Volume 10 Issue 3

Ground calcium carbonate (GCC) was modified with starch, sodium stearate, and sodium hexametaphosphate prior to the papermaking process. This paper is focused on the effect of shear on the modified GCC and considers the impact of adding modified GCC into paper. The coating efficiency of starch on GCC was investigated in terms of the shear-tolerance of the agglomerated filler. Experimental results showed that the precipitation temperature and the amount of crosslinking agent, sodium hexametaphosphate, both were important relative to shear tolerance. Lower precipitation temperature was beneficial for the starch coating. Within a certain range, more sodium hexametaphosphate led to a stronger complex. The results showed that 1.5% (based on MGCC) of sodium hexametaphosphate and a precipitation temperature of 60 °C were the optimum conditions for shear tolerance.

The chemical properties and fiber morphology of Fargesia fungosa at different culm ages and height portions were investigated. The variations in moisture, ash, SiO2, and toluene–alcohol extractive contents with culm ages were greater than they were with heights. The holocellulose varied neither significantly with age nor with height. The fiber length, width, length-to-width ratio, and wall thickness of F. fungosa increased with culm ages. Meanwhile, the middle portions of culms at all age classes had the highest values of fiber length and width. The lumen diameter decreased, whereas the wall-lumen ratio increased, with increasing bamboo ages and heights. The 3-year-old culms of F. fungosa are suitable for pulp and papermaking based on their fine chemical properties and fiber morphology.

The impact of fastener type (glued and unglued butterfly dovetail keys, glued and unglued H-shaped dovetail keys, one-pin dowel, two-pin dowels, and plywood spline) and wood composite material type on the bending moment capacity of L-shaped mitered frame joints under diagonal tension and compression loads was investigated. Specimens were constructed of laminated medium-density fiberboard (LamMDF) and laminated particleboard (LamPB). The glued joint specimens were constructed with polyvinyl acetate (PVAc) adhesive. In both tests, joints reinforced with two dowels had the highest bending moment capacity, whereas unglued joints fastened with H-shaped dovetail keys had the lowest capacity. Splined joints were characterized by the second highest bending moment capacity. Two-pin dowel joints had, on average, 47% greater capacity than one-pin dowel joints. The glued dovetail joints were 31% stronger than the unglued joints. There was no statistically significant difference between the bending moment capacities of butterfly and H-shaped dovetail keys. The LamMDF joints exhibited 7.8% greater capacity than joints constructed of LamPB. Overall, the bending moment capacity of joints loaded in compression was 22% higher than that of joints loaded in tension—when the moment arm in the compression specimens was taken at the inside corner of the joint.

During the process of fungal polysaccharide extraction for health care products and food factories, a large quantity of macro-fungi residues are produced, but most of the residues are abandoned and become environmental pollutants. A solid acid catalyst, prepared by sulfonating carbonized Phellinus igniarius residue, was shown to be an efficient and environmentally benign catalyst for the esterification of palmitate acid (PA) and methanol. As a comparison, two types of common biomass catalysts, wheat straws and wood chips, were prepared. In this study, characterizations, including scanning electron microscopy, thermo-gravimetric analysis, Fourier transform infrared spectrometry, Brunauer-Emmett-Teller assays and elemental analysis, and reaction conditions for the synthesis of methyl palmitate (MP) using solid acid catalysts were investigated. Experiments showed that the solid acid catalyst prepared from P. igniarius residue had a higher catalytic activity than the other two catalysts, and the highest yield of MP catalyzed by P. igniarius residue solid acid catalyst was 91.5% under the following optimum conditions: molar ratio of methanol/PA of 10:1, reaction temperature of 60 °C, mass ratio of catalyst/substrate of 2%, and a reaction time of 1.5 h. Thus, the use of this catalyst offers a method for producing MP.

Spent mushroom substrate (SMS) is a noxious byproduct of the mushroom industry. The aim of this work was to convert SMS into organic-mineral micronutrient (Zn(II), Mn(II), and Cu(II)) fertilizer via biosorption and examine the effect of its application in field tests on maize compared to commercial reference micronutrient fertilizer. Crop yield and crop quality were assessed, and multielemental analysis of grains was conducted for the evaluation of the fertilization effect on maize grains and to assess bioavailability of nutrients from fertilizers. Grain yield for maize treated with micronutrients delivered with SMS was noticeably higher (11.5%) than the untreated group and the NPK (nitrogen, phosphorus, potassium) fertilizer treated only group (2.8%). Bioavailability (TF) of micronutrients from SMS were comparable with reference micronutrient fertilizer (7% Zn, 4% Mn, and 2.3% Cu). The new product has the potential to be used as a micronutrient fertilizer. Satisfactory results of grain yield (6.4 Mg ha-1), high content of micronutrients (Zn 1.6%, Mn 1.2%, and Cu 1.8%), and macronutrients (P 1.0%, S 3.1%, Ca 8.2%, and K 0.2%) were observed. The bioavailability suggests that enriched SMS could be a good alternative to fertilizers in the present market.

Recombinant strain Xz6-1 was constructed by the protoplast fusion technique with the goal of endowing it with the ability to efficiently degrade pentachlorophenol (PCP). This compound was considered as a representative of possible compounds that can be obtained during the bleaching of pulp for papermaking. The potential of Xz6-1and Pseudomonas putida to treat PCP synthetic wastewater was explored. The majority of PCP was removed within the first 20 h; two degradation curves were obtained that followed first-order reaction kinetics. The kinetics data revealed that the rate constant for degradation of PCP for Xz6-1 was 0.063 h-1, a value that was over 50% greater than that of Pseudomonas putida (0.040 h-1). Aerobic granular sludge was highly fortified with Xz6-1 and Pseudomonas putida to provide PCP degradability improvements of 180.9% and 98.3%, respectively, relative to the original sludge. All results demonstrate that the protoplast fusion technique is an effective approach to construct a high-activity chlorophenol-degrading strain.

Recycling and deinking processes cause fiber damage because of hornification phenomena and increased external fibrillation. Mechanical refining has been used for many years to enhance the mechanical properties of paper. Biorefining of pulp using enzymes is receiving increasing interest for energy reduction at the refining step of the paper-making process. Moreover, enzymes have also been used for the enhancement of mechanical properties without affecting the drainage rate. As an alternative to mechanical refining treatment, a combination of an enzymatic treatment and cellulose nanofibril (CNF) addition was explored to enhance the mechanical properties of paper. The tests were carried out on a deinked pulp (DIP) suspension made of 50% old newspapers (ONP) and 50% old magazines (OMG). Various enzyme charges and CNF amounts were added to the mixture of ONP and OMG. All pulps (treated and untreated) were characterized from a morphological point of view, and the paper sheets made thereof were mechanically characterized. The combination of the enzymatic treatment with the addition of 3% CNF provided sufficient tensile strength for the paper to be used in high-performance applications.

Rice straw cellulosic ethanol fermentation waste (CEFW) and municipal solid waste derived fiber (MSWF) were used as alternative fibers for recycled paper making. The fibers were mixed with old newspaper (ONP) fiber at different mass ratios to produce standard recycled papers and paperboards. A “green” adhesive binder derived from kraft black liquor (BLDB) was used to improve the physical properties of the waste-derived paper products. The values of these properties increased linearly with increasing average fiber lengths, regardless of the type of fiber used in the products. BLDB improved the physical properties of the products by 50% for papers and 85% for paperboards, and the performance of this binder was comparable to a commercial urea formaldehyde resin binder. Thermal pressing, however, did not improve the physical properties of the binder-enhanced paper products. With the addition of the adhesive binder, CEFW and MSWF showed reasonable substitution potential for ONP fiber by providing suitable tensile and bursting strength in the recycled paper products. The critical fiber length, which produced the minimum strength properties for the recycled paper products, was approximately 1020 mm.

Thermally modified wood has high dimensional stability and biological durability.But if the process parameters of thermal modification are not appropriate, then there will be a decline in the physical properties of wood.A neural network algorithm was employed in this study to establish the relationship between the process parameters of high-temperature and high-pressure thermal modification and the mechanical properties of the wood. Three important parameters: temperature, relative humidity, and treatment time, were considered as the inputs to the neural network. Back propagation (BP) neural network and radial basis function (RBF) neural network models for prediction were built and compared. The comparison showed that the RBF neural network model had advantages in network structure, convergence speed, and generalization capacity. On this basis, the inverse model, reflecting the relationship between the process parameters and the mechanical properties of wood, was established. Given the desired mechanical properties of the wood, the thermal modification process parameters could be inversely optimized and predicted. The results indicated that the model has good learning ability and generalization capacity. This is of great importance for the theoretical and applicational studies of the thermal modification of wood.

The objective of this study was to investigate the anaerobic digestion performance and mechanism of corn stover pretreated with ammonia at three ammonia concentrations (2, 4, and 6%) and four moisture contents (30, 50, 70, and 90%). The physical and chemical structures as well as the changes in its chemical compositions of ammonia-pretreated corn stover were analyzed to understand its biogas production performance. The results showed that ammonia pretreatment could effectively improve the anaerobic digestion performance of corn stover and that the optimal biogas production performance was achieved with 4% ammonia and 70% moisture content. The maximum biogas yield reached 427.1 mL/gVS. The conversion rates of cellulose and hemicellulose were 80.60 and 68.5%, respectively, which is about 30 and 26% higher than those of the untreated corn stover, respectively. The composition and structure analyses showed that ammoniation pretreatment could rupture chemical bonds such as ester and ether bonds in the lignocellulose, partially degrade aliphatic and carbohydrate compounds, and bring anaerobes into sufficient contact with corn stover material, therefore helping to increase biogas yield.