Volume 10 Issue 4

Extracts from the inner stem bark of Berberis vulgaris were analyzed for their antioxidant activity using the 1,1-dipheny-2-picrylhydrazyl (DPPH) method and compared with ascorbic acid (AA) and butylated hydroxytoluene (BHT). The most active extracts were analyzed for their chemical composition using gas chromatography-mass spectrometry. Acetone extract was found to be the most active as an antioxidant agent at 98.61%, which was higher than the value of vitamin C (93.03%) at the concentration of 0.16 mg/mL. The major components identified in the acetone extract were tetracosanoic acid, methyl ester (26.36%), followed by phthalic acid, diisooctyl ester (20.93%), 1,2-bis(trimethylsiloxy) ethane (10.26%), and 1,2-benzendicarboxylic acid, diisononyl ester (8.70%). The dissolved water:methanol (1:1 v/v) partitioned from acetone extract afforded 12 fractions; among them, fraction F11 was found to have good antioxidant activity (95.41%) at the concentration of 0.16 mg/mL. The major compounds identified in F11 were N-methyl-4-(hydroxybenzyl)-1,2,3,4-tetrahydroisoquinoloine (28.82%), 9-α-hydroxy-17β-(trimethylsilyl-oxy)-4-anderostene-3-methyloxime (13.97%), ribitol, pentaacetate (9.76%), 1-methyl-4-[4,5-dihydroxyphenyl]-hexahydropyridine (6.83%), and 2-ethylacridine (4.77%).

Extruded wood-plastic composites (WPCs) are increasingly regarded as promising materials for future manufacturing industries. It is necessary to select and tune the post-processing methods to be able to utilize these materials fully. In this development, temperature-related material properties and the cooling rate are important indicators. This paper presents the results of natural cooling in a factory environment fit into a cooling curve function with temperature zones for forming, cutting, and packaging overlaid using a WPC material. This information is then used in the evaluation of manufacturability and productivity in terms of cost effectiveness and technical quality by comparing the curve to actual production time data derived from a prototype post-process forming line. Based on this information, speed limits for extrusion are presented. This paper also briefly analyzes techniques for controlling material cooling to counter the heat loss before post-processing.

The efficient biosynthesis of methane from renewable biomass resources is discussed in this paper. Herbal-extraction process residues (HPR) are an excellent raw material for anaerobic digestion because of their abundant trace elements and fermentation stability. Anaerobic co-digestion of wheat straw with HPR was evaluated at HPR/wheat straw ratios (based on total solids (TS), of wheat straw) of 3%, 5%, and 10 % with anaerobic sludge at 35±1 °C during 30-d anaerobic digestion. The best performance was achieved with 5% HPR added to the reactor, with cumulative methane production of 13,130 mL and cumulative methane yield of 260.5 mL/g TSadded, respectively. Cumulative methane production increased by 31.4% compared to the 9995 mL achieved in mono-digestion with wheat straw. Furthermore, higher activities of protease and total dehydrogenase and higher ATP levels were displayed during the co-digestion process. The high methane yield in this study demonstrates the great potential of co-digestion of renewable biomass as a feedstock for the economical production of methane.

The structure and properties of ethanol organosolv lignin (EOL) extracted from bamboo under various conditions were characterized. EOL yield increased at high temperatures of 160 to 200 °C and a reaction time of 1 to 3 h. The nitrogen content in lignin was low, with a maximum of 0.62%. The carbon content increased with increasing temperature and prolonged time, whereas oxygen content showed an inverse trend. EOL extracted from bamboo showed high purity levels (more than 95.5% Klason lignin) with low impurity contents (carbohydrate and ash). The severity of the process increased the carboxylic acid and phenolic hydroxyl group contents and also decreased the methoxyl group content. The molecular weight of EOL varied depending on the extraction condition. The FT-IR and NMR spectra revealed that the main structure did not significantly change. From the spectra, it is clear that EOL extracted from bamboo can be classified as an HGS (H–p-hydroxyphenyl, G–guaiacyl, and S–syringyl, respectively) type. Clear β-O-4, β-β, and β-5’ linkages were observed.

New formaldehyde-free and isocyanate-free bioplastics and biofoams were prepared by reacting ovoalbumin and dimethyl carbonate (DMC) at a moderate temperature. Analysis by 13C NMR revealed a reaction between dimethyl carbonate and the amino and/or hydroxyl groups of the side chain of amino acids. The densities were between 0.6 and 1.1 g/cm3 for the obtained plastics. Thermal and mechanical resistances peaked at 175 °C and 7.7 MPa, respectively. The Brinell hardness was 2. The prepared foam exhibited a density of 0.1 g/cm3 and an open cell structure. Impregnation with hexamethylene diamine (DAH) allowed for the preparation of materials with elastic mechanical behavior through the reaction of DAH and DMC. The new plastics and foams derived from ovoalbumin protein were markedly more environmentally friendly.

Coconut coir, an agricultural waste, was chemically modified using esterification by fatty acid chloride (oleoyl chloride and octanoate chloride) for oil spill removal purposes. The modified coir (coir-oleate and coir-octanoate) were characterized by spectroscopy, thermal studies, contact angle, and morphological studies. The modified coir exhibited an enhancement towards the hydrophobic property but a decreased thermal stability. The oil adsorption performance was tested using a batch adsorption system. The effect of sorbent dosage, oil concentration, and effect of adsorption time on the adsorption capacity of the modified coir were also studied. From the analysis, the long chain oleoyl chloride (C18) was shown to be a better modifier compared to octanoate chloride (C8). The isotherm study indicated that the oil adsorption fitted well to a Langmuir model rather than Freundlich model. From the kinetic study, the result revealed a good fit in pseudo-second order model for all samples studied. The study therefore suggests that esterified coconut coir can serve as a potential biomaterial for the adsorption of spilled oil during operational failures.

Deep eutectic solvents (DESs) are a relatively new topic in science. Their usage is not yet clearly defined, and the areas in which DESs may be applied are constantly growing. A simple and clean fractionation of the main components of biomass represents a very important step in creating a clean, renewable carbon economy. A major challenge is the use of DESs for fractionation of biomass components at lower temperatures, without the use of expensive raw materials. In this work, wheat straw was pretreated with six different DES systems composed of choline chloride with urea (1:2), malonic acid (1:1), lactic (1:9; 1:10), malic (1:1), and oxalic acid (1:1). The pretreated biomass was characterized in terms of lignin content, ash, and holocellulose. A deep eutectic solvent, composed of choline chloride and oxalic acid, was found to produce the best delignification results. The solvents are not selective in the process of delignification.

In this work, a facile, green approach to natural biomass bleaching is reported. It was found that Trichoderma reesei could produce alkaline xylanase and xylanase is highly active in alkaline environments. It has good environmental adaptability and could be used to reduce the use of bleaching chemicals for the pretreating process and degradation of hemicellulose so as to break the linkages of Lignin-carbohydrate complexes (LCCs). These particular properties benefit the pulp bleaching process and can improve the physical properties of the resulting paper. The optimum bleaching process conditions were as follows: dosage, 12 U/g; pH, 8 to 9; time, 60 minutes; and temperature, 70 °C. The xylanase can decrease the chemical oxygen demand (COD) of bleaching effluent by 41% as compared to the blank. Finally, after xylanase pretreatment, the whiteness, yellow index, tensile index, burst index, and elongation of the resulting paper were 54.8% ISO, 1.73, 33.93 N·m/g, 2.91 KPa·m2/g, and 2.91%, respectively.

To remove heavy metals from aqueous solution and reclaim valuable materials from mushroom byproducts, Flammulina velutipes spent substrate (FVSS) was developed as a novel biosorbent for copper ion removal. Batch experiments demonstrated that ion removal was pH-, biosorbent dosage- and initial metal concentration dependent. The maximum removal capacity of 15.56 mg/g was achieved at pH 6.0 with a biomass dosage of 3.0 g/L and initial copper ion concentration of 50 mg/L. The adsorption data were in compliance with the Langmuir isotherm and a pseudo-second-order kinetic model. Thermodynamic studies revealed the biosorption process was endothermic, random, and spontaneous. FT-IR spectral analysis confirmed that hydroxyl, amino, carbonyl, and phosphate groups on the biosorbent surface were involved in the biosorption. The uneven surface and porous structure of the biosorbent was propitious for quickly capturing the metal ions from aqueous solution. EDX spectra revealed that the copper ions were loaded on the surface of the biosorbent. XRD patterns showed the formation of copper-containing compounds.

One of the big global, environmental, and socioeconomic challenges of today is to make a transition from fossil fuels to biomass as a sustainable supply of renewable raw materials for industry. Growing public awareness of the negative environmental effects of petrochemical-based products adds to the need for alternative production chains, especially in materials science. One option lies in the value-added upcycling of agricultural by-products, which are increasingly being used for biocomposite materials in transport and building sector applications. Here, sunflower by-product (obtained by grinding the stems) is considered as a source of natural fibers for engineered biocomposite material. Recent results are shown for the main mechanical properties of sunflower-based biocomposites and the socioeconomic impact of their use. This paper demonstrates that sunflower stem makes a good candidate feedstock for material applications. This is due not only to its physical and chemical properties, but also to its socioeconomic and environmental rationales.