Methylene blue adsorption from aqueous solution by dehydrated peanut hull

Area of Science:

• Environmental Chemistry
• Materials Science
• Adsorption Science

Background:

• Industrial effluents often contain dyes like methylene blue (MB), posing environmental challenges.
• Effective and sustainable methods for dye removal are crucial for wastewater treatment.
• Agricultural by-products offer potential as low-cost adsorbent materials.

Purpose of the Study:

• To investigate the feasibility of using dehydrated peanut hull (DPH) as an adsorbent for removing methylene blue from aqueous solutions.
• To determine the optimal conditions for methylene blue adsorption using DPH.
• To analyze the adsorption mechanism and thermodynamic properties.

Main Methods:

• Peanut hull was dehydrated with sulfuric acid to create the DPH adsorbent.
• Batch adsorption experiments were conducted to study the effects of MB concentration, temperature, and particle size.
• Adsorption isotherms (Langmuir, Freundlich) and kinetics (pseudo-second order, intraparticle diffusion) were analyzed.
• Thermodynamic constants were evaluated using Langmuir model parameters at different temperatures.

Main Results:

• Dehydrated peanut hull demonstrated significant potential for methylene blue removal.
• Adsorption data were well-fitted by the Langmuir isotherm model, indicating monolayer adsorption.
• The adsorption process followed pseudo-second order kinetics, suggesting chemical adsorption.
• Intraparticle diffusion was identified as a significant rate-controlling step, especially at higher MB concentrations.

Conclusions:

• Dehydrated peanut hull is an effective and economical adsorbent for methylene blue removal from wastewater.
• The adsorption mechanism involves both surface adsorption and intraparticle diffusion.
• This study highlights the potential of agricultural waste valorization for environmental remediation.