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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.
This is more common in TCF bleaching sequences for two reasons: the acidic chlorine or chlorine dioxide stages tend to remove metal ions (metal ions usually being more soluble at lower pH), and TCF stages rely more heavily on oxygen-based bleaching agents, which are more susceptible to the detrimental effects of these metal ions.
The principal example is tert-butyl hypochlorite, which is a useful chlorinating agent. [3] Most hypochlorite salts are handled as aqueous solutions. Their primary applications are as bleaching, disinfection, and water treatment agents. They are also used in chemistry for chlorination and oxidation reactions.
[38] Most TCF pulp is produced in Sweden and Finland for sale in Germany, [36] all markets with a high level of environmental awareness. In 1999, TCF pulp represented 25% of the European market. [39] TCF bleaching, by removing chlorine from the process, reduces chlorinated organic compounds to background levels in pulp mill effluent. [40]
Industrial bleaching agents can be sources of concern. For example, the use of elemental chlorine in the bleaching of wood pulp produces organochlorines and persistent organic pollutants, including dioxins. According to an industry group, the use of chlorine dioxide in these processes has reduced the dioxin generation to under-detectable levels ...
Sodium hypochlorite is most often encountered as a pale greenish-yellow dilute solution referred to as chlorine bleach, which is a household chemical widely used (since the 18th century) as a disinfectant and bleaching agent.
Trichloroisocyanuric acid is an organic compound with the formula (CONCl) 3.It is used as an industrial disinfectant, bleaching agent and a reagent in organic synthesis. [1] [2] [3] This white crystalline powder, which has a strong "chlorine odour," is sometimes sold in tablet or granule form for domestic and industrial use.
Hypochlorite (ClO) also has a molecule-to-molecule bleaching potential the same as dichlorine. However, its lower molecular weight leads to a higher potential bleaching power. In the example of lithium hypochlorite, the molecular weight 58.39, so it only takes 58.39 grams (2.060 ounces) to equal the bleaching power of 70.90 grams (2.501 ounces ...