Treatment of TNT Red Water Using Ice Crystallization

Abstract

Crystallization of ice from TNT red water was studied using a scraped unit. Growth rate, crystal size distribution, and median particle size of ice crystals were measured. The effect of subcooling, temperature, growth rate, and crystal size on the treatment of red water was investigated. The relationship between ice crystal growth rate and effective distribution coefficient was correlated. From the plot of ice growth rate against subcooling degree, the order of the growth kinetic was in the range of 1.2 to 2.0 for various concentrations. The purity of ice crystals increased with increasing amounts of partial melt. Above 99 % of dinitrotoluene sulfonates in red water were removed after crystallization at a cooling rate of 1.0 K/min, a final crystallization temperature of −10 °C, and a yield of 50 %. The purity of ice crystal was significantly affected by the subcooling degree. Finally, it was shown that TNT red water of 9800 mg/L COD can be treated to provide water of 54 mg/L COD by scraped ice crystallization at a yield of 50 %.