Use of TOF-SIMS for the analysis of surface metals in H2O2-bleached lignocellulosic fibers

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 UV-vis. 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 charge.

Analysis of printing and writing papers by using direct analysis in real time mass spectrometry

“…The pulp is bleached using hydrogen peroxide (totally chlorine free, or TCF, bleaching), which removes conjugation (chromophores) but not the lignin [39,40]. Consequently, the amount of lignin is significantly higher in the BCTMP than the kraft pulps (3-4%), but the amount of extractives is comparable to the hardwood kraft pulp ( Table 2).…”

Chemical Study of the Variation in the Bleaching and Pulping Response of Predominantly Juvenile and Mature Northern Black Spruce Fractions

“…Specific gravity was determined by the maximum moisture content method. 11 NMR Analyses. Lignin samples were isolated from the pulps according to a method previously described.…”

“…Carbohydrates (cellulose and hemicelluloses) were determined by conducting an acid hydrolysis followed by standard capillary electrophoresis. Specific gravity was determined by the maximum moisture content method …”

Recycling potential of unbleached and bleached chemical pulps from juvenile and mature wood ofPopulus deltoides

“…Previous studies concerning JW and mature wood (MW) focused partly on the chemical composition (Bao et al 2001;Balakshin et al 2005;Kibblewhite et al 2010;DeMartini and Wyman 2011;Leppänen et al 2011), physical and morphological properties (Peszlén 1994;Yeh et al 2005Yeh et al , 2006Esteban et al 2008;Mäkinen et al 2008;Kojima et al 2009;Mansfield et al 2009), pulping, bleaching and papermaking properties (Orsler et al 1972;Mancosky and Lucia 2001;Fernando et al 2007), and manufacturing of laminated strand veneers (Weight and Yadama 2008), just to mention a few examples. Based on the quoted literature it is well known that the JW fibers of softwoods and hardwoods have lower density (Shi et al 2005), thinner cell walls, lower microfibril angle (MFA), shorter fibers, higher original lignin content, and give rise to lower pulp yields compared to MW.…”