Biosorption Behavior and Mechanism of Lead(II) from Aqueous Solution by Aerobic Granules(AG) and Bacterial Alginate(BA)

Lead(Pb) and its compounds are common pollutants in industrial wastewaters.To develop appropriate Pb 2+ treatment technologies,aerobic granules(AG) and bacterial alginates(BA) were studied as alternative biosorbents to remove Pb 2+ from aqueous solutions.The biosorption mechanism of AG and BA were further analyzed to determine which functional groups in AG and BA are active in Pb 2+ biosorption.In this paper,the Pb 2+ biosorption behavior of AG and BA was respectively investigated in batch experiments from the perspectives of the initial pH,contact time,and initial Pb 2+ concentration.The results showed that biosorption of Pb 2+ by AG and BA occurred within 60min at the initial Pb 2+ concentrations(0 150 mg L-1).The actual saturated Pb 2+ biosorption capability of AG was 101.97 mg g-1(dry weight of aerobic granular biomass).When the initial pH was 5,the biosorption capability of AG and BA was highest at the initial Pb 2+ concentrations(0 20mg L-1).During the process of Pb 2+ biosorption,K +,Ca 2+,and Mg 2+ were released.The Ion Chromatography(IC) and Fourier Transform Infrared Spectroscopy(FTIR) further highlighted the main role of ion exchange between Ca 2+ and Pb 2+ and sequestration of Pb 2+ with carboxyl(-COO) of AG and BA.This analogical analysis verifies that BA is responsible for biosorption of Pb 2+ by AG.At the same optimal pH,AG cultivated with different carbon source has different Pb 2+ biosorption capacity.The Pb 2+ biosorption by AG with sodium acetate as the sole carbon source is higher than AG with glucose as carbon source.