Enhanced Chromate Sorption Using Zinc‐Manganese Oxide Mesoporous Structures Decorated Carbon Nanocomposite Prepared from Battery Wastes

Abstract

Mesoporous zinc-manganese oxide decorated carbon nanocomposites, as promising low-cost candidates for chromate(VI) sorption, were developed via a one-pot facile route based on battery wastes. The improved-based carbon composite with (ZnMn2O4+MnO(OH)/Mn2O3·H2O/C (I-C)) was produced by in-situ hydrothermal growth. Furthermore, the treated composite of carbon with adding ZnSO4 solution (ZnMn2O4/C (T-C)). Nanocomposites were characterized comprehensively using FTIR, XRD, HR-TEM, XPS, EDX, and BET analyses. The T-C nanocomposite showed a significant enhancement of chromate sorption by 1.5 fold in comparison with I-C in terms of maximum capacity and equilibrium time. Langmuir and pseudo-second-order fit the experimental data well. The sorption process is spontaneous, endothermic, and governed by entropic. The interaction mode was elucidated via FTIR, XRD, and XPS data, unveiling a synergistic ion-pair sorption and redox mechanism. Elution and sorbent regeneration were successfully achieved using HCl (0.2 M) with high durability over seven cycles. Finally, both nanocomposites, especially T-C, demonstrated exceptional efficiency and selectivity in removing high levels of Cr(VI) from wastewater from tannery industries.