Pre-treatment of the paper pulp in the bleaching process using biodegradable chelating agents

• Type: Article in International Scientific Journal
• Date: 2015

Authors

Pinto, I.S.S. (Author) Other; Ascenso, O.S. (Author) Other; Barrros, M.T. (Author) Other; Helena Soares (Author) FEUP

Journal

Title: International Journal of Environmental Science and Technology

Vol. 12

Pages: 975-982

ISSN: 1735-1472

Publisher: Springer Nature

Indexing

ISI Web of Knowledge - 2 Citations

Scopus - 7 Citations

Scientific classification

FOS: Engineering and technology

Other information

Authenticus ID: P-00A-66S

DOI: 10.1007/s13762-013-0480-0

Abstract (EN): The aim of this work was to study the application of two biodegradable chelating agents, pyridine-2,6-dicarboxylic acid (PDA) and methylglycinediacetic acid (MGDA), in the treatment of the pulp, prior to hydrogen peroxide bleaching. Such compounds must remove transition metals (Mn, Fe and Cu) from pulp, that catalyze the degradation of hydrogen peroxide, and Ca, which is also problematic due to the formation of precipitates that accumulate in the equipment. Computer simulations were first performed to study the best conditions for metal complexation, and optimum pH was defined as 5-5.5 for PDA and 6.5-7 for MGDA. Metals removal from the pulp, as well as the subsequent bleaching process (Q-P1-Paa-P2), were tested experimentally, and performances were compared to ethylenediaminetetracetic acid (EDTA). PDA removed both Mn and Ca efficiently, leaving most Mg in the pulp after first chelation stage, while MGDA had a lower Ca removal, even using a higher pH and concentration. Residual hydrogen peroxide and kappa number after peroxide stages showed a similar bleaching efficiency between the studied compounds and EDTA.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8