Magnetic chitosan/anaerobic granular sludge composite: Synthesis, characterization and application in heavy metal ions removal

Abstract

In present study, magnetic anaerobic granule sludge/chitosan (M-CS-AnGS) composite was synthesized and applied to remove Pb(II) and Cu(II) from aqueous solution. The physicochemical properties of prepared M-CS-AnGS were characterized by using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), Zeta potential analysis and X-ray photoelectron spectroscopy (XPS). The factors affecting adsorption performance in view of different sorbents, adsorbent dosage, pH value and contact time were conducted to obtain optimum conditions of Pb(II) and Cu(II) onto M-CS-AnGS. The adsorption kinetics of Pb(II) and Cu(II) were better fitted with pseudo-second-order kinetic mode and Langmuir isotherm. The maximum adsorption capacities for Pb(II) and Cu(II) were 97.97 and 83.65mg/g, respectively. According to FTIR, Zeta potential and XPS analysis, it was found that the adsorption mechanisms Pb(II) and Cu(II) onto M-CS-AnGS were mainly caused by surface complexation and electrostatic attraction. In addition, M-CS-AnGS could be easily separated under an external magnetic field. The obtained result suggested that M-CS-AnGS composite could be used as a promising adsorbent for metal removal from aqueous solution.