Abstract :
Chlorinated phenolics are formed during chlorination stage of pulp bleaching. These phenolics are dissolved in the alkaline extraction stage. The bleach plant effluent therefore contains these compounds in appreciable amount. As these chlorophenolics are highly toxic in nature, efforts have been made to reduce their concentration by changing the bleaching parameters. In the present studies experiments were conducted with bamboo pulp employing CEH sequence of bleaching under varying conditions. The effect of changing the chlorination stage parameters like pH, temperature, pulp consistency and distribution of bleaching chemicals between C and H was changed. The effluent parameters and pulp characteristics have also been determined. The results show that the amount of all categories of chlorinated phenolics are reduced by increasing the pH (1.5–4.0), decreasing temperature (35-150C) and all chlorophenolics are decreased by decreasing the consistency (4-2%) and C:H ratio (65:35 to 45:55).
Keyword :
Bamboo, Bleaching, Chlorinated phenolics, Effluents.