Chlorophenols in textile dyeing sludge: Pollution characteristics and environmental risk control

Area of Science:

• Environmental Science
• Environmental Chemistry
• Industrial Chemistry

Background:

• Chlorophenols (CPs) are toxic contaminants accumulating in textile dyeing sludge.
• Sludge disposal poses environmental risks due to CPs.
• High-chlorine phenols are the predominant CPs in sludge.

Purpose of the Study:

• To evaluate the characteristics and risks of CPs in textile dyeing sludge.
• To analyze the pollution levels and potential risks of CPs.
• To investigate the effectiveness of the Fenton process for sludge conditioning.

Main Methods:

• Quantification of 19 CPs (Σ19 CPs) in sludge from five textile dyeing plants (TDPs).
• Assessment of pollution levels using ecological screening levels (ESLs).
• Analysis of potential risks using risk quotient (RQ) values and dioxin conversion rates.
• Application of the Fenton process for sludge conditioning with optimized parameters (reagent dose, H2O2:Fe2+ ratio, pH, reaction time).

Main Results:

• Total CP concentrations ranged from 170.90 to 6290.30 ng g-1 dry weight.
• CPs were found to pose a moderate to high environmental risk.
• The Fenton process increased CP content, but optimized conditions (180 mmol/L reagent dose, 1:1 H2O2:Fe2+, pH 3-4, 30 min) minimized this increase.

Conclusions:

• CPs in textile dyeing sludge represent a significant environmental concern.
• The Fenton process is a viable sludge conditioning method, but requires careful optimization to manage CP levels.
• This study provides valuable data for the textile dyeing industry regarding CP contamination and management.