Comparative study on removal of cationic and anionic dyes using biochar synthesized from dry leaves of Legerstroemia speciosa: Kinetics, isotherm and thermodynamic study

Pooja Adwani^1*, Bhanusree B¹, Meenakshi¹, Shakti Singh^2*, Jiwan Singh¹

¹Department of Environmental Science, Babasaheb Bhimrao Ambedkar University, Lucknow-226025, India

²Department of Chemical Engineering, University of Seoul, Seoul 02504, Republic of Korea

Cite this article: Adwani, P., Bhanusree, B., Meenakshi, Singh, S., Singh, J., 2024. Comparative study on removal of cationic and anionic dyes using biochar synthesized from dry leaves of Legerstroemia speciosa: Kinetics, isotherm and thermodynamic study. J. Appl. Sci. Innov. Technol. 3 (2), 86-96.

 

Highlights

• Dyes are natural or synthetic organic pollutants which can cause major health issues.
• Adsorption is very economical and effective technique to remove the organic pollutants.
• Removal capacity of cationic and anionic dyes using biochar was found to be 96% and 94%, respectively.
• Thermodynamic study confirmed the adsorption is favourable.

Abstract

The produced material was used in this study as an adsorbent to remove the organic pollutants such as methylene blue (MB) and methyl orange (MO) from an aqueous solution. Scanning electron microscopy (SEM), Fourier transform infrared spectra (FTIR), X-ray diffraction (XRD), Particle size analysis (PSA) characterization techniques were used to analyze morphological, chemical structure, nature and size of particles of an adsorbent. The dose study was performed to check optimum dose for removal of cationic dye (CD) and anionic dye (AD) which was 1g/L and 3 g/L, respectively. Different isotherm studies (Langmuir, Freundlich, Temkin, Dubinin- Radushkevich) were performed and confirm that the adsorption process followed Langmuir isotherm which means that adsorption is monolayer it was again confirmed by value of R² (0.98 for MB and 0.95 for MO). Kinetics study revealed that Pseudo-second-order (PSO) followed for both MB and MO which confirmed chemisorption. High value of ∆H⁰ was observed for MB confirmed that adsorption process is chemisorption. Negative value of ∆S⁰ revealed that process is spontaneous in nature. High removal percentages of MB and MO were achieved 95.7% and 94%, respectively, revealed that Legerstroemia speciosa biochar (LSB) is very effective adsorbent for the removal of organic pollutants (MB and MO).

Keywords: Methylene blue (MB); Methylene orange (MO); Biochar; Adsorption; Kinetics; Isotherm

Scope: Environmental Science & Engineering