Removal of Pb (II) from aqueous solution using nanoadsorbent of Oryza sativa husk: Isotherm, kinetic and thermodynamic studies

This research focus on the removal of Pb (II) ions from aqueous solution by adsorption process using nanoadsorbent developed from agricultural waste Oryza sativa husk (OSH). Surface morphology of nanoadsorbent was analyzed by FE-SEM, elemental composition by EDX and size by AFM. Attachment of functional groups on nanoadsorbent was determined by FTIR. The effect of pH, dose, contact time, initial concentration and temperature were investigated. Optimum adsorption of lead at pH 8, contact time 70 min at 60 °C temperature with 0.6 g/50 mL nanoadsorbent dose obeyed pseudo second order kinetic model with R(2) 0.996. Pb (II) adsorption was analyzed by Freundlich, Langmuir and Temkin models. Freundlich isotherm model with correlation coefficient R(2) 0.999 was best fitted. Thermodynamic parameters anticipated the adsorption process to be endothermic and spontaneous. Post adsorption elution was carried out successfully. Results demonstrate that OSH is a low cost and eco-friendly choice for Pb (II) remediation.