Removal of Fluoride from Aqueous Solution by Using Alum Sludge

Area of Science:

• Environmental Science
• Water Treatment Technologies
• Adsorption Processes

Background:

• Fluoride contamination in aqueous solutions poses environmental and health risks.
• Alum sludge, a byproduct of water treatment, is explored as a potential adsorbent for contaminant removal.

Purpose of the Study:

• To investigate the efficacy of treated alum sludge in removing fluoride from aqueous solutions.
• To determine the optimal conditions and understand the adsorption mechanism for fluoride removal.

Main Methods:

• Batch adsorption experiments were conducted varying contact time, adsorbent/adsorbate concentration, temperature, and pH.
• The influence of competing anions on fluoride removal was assessed.
• Adsorption data were analyzed using Langmuir isotherm and first-order kinetics models.

Main Results:

• Treated alum sludge demonstrated significant fluoride removal capabilities.
• The optimal pH for fluoride removal was determined to be 6.
• Adsorption equilibrium was reached within 240 minutes, following first-order kinetics and the Langmuir model.
• Fluoride loading increased with initial concentration but decreased with rising temperature.

Conclusions:

• Treated alum sludge is a viable and effective adsorbent for removing fluoride from water.
• The adsorption process is influenced by solution chemistry, including pH and the presence of other anions.
• Understanding the adsorption kinetics and isotherm models provides insights for optimizing water treatment processes using alum sludge.