Bleaching of Olive Tree Residues Pulp with Peracetic Acid and Comparative Study with Hydrogen Peroxide

Abstract

This paper considers the influence of the operating conditions used in the peracetic acid bleaching (concentration, 0.5-2.5%; consistency, 10-20%; pH, 6.5-7.5; temperature, 55-85°C; and process time, 30-150 min) and the hydrogen peroxide bleaching (concentration, 1-5%, and process time, 30-210 min) of olive wood trimming pulps on the yield, kappa index, and viscosity of the resulting pulp and on the strength-related properties (stretch index and burst index) of paper sheets derived from this material in an effort to determine the best bleaching conditions for this pulp. Low to medium hydrogen peroxide concentrations (1-3%) and a high process time (210 min) were desired in the bleaching of the pulp. A high peracetic acid concentration (2.5%), intermediate process time (90 min), and low consistency (10%) and temperature (55 °C) were required for peracetic acid bleaching. A comparison of peracetic and hydrogen peroxide bleaching under similar operating conditions revealed the former to result in a 13% lower brightness, a 33% higher kappa index, and a 9% higher viscosity than the latter. On the other hand, the stretch index and burst index were similar: the differences between the two were less than 0.5% for both indices.