Volume 15 Issue 4

3-Aminopropyl-trimethoxysilane was introduced into bis-triazinyl amino-stilbene through the condensation reaction to obtain fluorescent whitening agents (FWAs) having excellent photo-stability. Tetraethoxysilane was hydrolyzed and combined with FWAs through in situ polymerization to obtain nanosilica-loaded yellowing inhibitors (SiO2–FWAs). Ultraviolet (UV) spectroscopy showed that the ratios of the trans-isomer structure in FWAs after 3 h of UV irradiation was 5.41 times higher than those of the cis-isomer. Moreover, the absorption intensity in the UV region was increased distinctly after nano-silica loading. Fluorescence spectroscopy revealed that the fluorescence of SiO2–FWAs was more intense than that of FWAs. In addition, the fluorescence quantum yield of SiO2–FWAs reached 0.416, whereas that of the default FWAs was only 0.279. UV-aging test results showed that SiO2–FWAs can improve the initial whiteness and anti-yellowing performance of paper made from high-yield pulp (HYP). These results indicated that the as-prepared SiO2–FWAs not only exhibited more excellent UV absorption and fluorescence emission properties, but it also exerted better whitening and anti-yellowing effects on high-yield pulp paper than the default FWAs. The enhanced performance of SiO2–FWAs can be ascribed to the synergy between the excellent UV-scattering effect of nanosilica and the fluorescent whitening property of FWAs.

The adsorbable organic halides (AOX) produced during chlorine dioxide bleaching are highly toxic and difficult to degrade. Currently, AOX generation is mainly reduced by controlling conditions during bleaching. Studies on AOX removal in the natural environment are rarely reported. In this study, the adsorption of 2,4,6-trichlorophenol (2,4,6-TCP) on nut shell activated carbon was investigated. The effects of activated carbon dosage, adsorption time, and temperature on the removal of 2,4,6-TCP were examined. The optimal adsorption conditions was activated carbon dosage 0.20 g × L-1, adsorption time 130 min, and temperature 25 °C. The removal efficiency of 2,4,6-TCP was 91.5%. The adsorption kinetics and isothermal adsorption were studied, and a thermodynamic equation was established. The adsorption was more consistent with a pseudo-second-order kinetic model and Freundlich adsorption isotherm model. Thermodynamic studies showed that the adsorption of 2,4,6-TCP on activated carbon was a spontaneous exothermic process. These findings provide a new method for AOX removal in natural environments.

Strength grading of hardwoods is a prerequisite to use them in structural engineered wood products. However, hardwood strength grading is considerably less developed than it is for softwood species. Previous study has shown that white ash and yellow birch are promising species for the manufacture of glued-laminated timber. However, no strength grading procedure dedicated to hardwoods is available in Canada. The objective of this study was to identify the relevant indicating properties for predicting the ultimate tensile strength of the investigated species. A model selection approach allowed to identify the most performing models and to compare, for each species, the relative impact of the indicating properties. The indicating properties included in the final models were the density of the specimens, the dynamic modulus of elasticity, the sinus of the maximum local grain deviation (SGDmax) as well as the knot area index (KAI), derived from the knot area ratio. The final models revealed important differences between the two species, indicating that it may be relevant to grade them separately to ensure the most efficient utilization of the resource. The coefficients of determination between the actual and model predicted UTS were 0.82 for white ash and 0.78 for yellow birch.

Tissue materials development using 3D computational tools to predict the influence of the combination of different fibers can be employed in the design of innovative tissue products and furnish optimization. Fibrous materials can be designed using different 3D fiber models for each type of fibers, detailed to the point where the wall fiber thickness, fiber lumen, and collapse degree are considered and presented in this work. Eucalyptus, Pinus, and Picea kraft cellulose pulp fibers were selected because they are representative of differentiated fiber types. The fiber morphological measurements were obtained using two methods: one uses the fibers in suspension, without restraints, and the other uses a capillary fiber alignment. The results indicate good repeatability for both methods but differences of 14% for fiber length weighted in length, 2% for fiber width, 11% for coarseness, 35% for curl, and 88% for fines content. Scanning electron microscopy images were used to identify the fiber dimensions inside the tissue structure. Four different types of fiber models for eucalyptus fibers, with different fiber wall thickness and lumen dimensions, were presented and used to predict 3D computational fibrous structures.

The objective of this study was to characterize the substrates after their degradation by P. ostreatus within 60 days of cultivation in four Mexican mushroom-producing companies, in order to use it as a complement feed for ruminants. The acid detergent fiber (ADF), neutral detergent fiber (NDF), protein fraction, and mineral profile were analyzed after degradation. Crude protein (CP) of companies 1 and 4 increased by 6.1% and 6.8%, respectively (p ≤ 0.05). Soluble nitrogen reached 60% relative to un-degraded substrate with 43.8%. Proteins A, B1, and B3 fractions increased compared to controls (p ≤ 0.05) at some companies. The B2 fraction was decreased in all the degraded substrates (p ≤ 0.05), but the C fraction at companies 1, 2, and 3 presented no significant differences with respect to their controls (p ≤ 0.05). Crude fiber (CF), ADF, NDF, and hemicellulose (HC) decreased while dry matter digestibility (DMD) increased to 55.5-58% on degrade substrates. The mineral composition increased disproportionately. The substrate degraded by P. ostreatus by improving its digestibility and soluble protein content may be a low-cost food supplement. However, due to its mineral imbalance, it is not recommended as the sole food source for ruminants.

Based on the literature on the degradation mechanism and the change of micro-functional groups in the fermentation process of modified rice straw, this study aimed to solve the problems of low biogas production rate and poor stability of the biogas production system. In this work, mathematical equations were developed and combined with duck dung and rice straw mixed raw material to perform a fermentation test. The molecular micro-functional group changes of cellulose, hemicellulose, and lignin were studied to obtain the optimal ratio of mixed raw materials for fermentation and to explore the optimization mechanism of its fermentation biogas production. Experimental results showed that the optimal ratio of mixed raw materials was 2.8:1, and the inclusion of a suitable amount of Mn2+(concentration of 2 mol × L-1) was able to strengthen MnP activity and improve the ability of white-rot fungi to rupture β-O-4 bonds. A modification pre-treatment via activated carbon-based solid acid was performed, and the experimental group generated 15.8% more cumulative biogas than the control group. The biogas yield reached its peak when 300 g of inoculum was added to the pre-treatment at a concentration of 30%.

This study aimed to access different desirable characteristics of nine Hibiscus cannabinus L. accessions based on morphophysiological characteristics and fiber tensile strength for an effective selection of H. cannabinus plant improvement. Four China accessions (FH952, T15, T17, and T19), four Bangladesh accessions (HC2, HC95, V4202, and V4383), and V36 (control) accession were examined in a four-month cultivation period. The experimental design was arranged using randomized complete block design with three replications. Stem diameter was found to be significantly related (p ≤ 0.05) with all morphological and yield characteristics except for leaf dry weight and growth efficiency. Bigger stem diameter was an indicator of fiber yield in attempts to apply crossing and selection to improve performance. Photosynthesis rate also was found to be significantly related (p ≤ 0.05) with stomatal conductance, transpiration rate, instantaneous water use efficiency, and carboxylation efficiency. High photosynthesis rate could be an indicator to interpret the pattern of genetic variation of plant assimilation rate and its relation with environmental and agronomic factors. The fiber tensile modulus, however, was found to be inversely correlated with fiber diameter. The present study suggests the selection of control, V4383, HC2, and FH952 accessions for a breeding line as they possess high fiber yield, fiber strength, and photosynthetic efficiency.

Lignin plays a crucial role in enzymatic hydrolysis of lignocellulosic biomass. To evaluate the correlation between lignin properties and its effects on enzymatic hydrolysis, five organosolv lignins (OLs) were isolated from woody biomass, and their physico-chemical properties and structural features were characterized. The effects of OL addition on enzymatic hydrolysis of microcrystalline cellulose (pure cellulose) were assessed first, which showed their disparate effects. The addition of three OLs increased the 72 h hydrolysis yield by 7.4% to 10.1%, while the addition of other two OLs reduced the 72 h hydrolysis yield by 3.2% to 20.4%. A strong correlation between the enzyme distribution coefficient on lignins and the 72 h hydrolysis yields indicated that the enzyme-lignin interaction played a significant role in determining the lignin effects. More importantly, a correlation between lignin properties (hydrophobicity, zeta potential, and particle size) and the enzyme distribution coefficient was established. Identifying the key lignin properties will give insights to reduce the lignin inhibition by altering the lignin properties, thereby promoting enzymatic hydrolysis of lignocellulose.

To make full use of the processing residues of Pterocarpus macrocarpus Kurz and reduce the environmental pollution caused by synthetic dyes, natural dye was extracted from Dalbergia bariensis Pierre heartwood. The purpose of the work was to prepare natural dyes of Pterocarpus macrocarpus and identify the key color-producing components to better explore the mechanisms of combination between dyes and eucalyptus veneers. The main components of Pterocarpus macrocarpus heartwood were analyzed by ultra-high performance liquid chromatography with quadrupole-electrostatic field Orbitrap high resolution-mass spectrometry (UPLC-Q-EXACTIVE Orbitrap-MS). The best dyeing process and color fastness were measured. Research technology combining Fourier transform infrared spectroscopy (FTIR) and field emission scanning electron microscopy (FESEM) was used to explore the binding mechanism between eucalyptus veneers and dyestuffs. The UPLC-Q-EXACTIVE Orbitrap-MS results showed 16 flavonoids. The optimal dyeing process parameters of eucalyptus veneer were a 90 °C dyeing temperature, 12 h dyeing time, 4 wt% pigment, and 2 wt% NaCl. The FTIR and FESM results revealed that the dyeing was mainly achieved by physical adsorption and intermolecular hydrogen bonding.

The bleaching plant of a kraft pulp mill is the sector that consumes water and generates effluent with the highest volume. Water recycling is an attractive option to reduce water consumption and effluent generation. This study evaluated the technical feasibility of using treated effluent as washing water in the bleaching stages. The bleaching sequence was simulated in the laboratory using four types of washing water: deionized water, whitewater, low organic load effluent, and high organic load effluent. To achieve 90% ISO pulp brightness, the ClO2 consumption increased from 8.1 kg ClO2 odt-1 when using water to 13.8 and 16.3 kgClO2 odt-1 for the low and high organic effluents. Physical and optical tests of the hand-sheet papers did not show any statistical difference between various washing waters. The filtrates showed values that did not burden the efficiency of the effluent treatment plant. It was possible to use effluent in the bleaching stages, considering that the filtrates and the produced paper complied with the quality standards.