Rapid degradation of azo-dye using Mn–Al powders produced by ball-milling

Abstract

This study was conducted on the reduction reaction of the azo dye Reactive Black 5 by means of the Mn85Al15 particles prepared by melt-spinning and ball-milling processes. The morphology, the surface elementary composition and the phase structure of the powders were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction. The degradation efficiency of the ball milled powder was measured by using an ultraviolet-visible absorption spectrophotometer and the collected powder was analyzed by means of Fourier transform infrared spectroscopy technique to characterize the functional groups in the extract. The degradation of Reactive Black 5 and the analysis of the aromatic by-products were investigated by high performance liquid chromatography coupled with tandem mass spectrometry. The ball-milled powder shows higher degradation efficiency and the Reactive Black 5 solution was completely decolorized after 30 min. The degradation kinetics and the formation by-products depend on the pH and temperature of the solution. The analyses of the extracted product confirmed the cleavage of the (–N[double bond, length as m-dash]N–) bonds. Our findings are expected to pave the way for a new opportunity with regard to the functional applications of nanostructured metallic particle

Effective Dye Degradation by Graphene Oxide Supported Manganese Oxide

“…The results are illustrated in Figure 7c, from which it is clear that the nanocomposite presented a better performance from its precursor materials as well as from a mixture of the precursor materials at the same weight percentage as in the nanocomposite, which suggests the beneficial properties of the prepared nanocomposite. The above presented results are in agreement with those presented by Zhang et al [62] (with amorphous zero-valent iron) and Ben Mbarek et al [63] (with Mn-Al particles as the decolorizing material for RB5 aqueous solutions). Figure 8 shows the FTIR spectra of GO-MnO2 nanocomposite.…”

“…Upon contact with the GO-MnO2 acidic surface (pH = 3), RB5 exchanged electrons with MnO2. RB5 degradation could be described by equations of redox reactions [63]: RB5 molecules present on the spent nanocomposites' surface caused a shift in the band attributed to the C=C bond of the aromatic ring, indicative of adsorption through pi-pi interactions between the aromatic ring of the nanocomposites and the RB5 [66]. In the spectra of the nanocomposite after the adsorption/degradation of RB5, new bands appeared, indicating that new products were additionally formed as a result of the RB5 degradation.…”

“…Upon contact with the GO-MnO 2 acidic surface (pH = 3), RB5 exchanged electrons with MnO 2 . RB5 degradation could be described by equations of redox reactions [63]:…”

Application of mechanically alloyed MnAl particles to de-colorization of azo dyes

“…Therefore, in acidic conditions the mechanism proposed for the degradation of Orange II is the same as the one proposed in ref. [22] for RB5 degradation:…”

Comparison of the activities of C2N and BCNO towards Congo red degradation

“…In few words, the cleavage of the azo bond suddenly shifted the benzene and naphtalene absorption to wavelengths below 300 nm. The degradation mechanism for BCNO ought to be very similar to that of reagents such as metals which provide electrons to form aromatic amines [35]. Figure 13 shows the UV-Vis absorption spectra in the 200 to 800 nm range as a function of time for the 20 ppm CR solutions treated with the adsorbents/catalysts.…”