High Surface Area Activated Carbon from Banana Pseudostem via Optimized Synthesis

Key Takeaways

High-performance activated carbonActivated carbon is a form of carbon that has been processed to create a vast network of tiny pores, increasing its surface area significantly. This extensive surface area makes activated carbon exceptionally effective at trapping and holding impurities, like a molecular sponge. It is commonly More for phosphorus removal can be sustainably produced from banana pseudostem, a common agricultural residue.
Optimization of synthesis conditions—activation temperature, pyrolysisPyrolysis is a thermochemical process that converts waste biomass into bio-char, bio-oil, and pyro-gas. It offers significant advantages in waste valorization, turning low-value materials into economically valuable resources. Its versatility allows for tailored products based on operational conditions, presenting itself as a cost-effective and efficient More time, and chemical impregnation—enables the creation of materials with exceptionally high specific surface areas.
A specific synthesis protocol involving ZnCl₂ activation at produces activated carbon with a large surface area.
Post-pyrolysis acid soaking is a critical factor that significantly enhances the final surface area of the material.
The resulting material effectively removes phosphate from aqueous solutions through a combination of electrostatic interactions and ion exchange

Phosphorus contamination in water bodies, largely driven by agricultural runoff and domestic wastewater, is a significant environmental challenge leading to harmful algal growth and oxygen depletion. As reported in ACS Omega by Moisés de Souza Luz Faria and colleagues, banana pseudostem (BP) serves as an abundant and renewable precursor for producing high-quality activated carbon to address this issue. The study utilized a Central Composite Rotational Design (CCRD) to simultaneously optimize three key synthesis variables: activation temperature (AT), impregnation ratio (IR) with zinc chloride , and pyrolysis time (PT). This multivariate approach identified that IR had the most substantial influence on the specific surface area, followed by AT and then PT.

The optimized banana pseudostem activated carbon (BPAC) was produced at an AT of 400 degree Celsius , an IR of 2:1, and a PT of 60 minutes in an air-atmosphere muffle furnace. While the response surface methodology predicted a surface area of 1037 m²g^-1, the experimental material achieved an exceptionally high specific surface area of 2415 m²g^-1. This significant enhancement was attributed to post-pyrolysis factors not included in the original model, specifically the extended duration .the material spent soaking in HCl solution during the washing stage. This acid soaking step effectively unblocks pores and removes inorganic components, contributing to superior porosityPorosity of biochar is a key factor in its effectiveness as a soil amendment and its ability to retain water and nutrients. Biochar’s porosity is influenced by feedstock type and pyrolysis temperature, and it plays a crucial role in microbial activity and overall soil health. Biochar More development.

Structural characterization of the optimal BPAC confirmed a primarily amorphous structure^.. X-ray diffraction (XRD) analysis also identified the formation of simonkolleite, a lamellar zinc hydroxychloride, which likely acts as a specific binding site for phosphate ions through ion exchange and electrostatic attraction^.. The pHpH is a measure of how acidic or alkaline a substance is. A pH of 7 is neutral, while lower pH values indicate acidity and higher values indicate alkalinity. Biochars are normally alkaline and can influence soil pH, often increasing it, which can be beneficial More at the point of zero charge was found to be 7.30, indicating that phosphate adsorption is electrostatically favored at pH values below this threshold. Scanning electron microscopy (SEM) images further demonstrated increased surface roughness in the BPAC compared to the raw precursor, providing more area for contaminant interaction.

Batch adsorption assays revealed that phosphorus removal by BPAC followed pseudo-second-order kinetics, characteristic of a chemisorption process, and reached equilibrium in approximately 7 hours. The adsorption data fitted best to the Langmuir model, suggesting a monolayer adsorption on homogeneous energy sites. When compared to other adsorbents, this BPAC demonstrated competitive performance while offering the economic benefit of lower energy requirements during synthesis, as effective activation was achieved at 400 degree celcius —considerably lower than many traditional protocols.

Source: Faria, M. d. S. L., Andrade, T. d. A., Moreira, R. P. L., Sousa, R. d. C. S. d., & Borges, A. C. (2025). Activated Carbon from Banana Pseudostem: Multivariate Optimization of Synthesis and Adsorption Study for Phosphorus Removal. ACS Omega.

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Shanthi Prabha V

Shanthi Prabha V, PhD is a BiocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More Scientist and Science Editor at Biochar Today.