Efficient removal of lead and copper ions in aqueous solution by glutamic acid-functionalized SBA-15

In this work, novel glutamic acid-functionalized SBA-15 was prepared for sensitive and selective lead and copper ions removal from wastewater sample. The material was characterized by X-ray diffractometry, scanning electron microscope, Brunauer–Emmett–Teller surface area measurement and Fourier transform infrared spectroscopy. The as-prepared material maintains the coordination properties of glutamic acid to lead and copper ions and exhibited better adsorption performance than that of pure SBA-15. The effects of different parameters such as pH of the solution, adsorption time, initial concentration, ion selectivity and regeneration were investigated on the Pb(II) and Cu(II) adsorption by the prepared adsorbent. It was found that the adsorption process can reach equilibrium within 20 min and can be described by pseudo-second-order kinetic model. Adsorption isotherm analysis showed that the adsorption was in accordance with Langmuir adsorption isotherm model, and the maximum adsorption capacity of lead and copper ions was 12.14 mg/g and 13.29 mg/g, respectively. In addition, common co-existed ions have no interference on Pb(II) and Cu(II) adsorption. Moreover, adsorption–elution cyclic results demonstrated that Pb(II)- and Cu(II)-adsorbed composite adsorbent could be effectively regenerated by 0.5 mol/L of HCl, and the regenerated adsorbent could be employed for repeated use without significant deterioration in its real performances, demonstrating the good stability of the adsorbents. Therefore, the composite adsorbent can be used potentially to remove Pb(II) and Cu(II) ions from water samples in practical applications for environmental remediation. Graphic abstract Glutamic acid-functionalized SBA-15 can be used as adsorbent for efficient adsorption/desorption of Pb(II) and Cu(II) from wastewater.