Search

With advances in biotechnology, enzyme technologies have been increasingly applied to pretreat lignocellulosic biomass before the production of pulp. There are several driving forces, which include decreasing environmental impact from the traditional pulp and paper manufacturing processes, decreasing the overall production cost, and improving the product properties. This paper reviews recent developments in the area, particularly, related to the production of bleached pulp, dissolving pulp and pulp refining. This paper focuses on the mechanism and influencing factors of enzymatically assisted pulp bleaching to reduce adsorbable organic halide (AOX) formation and dissolving pulp production and focuses on saving energy in pulp refining. The enzyme technology is in the marketplace of the pulp and paper processes, and it is expected to gain more importance in the future. [ABSTRACT FROM AUTHOR]

Highlights • Enzyme and cold alkali assisted mechanical production of CNF were studied. • Cold alkali pretreatment could change cellulose structure from type I to type II. • Environment-friendly method for preparing high thermal stable CNF was obtained. Abstract In this work, cellulase, low-concentration cold alkali and cellulase combined with cold alkali were used to pretreat unbleached bagasse pulp from which cellulose nanofibrils (CNFs), about 30 nm in diameter, were successfully prepared through ultrafine grinding and high-pressure homogenization. X-ray diffraction analysis showed that cellulase pretreatment increased the crystallinity of CNFs. After low-concentration cold alkali pretreatment, the crystallinity of CNFs significantly reduced and the crystal structure of the cellulose changed from type I to type II. Thermogravimetric analysis showed that CNFs prepared by cellulase combined with cold alkali treatment produced more regenerated cellulose and had lower thermal stability. The use of cellulase and low-concentration cold alkali pretreatments combined with ultrafine grinding and high-pressure homogenization is an environment-friendly method for preparing CNFs. The use of low-concentration cold alkali reduces the consumption of alkali and clean water. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Nanocellulose-graphene-based materials used for supercapacitors are reviewed. • Design of different types of nanocellulose-graphene flexible supercapacitor electrode. • Broaden the application of nanocellulose-graphene in flexible energy storage devices. Abstract With the increasing consumption of global fossil energy and environmental pollution, the development of green renewable energy and efficient energy storage technology become an urgent problem to solve. Supercapacitors have drawn a great interest for use in wearable electronic devices due to their portability and stable performance. The electrode is very important when preparing a high-performance flexible supercapacitor, which requires good electrochemical performance and flexibility. Graphene and nanocellulose are excellent flexible electrode material for supercapacitors, and nanocellulose is often used as a substrate material for electronic devices because of its good biodegradability, mechanical flexibility and chemical reactivity. In this work, the structure design and assembly method of the nanocellulose-graphene composite materials used for flexible supercapacitors are reviewed. The mechanical flexibility, specific capacitance, electrochemical performance, cyclic stability, renewability and biodegradability are taken into account, so as to evaluate the performance of the composite materials and to better assess the merits of this material with respect to real applications. [ABSTRACT FROM AUTHOR]

Liupao tea (fermented dark tea) may improve the active function of hyperlipidemia. Utilizing a hyperlipidemia Sprague‐Dawley model and UPLC‐MS/MS metabolomics, we examined how the effect of Liupao and green tea extracts on hyperlipidemia and antoxidant enzyme levels and compared their constituents. The results showed that the two types of tea could reduce the levels of total cholesterol (TC), total triglyceride, and low‐density lipoprotein cholesterol (LDL‐C); increase the contents of bile acids and cholesterol in feces; and improve catalase and glutathione peroxidase (GSH‐Px) activities. Compared with the model control group, Liupao tea effectively reduced TC and LDL‐C levels by 39.53% and 58.55% and increased GSH‐Px activity in the liver by 67.07%, which was better than the effect of green tea. A total of 93 compounds were identified from two samples; the amounts of alkaloids and fatty acids increased compared with green tea, and ellagic acid, hypoxanthine, and theophylline with relatively high contents in Liupao tea had a significantly positive correlation with antihyperlipidemic and antioxidant effects. Therefore, Liupao tea had better antihyperlipidemic and antioxidant activities in vivo than green tea, which might be related to the relatively high content of some active substances. [ABSTRACT FROM AUTHOR]

Highlights: [•] Reaction between lignin model compound and ClO2 is researched by UV–vis. [•] Reaction mechanism of lignin model compound oxidation by ClO2 is derived. [•] Kinetics for lignin model compound oxidation by ClO2 is propose. [•] Bring new door open for resolving the environmental pollution in ECF bleaching. [ABSTRACT FROM AUTHOR]