Decolourisation of triphenylmethane dyes by biogenically synthesised iron nanoparticles from fungal extract

Figures & data

Figure 1. (A) Precursor solution containing 5 mM FeCl₃ and 5 mM FeSO₄ at pH 7, and (B) after mixing with the extract of F. proliferatum. Dark greenish colour indicates the presence of oxidised forms of iron, while the colour change to orange/brown is attributed to the formation of reduced forms of iron.

Figure 2. UV-vis spectra of the extract from F. proliferatum, the precursor salt solution (5 mM FeCl₃ + 5 mM FeSO₄, pH 7), and the Fe-NPs synthesised, sampled at various time intervals.

Figure 3. Scanning Electron Microscopy (SEM) micrographs of (A) Fe-NPs and (B) precursor precipitates at 50x (A1, B1) and 150x (A2, B2) magnification. Scale bar 1 µm/300 nm.

Table 1. Elemental composition of Fe-NPs and precursor precipitates determined by EDX-analysis

Percentage (%)	Fe	C	O	P	S	Pt
Fe-NPs	14.83	41.28	39.45	3.65	0.38	0.41
Precursor precipitates	21.10	6.97	69.32	-	2.03	0.32

- not detected.

Figure 4. Electron-Dispersive X ray (EDX) spectra for (A) Fe-NPs and (B) precursor precipitates.

Figure 5. FTIR-spectra of powderised (A) Fe-NPs and (B) precursor precipitates.

Figure 6. Decolourization Efficiency (DE, %) of Fe-NPs and precursor precipitates towards various TPM-dyes (MG-malachite green, MV-methyl violet, CV-crystal violet and CB-cotton blue). Means with the same letters and caption are not significantly different at HSD_{(0. 05)}. Error bars indicate Standard error of mean (±SEM).

Figure 7. Decolourization Efficiency (DE, %) for TPM-dyes (A) malachite green, (B) methyl violet, (C) crystal violet and (D) cotton blue, over 8 days. Means with the same letters and caption are not significantly different at HSD_(0.05). Error bars indicate Standard error of mean (±SEM).

Figure 8. UV-vis spectra of TPM-dyes (A) malachite green, (B) methyl violet, (C) crystal violet and (D) cotton blue, upon treatment with Fe-NPs.