Volume 12 Issue 1

Fly ash was modified using calcium oxide and carbon dioxide. The effects of reaction temperature, the rate of carbon dioxide, and the concentration of calcium hydroxide on the crystal shape of precipitated calcium carbonate coated on the surface of fly ash were studied. The effects of the crystal shape of precipitated calcium carbonate on the whiteness of modified fly ash were analyzed. The research showed that the crystal shape of precipitated calcium carbonate was lamellar when the reaction temperature, the rate of carbon dioxide, and the concentration of calcium hydroxide were 20 °C, 0.2 L/min, 20%, respectively, which was conducive to the higher whiteness of modified fly ash.

Laccase activity and stability were improved and modified through the interaction between laccase amino acid residues (e.g., amino groups (-NH2) and carboxyl groups (-COOH)) and the chemical reagents thiourea dioxide (TDO) and L-phenylalanine methyl ester hydrochloride (L-PME). Compared with the control sample, the activity of the laccase modified with these chemical reagents was increased by 209% and 50%, respectively. The stability of the laccase modified with L-PME increased by 56.9%. However, the laccase modified with TDO only improved slightly. It was clear that reagent L-PME was more efficacious than TDO. The paper formed with addition of L-PME-modified laccase exhibited better performance in terms of tensile strength, bursting strength, and tear strength, which increased by 13%, 10%, 9%, respectively, compared with the paper formed with unmodified laccase.

Poplar wood fibers (WFs) were pretreated with ionic liquid (IL) 1-butyl-3-methylimidazolium chloride ([C4mim]Cl) at 125 °C for 1 h, and the influence of the wood loadings (5%, 15%, 30%, and 50%) on the pretreatment efficiency and downstream acetylation was studied. The crystallinity and lignin content of the WFs decreased after IL pretreatment at low wood loadings, especially at 5%. Wood fiber acetylation was performed under a molar ratio (acetic anhydride/–OH in the WFs) of 2:1, with toluene as the reaction medium and pyridine as the acid capturer. Ionic liquid pretreatment at 5% and 15% loading greatly contributed to the increase of weight percent gain (WPG) after acetylation, leading to much higher reaction efficiency, or lower energy consumption. The acetylated products that underwent pretreatment (mainly at 5% loading) had slightly higher thermal stability than those that did not undergo pretreatment. The crystallinity and moisture sorption ability of the products were determined primarily by the WPG value.

Farmers are reluctant to establish short-rotation coppice because too many uncertainties remain about its economic feasibility. Up to now, most progress has been accomplished by increasing plantation yields through genetic improvement and by reducing management costs through mechanization. In contrast, the potential increase of value recovery has received much less attention. We therefore compared whole-tree chipping with integrated harvesting to test whether more profit could be made by producing pulpwood logs and wood chips, rather than wood chips only. The two systems were compared side-by-side with identical machinery on the same field. Chip production cost was higher for integrated harvesting (15 € Mg-1), because the system was less productive (9 Mg h-1), as compared with whole-tree chipping (9 € Mg-1 and 25 Mg h-1). Pulpwood log production only occurred with the integrated harvesting system, at a cost of 8 € Mg-1. Integrated harvesting incurred higher production costs, but also accrued better value recovery. Under current market conditions, the two systems offered similar profits, in the vicinity of 5000 € ha-1. However, integrated harvesting offered higher flexibility, with a potentially better resilience to market fluctuations.