Adsorptive remediation of Pb(II) using acid-activated fungal–areca palm biochar: equilibrium modelling and ANN-based prediction

The current study evaluates the adsorption efficiency of a modified mixed biochar derived from Penicillium oxalicum, Emmia lacerata, and Areca palm leaves in the ratio of 5:4:5 for effective removal of Pb(II) from aqueous solutions. The adsorption performance was enhanced through chemical modification. The EDX analysis indicates the appearance of Pb after adsorption. The FTIR analysis has confirmed the shift in –OH, C = O, and C–O/S = O, representing the metal binding. The TGA result has demonstrated the thermal stability of the adsorbent with maximum weight loss attained between 150 and 300 ℃. The batch adsorption study was performed at an adsorbent dosage of 2.4 g/L, pH 5, initial Pb(II) concentration of 25 mg/L, contact time of 120 min, and temperature of 303 K, under which high removal efficiency was attained. The Redlich-Peterson model has been found to be the best fit with R² value of 0.9874, where the maximum monolayer adsorption capacity of 154.7 mg/g was attained from Langmuir model. The thermodynamic parameters indicated an exothermic process with ΔH° value ranging from − 63.20 to − 14.70 kJ/mol along with with negative ΔG° values from − 9.80 to − 0.10 kJ/mol across 303–333 K, confirming spontaneous adsorption. The kinetic modelling revealed that the pseudo-second order provided best fit to the experimental data with an R² value ranging from 0.9643 − 0.9587. The ANN has effectively predicted the adsorption performance, with an R value of 0.99228 across the validation, testing and training datasets. The results attained from the studies indicate the potential applicability of adsorbent in wastewater treatment.