The structure of siderite aggregates and its weathering products from the Ruza deposit, Moscow Region, has been studied by X-ray phase analysis and electron microscopy. The initial siderite is a dense FeCO 3 aggregate of micron-sized grains. The nodules are covered with an ocher weathered crust, the color intensity of which varies from light yellow to brown-black. A successive replacement of siderite by FeOOH goethite and lepidocrocite was revealed. It is accompanied by a sharp decrease in volume (∼ 30 %) and the formation of a microporous structure.
High-lignin content cellulose nanofibrils (LCNF) were successfully prepared from thermomechanical pulp through TEMPO-catalyzed oxidation, followed by ultrasonic treatment. Preparation protocols of the LCNFs included use of the mild pre-hydrolysis of the thermomechanical pulp and adjustment of sodium hypochlorite loading for the samples with the 23.8 and 14.1 wt.% lignin content, resulting in the increase of the carboxyl group content from 0.70 to 1.24 mmol/g. LCNFs had a diameter of 14 ± 5 nm (AFM evaluation); and the LCNF morphology was affected by contents of both lignin and carboxyl groups. The translucent LCNF films were prepared by solution casting technique. They exhibited the heightened water contact angle of 75-82 • , an increased thermal stability up to 275 • C compared to lignin-free cellulose nanofibril films (39 • and 203 • C, respectively), and excellent UV-blocking ability in a wide spectrum range from 200 to 375 nm. The said LCNFs can be successfully used for manufacturing the packaging materials and/or making the biopolymer composites.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.