A study on the use of waste wool to remove mercury from industrial effluents

A study on the feasibility of using waste wools and waste wool/man-made fibre blends as commercial mercury scavengers has been carried out. The study examined the absorption of elemntal (1-100ppm), inorganic (1-200ppm) and phenyl mercury by waste wools. Inorganic mercury absoption by wool has been studied over a range of pH (0.5 - 12), temperature (1 -70 deg C), chloride ion (0.5% - 25%), and wool liquor ratios (1:100 - 1:500). Increased merucry absorption occurs at elevated temperatures nd low, wool-liquor ratios. The effect of choride ion is to increase merucry removal in acidic conditions and to decrease removal in alkali conditions. Trials on real and simulated industrial effluents showed that pH adjustment of storng alkali effluents was necessary, but efficent mercury removal could be obtained. The high efficency of mercury removal from simulated chlor-alkali plant effluents using the 'once through' process shows wool to have a high potential in this application. Recovery of mercury from wool is possible be degrading wool with strong alkali or acid, or less efficently with degradation using sodium cholride solution. 'Dumping' mercury contaminated wool was found to be an unsatifactory disposal method. An attempt has ben made to estimate the cost of using wool to treat mercury effluents and compares favorably with the costs of other methods of mercury removal.