Comparative chromium adsorptive capacity of different low-cost materials using fixed bed column

Area of Science:

• Environmental Science
• Water Treatment Technologies
• Adsorption Processes

Background:

• Heavy metals, particularly chromium(VI), pose significant environmental threats due to their toxicity and persistence.
• Adsorption is an effective method for heavy metal remediation, offering flexibility and high-quality treated water.
• Fixed-bed column adsorption is a continuous process suitable for large-scale water treatment.

Purpose of the Study:

• To assess the chromium(VI) adsorption efficiency of activated charcoal, sawdust, and rice husk in a fixed-bed column.
• To investigate the impact of operational parameters (flow rate, bed height, metal concentration) on chromium(VI) adsorption.
• To determine optimal parameters for chromium(VI) removal using breakthrough curve analysis.

Main Methods:

• Continuous adsorption experiments were conducted in a fixed-bed column.
• Three adsorbent materials (activated charcoal, sawdust, rice husk) were tested for chromium(VI) removal.
• Breakthrough curve analysis was used to evaluate adsorption performance and optimize operational parameters.

Main Results:

• Activated charcoal demonstrated the highest chromium(VI) adsorption efficiency, followed by rice husk, then sawdust.
• Optimal parameters for chromium(VI) removal (30 mg L⁻¹) included a bed depth of 30 cm and a flow rate of 30 mL min⁻¹.
• Lower metal concentration, reduced flow rate, and increased bed height led to longer breakthrough times, indicating greater treatment capacity.

Conclusions:

• Activated charcoal is highly effective for chromium(VI) removal, but sawdust and rice husk offer economical and accessible alternatives.
• The Yoon-Nelson model accurately described the chromium(VI) adsorption process in the fixed-bed system (R² = 0.9476).
• Operational parameters significantly influence the efficiency and capacity of chromium(VI) adsorption in fixed-bed columns.