Recovery of Sodium Hydroxide Form Embilipitiya Black Liquor by Electrodialysis
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Date
1996-08-10
Authors
Arulalanantham, M. E. I. N.
Shanthini, R.
Journal Title
Journal ISSN
Volume Title
Publisher
University of Peradeniya, Peradeniya
Abstract
A new type of electrodialyser unit to fractionate the Embilipitiya black liquor into sodium hydroxide, lignin and organic acids has been proposed and experimented in this work. Lignin deposition on and the consequent damage to the anode-side cellophane membrane that are generally associated with electrodialysis have been eliminated in the proposed unit. Also, bubbling of liquor in the anode compartment has been eliminated and erosion of anode electrode has been minimized. Even with the use of an ordinary membrane, such as cellophane, the cathode compartments of the proposed unit yield sodium hydroxide solutions of strength 0.1 M or more which has a good market value. Lignin which has a very high fuel value can easily be isolated from the end products of electrodialysis. Most importantly the polluting black liquor, upon electrodialysis followed by filtration, yields an almost colourless liquor with a pH of 6.1 and a TDS of 0.23 g/l which could be discharged on land for irrigation purposes as per the environmental standards of Sri Lanka. Thus an environmentally hazardous black liquor has been changed to an environmentally friendly liquor with valuable byproducts.
Description
Keywords
Agriculture , Sodium Hydroxide , Embilipitiya , Electrodialysis
Citation
Proceedings of the Annual Research Sessions, August 10,1996, Uninversity of Peradeniya, Peradeniya, Sri Lanka, pp 91-100