A review on progress of heavy metal removal using biosorbents of poly-γ-glutamic acid

This paper aims to carry out an exhaustive review of the literature on adsorption of poly-γ-glutamic acid for heavy metals. poly-γ-glutamic acid (simply as γ-PGA) shows a notable affinity for various kinds of heavy metals including Cr3+, Cu2+, Pb2+, Hg2+, Ni2+, Cd2+ and Zn2+. Adsorptive selectivity of γ-PGA on common heavy metals was summarized. The influencing factors (pH, temperature, adsorption time and initial concentration) of the adsorption process were discussed. Several effective modification methods of γ-PGA are also reviewed.