Removal of lead heavy metal from wastewater by crystallization process and investigation of the effective parameters

Lead (Pb) is one of the heavy metals having high and long-term toxicity even at very low concentrations which limits the reusability and recyclability of industrial wastewaters. In this study, the removal and recovery of Pb from synthetic wastewater by a new form of precipitation method named crystallization process in a batch system was investigated. This process has gained increasing attention in recent years because of being in access, low cost, high efficiency and no need to recover the used materials. The efficacy of removal was dependent on the factors such as pH, initial lead concentration, carbonate: lead molar ratio and amount of seed crystals. The results of the experiments performed in this study showed that when the pH is in the range between 8-9, the initial concentration of lead is 100 mg /L, the molar ratio of carbonate to lead is 3:1 and the amount of seed particles is 0.25 g dissolved in 100 ml, the lead removal efficiency is obtained as 99%. AAS, SEM and EDS analyzes were used to confirm and justify the above results.