Work

Manganese Dioxide Modified Low-Temperature Pyrolytic Carbon Rich in Oxygen-Containing Functional Groups for Efficient Vanadium Ion Adsorption

Year: 2026

Type: article

Abstract: Vanadium-bearing wastewater threatens aquatic ecosystems and human health, calling for efficient, low-cost adsorbents. In this study, low-temperature pyrolytic carbon rich in oxygen-containing functional groups is prepared from Camellia oleifera fruit shells (COS) and modified with KMnO4 to obtain a carbon–MnO2 composite (BC-KMnO4). The adsorbents are characterized by XRD, FT-IR, XPS, Raman, N2 adsorption–desorption, and SEM, and their vanadium adsorption performance is evaluated through batch experiments, isotherm and kinetic modeling, and DFT–MD simulations. KMnO4 modification introduces δ-MnO2 nanoparticles together with additional oxygen-containing functional groups. Under certain test conditions (m = 1.2 g, T = 70 °C, C0 = 300 mg L−1, V = 100 mL, t = 72 h, pH = 5), BC-KMnO4 exhibits a high adsorption capacity of 24.76 mg g−1, exceeding those of pristine biochar (14.52 mg g−1), COS-KMnO4 (22.65 mg g−1), and pure MnO2 (13.25 mg g−1). The regeneration cycle test of the adsorbent demonstrates that the adsorbent possesses favorable short-term laboratory reusability. DFT–MD simulations further reveal that oxygen-containing functional groups and MnO2 synergistically enhance adsorption, with C-TO/MnO2 displaying the lowest surface electrostatic potential and the highest adsorption energies toward H2VO4− and HV2O5−. The composite retains its structure after adsorption. This work offers an instructive strategy for the high-value production of biomass-derived carbon adsorbents.

Source: Sustainability

DOI: 10.3390/su182010363