Adsorption of malachite green dye using low-cost adsorbent derived from java apple leaves (syzyium samarangense)

• Published in: Sadhana (Bangalore) Vol. 48; no. 3
• Main Authors: Bhat, S Sneha, Narayana, B, Bhat, J Ishwara
• Format: Journal Article
• Language: English
• Published: New Delhi Springer India 15.07.2023
• Subjects: Engineering; Java apple leaves; malachite green; adsorption; isotherm; free energy change; second order kinetics
• ISSN: 0973-7677; 0973-7677
• DOI: 10.1007/s12046-023-02214-z

In the current research, Java Apple leaves were used to prepare activated carbons using physical, chemical and microwave activation processes. These highly surface-area activated carbons were used to investigate the adsorption of the cationic dye malachite green. To better understand the adsorption process, variables such as contact time, initial dye concentration, and temperature were used in batch tests. FTIR, FE-SEM, XRD and TGA techniques were used to analyse prepared carbons. In activated carbons, there is a strong peak at 2902 cm −1 which is a consequence of the methylene group being stretched asymmetrically. While TGA demonstrated the stability of activated carbons as a function of temperature, XRD demonstrated the existence of crystalline nature in them. The surface morphology of activated carbon was revealed by SEM pictures. Adsorption isotherms were investigated using both the Langmuir and the Freundlich isotherms. For physically modified carbon, the adsorption capability of the adsorbent was discovered to be 64.37 mg/g at room temperature. About 95.5–91.8% of the dye was removed for an initial dye concentration in the range of 20–100 mg/g in 1 hour. Kinetic data were analysed by the second-order kinetic equations, and the maximum rate constant value was 0.025 (mg/min). The van't Hoff equation was used to calculate the thermodynamic parameters ∆H # , ∆S # , and ∆G # . In comparison to the other two synthesized activated carbon materials, physically modified carbon is more efficient at adsorbing the dye malachite green. It can be attributed to the maximum ∆G # of − 12.56 kJ/mol. Graphical Abstract