The adsorption mechanism of Hg(II) on oxygen-containing MXene was systematically investigated through comprehensive characterization and kinetic modeling. The material’s high surface reactivity stems from the deliberate incorporation of oxygen functional groups during mild etching and ultrasonic delamination, resulting in a rich array of Ti–O, O–H, and C–O sites. These functional groups serve as active centers for both electrostatic attraction and chemical bonding with Hg(II) species. XPS analysis revealed significant shifts in binding energy following adsorption: the Ti 2p peaks shifted slightly toward lower values, while the O 1s component corresponding to O–H and CeOeC bonds exhibited a 0.6 eV and 0.3 eV downward shift, respectively. Concurrently, the C 1s peak associated with carboxyl groups (COO⁻) showed a 0.FAHD2A Antibody web 1 eV upward shift, indicating electron donation from the functional groups to mercury ions—consistent with chemisorption.
FTIR spectroscopy further confirmed these interactions. A prominent peak at 3445 cm⁻¹, attributed to O–H stretching vibrations, intensified after adsorption, suggesting increased hydrogen bonding or coordination with Hg(II). The CeO bond vibration at 1024 cm⁻¹ also shifted, reflecting changes in bond strength due to interaction with mercury. Notably, no new peaks appeared in the FTIR spectrum after Hg(NO₃)₂ adsorption, implying that the process occurred primarily via surface complexation rather than precipitation. In contrast, XRD patterns after HgCl₂ adsorption revealed distinct crystalline peaks at 2θ = 21.4°, 28.1°, 32.8°, and 46.2°, corresponding to crystalline HgCl₂, confirming the formation of solid-phase products during adsorption in chloride-rich media.
Zeta potential measurements demonstrated that the MXene surface becomes increasingly negative above pH 2.03, promoting electrostatic attraction of cationic Hg²⁺ and HgOH⁺ species. This explains the observed increase in adsorption capacity with rising pH up to 4–5, beyond which hydroxide precipitation may reduce availability. However, even at pH 2.0, the adsorbent retained over 90% of its maximum capacity, underscoring the resilience of surface functional groups under extreme acidity—a critical advantage for treating industrial effluents.
Kinetic data fitting using the Elovich model yielded a high initial sorption rate (a ≈ 10.5 mg/g·min), supporting rapid surface reaction. Combined with Boyd model results, the data suggest that adsorption is not limited by internal diffusion but is governed by external mass transfer and interfacial reactions. The absence of a linear fit in the intra-particle diffusion model further confirms that multiple mechanisms operate simultaneously.CCNE1 Antibody References
These findings collectively indicate that Hg(II) removal proceeds through a dual mechanism: (1) electrostatic attraction of Hg²⁺/HgOH⁺ to negatively charged oxygen sites, and (2) covalent-like coordination involving Ti–O and O–H groups, particularly effective in forming stable complexes with Hg(OH)₂.PMID:34137279 The presence of Cl⁻ promotes precipitation of HgCl₂ crystals, enhancing physical retention. Thus, the MXene’s performance is not only due to high surface area but also to the synergistic effect of tailored surface chemistry and dynamic speciation response. This mechanistic understanding paves the way for rational design of next-generation MXene-based adsorbents for heavy metal remediation.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com
