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Insights into enhanced removal of Cd2+ from aqueous solutions by attapulgite supported sulfide-modified nanoscale zero-valent iron
- Source :
- Water Science and Technology, Vol 86, Iss 12, Pp 3163-3180 (2022)
- Publication Year :
- 2022
- Publisher :
- IWA Publishing, 2022.
-
Abstract
- The sulfidation of nanoscale zerovalent iron (nZVI) has received increasing attention for reducing the oxidizability of nZVI and improving its reactivity toward heavy metal ions. Here, a sulfide (S)-modified attapulgite (ATP)-supported nanoscale nZVI composite (S-nZVI@ATP) was rapidly synthesized under acidic conditions and used to alleviate Cd2+ toxicity from an aqueous solution. The degree of oxidation of S-nZVI@ATP was less than that of nZVI@ATP, indicating that the sulfide modification significantly reduced the oxidation of nZVI. The optimal loading ratio was at an S-to-Fe molar ratio of 0.75, and the adsorption performance of S-nZVI@ATP for Cd2+ was significantly improved compared with that of nZVI@ATP. The removal of Cd2+ by S-nZVI@ATP was 100% when the adsorbent addition was 1 g/L, the solution was 30 mL, and the adsorption was performed at 25 °C for 24 h with an initial Cd2+ concentration of 100 mg/L. Kinetics studies showed that the adsorption process of Cd followed the pseudo-second-order model, indicating that chemisorption was the dominant adsorption mechanism. The adsorption of Cd2+ by S-nZVI @ATP is dominated by the complexation between the iron oxide or iron hydroxide shell of S-nZVI and Cd2+ and the formation of Cd(OH)2 and CdS precipitates. HIGHLIGHTS S-nZVI was loaded on ATP, effectively preventing nZVI agglomeration, and the sulfide modification significantly reduced the oxidation of nZVI.; Cd2+ removal was mailly attributed to complex with the iron oxides or iron hydroxide shell of S-nZVI.; S-nZVI@ATP showed a stable adsorption effect on Cd2+ over a wide pH range.; The removal of Cd2+ by S-nZVI@ATP follows the quasi-second-order kinetic adsorption model.;
Details
- Language :
- English
- ISSN :
- 02731223 and 19969732
- Volume :
- 86
- Issue :
- 12
- Database :
- Directory of Open Access Journals
- Journal :
- Water Science and Technology
- Publication Type :
- Academic Journal
- Accession number :
- edsdoj.29fd5ba50aa412290662d1143f17fa8
- Document Type :
- article
- Full Text :
- https://doi.org/10.2166/wst.2022.394