Removal of Lead Ions from Aqueous Solution by Nano Zero-Valent Iron (nZVI)

Background: The nanoscale zero-valent iron (nZVI) has good potential for heavy metals removal from aqueous solution because it has special physicochemical properties. In addition, it could remove Lead from aqueous solution. Objectives: The aim of this study was to study Lead removal from aqueous solution with nZVI and investigate the effect of pH, contact time, nZVI dosage and Lead concentration in this process. Methods: This study was done with the batch technique at room temperature. Final Lead concentration was measured by the ICP-AES machine. The effect of pH, contact time, nZVI dosage and Lead initial concentration on removal efficiency were determined with the DOE software for 21 analyses. In addition, isotherm and kinetic models were derived from earnings data. Results: The results showed that high removal of Lead with nZVI was at pH 9, contact time of five minutes, nZVI dosage of 0.1 g/L and Lead initial concentration of 10 mg/L, with 80% - 100% Lead removal efficiency. Results of isotherm model indicated that Freundlich isotherm was a good model for 10 and 100 mg/L of Lead initial concentration when other parameters were variable. In addition, kinetic studies showed that the second-order kinetic model was the best model for 10 mg/L of Lead concentration with other parameters being variable. Conclusions: The findings of this study indicated that nZVI could be a good adsorbent for Lead removal from aqueous solution. Based on the results, the Freundlich isotherm was the goodness-of-fit model for this process. The second order kinetic model was the best for low concentration of Lead ion removal from aqueous solution.