Synthesis of biochar-iron oxide magnetic nanocomposite for efficient and rapid removal of Pb(II) heavy metal from water

In this study, magnetic biochar-iron oxide (MBC-IO) nanocomposite was easily synthesized as a strong adsorbent to remove toxic Pb(II) heavy metals from aqueous solutions. The physical and chemical properties of the prepared adsorbent were analyzed using SEM, FTIR, XRD, BET, and zeta-potential analyses. An experimental design, using the response surface methodology (RSM), was implemented to study the effect of operational parameters on the Pb(II) adsorption performance. The maximum adsorption capacity of MBC-IO nanocomposite was found to be 504 mg/g, at an adsorbent dosage of 0.08 g/L, pH 7, contact time of 10 min, and initial lead concentration of 50 mg/L. The kinetics and isotherm studies illustrated that the adsorption data were well described by pseudo-second-order and Langmuir models, respectively. In addition to rapid Pb2+ removal, the synthesized adsorbent was also employed to compare the adsorption capability of Cd2+, Co2+, and Ni2+ cations that had significant efficiency in the removal of heavy metals. The reusability investigation depicted that MBC-IO nanocomposite exhibits magnetic properties, enabling its facile separation from aqueous solutions with the assistance of an external magnetic field. These capabilities make the synthesized nanocomposite a good candidate for water purification industries.