Removal of Lead from Aqueous Solution: Using New Absorbents Prepared from Modified Pistachio Husk

Heavy metals such as lead are as important environmental pollutants. The aim of this study was to investigate the removal of lead from aqueous using two modified pistachio husk. In this study, the capability of lead removal from aqueous solution was investigated using modified pistachio husk. The pistachio husk were pretreated using distilled water and were modified with 0.4 mol/L NaOH and 0.4 mol/L HNO3, separately, and their absorption’s ability were compared. Lead absorption was studied in batch reactor. After assessment of the effect of pH in lead absorption by single factor, the absorption experiments were studied by Taguchi method according L16 array. In this method the effects of four factors (initial concentration of lead, pH, absorbents dosages and contact times) were studied. This study showed that the maximum absorption efficiency of lead happened using the alkali modified pistachio husk up to 91.25%, with 20 mg/l initial concentration of lead, pH=4, 1.5 hr of contact times and the absorbent dosage of 0.5 g/l. However, at the same condition the maximum absorbent efficiency by acidic modified pistachio husk achieved up to 89.05%. Moreover, at the same condition the maximum absorption capacity achieved up to 36.5 and 33.4 mg/g by alkali and acidic modified pistachio, respectively. Based on the results of this study, the alkali modified pistachio husk has more potential than acidic modified pistachio husk to remove lead from aqueous solutions, and could be considered as inexpensive absorbent.