Eucalyptus bleached kraft pulp production, an important sector of the Brazilian national economy, is responsible for generating large volume, high pollutant load effluents, containing a considerable fraction of recalcitrant organic matter. The objectives of this study were to quantify the biological activity of the effluent from a eucalyptus bleached kraft pulp mill, characterize the nature of ...

Enzymatic treatment of different sulphite pulps with cellulases has been studied in this work. Endoglucanases were shown to beneficially alter the properties of both paper-grade and dissolving-grade pulps. In the case of the paper-grade pulp, the treatment with endoglucanase resulted in a considerable reduction of the pulp refining time without decrease in strength properties. While for the dis...

Three selected alkali-based organosolv pulps (alkali-sulfite-anthraquinone-methanol (ASAM), alkali-anthraquinone-methanol (organocell) and ethanol-soda) from agrofibre crop giant reed (Arundo donax L.) were bleached by an ozone-based TCF (totally chlorine- free) bleaching sequence AZE(R)QP (where A is an acidic pulp pre-treatment, Z is an ozone stage, (E(R)) is an alkaline extraction in the pre...

Aalto University, P.O. Box 11000, FI-00076 Aalto www.aalto.fi Author Raili Pönni Name of the doctoral dissertation Changes in accessibility of cellulose for kraft pulps measured by deuterium exchange Publisher School of Chemical Technology Unit Department of Forest Products Technology Series Aalto University publication series DOCTORAL DISSERTATIONS 68/2014 Field of research Forest Products Che...

Xylanase activity was isolated from crude extracts of Trichoderma harzianum strains C and 4 grown at 28 degree C in a solid medium containing wheat bran as the carbon source. Enzyme activity was demonstrable in the permeate after ultrafiltration of the crude extracts using an Amicon system. The hydrolysis patterns of different xylans and paper pulps by xylanase activity ranged from xylose, xylo...

There is a general interest among paper and board makers to produce lighter and bulkier paper and board products. The aim of the present study was to characterize chemically crosslinked hardwood kraft fibers regarding their potential in making bulky paper and board. Crosslinking agents are molecules that contain two or more reactive ends that form inter-chain covalent bonds with cellulosic hydr...

Sugarcane bagasse was delignified with alkali and peracetic acid in a two-stage process to obtain pulps with high yield and low kappa number. The experimental results indicated that alkali pretreatment prior to peracetic acid (PAA) delignification could significantly reduce PAA loading by partially removing lignin and swelling the fibers. An optimum condition for the two-stage delignification w...

In this study, Eucalyptus globulus stumpwood samples collected from six different sites in Portugal were evaluated for their ease of pulping, using two delignification processes (kraft and alkaline sulfite-anthraquinonemethanol (ASAM)). Morphologically, the stumpwood included fibers with a mean length of 0.930 mm, diameter of 21.4 μm, lumen width of 9.1 μm, and cell-wall thickness of 6.1 μm. Th...

Kraft lignin, a by-product of the pulp and paper industry, was explored as an adsorbent for six dietary oils and was compared to chitosan, which is widely used in the pharmaceutical market. The dissolution and adsorption efficiency of kraft lignin were tested at an acidic pH corresponding to the stomach, as well as at a basic pH corresponding to the intestine. Results showed that kraft lignin i...