The effect of Fenton chemistry on the production of microfibrillated cellulose - characterization and paper board application

• A fully bleached birch (Betula verucosa) sulphate pulp was treated with acidic hydrogen peroxide in the presence of ferrous iron (i.e. Fenton's reagent) and thereafter treated mechanically in a colloid mill to produce microfibrillated cellulose (MFC). The produced MFCs were chemically and morphologically characterized and compared with MFCs produced with enzymatic (monocomponent endoglucanase) pre-treatment (Figure 1). As a reference MFC produced with only acid pre-treatment was also included in the study.The Fenton pre-treatment increased the total charge of the fibres, decreased the viscosity and introduced new carbonyl groups. Addition of 10 and 50 kg/t hydrogen peroxide resulted in a yield loss of 2 and 4%, respectively. The enzymatic hydrolysis did not substantially change the total charge or the carbonyl group content of the pulp and did not release any organic material. The Fenton pre-treated pulps were easier to process mechanically, i.e. they reached a higher specific surface (BET) area and thereby a higher surface charge at a given mechanical treatment time, indicating a potential to reduce the energy demand in the final mechanical processing stage. The Fenton pre-treatment produced microfibrillated cellulose that in a water suspension (0.5% consistency) was stable with respect to sedimentation for at least eight weeks (Figure 2). Further, the Fenton pre-treatment gave a MFC product that contained a higher amount of small well fibrillated particles, as indicated by fractionation and scanning electron microscopy, compared with the enzymatic and acid pre-treatment methods studied.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Kemiteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Chemical Engineering (hsv//eng)

Nyckelord

Microfibrillated cellulose

birch sulphate pulp

Fenton chemistry

enzymatic hydrolysis

carbonyl groups

total and surface charge

fractionation

suspension stability

Chemical Engineering

Kemiteknik

Publikations- och innehållstyp

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