Sorption equilibrium and kinetics of basic dye from aqueous solution using banana stalk waste

Area of Science:

• Environmental Science
• Materials Science
• Chemical Engineering

Background:

• Industrial wastewater often contains toxic basic dyes, posing environmental risks.
• Agricultural waste like banana stalk waste (BSW) presents an underutilized resource for remediation.

Purpose of the Study:

• To investigate the efficacy of banana stalk waste (BSW) as a low-cost adsorbent for removing methylene blue (MB) dye from aqueous solutions.
• To determine the optimal conditions and adsorption mechanism for MB removal using BSW.

Main Methods:

• Batch adsorption experiments were conducted to study the effect of pH and initial dye concentration.
• Sorption isotherms were analyzed using Langmuir, Freundlich, and Temkin models at 30°C.
• Sorption kinetics were evaluated using pseudo-first-order, pseudo-second-order, and intraparticle diffusion models.

Main Results:

• BSW demonstrated remarkable methylene blue sorption across a wide pH range (4.0-12.0), with optimal performance observed at neutral to alkaline conditions.
• The Langmuir isotherm model best described the equilibrium data, indicating a maximum monolayer adsorption capacity of 243.90 mg/g.
• The pseudo-second-order kinetic model accurately represented the sorption process, suggesting chemisorption as the rate-limiting step.

Conclusions:

• Banana stalk waste is a highly effective and economical adsorbent for methylene blue removal from wastewater.
• The study highlights the potential of agricultural waste valorization for sustainable environmental management and water purification.