Investigating the Adsorption Efficiency of Banana Pseudo-Stem Derived Biochar for Polyethylene Microplastic Removal from Aqueous Solutions

Abstract

Microplastic pollution, particularly from polyethylene terephthalate (PET), has emerged as a significant environmental concern due to its persistence and toxicity in aquatic systems. This study evaluates the use of banana pseudo-stem (BPS) biochar as a low-cost, sustainable adsorbent for removing PET microplastics from water. Biochar was synthesized at 450°C, 550°C, and 650°C using slow pyrolysis. PET microplastics (<150 ?m) were prepared from plastic waste and used to create stock solutions. Batch adsorption experiments were conducted under varying pH (4, 7, 9), dosage (2, 4, 6 mg), and contact times (30–90 min). Characterization via TGA, FTIR, and CHNS revealed that higher pyrolysis temperatures enhanced the aromaticity, surface area, and carbon content of the biochar. The highest adsorption efficiency was recorded at 650°C, with 6 mg of biochar at pH 9. These findings support the potential of BPS biochar as an environmentally friendly and effective solution for microplastic removal and valorization of agricultural waste.

Introduction

Microplastic pollution—plastic particles smaller than 5 mm—has become a major environmental concern due to their persistence, toxicity, and widespread presence in water, soil, and air. Polyethylene Terephthalate (PET), commonly used in packaging, is a significant contributor to microplastic contamination and poses risks through bioaccumulation.

Conventional microplastic removal methods are often costly, inefficient, or impractical on a large scale. Biochar, a carbon-rich material made by pyrolyzing biomass under limited oxygen, is gaining attention for pollutant adsorption due to its porous structure and surface chemistry. This study explores biochar derived from banana pseudo-stem (BPS), an abundant agricultural waste, for removing PET microplastics from water.

BPS biochar was produced at three pyrolysis temperatures (450°C, 550°C, and 650°C), characterized for thermal stability, elemental composition, and surface functional groups. Higher pyrolysis temperatures increased carbon content and aromaticity, enhancing biochar’s hydrophobicity and adsorption capacity via mechanisms like π–π stacking and electrostatic attraction.

Batch experiments showed that microplastic adsorption improved with increasing biochar dosage, contact time, and pyrolysis temperature. Optimal removal occurred at pH 9 using biochar produced at 650°C, highlighting the role of surface charge and chemical interactions in adsorption.

Overall, BPS-derived biochar demonstrates promising, sustainable potential for effective microplastic remediation in water, addressing both biomass waste utilization and pollution control.

Conclusion

This study successfully demonstrates the potential of biochar derived from banana pseudo-stem (BPS) as a cost-effective and environmentally sustainable adsorbent for the removal of polyethylene terephthalate (PET) microplastics from aqueous solutions. Through systematic experimentation involving pyrolysis at three different temperatures (450°C, 550°C, and 650°C), varying biochar dosages, and multiple pH conditions, the adsorption efficiency was thoroughly evaluated. Furthermore, the characterization of biochar using TGA, CHNS elemental analysis, and FTIR confirmed the structural evolution of the material with temperature, highlighting the development of functional groups and surface features critical to adsorption mechanisms such as electrostatic interaction, ?–? stacking, and hydrophobic forces. Overall, the study validates the conversion of agricultural waste into a functional material for microplastic remediation. The approach aligns with principles of circular economy and sustainable development by addressing two key environmental concerns: plastic pollution and biomass waste utilization. This work lays the foundation for scaling up biochar-based technologies for microplastic removal and invites future exploration in real-world wastewater treatment systems.

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Copyright

Copyright © 2025 Prof. Dr. Jagdish Rameshrao Dhanuskar , Aditya Appasaheb Gaund . This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.