Enhancing Commercially Iron Powder Electron Transport by Surface Biosulfuration to Achieve Uranium Extraction from Uranium Ore Wastewater

Abstract

The zero-valent iron (ZVI) has attracted increasing attention due to the enhanced reactivity of ZVI to uranium wastewater. However, ZVI practical application is hampered due to its susceptibility to oxidation and the formation of passivation layers during storage and in situ restoration. To address these issues, we used a biosulfuration approach to modify ZVI for application in uranium ore wastewater treatment. A series of physicochemical characterization tools and photoelectronic analyses showed that BS-ZVI considerably increased carrier separation efficiency and visible light absorption capacity, resulting in a significant photoassisted enhancement effect on uranium extraction. Accordingly, the uranium removal efficiency of BS-ZVI reached 91% within 60 min, and its maximum adsorption capacity was 336.3 mg/g. By analyzing the mechanism, the improved U(VI) removal performance was mostly responsible on the dissolution of the passivation layer on the surface of ZVI, the generation of Fe(II) and FeS, and the important role of Shewanella putrefaciens extracellular polymers (EPS). Overall, the BS-ZVI biohybrid merges with the high activity of ZVI, bio-FeS, and self-regeneration ability of bacteria, expanding a promising new approach for sustainable treatment of uranium mine wastewater.

Hollow S-Doped ZnFe2O4 Microcubes with Magnetic Separability for Photocatalytic Removal of Uranium(VI) under Different Light Intensity

“…EIS spectra depicted in Figure b illustrate that S 3 -H-ZFO has the least impedance arc radius, implying a decrease in resistance to transport photogenerated electrons. This further demonstrates that moderate S doping enhances electron transport efficiency. , Excessive S doping leads to a decrease in photocurrent response intensity and an increase in impedance value, consistent with the previously observed morphological collapse in SEM images and weakened photocatalytic performance. Furthermore, Figure S9 shows that the fluorescence intensity of S 3 -H-ZFO is significantly weaker than that of H-ZFO, confirming the lower rate of photogenerated electron–hole complexation in the S 3 -H-ZFO photocatalyst, which is consistent with the observations above.…”

Enhanced Photocatalytic Removal of U(VI) from Real Radioactive Wastewater by Modulating the Surface Charge Microenvironment in Porphyrin-Based Hydrogen-Bonded Organic Framework

“…The separation rate and transport rate of photogenerated electron–hole (e – –h + ) pairs generated by metalloporphyrins were evaluated using electrochemical impedance spectroscopy (EIS) and transient photocurrent response (TPR). The former (Figure d) showed that Ni/DAT-porphyrin has the smallest impedance arc radius when compared with Co/DAT-porphyrin and Cu/DAT-porphyrin, indicating that the e – –h + pairs could be separated more effectively in Ni/DAT-porphyrin . The latter (Figure e) demonstrated that the photocurrent of Ni/DAT-porphyrin is higher than those of the other two metalloporphyrins, revealing the higher charge transfer efficiency in Ni/DAT-porphyrin.…”

Stabilization of Uranium in Acid Ore Wastewater through Hydrothermal Mineralization-Induced Crystallization

“…To the best of our knowledge, there are many methods for treating the U­(VI) wastewater including reduction of U­(VI) into U­(IV) by photocatalytic , and zerovalent iron, − adsorption of U­(VI) by porous materials, − and precipitation of U­(VI) into precipitates. − Among them, the reduced U­(IV) could be possibly reoxidized into U­(VI), while the adsorbed U­(VI) could be desorbed due to the change in the geochemical conditions. They performed the potential migration and leaching risk .…”