The demand for clean water is on the increase as rapid industrialization is still contributing to pollution. Nowadays, as water is the basic need for mankind, efforts have gathered momentum to decontaminate it in order to address the acute shortage of clean and pure water. Maize tassel was used as the precursor for making activated carbon for the adsorption of Pb(II) ions. The product obtained was characterized and utilized for the removal of Pb(II) from aqueous solutions over a wide range of initial metal ion concentration (10–50 mg/L), contact time (5–300 min), adsorbent dose (0.1–2.5 g), and pH (2–12). The optimum set of conditions for biosorption of Pb(II) ion were found to be initial concentration 10 mg/L, dosage 1.2 g, and pH 5.4. The adsorption data conformed to both the Langmuir and the Freundlich isotherms but fitted best into the Langmuir model. The R² for Langmuir equation was 0.9997 and that for Freundlich was 0.9515. The Langmuir monolayer adsorption capacity of the activated carbon was calculated to be 37.31 mg/g. The results indicate that activated carbon might be used to effectively adsorb Pb(II) ions from wastewater treatment plants.

The potential of goat dung-derived activated carbon as an adsorbent for the removal of lead from aqueous solution in a batch system was studied. Physicochemical properties of the biosorbent were characterized by means of X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectroscopy. Batch adsorption experiments were carried out as a function of pH, contact time, adsorbent dosage, initial concentration and temperature. The adsorption showed a pH dependent profile and an optimum value at pH 4.5. The adsorption isotherm modelling showed that the equilibrium data fitted better to the Freundlich than the Langmuir model. Kinetic data were properly fitted with the pseudo-second-order kinetic model. Furthermore, the thermodynamic parameters indicated that the adsorption reaction was endothermic and a spontaneous process.