High efficiency removal of Pb(II) in aqueous solution by a biochar-supported nanoscale ferrous sulfide composite

A biochar-supported nanoscale ferrous sulfide composite was prepared and applied for the treatment of Pb(II) ions in aqueous solution. The experimental results of SEM, EDS, XRD, and FT-IR spectroscopy clearly implied that the biochar was successfully modified with nanoscale ferrous sulfide composite. The maximum adsorption capacity of Pb(II) ions by FeS@biochar reached 88.06 mg g(-1). Compared with other reported adsorbents, the removal rate of Pb(II) ions by FeS@biochar was higher. The pseudo-second-order kinetic model and Langmuir isotherm model could better fit the experimental adsorption results. The removal rate of Pb(II) ions by FeS@biochar was controlled by the chemical reaction and monolayer adsorption on the surface of FeS@biochar. The mechanisms of Pb(II) removal from aqueous solutions by biochar involved electrostatic attraction, hydrogen bonding, physical adsorption, ion exchange, and chemical precipitation. Additionally, the chemical stability and reusability of FeS@biochar were good. It is also an environment-friendly material for low-cost wastewater treatment.

Automated summary

FeS@biochar was successfully prepared and demonstrated effective removal of Pb(II) ions from aqueous solutions, with a higher removal rate compared to other adsorbents. Kinetic and isotherm models showed good fit with experimental results, with the removal controlled by chemical reactions and monolayer adsorption on the surface. The mechanisms of Pb(II) removal included electrostatic attraction, hydrogen bonding, physical adsorption, ion exchange, and chemical precipitation, showcasing FeS@biochar's potential for environmentally friendly wastewater treatment.