Accessible Unlicensed Requires Authentication Published by De Gruyter February 28, 2008

The fate of phosphorus in the bleaching of spruce TMP with the new bleaching agent – THPS

Thomas Q. Hu, Eric Yu, Brian R. James and Paolo Marcazzan
From the journal


Tetrakis(hydroxymethyl)phosphonium sulfate (THPS) is a newly discovered, phosphorus-based bleaching agent that has been successfully tested in a pulp mill trial. The fate of phosphorus (P) and the chemistry in the course of THPS bleaching of a spruce TMP have been studied. The amount of P introduced into the THPS-bleached pulp depends on THPS dose and the bleaching conditions and it correlates well with the brightness gain. The P introduced into THPS-bleached pulp is covalently bonded to the pulp. The THPS-bleached and tetraethylphosphonium chloride-treated pulps have been additionally treated with calcium chloride before P analysis, and the results of these experiments support the covalent bonding hypothesis. Bleaching with 0.1 and 3.0% THPS (% based on oven-dried pulp) at 60 and 110°C leads to pulps with 0.13 and 2.17 mg P g-1 pulp, respectively, which corresponds to 0.08 and 1.4% THPS. More precisely, P is covalently bonded to lignin chromophores, such as lignin coniferaldehydes. This was found by P-content analysis, UV-visible spectroscopy, and 31P{1H} NMR studies of a crude milled wood lignin (crude MWL) and a partially purified MWL isolated from a THPS-bleached pulp.

Corresponding author. FPInnovations – Paprican Division, Vancouver, British Columbia, Canada V6S 2L9

Received: 2007-11-7
Accepted: 2008-1-29
Published Online: 2008-02-28
Published Online: 2008-02-28
Published in Print: 2008-07-01

©2008 by Walter de Gruyter Berlin New York