

Energy recovery of lignocellulosic waste material in the form of liquid fractions can yield alcohol-based fuels such as bioethanol or biobutanol. This study examined biobutanol derived from lignocellulosic material that was then used as an additive for diesel engines. Biobutanol was used in fuel mixtures with fatty acid methyl ester (FAME) obtained by esterification of animal fat (also a waste material) in the amounts of 10%, 30%, and 50% butanol. 100% diesel and 100% FAME were used as reference fuels. The evaluation concerned the fuel’s effect on the external speed characteristics, harmful exhaust emissions, and fuel consumption while using the Non-Road Steady Cycle test. When the percentage of butanol was increased, the torque and the power decreased and the brake specific fuel consumption increased. The main advantage of using biobutanol in fuel was its positive effect on reducing the fuel’s viscosity.

An inorganic sodium hydroxide aqueous solution was developed for the dissolution of ball-milled softwood. Extractive-free Masson pine powder was prepared from the wood meal by planetary ball milling for various lengths of time. The effects of ball milling on the dissolution and regeneration of Masson pine powder were investigated. After 4 h of ball milling, the wood powder was completely dissolved in 6 wt% NaOH aqueous solution under vigorous magnetic stirring for 10 to 20 min at room temperature. The alkaline nitrobenzene oxidation products yield of 4 h ball-milled wood was very close to that of coarse wood meal without ball milling. Regeneration of the lignin fraction was easier than cellulose during the acid neutralization process, and the dialysis regeneration yield of total biomass was 91.1%. Therefore, the complete dissolution of the Masson pine in sodium hydroxide solution is of great potential for enhancing lignin isolation with a very little structural change.