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Conversion of sodium salicylate to salicylic acid by bipolar electrodialysis: the limiting current density

Law, Jeng Yih and Sairi, Masniza and Sarmidi, Mohamad Roji (2004) Conversion of sodium salicylate to salicylic acid by bipolar electrodialysis: the limiting current density. In: Regional Symposium on Membrane Science and Technology 2004, 21-25 April 2004, Puteri Pan Pacific Hotel, Johor Bahru, Johor, Malaysia.

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Abstract

Salicylic acid (C7H6O3) is of paramount industrial importance because it is used as an intermediate in the manufacture of pharmaceutical products such as aspirin and as an intermediate in the production of dyes and agrochemical and perfumery products. Electrodialysis using bipolar membrane is an alternative method to convert sodium salicylate to salicylic acid. The effective membrane transfer area of each cell pair in the electrodialysis stack was 38.5 cm2. It is desirable to carry out the electrodialysis process at high current density in order to reduce the operating cost and achieve a fast water dissociation process. In this paper the characteristic of current-voltage curve is discussed. The behaviour of limiting current density (LCD) and the enhanced water dissociation current density (WDCD) were investigated in various sodium salicylate (NaSA) concentrations between 2 g/ L (0.2%) and 20 g/ L (2%). An effective method of studying these parameters is by determining current-voltage curve. The bipolar membrane (BP-1) was used in conjunction with monopolar ion exchange membranes (AMX and CMX membranes). The results indicate that an increase in the concentration of sodium salicylate led to an increase of the LCD and WDCD of bipolar membrane. All the current-voltage curves have shown a typical characteristic of S-type shape.

Item Type:Conference or Workshop Item (Paper)
Uncontrolled Keywords:Bipolar electrodialysis, ion exchange membranes, salicylic acid, sodium salicylate, water dissociation current density
Subjects:T Technology > T Technology (General)
Divisions:Chemical and Natural Resources Engineering (Formerly known)
ID Code:6312
Deposited By: Norhani Jusoh
Deposited On:02 Sep 2008 07:08
Last Modified:01 Jun 2010 15:41

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