Study on the pollution characteristics and emission factors of PCDD/Fs from disperse dye production in China.

According to an analysis of the input and output of polychlorinated dibenzo-p-dioxin and dibenzofurans (PCDD/Fs) of two disperse dye manufacturers, the average PCDD/F emission factor was 56.3 μg I-TEQ/T product, and dioxin was mainly emitted with products and solid waste. The PCDD/F concentrations of different series of disperse dyes varied from 2.87 to 323 pg I-TEQ/g, and the dominant congener was OCDD or 2,3,7,8-TCDF with the highest ratio of 83.4% or 79.3%, respectively. The distributions of PCDD/F congeners in raw materials and the products were different, indicating that the structure of PCDD/Fs greatly changed in the synthesis process. PCDD/Fs in the wastewater and sludge of the companies are mainly from the production process of a product with dominant emission factors. Our results confirm that disperse dyes may be a source of PCDD/Fs, resulting in human exposure and environmental contamination.