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Recycling hazardous textile effluent sludge in cement-based construction materials: Physicochemical interactions
Bao Jian Zhan1, Jiang-Shan Li1, Dong Xing Xuan1
1Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, People's Republic of China.
Journal of Hazardous Materials
|August 25, 2019
Summary
Textile effluent sludge (TES) incorporation into ordinary Portland cement (OPC) delays hydration and reduces mechanical strength. However, TES-OPC blends effectively stabilize toxic metals, posing no environmental risk.
Area of Science:
- Materials Science
- Environmental Engineering
- Civil Engineering
Background:
- Textile effluent sludge (TES) is a significant waste product from the textile industry.
- Previous research has explored using TES in cement-based materials, but physicochemical interactions with ordinary Portland cement (OPC) remain understudied.
Purpose of the Study:
- To investigate the effects of varying TES dosages (0-20% by OPC) on OPC-TES blends.
- To analyze hydration, mechanical strength, microstructure, and metal leachability.
Main Methods:
- Hydration progress monitoring.
- Mechanical strength testing (compressive and flexural).
- Microstructure analysis (SEM, MIP).
- Metal leachability assessment.
Main Results:
- TES significantly delayed early-age OPC hydration.
- Increased TES dosage reduced portlandite content.
- Mechanical strength decreased significantly with higher TES content (up to 71% compressive, 42% flexural at 20% TES).
- TES introduced weak interfaces and increased porosity, particularly macropores.
- All toxic metals in TES were stabilized in the OPC-TES matrix, showing low mobility.
Conclusions:
- Incorporating TES into OPC negatively impacts early hydration and mechanical performance.
- The microstructure of OPC-TES blends is characterized by increased porosity and weak interfaces.
- TES poses no environmental risk when incorporated into OPC due to effective metal stabilization.
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