Effects of pH in Hydrogen Peroxide Bleaching of Cotton Fabrics Pretreated with Ferrous Sulfate

This study puts particular emphasis on the role of copper ions in the performance of hydrogen peroxide bleaching (P-stage). Owing to their variable levels across the bleaching line due to washing filtrates, bleaching reagents, and equipment corrosion, these ions can play a major role in hydrogen peroxide decomposition and be detrimental to polysaccharide integrity. In this study, a Cu-contaminated D0(EOP)D1 prebleached pulp was subjected to an acidic washing (A-stage) or chelation (Q-stage) before the alkaline P-stage. The objective was to understand the isolated and combined role of copper ions in peroxide bleaching performance. By applying an experimental design, it was possible to identify the main effects of the pretreatment variables on the extent of metals removal and performance of the P-stage. The acid treatment was unsuccessful in terms of complete copper removal, magnesium preservation, and control of hydrogen peroxide consumption in the following P-stage. Increasing reaction temperature and time of the acidic A-stage improved the brightness stability of the D0(EOP)D1AP bleached pulp. The optimum conditions for chelation pretreatment to maximize the brightness gains obtained in the subsequent P-stage with the lowest peroxide consumption were 0.4% diethylenetriaminepentaacetic acid (DTPA), 80ºC, and 4.5 pH.

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The Effect of Microwave Treatment on the Hydrogen Peroxide Bleaching of Soda-AQ Wheat Straw Pulp

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.236-238.1307 ◽

2011 ◽

Vol 236-238 ◽

pp. 1307-1312

Author(s):

Chao Jun Wu ◽

Chuan Shan Zhao ◽

Jun Li ◽

Ke FU Chen

Keyword(s):

Hydrogen Peroxide ◽

Wheat Straw ◽

Fiber Length ◽

Weighted Average ◽

Microwave Treatment ◽

Arithmetic Average ◽

Peroxide Bleaching ◽

Bleached Pulp ◽

Infra Red ◽

Wheat Straw Pulp

In this paper, the effect of microwave treatment on the hydrogen peroxide bleaching of Soda-AQ wheat-straw pulp was investigated. The results showed that microwave treatment could increase the brightness of the hydrogen peroxide bleached pulp. The fiber coarseness of microwave enhancing peroxide bleached pulp was higher than that of the peroxide bleached pulp. However, the arithmetic average fiber length, the length weighted average fiber length and weight weighted average fiber length of the former was lower than that of the latter. Fourier transform infra-red spectroscopy (FTIR) and X-ray diffraction (XRD) spectra showed that CrI(%) crystallinity of microwave enhancing peroxide bleached pulp was similar as that of the peroxide bleached pulp but all higher than that of the Soda-AQ wheat-straw pulp. N·O′KI infra-red crystalline index of microwave enhancing peroxide bleached pulp were lower than that of the peroxide bleached pulp. The FTIR spectra of lignin showed that the microwave treatment had some influences on the methoxyl and phenolic group in lignin.

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Influence of Hydrogen Peroxide Bleaching Gels on Color, Opacity, and Fluorescence of Composite Resins

Operative Dentistry ◽

10.2341/11-189-l ◽

2012 ◽

Vol 37 (5) ◽

pp. 526-531 ◽

Cited By ~ 10

Author(s):

CRG Torres ◽

CF Ribeiro ◽

E Bresciani ◽

AB Borges

Keyword(s):

Hydrogen Peroxide ◽

Composite Resin ◽

Color Change ◽

Composite Resins ◽

Control Group ◽

Peroxide Bleaching ◽

Color Changes ◽

Tukey Test ◽

Bleaching Gels ◽

Bleaching Treatment

SUMMARY The aim of the present study was to evaluate the effect of 20% and 35% hydrogen peroxide bleaching gels on the color, opacity, and fluorescence of composite resins. Seven composite resin brands were tested and 30 specimens, 3-mm in diameter and 2-mm thick, of each material were fabricated, for a total of 210 specimens. The specimens of each tested material were divided into three subgroups (n=10) according to the bleaching therapy tested: 20% hydrogen peroxide gel, 35% hydroxide peroxide gel, and the control group. The baseline color, opacity, and fluorescence were assessed by spectrophotometry. Four 30-minute bleaching gel applications, two hours in total, were performed. The control group did not receive bleaching treatment and was stored in deionized water. Final assessments were performed, and data were analyzed by two-way analysis of variance and Tukey tests (p<0.05). Color changes were significant for different tested bleaching therapies (p<0.0001), with the greatest color change observed for 35% hydrogen peroxide gel. No difference in opacity was detected for all analyzed parameters. Fluorescence changes were influenced by composite resin brand (p<0.0001) and bleaching therapy (p=0.0016) used. No significant differences in fluorescence between different bleaching gel concentrations were detected by Tukey test. The greatest fluorescence alteration was detected on the brand Z350. It was concluded that 35% hydrogen peroxide bleaching gel generated the greatest color change among all evaluated materials. No statistical opacity changes were detected for all tested variables, and significant fluorescence changes were dependent on the material and bleaching therapy, regardless of the gel concentration.

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The effect of hydrogen peroxide bleaching of canola meal on product colour, dry matter and protein extractability and molecular weight profile

International Journal of Food Science & Technology ◽

10.1111/ijfs.12065 ◽

2013 ◽

Vol 48 (5) ◽

pp. 1071-1085 ◽

Cited By ~ 3

Author(s):

Ihsane El-Kadiri ◽

Mohamed Khelifi ◽

Mohammed Aider

Keyword(s):

Hydrogen Peroxide ◽

Molecular Weight ◽

Dry Matter ◽

Canola Meal ◽

Peroxide Bleaching ◽

Protein Extractability

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Control of 2-Methylisoborneol and Geosmin by Ozone and Peroxone: A Pilot Study

Water Science & Technology ◽

10.2166/wst.1992.0064 ◽

1992 ◽

Vol 25 (2) ◽

pp. 291-298 ◽

Cited By ~ 16

Author(s):

B. Koch ◽

J. T. Gramith ◽

M. S. Dale ◽

D. W. Ferguson

Keyword(s):

Hydrogen Peroxide ◽

Ferrous Sulfate ◽

Contact Time ◽

Pilot Scale ◽

Ozone Dose ◽

Ammonia Addition ◽

Removal Efficiencies ◽

Odorous Compounds ◽

Water District ◽

Percent Removal

A pilot-scale study of ozone and PEROXONE (ozone in combination with hydrogen peroxide) for the removal of the odorous compounds 2-methylisoborneol (MIB) and geosmin in drinking water has been conducted at the Metropolitan Water District of Southern California. The study investigated the effects of ozone dosage, ratio of hydrogen peroxide to ozone (H202/03), and contact time. It was found that MIB and geosmin removal increased with higher applied ozone doses, but longer contact times over the range of 6-12 min were not significant. It was determined that 80-90 percent removal could be achieved with an ozone dose of approximately 4.0 mg/l, as compared to an ozone dose of approximately 2.0 mg/l at a H202/03 ratio of 0.2. Also investigated were the effects of alternative contactor configurations, ferrous sulfate as an alternative coagulant, bromide and ammonia addition, and simulated turbidity on the removal efficiencies of the two odorous compounds.

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