Colour removal from model solutions by coagulation--surface charge and floc characterisation aspects.

Area of Science:

• Environmental Chemistry
• Water Treatment Technologies
• Colloid and Surface Science

Background:

• Industrial dye effluents pose significant environmental challenges.
• Chemical coagulation is a widely used method for treating dye-bearing wastewater.
• Understanding surface charge dynamics is crucial for optimizing coagulation processes.

Purpose of the Study:

• To investigate the effectiveness of chemical coagulation for color removal from dye solutions.
• To analyze the role of surface charge progression in the coagulation process.
• To evaluate common coagulants (alum, aluminum chloride, ferric chloride) for dye removal.

Main Methods:

• Testing two commercial dyes (CI Acid Blue 113, CI Disperse Blue 26) with three coagulants.
• Investigating process parameters: coagulant type, dose, and solution pH.
• Analyzing surface charge, color removal efficiency, and floc characteristics via image analysis.

Main Results:

• High color removal rates achieved with all tested coagulants, though dosages varied.
• Surface charge neutralization correlated with dye colloid destabilization and removal.
• Sweep coagulation mechanism observed, preventing re-stabilization at higher coagulant doses.

Conclusions:

• Chemical coagulation is highly effective for removing CI Acid Blue 113 and CI Disperse Blue 26.
• Both charge neutralization and sweep coagulation contribute to efficient dye removal.
• Floc characteristics analysis provides insights into the physical aspects of the treatment process.