Carbohydrate Polymers 148 (2016) 69–77 Contents lists available at ScienceDirect Carbohydrate Polymers journal homepage: www.elsevier.com/locate/carbpol Nanofibrillated cellulose from tobacco industry wastes Glaiton Tuzzin, Marcelo Godinho, Aline Dettmer ∗ , Ademir José Zattera Engineering of Processes and Technologies Post-Graduate Program, University of Caxias do Sul, Caxias do Sul, Rio Grande do Sul, Brazil a r t i c l e i n f o Article history: Received 4 February 2016 Received in revised form 6 April 2016 Accepted 9 April 2016 Available online 12 April 2016 Keywords: Tobacco Waste Steam explosion Nanocellulose a b s t r a c t Tobacco stems waste underwent steam explosion pulping for nanofibrillated cellulose (NFC) production. In order to obtain NFC hydrogels, the pulp obtained by steam explosion was bleached and refined in a grinder employing specific energy of up to 5067 kWh/t. Eucalyptus kraft pulp was processed under the same conditions to produce NFC hydrogels, later used in order to compare with NFC hydrogels from tobacco stems waste. According to statistical analysis, the optimum tobacco stems pulping condition was obtained with a severity index of log 3.0 and active alkali of 16.25%. These conditions allowed obtaining a bleached pulp with Schopper Riegler degree of 46. Electronic microscopy with field emission showed a higher presence of nanofibers in the tobacco stems pulp than in commercial eucalyptus kraft pulp, both after refining. Thermal analysis indicated that tobacco stems pulp degrade at lower temperatures than eucalyptus kraft pulp. FTIR analysis did not indicate chemical bonding differences between the two pulps. © 2016 Elsevier Ltd. All rights reserved. 1. Introduction The demographic and economic expansion has been demand- ing higher amounts of natural resources worldwide. Hence, waste generation grows and becomes a threat to ecological equilibrium and to human survival. Tobacco industry employs tobacco leaves for cigarette and cigar production (Peˇ sevski et al., 2010). According to data of the Brazilian Association of Tobacco Growers, Brazil produced 607 thousand tons of tobacco in the 2015/16 harvest. About 4% of the tobacco leaves processed become a waste, which is basically constituted of tobacco stems (leaves midribs) and dust from processing. Tobacco stems correspond to about 20% of the total leaves weight (Browne, 1990) and present a higher cellulose content (up to 23%) than the leaf lamina (Leffingwell, 2001; Wakeham & Silberman, 1966). Since cellulose confers an unpleasant taste when burnt, tobacco stems are not directly used in cigar and cigarette production (Leffingwell, 2001). In order to allow tobacco stem use, it is laminated and turned into reconstituted tobacco, to which flavorings and humectants are added (Browne, 1990). However, reconstituted tobacco is only used in low quality cigarette, thus not consuming all the waste produced (Peˇ sevski et al., 2010). Tobacco stalks, in their turn, are directly disposed on the land used for tobacco cultivation. They can have up to 40% of cellulose ∗ Corresponding author at: Rua Francisco Getúlio Vargas, 1130, Caxias do Sul, 95070-560 Rio Grande do Sul, Brazil. E-mail address: alinedettmer@gmail.com (A. Dettmer). content in weight, which makes it an interesting raw material for papermaking or for the production of other cellulose derivatives (Shakhes et al., 2011; Agrupis, Maekawa, & Suzuki, 2000). Among all the cellulose derivatives, one has been attract- ing particular interest: nanocellulose. Some advantages of this new material, which is obtained from renewable sources, is its high area/volume ratio, high Young’s modulus, its capability of being biodegraded, and its nontoxic characteristics (Flauzino Neto, Silvério, Dantas, & Pasquinia, 2013). Nanocellulose can also be obtained from agricultural wastes like pineapple leaves (Cherian, Leão, Souza, Pothan, & Kottaisamy, 2010), banana tree stalk (Deepa et al., 2011), wheat straw (Kaushik & Singh, 2011), rice husk (Kalita et al., 2015), and pinecone (Rambabu, Panthapulakkal, Sain, & Dalai, 2016). Nanocellulose may be applied in nanocomposites, in elec- tronic devices, in cosmetic products, and in membranes, among others (Eichhorn et al., 2010). Different processes may be used to produce nanocellulose. Acid hydrolysis produces nanocrystalline cellulose—NCC (Klemm et al., 2011; Johar, Ahmad, & Dufresne, 2012). Bacterial nanocellulose (BNC) is produced from sugar consumption by bacteria of the genus Gluconacetobacter (Dufresne, 2013; Klemm et al., 2011). Although both processes present high yields, NCC production generates high amounts of wastewater and BNC production is expensive (Klemm et al., 2011). In 1979, researchers at the ITT Rayonnier developed a mechan- ical process that enables nanofibers production from sulfite pulp employing high-pressure homogenizers. This material, known as microfibrillated cellulose (MFC) or nanofibrillated cellulose (NFC), displays a gel-like behavior. However, this process of obtaining http://dx.doi.org/10.1016/j.carbpol.2016.04.045 0144-8617/© 2016 Elsevier Ltd. All rights reserved.