Removal of Pb (II) From Wastewater Using Henna; Optimization of Operational Conditions

This paper studies the removal of Pb (II) using Lawsonia inermis (Henna). In recent years, the use of low price adsorbent has received much attention. Adsorption experiments were performed in the batch system at ambient temperature (25 ℃). The effects of some parameters, such as time, initial metal concentration, pH, and adsorbent dose, were investigated. The optimum conditions were obtained at pH of 6, initial metal concentration of 10 ppm, contact time of 80 min, and adsorbent dose of 0.75 g/L. To study the adsorbent morphology, Scanning Electron Microscope (SEM) and Fourier transform infrared spectroscopy (FTIR) were used before and after adsorption of Pb (II) ions. Sorption of Pb (II) was evaluated by Freundlich and Langmuir isotherms. The results indicate that the Freundlich isotherm model describes the adsorption of Pb (II) better than the Langmuir isotherm model. Also, it is observed that the pseudo-second-order kinetic model fits well with the experimental data.