Removal Efficiency of Lead (II) by A Biopolymer Poly-γ-Glutamic Acid

Lead(II) is a typical industrial pollutant which is harmful to people's health. In this study, a new environmental-friendly material, the edible biopolymer poly-gamma-glutamic acid (gamma-PGA) was applied to adsorb lead(II). The results revealed that gamma-PGA had pronounced binding effects on lead(II) and its metal adsorption capacity was affected by lead(II) concentration, gamma-PGA dose and pH of the solution. For lead(II) concentration, the removal rate of lead(II) increased with the decrease of the metal concentration. For gamma-PGA dose, the removal rate of lead(II) increased with the increase of gamma-PGA dose until the turning point at 4000 mg/L and then the tendency was adverse. The maximum removal rate was 92.8 % when lead(II) and gamma-PGA concentration was 1000 mg/L and 4000 mg/L separately. For pH, the metal adsorption capacity was weak when pH<4 and the optimal result occurred at pH 5-6.