Macroporous alginate substrate-bound growth of Fe super(0) nanoparticles with high redox activities for nitrate removal from aqueous solutions

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 298; pp. 206 - 213
• Main Authors: Lee, Chung-Seop, Gong, Jianyu, Huong, Chi Vu, Oh, Da-Som, Chang, Yoon-Seok
• Format: Journal Article
• Language: English
• Published: 15.08.2016
• Subjects: Agglomeration; Alginates; Aqueous solutions; Chemical engineering; Covalence; Nanoparticles; Nitrates; Surface area
• ISSN: 1385-8947
• DOI: 10.1016/j.cej.2016.03.113

The agglomeration of zero-valent iron nanoparticles (Fe super(0) NPs) can significantly decrease the effective surface area of nanoparticles and thus reduce their catalytic performance. To avoid such agglomeration, a two-part Fe super(0) NP-immobilization approach was developed: (1) The fabrication of a macroporous alginate substrate (MAS) that provided a large surface area capable of sustaining a high load of stable and well-dispersed Fe super(0) NPs (26.06 wt.%). (2) A facile chemical reductive growth procedure to generate Fe super(0) NPs (ca. 50-100 nm) that are covalently anchored to the surface of the MAS. The macroporous alginate substrate-supported Fe super(0) nanoparticles (Fe super(0) NPs/MAS) removed >96.5% of nitrates from an aqueous solution within 30 min, whereas unsupported Fe super(0) NPs removed only 44.7% of nitrates over a longer period of time. These results demonstrate that MAS acts in a way to prevent the agglomeration of Fe super(0) NPs and, in turn, to promote their redox activity compared to unsupported Fe super(0) NPs. On the basis of our experimental results, a grow mechanism of Fe super(0) NPs on the MAS was proposed, and potential implications for environmental applications of Fe super(0) NPs/MAS were discussed.