Using neutral sulfite semichemical pulp to adsorb lignocelluloses from prehydrolysis liquor of the kraft-based dissolving pulp process

摘要

The effective use of prehydrolysis liquor (PHL), from the kraft-based dissolving pulp production process, may fit into the concept of integrated forest biorefinery (IFBR). The dissolved organics in the PHL include hemicelluloses, lignin, acetic acid, furfural and extractives. Adsorption of hemicelluloses and lignin onto the neutral sulphite semichemical (NSSC) pulp fibres may be a potential method of utilizing the dissolved organics in the PHL. The principal goal of this work was to study the adsorption of lignocelluloses of PHL onto the NSSC pulp fibres. In addition to the typical process variables, the effect of using polymers, such as coagulant and flocculant, on increasing the adsorption, was investigated. The effects of time and temperature were examined. It was shown that adsorption reached its maximum almost in 1 h. Also, it was demonstrated that a higher temperature improved the adsorption. Furthermore, the use of cationic polymers, such as polydiallyl dimethyl ammonium chloride (PDADMAC), a coagulant (Nalkat 2020) and flocculant (Ultimer 1470), could enhance the adsorption of lignocelluloses from PHL onto NSSC pulp fibres. The maximum lignin and hemicelluloses adsorption was 160 mg/g and 320 mg/g onto pulp (58% and 22% removal from PHL), respectively. It is concluded that lignocelluloses of the PHL can be adsorbed onto NSSC pulp fibres so as to work as papermaking additives; and typical polymers, such as coagulant and flocculant, can be used to enhance the lignocelluloses adsorption.