Synthesis and Characterization of Cellulose Nanofibers from Wood Waste

Abstract

Cellulose of wood waste i.e., Eucalyptus bark, and sugarcane bagasse were evaluated for the synthesis of cellulose nanofibers and the commercialization of many valuable products. The mechanical and chemical procedures for the conversion of cellulose to its nano sized forms were carried with specific protocols. The wood waste in the form of eucalyptus bark was put forwarded for the synthesis of nano cellulose fibers via chemical method by subjecting them with alkali treatment followed by oxidizing it with HNO3-NaNO2 mixture. The bark of eucalyptus converted to its powder form and further treated with strong alkali hydrolysis followed by strong acid treatment. Sugarcane bagasse was divided into two separate sections. i.e the outer and the inner part. Sugarcane bagasse and eucalyptus bark both were treated with benzene and ethanol with ratio of 2:1 respectively in Soxhlet apparatus to eliminate the existing wax content in the samples. Both were treated via these two methods for nanofibers extraction. Sodium chlorite and acetic acid were added in the dewaxed samples to leach out the lignin part of samples separately followed by thoroughly washing and filtration. Alkaline treatment of samples via the use of potassium hydroxide solutions to individualize hemicellulose, remaining starch content and pectin part. The resultant micro sized fibers were converted to nano sized by ultrasonication method and results were illustrated. The zeta sizer results of external part of sugarcane bagasse showed particle size distribution i.e., 151.1±19.76 d.nm and 26.68±2.33 d.nm and inner part showed 259.1±68.4 d.nm. Particle size distribution 88.48±5.20 d.nm and 132.5±9.67 d.nm showed by bark sample via chemical and mechano-chemical method respectively. The zeta potential results of sugarcane bagasse reflected reliability and stability with values of -29.5±7.31 mV and -15.3±8.70 mV of outer and inner parts respectively. Eucalyptus bark zeta potential exhibited -29.3±9.45 mV and -32.5±9.56 mV via both methods. All the samples revealed antimicrobial activity against bacillus subtilis, pseudomonas aeruginosa and klebsiella pneumonia with chloramphenicol C30 being used as positive control. The nanofibers synthesized could be subjected for commercialization, synthesis of novel items and further implementation in pharmaceutical and food industries.