In an attempt to explain variations in delignification behaviors among different hardwood species, the kraft pulping delignification rates of Eucalyptus urograndis, E. nitens, E. globulus, sweet gum, maple, red oak, birch, red alder, cottonwood, and acacia were obtained and correlated with their respective lignin chemical structures. Since H-factor for hardwood is calculated based on the softwo...

Oxidation of the manganese-substituted polyoxometalate [SiW(11)Mn(II)(H(2)O)O(39)](6-) (SiW(11)Mn(II)) to [SiW(11)Mn(III)(H(2)O)O(39)](5-) (SiW(11)Mn(III)), one of the most selective polyoxometalates for the kraft pulp delignification, by versatile peroxidase (VP) was studied. First, SiW(11)Mn(II) was demonstrated to be quickly oxidized by VP at room temperature in the presence of H(2)O(2) (K(m...

a study was carried out on totally chlorine-free (tcf) bleachability of dimethyl formamide (dmf) treated bagasse pulps exposed to cz-3 and fp 90031-sp strains of white-rot fungus ceriporiopsis subvermispora. this process involved an oxygen and peroxide stage bleaching sequence. the effect of enzymatic stage on bleachability properties was studied and compared with control pulps, processed witho...

oxygen delignified kraft pulp from eucalyptus (e. urophylla × e. grandis) was catalytically pretreated in aerobic condition using ammonium persulfate in present of catalists like cupric acetate and/or cobalt acetate in acetic acid-water solution, i. e. s2o82--cu2+, s2o82--co2+ and s2o82--(cu2++co2+). final bleached pulp after pretreatment with the three catalytic systems showed higher delignifi...

The present study was conducted to analyze the effect of three different organicsolvents (Ethanol, Methanol and Acetone) on delignification rice husk (basmati rice). Two differentconcentrations (50% and70%) temperatures (160° C, 180° C 200° C) wereused. major experimental groups were designed, autocatalytic (without catalyst) catalytic(with 1% sulphuric acid as catalyst), each with subgroups re...

Kraft pulping of hydrolyzed green bamboo (Dendrocalamopsis oldhami) chips was performed under various conditions to determine the effects of process variables (alkali charge, sulfidity, cooking temperature, and cooking time) on the dissolution of the lignocellulosic components, i.e. lignin, pentosans, and cellulose. Meanwhile, the kinetics of kraft delignification of hydrolyzed bamboo was inves...

Microwave-assisted dilute acid/alkali pretreatment is an efficient and rapid method of removing lignin and hemicellulose, however, the optimized parameters for the maximum efficiency have to date not been presented in the literature. The purpose of this study was to determine those conditions by examining the effects of three factors: microwave power, temperature, and time on delignification in...

The kraft pulps produced from heartwood and sapwood of Eucalyptus globulus at 130 oC, 150 oC, and 170 oC were characterized by wet chemistry (total lignin as sum of Klason and soluble lignin fractions) and pyrolysis (total lignin denoted as py-lignin). The total lignin content obtained with both methods was similar. In the course of delignification, the py-lignin values were higher (by 2 to 5%)...