Adsorption of lead (II) ions on kaolinite from aqueous solutions: isothermal, kinetic, and thermodynamic studies

Due to industrial activity, heavy metal contamination is present in water, air, and soil around the world. Due to this circumstance, serious environmental issues arise. In this investigation, kaolin (NK), which was employed as an adsorbent, was transported from the beds in Karaçayır, Uşak, Turkey. Natural kaolin (NK) clay underwent batch processing to remove Pb2+. Investigations were done into how adsorption is impacted by contact duration, adsorbent dosage, temperature, and solution pH. Kaolin’s BET surface area was found to be 8.085 m2/g, while its pore volume was found to be 0.0537 cm3/g. The best working conditions were found to be a pH of 6.87 and an equilibrium period of 80 min. It was discovered that the Langmuir isotherm model was the most suitable one. At 298 K, 308 K, and 318 K, respectively, the adsorption capacities of NK were calculated to be 4.24, 5.69, and 6.08 mg/g. The removal capacity of Pb2+ solution by NK at a 200 mg/L concentration was found to be 42.4%, 56.9%, and 60.8%, respectively, depending on the temperature. The pseudo-second-order kinetic model agreed with this. It was revealed that NK had a maximum desorption efficiency of 93.07%. Through this process, the potential of NK as an eco-friendly adsorbent for heavy metal removal was shown.