Jamun seed stone adsorbent for the removal of crystal violet dye from aqueous solutions: An RSM based approach

Abstract

This study aims to apply Indian jamun seed stone (JSS) as an adsorbent for the removal of crystal violet (CV) dye from aqueous solution. The adsorbent was characterized with FTIR, SEM, and EDX techniques. Batch adsorption studies were performed for optimization of independent variables developed by CCD of RSM. The developed design matrix was found to be significant with a p-value < 0.0001, and the F-value was observed to be 125.4. The lack of fit was noted as non-significant, with a value being > 0.05, and the correlation coefficients, adjusted and predicted, were all close to one, making the model reliable and significant. The loading capacity of JSS was calculated to be 129.2 g mg^-1 towards CV ions from aqueous solutions. The isotherm analysis confirms the applicability of Langmuir and the Freundlich models to the present system, and the D-R isotherm confirms the physisorption mechanism for the removal of CV ions by JSS. The activation energy (E_a) was calculated from kinetic studies to be 32.46 kJ mol^-1, which supports the physisorption. The thermodynamics investigations suggest the spontaneous exothermic nature of the CV ions removal by JSS. The results conclude that JSS is an excellent adsorbent for the removal of CV ions from aqueous solutions.

KEY WORDS: Jamun seed stones, Crystal violet, Adsorption, RSM

Bull. Chem. Soc. Ethiop. 2026, 40(10), 2145-2156.                             

DOI: https://dx.doi.org/10.4314/bcse.v40i10.7