Purification of acetic acid wastewater using layer melt crystallization

Ice crystalline layers were prepared from a binary eutectic mixture of acetic acid and water using layer melt crystallization. The crystalline layers were obtained under the conditions of the cooling temperature at 269, 268, and 267K, the feed compositions of 0.5, 1.0, and 5.0wt% acetic acid, and the cooling rates of 0.1, 0.5, and 1.0K/min. After crystallization, sweating operations were carried out for various crystalline layers obtained in crystallization. The effect of sweating on the impurity behavior inside crystalline layer was investigated. The crystalline layer formed in higher growth rate was purified more easily by sweating operations. Effective distribution coefficient in the sweating process was in the range of 0.2 to 0.01, which depended on the crystalline layers formed in crystallization process. Eventually, layer melt crystallization can be used for the treatment of acetic acid wastewater.