Waste metal hydroxide sludge as adsorbent for a reactive dye

Area of Science:

• Environmental Science
• Materials Science
• Chemical Engineering

Background:

• Textile industry wastewater contains reactive dyes, posing environmental challenges.
• Industrial waste sludge, rich in metal hydroxides, presents an underutilized resource.
• Developing cost-effective adsorbents is crucial for efficient dye removal.

Purpose of the Study:

• To evaluate industrial waste sludge as a low-cost adsorbent for Remazol Brilliant Blue dye.
• To characterize the sludge adsorbent and understand its adsorption mechanisms.
• To assess the adsorption performance in simulated real textile effluent.

Main Methods:

• Sludge characterization: chemical composition, pH(ZPC), particle size, textural properties, metal mobility.
• Adsorption isotherms at varying temperatures (25, 35°C) and pH (4, 7, 10).
• Kinetic studies, desorption tests, and analysis using Langmuir, Freundlich, and pseudo-second-order models.

Main Results:

• Adsorption equilibrium data fitted well to Langmuir and Freundlich models.
• Maximum adsorption capacity of 91.0 mg/g at 25°C and pH 7 (Langmuir fit).
• Pseudo-second-order kinetics indicated good agreement; ion-exchange mechanism identified.

Conclusions:

• Industrial sludge is a viable, low-cost adsorbent for reactive textile dyes.
• Adsorption performance is pH and temperature-dependent, with ion-exchange being a key mechanism.
• The adsorbent shows potential for treating real textile effluents, demonstrating practical applicability.