Research Articles

Effects of two different modified treatments were investigated relative to the chemical and mechanical properties of pretreated corn stalk particles and their composites prepared with a modified lignosulfonate (ML) binder. Corn stalk particles (CP) first were prepared by treating corn stalk particles with oxalic acid in ultrasonic conditions (pretreated corn stalk particles, PCP). These particles were then modified by treatment with either laccase-vanillin system with ultrasound (LU) or polyethylenimine-glutaraldehyde with ultrasound (PU), and the surface chemistries of the modified PCP and mechanical properties of LU-PCP/ML composites and PU-PCP/ML composites, such as modulus of rupture (MOR), modulus of elasticity (MOE), internal bonding strength (IB), 24-h thickness swelling (TS), and crystallinity were compared. Both modified treatments dramatically enhanced the mechanical properties of the composites. The MOR, MOE, and IB of the PU-PCP/ML composites were improved by up to 148%, 81%, and 62%, respectively, compared to LU-PCP/ML. Moreover, the 24-h TS of the LU-PCP/ML composites was reduced by 16%. These results show that the pretreatment method of CP and ultrasonic collaborative treatment of PCP can effectively improve the properties of its composites. Modified PCP with PU was more favorable for surface chemical and mechanical properties.

Adsorption is one of the most significant approaches for treatment of wastewater. An adsorbent with high mechanical strength, good renewability, and high efficiency is expected for practical applications. In this paper, a cationic xylan-based aerogel composed of xylan, polyvinyl alcohol, and agarose was fabricated to adsorb pectin, which is a typical anionic trash substance in the papermaking white water. The freeze-drying method was used to prepare the aerogel. A cationic xylan-based aerogel with high mechanical strength (34.676 MPa at 50% strain) was obtained. FT-IR results illustrated that the hydrogen bonds between three components contributed to the formation of aerogels. The addition of cationic xylan led to a slight decrease of crystallinity and thermostability of the aerogels. The maximum adsorption capacity of anionic pectin was 19.52 mg/g. Moreover, the aerogels maintained a high pectin-adsorption capacity after five recycles. This new cationic xylan-based aerogel offers potential possibilities for the development of value-added hemicellulose-based materials and the purification of papermaking white water in practical applications.

To improve the accuracy of discrete element simulation parameters of sugarcane tail-leaf (STL) feed during dust removal and crushing, this study used a combination of physical tests and EDEM software simulations to calibrate the discrete element simulation parameters of crumbs and dust in the feed. Taking the experimental physical stacking angle (SA) as the response value, the second-order regression models of SA and significant factors were established by Plackett-Burman test, steepest climb test, and Box-Behnken test. Variance analysis and interaction effect analysis were conducted. Taking the accumulation angle of 41.27° obtained by physical experiments as the target value, the significant parameters were optimized. The optimal combination of the following parameters was obtained: tail stem-dust static friction coefficient (SFC) of 0.46, tail leaf-dust coefficient of sliding friction (COSF) of 0.205, JKR surface energy of 0.26, and dust-steel collision recovery coefficient (CRC) of 0.338. Through software simulation verification, the average value was 40.81°, and the relative error of the SA with the physical experiment was 1.13%. The results showed that the calibrated parameters are real and reliable, which can provide a theoretical reference for the design optimization of the straw crushing device, feed processing device, and other related components.

Seed orchards with high hereditary qualities and the improvement studies used are of great importance. This study was carried out on individuals in a Boyabat grafted black pine seed orchard, Sinop. The morphological and micromorphological measurements of the characteristics were performed on needle samples taken from individuals, and the genetic diversity was determined on a clonal basis. According to the analysis of variance applied to the data obtained from the measurements and the morphological and micromorphological characters of the clones, it was determined that there was a significant difference among the clones at the P<0.001 confidence level.  In this context, according to Duncan’s Range test, the creation of a large number of groups is an indicator of it. The highest heritability rates were obtained in needle diameter, stipule diameter, number of the dorsal stoma, and needle length characteristics.

Not only is the use of waste heat an important way for companies to reduce fuel costs but it is also an important step in achieving the goal of decreasing peak carbon dioxide emissions. Solid fuels still make up a large proportion of China’s energy consumption structures, and the amount of ash generated and the remaining thermal resources are enormous. When considering coal alone, the theoretical recoverable amount of waste heat associated with the ash can be as much as 15.87 Mt of standard coal per year. An analysis of thermal energy utilization of high temperature ash (TEUHA) was conducted. It was found that the existing direct utilization method had a thermal efficiency in the range of 12% to 92%. However, the process is complicated, and the heat carrier is susceptible to contamination. Indirect utilization could avoid pollution issues, but heat loss was severe and maximum thermal efficiency was calculated as only 59%. Combined with the waste heat characteristics of the ash and the heat demand, a “Point-Point” model of TEUHA using phase-change materials as the heat carrier is proposed. This approach not only avoids ash pollution to the thermal environment, but it also increases the energy harvesting efficiency and realizes a high-quality utilization of thermal energy.

Microcrystalline cellulose (MCC) is a green material that has widespread applications in pharmaceuticals, food, cosmetics, and other industries because of its biocompatibility, biodegradability, hydrophilicity, and acid-insolubility. In this study, MCC was prepared from cotton waste via alkaline treatment and sulfuric acid hydrolysis. Further, the synthesized cotton-based MCC was characterized using Fourier transform infrared (FTIR), X-ray photoelectron, and energy dispersive X-ray spectroscopies. Based on these results, the major components were identified as carbon and oxygen. This finding was evidenced by the FTIR analysis, which displayed peak wavenumbers at 3446.9, 2891.1, 1649.5, 1380.1, 1061.2, and 1050 to 1150 cm^-1. The surface morphology was also examined by field emission scanning electron microscopy and field emission transmission electron microscopy, which showed that the prepared MCC has a smooth surface and a consistent, rod-like shape. In addition, the MCC exhibited the typical diffraction peaks of a crystalline structure of cellulose II at 12.2°, 20°, and 22.03°, which correspond to the diffraction planes of 1-10, 110, and 020, respectively, and had a crystallinity index of 78.7%. Moreover, the prepared MCC had a diameter of 37.8 µm and exhibited good stability with a peak at -76.5 mV. Further, the cotton-based MCC exhibited high thermal stability, as revealed by the TGA.

The pyrolysis of corn stalk (CS) was carried out to investigate the effect of wet torrefaction (WT) pre-treatment and Zn/Ni-HZSM-5 on the production of bio-oil characteristics. The synergy between WT and the loaded metal catalyst was also analyzed. The oxygen content of the CS was reduced from 50.5% to 40.8% with WT, and hemicellulose was almost removed. WT pretreatment also significantly reduced the oxygenated compounds of bio-oil and increased the selectivity of phenols, aromatics, and anhydro-sugars. The addition of catalyst improved the deoxygenation, oligomerization, and aromatization during pyrolysis. The loading of Zn and Ni could optimize the pyrolysis reaction path and increased the relative content of monocyclic aromatics (MAHs) from 3.58% to 9.67% and 6.44% during the pyrolysis of CS-WT, respectively, and bimetallic catalyst further enhanced the relative content of MAHs to 11.1%. The relative content of aromatics below C9 was higher than other groups (14.8%). Thus, the WT pretreatment of raw materials and synergistic effect of catalysts can jointly optimize the biomass pyrolysis reaction.

Natural dyes are widely available and mainly extracted from natural plants with green, safe, and sustainable characteristics. This study used Cinnamomum camphora fruit peel as the raw material under the premise of minimizing chemical reagents and employed the microwave-extraction method to extract the dyes from C. camphora fruit peel. The dye extraction conditions were optimized using response surface software via the Box-Behnken model to formulate a response surface test protocol. The results showed that optimizing the experimental conditions by the response surface method was reliable. The optimal extraction condition was found to be material-liquid ratio 1:20 (g: mL), microwave time 90 s, and microwave power 420 W. It is of practical application value to improve the extraction quantity of C. camphora fruit dye. At the same time, the infrared spectrum and HPLC-MS analysis of Cinnamomum camphora fruit dye were analyzed, and the stability of the dye was tested.

The preparation of bio-butanol from corn starch requires saccharification and fermentation processes. In view of the fact that the pH value at the later stage of fermentation is applicable to the enzymatic hydrolysis of glucoamylase, the effects of simultaneous saccharification and fermentation (SSF) and separate hydrolysis and fermentation (SHF) were compared in this paper. 11.2 g/L butanol and 21.5 g/L total solvent could be obtained by the SSF process, while the yield was 9.74 g/L butanol and 17.2 g/L total solvent in the SHF process. The SSF process required a shorter overall process time (120 h) than the SHF process (144 h) and resulted in a large increase of 38.9% in butanol productivity (2.25 g/Ld for SSF compared to 1.62 g/Ld for SHF). These results show that the application of SSF can reduce the fermentation overall time, simplify the fermentation process, and reduce equipment investment and operating costs.

Lignin structure is known to have significant effects on the enzymatic hydrolysis efficiency (EHE) of lignocellulose. In this study, the lignin produced from corn stalk pretreated with p-toluenesulfonic acid (PCS) was used to prepare carboxylated and quaternized lignin (CQCL) and epoxidized lignin (ECL), and the effect of the two modified lignin forms on the EHE of PCS was investigated. The results showed that EHE after adding CQCL (83.7%) was higher than adding ECL (60.8%). To explore the reasons, the unproductive adsorption, cellulase-lignin interaction, and molecular dynamics experiments were conducted. The results showed that the smaller hydrophobic interaction and electrostatic attraction between CQCL and cellulase caused less unproductive adsorption between CQCL and cellulase than ECL. Additionally, CQCL and ECL changed differently the conformations of key amino acid residues of cellobiohydrolase I and endoglucanase II, which was also responsible for the higher EHE after adding CQCL.