Bulk Disposal of Unserviceable Toxic Cresylic Acid Waste Using Polymerisation Technique

Abstract

A bulk amount of unserviceable toxic cresylic acid waste has been disposed off in a safe and environmentally benign manner. A process to immobilize this waste into non-toxic solid cresol formaldehyde polymer has been developed. Initial study was performed for 1.0 Kg batch size for optimizing the process parameters and conditions, and on the basis of this data, process was scaled-up for bulk disposal (100 Kg / batch). The effect of ratio of reactants, type of catalyst [H₂SO₄, NaOH and Ca(OH)₂], catalyst concentration, reaction temperature and reaction time have been studied in a batch process. Maximum immobilization in the 1.0 Kg batch studies was obtained when cresylic acid and formaldehyde were taken in a molar ratio 1 : 1.5 using NaOH as a catalyst. For bulk polymerization, a ratio of 1.0 : 1.2 (cresylic acid : formaldehyde) with NaOH {0.7 % (wt. / wt. of total charge)} was found optimum. The final polymerized product has been buried as per standard procedure in two brick lined pits and finally, the site has been declared as free from the toxic waste.