Abstract
Nanoporous structures were fabricated from Fe76Si9B10P5 amorphous alloy annealed at 773 K by dealloying in 0.05 M H2SO4 solution, as a result of preferential dissolution of α-Fe grains in form of the micro-coupling cells between α-Fe and cathodic residual phases. Nanoporous Fe-Si-B-P powders exhibit much better degradation performance to methyl orange and direct blue azo dyes compared with gas-atomized Fe76Si9B10P5 amorphous powders and commercial Fe powders. The degradation reaction rate constants of nanoporous powders are almost one order higher than those of the amorphous counterpart powders and Fe powders, accompanying with lower activation energies of 19.5 and 26.8 kJ mol−1 for the degradation reactions of methyl orange and direct blue azo dyes, respectively. The large surface area of the nanoporous structure, and the existence of metalloids as well as residual amorphous phase with high catalytic activity are responsible for the enhanced azo-dyes degradation performance of the nanoporous Fe-Si-B-P powders.
Highlights
Azo dyes have been widely used in the printing and dyeing industry
A series of research works have been conducted to improve the reactivity of these zero-valent iron materials, such as by improving the specific surface area of iron powders (nanoscale Zero-valent iron (ZVI) (NZVI) [10,11]), doping with additional metals
In our previous research [23,24], α-Fe grains in nanocrystalline Fe83.3 Si3 B10 P3 Cu0.7 and Fe85.2 B10–14 P0–4 Cu0.8 alloys are preferentially dissolved in the form of micro-coupling cells between anodic α-Fe grains and cathodic residual amorphous phases
Summary
Azo dyes have been widely used in the printing and dyeing industry. Under the special conditions, azo dyes can be disintegrated into more than 20 kinds of aromatic amines which are harmful to the environment. Zero-valent iron (ZVI), such as iron powders and iron-based amorphous alloys, which are inexpensive, resourceful and non-toxic, has been successfully utilized in wastewater treatment industry [1,2]. ZVI has been reported to be efficient in the reductive decomposition of chlorinated organic compound [3,4], heavy metals [5] and azo dye [6]. Rapid decay of the degradation efficiency of the iron powders occurs due to the ready rusting, which restricts the extensive utilization in degrading azo dyes. The degradation efficiency of iron based amorphous alloys in decomposing azo dyes is much higher than that of the crystalline ZVI due to its amorphous structure and the addition of metalloids [7,8,9]. A series of research works have been conducted to improve the reactivity of these zero-valent iron materials, such as by improving the specific surface area of iron powders (nanoscale ZVI (NZVI) [10,11]), doping with additional metals (such as Pd [4,12], Ni [13], and Cu [14])
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
