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Updated: Sep 28, 2026
Preparation of Biomass-based Mesoporous Carbon with Higher Nitrogen-/Oxygen-chelating Adsorption for Cu(II) Through Microwave Pre-Pyrolysis
Published on: February 12, 2019
Experimental Study and DFT Calculation Analysis of Pb(II) and Cd(II) Adsorption from Water by MgCl2‑Modified
Zemin Zhang1,2, Jinhui Li1,3, Wei Ding1,3
1School of Chemistry and Materials Engineering, Liupanshui Normal University, Liupanshui 553004, China.
Abstract:
MgCl2-modified kiwifruit pomace biochar (MgBC) was synthesized and applied for Pb-(II) and Cd-(II) removal from water. The material exhibited a mesoporous structure (71.88 m2/g) and achieved high adsorption capacities of 604.70 mg/g for Pb-(II) and 304.98 mg/g for Cd-(II), with Langmuir maxima of 763.82 and 532.80 mg/g, respectively. In binary-metal systems, MgBC showed preferential Pb-(II) uptake, and Cd-(II) coexistence unexpectedly enhanced Pb-(II) adsorption. Density functional theory (DFT) and molecular dynamics (MD) simulations revealed three adsorption configurations: direct surface bonding (MgBC-Pb/Cd), hydroxyl-mediated interactions (MgBC-OPb/OCd) and defect-site occupation (MgBCPb/Cd). Adsorption energies followed MgBC-Pb (-2.93 kcal/mol) < MgBC-OPb (-2.57 kcal/mol) < MgBC-Cd (-1.09 kcal/mol) < MgBC-OCd (-0.08 kcal/mol) ≪ MgBCCd (298 kcal/mol) and MgBCPb (408 kcal/mol), which confirms chemisorption by direct and hydroxyl-assisted pathways as the dominant mechanisms with Pb-(II) being thermodynamically more favorable. Projected density of states (PDOS) analyses corroborated the adsorption capacity: MgBC-Pb > MgBC-OPb > MgBC-Cd > MgBC-OCd ≫ MgBCPb and MgBCCd. This work provides atomic-scale mechanistic insights and a sustainable strategy for converting agricultural waste into an effective biochar adsorbent for heavy metal removal.
