Use of TOF-SIMS for the analysis of surface metals in H2O2-bleached
Douglas G. Mancosky and Lucian A. Lucia
Institute of Paper Science and Technology, Georgia
Institute of Technology, 500 10th St., NW, Atlanta, GA 30318-5794, USA
Abstract: Oxidation of cellulose, caused by metal-catalyzed
hydrogen peroxide decomposition, is one of the main potential reactions
that can occur during the alkaline peroxide bleaching of pulp. This
oxidation decreases the individual fiber strength and thus the sheet
strength. The bleaching reaction should be controlled to limit cellulose
degradation. The goal of this project was to characterize the fiber
surface metal distribution using time-of-flight secondary ion mass spectrometry
(TOF-SIMS) on laboratory-generated hydrogen peroxide-bleached pulps.
For this study, a single black spruce was chosen and kraft pulped.
Peroxide bleaching was conducted via benchtop polyethylene bag bleaching
in a temperature-controlled waterbath. The overall metals content was
determined using inductively coupled plasma (ICP), whereas the surface
metals were determined with TOF-SIMS. Many fundamental approaches to
study metal identity and content in fibers have been undertaken, including
ICP, electron spectroscopy for chemical analysis (ESCA), X-ray fluorescence,
and UVvis. None of these methods can provide the localized density
distribution and metal-mapping ability that is available through TOF-SIMS.
It has spectacular imaging capabilities that were exploited for evaluating
metals on the fiber sheets used in this work.
The samples were subjected to other sheet and fiber testing. Tests
conducted on select samples included brightness and viscosity. Factors
in this experiment included metal addition, chelation, and peroxide
* An issue of reviews and research papers based on
presentations made at the IUPAC/ICSU Workshop on
Electrochemistry and Interfacial Chemistry in Environmental Clean-up
and Green Chemical Processes, Coimbra, Portugal, 6-7 April, 2001.
** Corresponding author.
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