Synthesis and Evaluation of an Innovative Biochar Nanocomposite Adsorbent Derived from Cycas Revoluta Seeds, with Potential Applications in the Removal of Cationic Dyes

Abstract

In this study, novel and functional adsorbents were synthesized by using Cycas revoluta seed (CS) biomass. The biomass was subjected to a slow pyrolysis process at a final temperature of 500°C with a heating rate of 10°C/min to synthesize Cycas revoluta seed biochar (CSB). After the thermochemical conversion of biomass into biochar, the nanocomposite structure (ZrO2NP@CSB) was synthesized by adding 5% zirconium oxide (ZrO2) nanoparticles into biochar to increase the adsorption capacity. The synthesized adsorbents (CS, CSB, and ZrO2NP@CSB) were characterized by XRD, FTIR, SEM, and EDX. The adsorption efficiency of these three adsorbents was investigated to remove Malachite Green (MG) and Methylene Blue (MB) dye from an aqueous solution. According to the results obtained from the adsorption experiments of the nanocomposite structure, solution pH had a significant effect on the process and the highest adsorption efficiencies were achieved at pH 9. The optimum adsorbent dose was 0.5 g/L. The process reached an equilibrium after 45 minutes and 90 minutes for MG and MB, respectively. The relevant data were in good agreement with the pseudo-second-order kinetic model. The maximum adsorbent capacities were 129.87 and 117.93 mg/g for MG and MB, respectively. The adsorption mechanism follows a monolayer Langmuir isotherm model. Experiments were carried out at different temperatures (25, 35, 45°C) to determine the effect of temperature on adsorption, and dye removal efficiency slightly increased with temperature. When repeated batch adsorption experiments were compared for raw biomass, biochar, and biochar nanocomposite adsorbents, it was observed that the raw adsorbent had a lower adsorption capacity than the biochar adsorbent. It was found that the biochar nanocomposite had the highest adsorption capacity among these three adsorbents. The findings suggest that ZrO2NP@CSB composite is a promising, cost-effective, and functional material for water treatment and can be employed as an alternative adsorbent for removing dyes.

Keywords

• Adsorption
• Biochar
• Nanocomposite
• Water treatment

References

1. Gezginci, E. & Pehlivan, E. (2024). Synthesis and evaluation of an innovative biochar nanocomposite adsorbent derived from Cycas revoluta seeds, with potential applications in the removal of cationic dyes. The Eurasia Proceedings of Science, Technology, Engineering & Mathematics (EPSTEM), 29, 92-105.