Enhanced Removal of Nickel and Ferrous Ions Using a Modified, Eco‐Friendly Adsorbent: A Kinetics, Isotherms, and Thermodynamics Study

Abstract Water contaminated with heavy metal ions can be effectively treated using abundant and available eco‐friendly adsorbent. The synthesized sulphonic‐impregnated Pomegranate peel powder (SIPP) was fully characterized using different techniques and used to remove and decontaminate of heavy metal from water solutions. Various factors affecting the adsorption process of nickel (Ni 2+) and ferrous (Fe 2+ ) have been studied. SIPP's sorption capacities for Fe 2+ and Ni 2+ were determined to be 36 and 165 mg/g, respectively. The obtained equilibrium data proved that Langmuir isotherm was the best and gave satisfactory results. The maximum adsorption capacity according to Langmuir = 50.25 and 373 for Fe 2+ and Ni 2+ , Respectively. Fe 2+ ( R 2 = 0.968) and Ni 2+ ( R 2 = 0.982) were found to be best described by the Freundlich isotherm, which was selected based on the highest R 2 value. The adsorption process was physical according to activation energy; E D = 0.171 kJ/mol and 0.189 kJ/mol for Fe 2+ and Ni 2+ , respectively. The experimental data fitted well with pseudo‐second‐order kinetic model. Thermodynamic nature was found to be exothermic from negative free energy for both metal ions. Even after three cycles, SIPP maintains greater metal ion removal efficiency. SIPP demonstrates its ability to adsorb and remove heavy metals from large volumes of solution.