Study on the removal of Pb(II) from water by coated sulfur-modified nanoscale zero-valent iron

Abstract

Being prepared by a liquid-phase reduction method, sulfur-modified nanoscale zero-valent iron (S-nZVI) was then coated with sodium alginate (SA) to form gel beads (SAS-nZVI) which are capable of removing Pb(II) from water. SAS-nZVI was characterized by SEM, EDS, FTIR, XRD, and BET, and its removal effect on Pb(II) in water, including the effects of pH, adsorbent dosage, shaking time, and initial concentration of lead, was also studied. The results demonstrated that the maximum removal efficiency of Pb(II) by SAS-nZVI was 97.89%, and the maximum uptake was 246.40 mg/g. In the Pb(II) removal behavior study, the pseudo-second-order kinetic model and the Langmuir isotherm model were found to fit the adsorption process well. SAS-nZVI was easier to recycle from the reaction system, and the removal efficiency of SAS-nZVI to Pb(II) in water was still able to reach 82.75% after five cycles. Therefore, this study suggests that SAS-nZVI has a high removal capacity for Pb(II) and great potential in water pollution treatment. HIGHLIGHTS The prepared SAS-nZVI nanocomposites not only reduce agglomeration, and improve oxidation resistance, but also show good dispersion.; SAS-nZVI is more easily separated from the reaction system, avoiding nZVI draining in practical applications, and causing secondary pollution.; SAS-nZVI has better cycle utilization. After five cycles, the Pb(II) removal rate was still 82.75%.;

Keywords

• adsorption
• gel beads
• lead(ii)
• recycling
• sulfidated nanoscale zero-valent iron