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Indian Journal of Chemical Technology, Vol.16, No.6, 523-528, 2009
Alkoxygen and alkoxygen-AQ delignification of Ipomea carnea and Cannabis sativa
Molecular oxygen is a specific oxidizing agent for lignin but its low solubility in cooking liquor causes a serious problem of mass transfer in a heterogeneous chemical pulping process with wood. The anatomy of Ipomea carnea and Cannabis sativa permit much easier diffusion and penetration of the molecular oxygen into the reactive zones of fiber wall. The low lignin content and more open and looser fiber structure of L carnea and C sativa makes them Suitable for alkoxygen delignification. Due to their identical cooking conditions except liquor to wood ratio mixed cooking of I. carnea and C sativa by alkoxygen delignification process is able to produce good quality pulp because the pulp blend has unique morphological characteristics of L carnea which resembles with softwoods with respect to cell wall thickness and lumen diameter along with long fibers of C sativa in which L carnea deficits. The present study aims at optimizing the various operating parameters of alkoxygen delignification process for L carnea and C sativa. An oxygen pressure of 10 kg/cm(2) at 16% alkali dose, cooking temperature of 160 degrees C for 120 min produces screened pulp yield 53.5% at kappa number 30 for C. sativa and 46.1% at kappa number 27 for I. carnea. The addition of 0.1% AQ at O(2) pressure of 10 kg/cm(2) improves pulp yield by 1.6% for C sativa and 1.1% for L carnea with a decrease of kappa number by 2 units in both the cases. L carnea shows good bleaching response compared to C sativa. Therefore, I. carnea pulp may be used as brightness improver to enhance the overall brightness of the blend.