Optimization of Hemp Bast Microfiber Production Using Response Surface Modelling

Abstract

Non-wood biomass is particularly attractive as a cellulose source because of the lower lignin content. However, optimal cellulose extraction conditions are required as lignin content varies between plant sources. Further, the use of organic acids in place of harsh mineral acids is of interest in “greening” the cellulose production process. This study sought to establish optimum parameters for the extraction of cellulose microfibers (CMFs) from hemp (Cannabis sativa) biomass, using maleic and formic acids. Hemp fibers were pre-treated in NaOH (4 wt%) and aqueous chlorite in acetate buffer before ultrasonic treatment to break down bundles. The CMFs produced were compared with those generated from sulfuric acid hydrolysis. Response surface methodology (RSM) was used to determine combinations of three processing conditions, including acid concentration (45–64%), hydrolysis time (30–90 min), and temperature (45–65 °C). A central composite design (RSM-CCD) model with 21 experimental runs was optimized using MODDE 13.1 software. The model suitably described the data (R2 = 0.99; R2adj = 0.96). Microfibers with an average width of 6.91 µm, crystallinity range 40–75%, and good thermal stability were produced. Crystallinity was influenced by all three factors. The optimal crystallinity predicted by the model was 83.21%, which could be achieved using formic acid 62 wt% formic acid, 36 min hydrolysis time, and 47 °C hydrolysis temperature. These conditions resulted in a crystallinity degree of 82%. These data suggest formic acid can be used as an alternative to sulfuric acid for synthesis of cellulose microfibers from biodegradable hemp waste fibers.

Extraction, Purification, and Component Identification of Monoterpene Glycosides from Paeonia suffruticosa Seed Meal

“…The interactive effects of the five test variables on the monoterpene glycoside yield are shown in Figure 2. The steeper the slope of the response surface, the more significant the change of response value, with a flat slope indicating an unobvious effect [22]. Figure 2 shows that the interaction between the five factors was significant.…”

“…Therefore, the static adsorption time of LSA-900C macroporous resin for monoterpene glycosides from P. suffruticosa seed meal should be about 6 h, while the static desorption should be about 3 h. The interactive effects of the five test variables on the monoterpene glycoside yield are shown in Figure 2. The steeper the slope of the response surface, the more significant the change of response value, with a flat slope indicating an unobvious effect [22]. Figure 2 shows that the interaction between the five factors was significant.…”

The Physicochemical Method Uses Industrial Leftover Hemp Fibre Cellulose to Make Micron-Sized Hemp Powder

“…This may influence the fibers' mechanical and physical properties, such as stiffness, strength, fineness, and moisture absorption. Hydrolysis can decrease the fiber diameter of [24]. (c-g) THF, after 200℃, fiber roughness increased.…”