Volume 15 Issue 2

Effects of biochar on different soil types were studied in soil column experiments. The results showed that the biochar decreased filtrate heavy metals concentration by 89.0% to 95.7% (Cd) and 93.2% to 99.3% (Pb) compared with the control. The biochar application changed 2.3% to 9.84% of the exchangeable Cd fraction Pb to residual fractions, so the bioavailable Cd and Pb were reduced by 4.48% to 10.69% (Cd) and 11.74% to 16.42% (Pb) in surface soil (0 to 4 cm). Through increasing the soil ratio, the concentration of bioavailability of Cd and Pb was decreased 13.84% to 16.15% and 4.02% to 13.40% in 4 to 8 cm soil. With sandy soil, the application of biochar effectively reduced the down migration of heavy metals, and accomplished the conversion of 100.0% and 95% exchangeable Cd and Pb fractions into 13.1 to 43.9% residual Cd and 11.6 to 100.0% residual Pb. The SOM and pH also increased 1.2 to 2.3 g kg-1 and 0.01 to 0.31 with biochar application. The biochar effectively increased the SOM content, and stabilized heavy metals, then reduced the migration of Cd and Pb.

Reaction wood is characterized by having different anatomical and chemical features than normal wood. The different composition of cell walls, the higher quantitative proportion of thick-wall fiber cells, diameter, and the abundance of vessels have remarkable effects on reaction wood’s physical and mechanical properties. Reaction wood has fewer vascular cells. In addition, it has a smaller lumen diameter, which results in reduced permeability. Therefore, reaction wood is more difficult to dry at a certain moisture content. The differences in the drying times of the reaction wood and the normal wood were largest at a temperature of 60 °C and durations greater than 30 h, and the reaction wood dried more slowly. At a temperature of 120 °C, the differences in drying time were minimalized, and drying end times were almost identical. The expected negative effect of higher temperature on the morphology of reaction wood and opposition wood was not confirmed.

Excess lignocellulose fines in some fiber processing mills cause issues and hurt product quality. To use this type of biomaterial as a resource, surplus fines can be separated and dissolved with solvents for further transformation. Therefore, 1-butyl 3-methyl imidazolium chloride ionic liquid (IL) was used as a powerful green solvent for a rapid dissolution process. However, a low degree of polymerization (DP) of the cellulose in fines and the effects of lignin content and its structure on the process and film properties are controversial subjects. This study demonstrated that the three dimensional structure of lignin did not permit the raw bagasse fines (prior to pulping) to dissolve in the IL even after several hours. However, following decomposition of the lignin structure by pulping, the fiber fines were readily dissolved. Further, all the fabricated films from the fiber fines exhibited satisfactory strength properties, despite the fact that the cellulose had a low DP. The films from bleached fiber fines showed higher tensile strength than those containing lignin, although the cellulose chain was longer and had a higher DP for the latter. Lignin resulted in reduced transparency, and higher absorption of ultraviolet radiations, but it did not affect the surface roughness of the films.

To give cellulose fibers dual characteristics of warming and fluorescence, graphene oxide (GO) and fluorescent particles were simultaneously dispersed into the regenerated cellulose spinning solution through blending modification and post-reduction methods. After dry-jet wet spinning and reducing in hydrazine hydrate solution, the reduced graphene oxide (RGO)/regenerated composite fibers with different mass ratios of filler were completed. Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), fluorescence microscopy, and other methods were used to characterize the structure and morphology of fibers. Test results showed that the thermal stability and infrared emissivity increased gradually with the increase of GO. The crystallinity and strength of the composite fiber first increased and then decreased. This type of fiber also had luminescent properties after addition of fluorescent agent. However, when too much fluorescent agent was added, the thermal stability, infrared emissivity, crystallinity, and other properties mentioned above were affected to some extent. According to the comprehensive analysis, when the amount of GO added was 1 wt% and fluorescent added was 3 wt%, respectively, the luminescence characteristic and far-infrared emissivity of the fibers were remarkably improved.

Pyrolysis experiments were conducted in a tubular furnace from room temperature to 600 °C at 5 °C /min, and kept for 15 min. The light tar was then derived from the liquid products of pyrolysis by n-hexane supersonic extraction. Gas chromatography–mass spectrometry was employed to analyze the light tars from cotton stalk (CS) pyrolysis, Shenmu coal (SM) pyrolysis, and co-pyrolysis of CS/SM. Microcrystalline cellulose (MCC) was selected as a model compound, and the light tar from co-pyrolysis tar of MCC/SM was investigated for comparison. The results indicated that CS improved the yields and quality of phenols and benzenes in co-pyrolysis tar and that MCC had excellent performance in the formation of mononuclear aromatics during the co-pyrolysis of MCC/SM. Based on the pyrolytic behavior of CS and SM, the mechanisms of aromatic formation were further determined. It was shown that the free radicals that cracked from CS accelerated the formation of aromatics. The alkyl and mononuclear aromatic radicals of CS pyrolysis combined with the radicals from the SM aromatic structure, which then converted to benzenes and phenols. Finally, the most favorable reaction routes of mononuclear aromatics formation were proposed.

Characteristics and performances of a blended jatropha bio-epoxy/epoxy as a matrix in carbon fiber reinforcement was studied. The amount of bio-epoxy was arranged from 0 wt%, 25 wt%, 30 wt%, 40 wt%, and 50 wt% of the total matrix. Several analyses were performed to characterize and observe their performance. Fourier transform infrared spectroscopy, thermal analysis, physical characteristics, flammability, and soil burial were conducted, as well as mechanical tests. The results showed that introducing bio-epoxy in the matrix changed characteristics and increased or decreased their performance. Blending more than 25 wt% of bio-epoxy led to improved thermal stability between 280 °C to 350 °C and better biodegradability. However, tensile and flexural strength as well as modulus of elasticity decreased once the proportion of bio-epoxy was greater than 25 wt%. The paper proposed an optimal amount of jatropha bio-epoxy so that an alternative biocomposite application could be introduced to minimize carbon footprint in the environment.

Biomass is a class of abundant renewable resource. Its efficient use in the field of biobased materials is one of the important ways for implementation of sustainable development strategies. 2,5-Furandicarboxylic acid (FDCA) as a potential alternative of terephthalic acid (PTA) to make alipharomatic polyesters, can be obtained in mass amount from cellulose via bio- or chemical process. For this reason, FDCA-based polyesters have gained high interest recently. This review systematically summarizes recent progress in the making of FDCA-based polyesters (including poly(ethylene 2,5-furandicarboxylate) (PEF), poly(propylene 2,5-furandicarboxylate) (PPF), poly(butylene 2,5-furandicarboxylate) (PBF), poly(hexylene 2,5-furandicarboxylate) (PHF), and their copolyesters), especially highlighting the progress and fundamental aspects for their synthesis and properties. Significant advantages (and also disadvantages) of the FDCA-based polyesters are clearly indicated relative to price, performance, and sustainable development, in reference to traditional petroleum-based polyesters in industrial application. The goal of this review is to provide useful information regarding the synthesis and properties of FDCA-based polyesters.

Sugars, starches, and cellulose materials are used for ethanol production. When producing a liter of alcohol, 10 to 15 liters of liquid waste are generated. This waste is called vinasse, and it generates negative impacts on the environment. The process of storing and disposing vinasse in soils generates emissions to the atmosphere, mainly methane. Anaerobic treatment allows for the capture and generation of more biogas, therefore allowing mitigation of the environmental impacts. The microbial diversity present in the anaerobic digestion (AD) of vinasse is strongly related to the efficiency and quality of methane production. The gene 16s rDNA-based molecular techniques have been the most commonly used techniques for monitoring microbial communities present in the digesters. However, the identification is not enough. Rather, it is necessary to know the metagenomic functionality in this type of habitat. This review provides a comprehensive overview of methods to identify the microorganisms in the anaerobic digestion of vinasse. In addition, microbial community identification in vinasse reactors and their relationship with methane production are reviewed.

Based on publications related to the use of micro- and nanofibrillated cellulose (MNFC) in papermaking applications, three sets of parameters (intrinsic and extrinsic variables, furnish composition, and degree of dispersion) were proposed. This holistic approach intends to facilitate understanding and manipulation of the main factors describing the colloidal behavior in systems comprising of MNFC, pulp fibers, and additives, which directly impact paper product performance. A preliminary techno-economic assessment showed that cost reductions driven by the addition of MNFC in paper furnishes could be as high as USD 149 per ton of fiber (up to 20% fiber reduction without adverse effects on paper’s strength) depending on the cost of papermaking fibers. It was also determined that better performance in terms of strength development associated with a higher degree of MNFC fibrillation offset its high manufacturing cost. However, there is a limit from which additional fibrillation does not seem to contribute to further strength gains that can justify the increasing production cost. Further research is needed regarding raw materials, degree of fibrillation, and combination with polyelectrolytes to further explore the potential of MNFC for the reduction of weight of paper products.

This review article considers the role of fatty acids and the mutual association of their long-chain (e.g. C18) alkyl and alkenyl groups in some important aspects of papermaking. In particular, published findings suggest that interactions involving fatty acids present as condensed monolayer films can play a controlling role in pitch deposition problems. Self-association among the tails of fatty acids and their soaps also helps to explain some puzzling aspects of hydrophobic sizing of paper. When fatty acids and their soaps are present as monolayers in papermaking systems, the pH values associated with their dissociation, i.e. their pKa values, tend to be strongly shifted. Mutual association also appears to favor non-equilibrium multilayer structures that are tacky and insoluble, possibly serving as a nucleus for deposition of wood extractives, such, as resins and triglyceride fats, in pulp and paper systems.