دانلود رایگان مقاله فرآیند تولید نانو کریستالی سلولز تجاری پایدار با بازیافت اسید

Abstract

Nanocrystalline cellulose (NCC) is a biomaterial having potential applications in a wide range of industries. It is industrially produced by concentrated acid hydrolysis of cellulosic materials. In this process, the sulfuric acid rich liquor can be concentrated and reused. However, removal of sugar monomers and oligomers is necessary for such recycling. Membrane and ion exchange technology can be employed to remove sugars; however, such technologies are not efficient in meeting the quality required to recycle the acid solution. As a part of the present study, activated carbon (AC) has been evaluated as an adsorbent for sugar removal from the acidic solution generated during commercial nanocrystalline cellulose manufacturing process. Almost complete removal of sugar can be achieved by this approach. The maximum sugar removal observed during this study was 3.4 g/g of AC. Based on this finding, a sustainable method has been proposed for commercial nanocrystalline cellulose manufacturing.

4. Conclusions

AC can be used as an adsorbent for sugar removal from the waste acid stream of the nanocrystalline cellulose (NCC) manufacturing process. The approach may help efficient recycling of the acid used in the process. Of the factors evaluated, increasing sugar concentration, AC concentration and time aided adsorption while increasing temperature had a negative effect. Additionally, the AC used in this approach can be recycled for at least 4–5 subsequent batches of reaction. Investigation using response surface methodology has shown that among AC concentration and reaction time, the former is the dominant factor to control sugar removal. By increasing the AC concentration, it would be possible to increase the sugar removal efficiency, considering the cost and possible loss ofthe acid solution, application of more than 50 g/L should not be considered.