Adsorptive performance of new Mn-Fe@activated carbon magnetic nanohybrid material synthesized from black cumin (Nigella sativa) industrial processing wastes for lead removal

Abstract

In this study, the adsorptive property of a novel manganese ferrite-activated carbon magnetic nanohybrid (Mn-Fe@BAC) material synthesized by coating with manganese ferrite (MnFe₂O₄) nanoparticles of activated carbon (BAC) produced under optimized carbonization conditions with potassium carbonate activation method from industrially processed black cumin (Nigella sativa) waste was used as an adsorbent in remediation of artificially contaminated water with lead (II) ions (Pb²⁺). Experiments were performed to examine the systematic effects of process parameters such as synthesized material amount, initial Pb²⁺ ion concentration, interaction time, and system temperature on the investigated adsorption system at the pH (5.06) of Pb²⁺ in an aqueous solution. Experimental kinetic and equilibrium isotherm data were analyzed in commonly used models and were well-fitted by pseudo-second-order and Langmuir models, respectively. The kinetic sorption mechanism was found to occur in multiple steps. The maximum Pb²⁺ adsorbing ability of the Mn-Fe@BAC was 294 mg/g at 20 °C. Thermodynamic analysis showed that the process was spontaneous and exothermic. In addition, it showed reuse stability up to four adsorption–desorption cycles for Pb²⁺ ions. In conclusion, this study highlights that it is an ultra-effective adsorbent that can be easily separated magnetically in the remediation of water contaminated with Pb²⁺ ions.