科研之友
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摘要
Acid mine drainage （AMD） contaminated areas are prone to the formation of schwertmannite due to its low pH and high sulfate concentration. Considering its large specific surface area and abundant active sites，Schwertmannite enjoys the pivotal position on As reservoir in AMD. Notably，the variations of ferrous oxidation rate typically contribute to different microscopic morphology and physicochemical properties during the formation processes of schwertmannite，affecting the migration and morphological transformation of As. Therefore，our study regulated the oxidation of Fe（II） to establish different schwertmannites （Sch1，Sch2 and Sch3） by modulating dropwise addition of hydrogen peroxide （H2O2）（one-time addition，0.2 h·mL-1 and 1 h·mL-1），on this basis of which the structural properties of synthetic schwertmannites and their adsorption behaviors of As（V）were further explored. Data showed that as H2O2 droplet acceleration rate decreased，the oxidation rate of Fe（II）was found diminished and the micromorphology of schwertmannite changed from smooth to spherical burr whisker surface，followed by increasing particle size of schwertmannite and diverse specific surface area as Sch1<Sch3<Sch2. Additionally，the adsorption capacity of Sch2（139.2 mg·g-1）for As（V）was obviously strengthened compared to that of Sch1（118.9 mg·g-1）and Sch3（130.3 mg·g-1）whereas adsorption kinetics demonstrated the fastest As（V）adsorption rate of Sch3. Then，the analysis of FTIR and［SO42-］［/ As（V）］exchange coefficient suggested that the prominent adsorption rate was associated with the exchange between the ample ≡Fe-OH/OH2 site on the surface of slow-forming schwertmannites and As（V）. These results further indicated that the differences in ferrous oxidation rates engaged in developing schwertmannites with distinct physical and chemical properties，which in turn posted a substantial effect on their adsorption behaviors on As（V）. ? 2023 Science Press.
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