Locally available agroresidues as potential sorbents: modelling, column studies and scale-up

Area of Science:

• Environmental Science
• Materials Science
• Chemical Engineering

Background:

• Methylene blue is a common industrial dye pollutant.
• Agricultural waste materials offer potential for sustainable dye removal.
• Effective and economical wastewater treatment methods are crucial.

Purpose of the Study:

• To evaluate sawdust, cotton stalk, and groundnut shell as adsorbents for methylene blue removal.
• To investigate the influence of operational parameters on dye sorption.
• To analyze the adsorption kinetics, isotherms, and thermodynamics.

Main Methods:

• Batch sorption experiments were conducted.
• Effects of initial dye concentration, temperature, and particle size were studied.
• Sorption data were fitted using Freundlich and Sips isotherm models.
• Kinetic and thermodynamic analyses were performed.

Main Results:

• Sorption capacity increased with initial dye concentration and temperature.
• Smaller particle sizes enhanced dye removal efficiency.
• Maximum sorption capacities were 9.22 mg/g (sawdust), 8.37 mg/g (cotton stalk), and 8.20 mg/g (groundnut shell).
• The process followed pseudo-second-order kinetics with film diffusion as the rate-limiting step.
• Sawdust exhibited superior performance compared to other sorbents.

Conclusions:

• Agricultural wastes are effective biosorbents for methylene blue.
• Sawdust is the most efficient adsorbent among those tested.
• Scaled-up sawdust columns can treat significant volumes of wastewater effectively.