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Bleaching of wood pulp is the chemical processing of wood pulp to lighten its color and whiten the pulp. The primary product of wood pulp is paper , for which whiteness (similar to, but distinct from brightness) is an important characteristic. [ 1 ]
Elemental chlorine-free bleaching is more environmentally friendly since it eliminates the use of hypochlorite and replaces chlorine with chlorine dioxide or sodium chlorate. [3] Totally chlorine-free bleaching utilizes oxygen and hydrogen peroxide. This is the most environmentally friendly process since it eliminates all chlorinated pollutants ...
This pulp is manufactured for uses that require a high chemical purity, and particularly low hemicellulose content, since the chemically similar hemicellulose can interfere with subsequent processes. Dissolving pulp is so named because it is not made into paper, but dissolved either in a solvent or by derivatization into a homogeneous solution ...
The traditional ECF sequence is DEopDEpD [1]: 14 using the common letter symbols for bleaching stages, [2] though many improved sequences are available. [1]: 15 Totally chlorine free (TCF) is paper that does not use any chlorine compounds for wood pulp bleaching.
The procedure is the same for paper processing except that the EDTA and thiosulfate are mixed in 'bleachfix'. In reversal processing, residual silver in the emulsion after the first development is reduced to a soluble silver salt using a chemical bleach, most commonly EDTA. A conventional fixer then dissolves the reduced silver but leaves the ...
Recycling paper decreases the demand for virgin pulp and thus reduces the overall amount of air and water pollution associated with paper manufacture. Recycled pulp can be bleached with the same chemicals used to bleach virgin pulp, but hydrogen peroxide and sodium hydrosulfite are the most common bleaching agents. Recycled pulp, or paper made ...
This is an accepted version of this page This is the latest accepted revision, reviewed on 29 September 2024. Not to be confused with sodium chloride. Sodium chlorite The sodium cation Space-filling model of the chlorite anion Names IUPAC name Sodium chlorite Other names Chlorous acid, sodium salt Textone Identifiers CAS Number 7758-19-2 Y 49658-21-1 (trihydrate) Y 3D model (JSmol) Interactive ...
Paper is a thin sheet material ... Paper made from chemical pulps ... Americans also use in the order of 16 billion paper cups per year. Conventional bleaching of ...