A Comparative Study of Acid Hydrolysis of Cellulosic Waste (Waste of Hosiery Industry) for Manufacturing Microcrystalline CelluloseAuthor(s): Y. P. Chauhan, S. V. Khedkar, S. L. Bhagat and A. P. Pardey
Waste management is one of the biggest problems faced by the human beings in industry. Hosiery industries are having the abundant waste of the cotton rags and fabric cuttings during the manufacturing the finished products. Near about 8-9% of waste is generated from these industries. As cotton is having highest percentage of cellulose (87-96%), it can be used for manufacturing microcrystalline cellulose (MCC). Microcrystalline cellulose is used in various industries like pharmaceutical, food, cosmetics etc. It can be derived by number of process like reactive extrusion, enzyme mediated, steam explosion and acid hydrolysis. Out of these processes, the acid hydrolysis is used in present study, because it requires shorter reaction time than others. It can be made continuous and it requires less amount of acid and produces smaller particles of microcrystalline cellulose. For this study, three acids have been used, hydrochloric acid (HCl), sulphuric acid (H2SO4), and nitric acid (HNO3) for the production of MCC. To find the best concentration of acid for getting the higher yield in the process, the different concentrations were tried. 2.1N Hydrochloric acid was found to give the highest yield of 93%, 40% (by weight) concentration of sulphuric acid gives the 90% yield and 65% (by weight) concentration of nitric acid gives the 82% yield. The MCC produced from hydrochloric acid is the fine powder and requires no further grinding where as the MCC produced from the other two acids is in the form of white pellets, which requires further mechanical grinding resulting in the increase in manufacturing cost. The FTIR spectrum shows the similarity with the commercial microcrystalline cellulose and is characteristic of cellulose type I.