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Elemental chlorine free (ECF) is a technique that uses chlorine dioxide for the bleaching of wood pulp. It does not use elemental chlorine gas during the bleaching process and prevents the formation of dioxins and dioxin-like compounds , carcinogens .
Chlorine dioxide is sometimes used in combination with chlorine, but it is used alone in ECF (elemental-chlorine-free) bleaching sequences. It is used at moderately acidic pH (3.5 to 6). The use of chlorine dioxide minimizes the amount of organochlorine compounds produced. [8]
Elemental chlorine bleaching uses chlorine and hypochlorite. 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 ...
The key to delivering a powerful sanitising agent is to form hypochlorous acid without elemental chlorine - this occurs at around neutral pH. Hypochlorous is a weak acid and an oxidizing agent. [ 3 ] This "acidic electrolyzed water" can be raised in pH by mixing in the desired amount of hydroxide ion solution from the cathode compartment ...
See {{Element-symbol-to-oxidation-state-data/doc}} for an overview. This list pulls data from {{Element-symbol-to-oxidation-state-data}} for each element then formats the result with {{Element-symbol-to-oxidation-state-row}}
Additional postulates and their ranking may expand the range of compounds to fit a textbook's scope. As an example, one postulatory algorithm from many possible; in a sequence of decreasing priority: An element in a free form has OS = 0. In a compound or ion, the sum of the oxidation states equals the total charge of the compound or ion.
In the past, plants using elemental chlorine produced significant quantities of dioxins, [35] persistent and very toxic organic pollutants. From the 1990s onward, the use of elemental chlorine in the delignification process was substantially reduced and replaced with ECF (Elemental Chlorine Free) and TCF (Totally Chlorine Free) bleaching processes.
For example, the relative atomic mass of chlorine is 35.453 u, which differs greatly from a whole number as it is an average of about 76% chlorine-35 and 24% chlorine-37. Whenever a relative atomic mass value differs by more than ~1% from a whole number, it is due to this averaging effect, as significant amounts of more than one isotope are ...