Biomimetic TCF Bleaching of Pulp by Simple Inorganic Complexes of Cupric/Cobalt Acetate

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. S۲O۸۲--Cu۲+, S۲O۸۲--Co۲+ and S۲O۸۲--(Cu۲++Co۲+). Final bleached pulp after pretreatment with the three catalytic systems showed higher delignification (۲۳.۴۵%, ۲۱.۸۵% and ۱۹.۶۳% respectively), better optical properties (۸۲.۹۳, ۸۲.۱۸ and ۸۱.۹۲% ISO brightness respectively) and pulp viscosity (۷۸۷, ۷۹۱ and ۷۶۲ mL/g respectively; mL/g: intrinsic viscosity unit of pulp)than the control pulp (۱۴.۱۲% delignification, ۷۷.۳۳% ISO brightness and ۷۴۶ mL/g viscosity). S۲O۸۲--Cu۲+ and S۲O۸۲--Co۲+ showed similar reduction in hydrogen peroxide consumption (۶۱.۹۱%, ۶۲.۴۸%), and S۲O۸۲--(Cu۲++Co۲+) showed a greater reduction in hydrogen peroxide consumption than the two treatments (۸۳.۰۵%). Some improvements in tensile and tear strength of the resulting pulp were observed. The new sequence also yields composite effluents with larger percentage of lignin aromatic compounds compared to the control.

کلیدواژه ها:

Cupric/cobalt acetate ، Ammonium persulfate ، TCF bleaching ، Eucalyptus pulp ، Aromatic compounds