Yield loss during bleaching of pulp of Pinus radiata previously delignified with oxygen

• Published in: Environmental science and pollution research international Vol. 27; no. 34; pp. 43403 - 43411
• Main Authors: Gomes, Regina Maria, Baptista, Renato de Oliveira, de Almeida, Eduardo Leite, Batista, Ana Claudia Gama, de Souza, Elias Costa
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.12.2020; Springer Nature B.V
• Subjects: Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Bleaching; Brightness; Carbon; Chemical oxygen demand; Chemical treatment; Chromophores; Earth and Environmental Science; Ecotoxicology; Effluents; Environment; Environmental Chemistry; Environmental Health; Environmental science; Filtrate; Gravimetry; Halogens; Kraft pulp; Organic carbon; Organic loading; Oxygen; Pinus radiata; Pollutants; Pollution load; Pulp; Short Research and Discussion Article; Total dissolved solids; Total organic carbon; Waste Water Technology; Water Management; Water Pollution Control; COD; TOC; Indirect determination; Bleaching stages; ECF sequence
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-020-11030-5

The pulp bleaching process removes or transforms the chromophore groups in the pulp, so that the final product reaches a desired brightness. However, this chemical treatment inevitably results in yield loss. Therefore, the objective of this work was to quantify the yield loss caused during the bleaching of kraft pulp of Pinus radiata delignified with oxygen. The material was submitted to three distinct ECF sequences (D 0 (EPO)D 1 D 2 , D 0 (EPO)D 1 P, and Z/EDP). At the end of each bleaching stage, the pulp brightness and the loss of gravimetric yield of the process were determined, and the generated filtrates were collected. From these filtrates, the pollutant load of the effluent was determined by measuring the content of total dissolved solids, the chemical oxygen demand, the concentration of total organic carbon carbon, and the adsorbable organic halogens. Among the whole sequences, the Z/EDP sequence had the lowest gravimetric yield, the highest pollutant load in the collected filtrate, and lowest potential for adsorbable organic halogens generation. There was good correlation between the loss of yield from the bleaching process and the organic load of the generated effluent; and among the techniques studied, the quantification of total organic carbon was the most appropriate method for the indirect quantification of the yield loss during the bleaching process of the studied material.