Progress in improving the properties of dissolving pulp by enzymes / 生物工程学报

Dissolving pulp consists of high purity cellulose and is widely used to as raw materials for the production of regenerated cellulose fiber, cellulose ester and cellulose ether. The characteristic of dissolving pulp affects greatly the production and processing performance of subsequent products. The α-cellulose content, hemicellulose content, pulp viscosity, ash, transition metal ion content, fiber morphology, molecular weight distribution of cellulose and the reactivity are the important properties. Because of its green, mild and high efficiency, the application of enzymes in improving the properties of dissolving pulp has a promising application prospect and has been researched significantly. In this review, the main properties of dissolving pulp are presented first, followed by a recommendation of the enzymes to improve these properties. The application and current research of cellulase and xylanase in improving the properties of dissolving pulp are emphasized. The main problems and the future research areas in improving the properties of dissolving pulp by enzymes are revealed. Finally, the technology prospects in this field are proposed.

Progress in pitch control in pulp by enzymes / 生物工程学报

Pitch deposits have negative effects on product quality, machine performance and production line profitability during pulp and paper manufacture. As traditional pitch control technology cannot provide satisfactory solutions in the pitch deposits, the enzymatic treatment has been rapidly developed for its high efficiency and pollution-free property. In this review, the chemical composition and present form of the pitch in pulp is first introduced, followed by a description of the pitch control enzymes. The emphasis is on the current research on enzymatic solutions to pitch problems, including the reaction mechanism, technology, and the present main problems of lipase, sterol esterases, laccase and lipoxygenase. Finally, the technology prospects in this field are proposed.

Removal of NOx from flue gas with iron filings reduction following complex absorption in ferrous chelates aqueous solutions.

A novel process for removal of nitrogen oxides (NOx) from flue gases with iron filings reduction following complex absorption in iron-ethylenediaminetetraacetic acid aqueous solution is proposed. The reaction mechanism involved in the process is discussed briefly. The parameters influencing the process, including the concentration of ferrous chelates, initial pH, amount of iron filings, temperature, flow rate of the flue gas, and inlet nitric oxide concentration and oxygen content of the flue gas, are researched in detail. The optimal NOx removal conditions are established. The regeneration and circular utilization of the absorption solution also is studied.