Studying the Characteristics of Polystyrene- Modified Cocoa (<i>Theobroma cacao</i>) Wood Cellulose Acetate Membrane

Abstract

In this work, cellulose was obtained from cocoa wood (Theobroma cacao) by the chlorite pulping process. The harnessed cellulose was acetylated by the process of step-wise acetylation to a degree of acetylation (DA) of 2.06. Ten percent (10%) solution of the acetylated cellulose material in acetone was used to cast membrane. Polystyrene was used to modify the cellulose acetate and was also used to cast membranes. The modified and unmodified membranes were characterized in terms of their salt rejection capacity, extent of dissolved solid (DS) removal, fold endurance, water permeability, swellability in organic liquids and organic liquid separation potentials. The modification of the cellulose acetate with polystyrene increased its potential for salt rejection by 91.10%, dissolved solid (DS) removal by 98.06, fold endurance by 100%, but decreased its permeability to water by 10%. The result of the permeation test for organic solvents showed a variation in the permeation rate of the organic liquids ranging from 6.08x10^-4molcm^-2sec^-1 for hexane, to 9.67x10^-4molcm^-2sec^-1 for ethanol. Overall, the modification of the cocoa wood cellulose acetate membrane with polystyrene has led to improvement of properties.

Keywords: cellulose acetate, cocoa wood, membrane, modified, polystyrene.