Optimization of Tcf Single-stage Bleaching of Abaca Soda Pulp with a Mixture of Peracetic Acid and Sodium Perborate

The influence of operating variables [viz: temperature 55-85°C, process time 30-120 min, pH 9-11,peraceticacid concentration 0.5-3.5% oven dried pulp (o.d.p.)., and sodium perborate concentration 1-5% o.d.p.] on the bleached pulp characteristics [viz: viscosity (VI), brightness (BR), kappa number (KN)], and resulting paper sheets properties [viz: breaking length (BL), stretch (ST), tear (TI), and burst index (BI)] was studied. The factorial experimental design of central composition was used to derive polynomial equations that reproduce experimental results with errors less than 5%. The most appropriate bleaching conditions were determined as: temperature 77°C; time 99min; pH 10.5; sodium perborate concentration 1% o.d.p., peracetic acid concentration 2.5% o.d.p. This set of operational variables provides pulp with high brightness (80.6%), good strength (breaking length: 4139 m, tear index: 17.64 mNm 2 /g, stretch index: 4.82%, burst index: 3.36 kN/g) and pulp-related (viscosity: 1174 ml/g, kappa number6.84) properties, combined with cost and environmental benefits.