Bioremoval of crystal violet dye from aqueous solutions using Physalis Peruviana calyx: mechanism, biosorption isotherms, kinetic modeling, and thermodynamic analysis

Abstract The objective of this study is to examine the potential of the calyx of Physalis peruviana (PPC) as a biosorbent for the removal of the highly toxic Crystal violet dye (CV) from aqueous solutions. In order to characterise the biosorbent, a series of analyses were conducted, including FTIR, SEM, EDX, and zero point of charge analyses. The compatibility of the Langmuir, Freundlich, and Dubinin-Radushkevich isotherm models was evaluated in order to assess the biosorption isotherms. The Langmuir isotherm model, which exhibited the highest correlation coefficient (R² = 0.930), was identified as the most accurate description of the biosorption process. At 25 °C and a natural pH (4.8), the monolayer biosorption capacity was determined to be 144 mg g − 1 . The biosorption kinetic mechanism was found to align with both the PSO. (R² = 0,943), and the IPD model (R² = 0,990). The thermodynamic parameters indicated that the biosorption process is heat-absorbing (ΔH°>0) and spontaneous (ΔG°0). It was thus determined that biological waste PPC can be evaluated as a cost efficient, renewable and effective biosorbent in CV removal and as an alternative to other sorbents that have been previously reported.