Banana pseudo stem- and palm kernel shell-based biochars by microwave for methylene blue adsorption

This study investigates the adsorptive properties of biochars derived from banana pseudostem (BP) and palm kernel shell for methylene blue (MB) removal. The biochars were prepared using a microwave-assisted method, resulting in unique surface characteristics. The BP-based biochar (BP-C) exhibits a high surface area of 46.6 m2/g with MB capacity of 165 mg/g, surpassing that of palm kernel shell-based biochar (PK-C) with a capacity of 34.9 mg/g. Both biochars show a good fit to Langmuir model, implying a monolayer adsorption of MB on homogeneous surface. However, the kinetic analysis suggests that BP-C is driven by chemisorption while that of PK-C is physisorption. The thermodynamic analysis shows that the MB adsorption onto BP-C is spontaneous and favorable particularly at elevated temperatures and low MB concentrations. To conclude, this work highlights the promising BP-C as effective adsorbent for dye removal, offering insights into sustainable dye wastewater treatment application.