Earth-abundant Fe2O3 is a promising material for the negative electrode of supercapacitors by virtue of its wide potential windows. However, the unsatisfactory electrical conductivity and poor ionic diffusion rate within Fe2O3 results in degraded electrochemical performance. In this work, to address these issues, we demonstrate an easy method to synthesize Fe-based zeolitic imidazolate framework (Fe–ZIF) derived α–Fe2O3@C with remarkable supercapacitive properties. The as-obtained α–Fe2O3@C electrode, with the particular benefit of dispersed distribution of carbon, enabling fast electrochemical response, presents a prospective specific capacitance of 161 Fg−1 at a current density of 1 Ag−1. Furthermore, by using the α–Fe2O3@C architecture as the negative electrode, we fabricated a supercapacitor with Na0.5MnO2 as the positive electrode. Our supercapacitor shows a high energy density of 25 Whkg−1, while the corresponding power density is 2400 Wkg−1 at a current density of 2 Ag−1.
The widespread use of methyl tert-butyl ether (MTBE) in gasoline has led to persistent groundwater contamination. Recently, permeable reactive barriers (PRBs) have emerged as a key in situ remediation technology for treating with such contamination. Various reactive media have been employed to intercept and degrade pollutants, but their short half-lives, instability, and poor dispersion in heterogeneous geological conditions limit their effectiveness and further applications. In this study, we designed a double-column PRB system incorporating slow-release oxidants (PLA@CP-CA) and Fe-based zeolite as heterogeneous Fenton catalysts. Calcium peroxide (CaO₂) was selected as the oxidant instead of hydrogen peroxide (H₂O₂) due to its higher stability, ease of transport, and prolonged release, facilitating sustained pollutant degradation. However, the direct use of CaO₂ raises groundwater pH, so citric acid (CA) was employed as a buffer to regulate pH during CaO₂ dissolution, thereby enhancing the efficiency of the heterogeneous Fenton process. Electron paramagnetic resonance (EPR) spectroscopy and radical trapping experiments confirmed that multiple reactive species, including ·OH, O 2 – ·, and ¹O₂, contributed synergistically to MTBE degradation. To mitigate calcium peroxide leakage, polylactic acid (PLA) was used to encapsulate the oxidant (PLA@CP-CA) under anhydrous conditions. The Box–Behnken design (BBD) in response surface methodology (RSM) optimized the PLA@CP-CA formulation, achieving an optimal H₂O₂ release capacity of 3.22 mmol/g with a mass ratio of PLA/CP/CA at 0.67:1.77:1.17. Approximately 97% of MTBE was remediated within 192 hours using the double-column PRB, demonstrating the efficacy of the controlled oxidant release from PLA@CP-CA in promoting MTBE degradation. This heterogeneous Fenton system, combining PLA@CP-CA with Fe-S-1, offers a promising approach for in situ remediation in MTBE-contaminated environments.
危险品化学品经营许可证（带存储）