Synthesis and Structural Studies of Manganese Ferrite and Zinc Ferrite Nanocomposites and Their Use as Photoadsorbents for Indigo Carmine and Methylene Blue Dyes

Abstract

Solar-moderated adsorptions of indigo carmine and methylene blue dyes were investigated using manganese and zinc ferrite capped with biochar prepared from the root of Chromolaena odorata . TEM micrograph of the as-prepared manganese ferrite nanocomposites (MnFe 2 O 4 @BC) revealed octagonally shaped particles with an average size of 42.64 nm while the zinc ferrite nanocomposite (ZnFe 2 O 4 @BC) micrograph revealed mixtures of rod- and cone-shaped particles with an average size of 43.82 nm. Biochar capping of MnFe 2 O 4 @BC reduced the band gap from 3.63 to 2.08 eV. The nanocomposite surface areas were 197.64 and 92.14 m 2 /g for MnFe 2 O 4 @BC and ZnFe 2 O 4 @BC, respectively. Photoadsorption of the as-prepared nanocomposites showed that 10 mg of ZnFe 2 O 4 @BC effectively removed 69.07 and 98.60% of 70 mg/L indigo carmine and methylene blue dyes while MnFe 2 O 4 @BC removed 77.65 and 94.83% of indigo carmine and methylene blue dyes after 2 h of equilibration under visible light irradiation, respectively. The nonlinear form of the Langmuir isotherm had a better approximation to the experimental solid-phase concentration ( q e ) for the adsorption of indigo carmine dye using both nanocomposites. In contrast, the linear form gave a better goodness-of-fit for the adsorptions of methylene blue dye. The manganese ferrite (MnFe 2 O 4 @BC) and zinc ferrite (ZnFe 2 O 4 @BC) nanocomposites showed no inhibition of Escherichia coli and Staphylococcus aureus , which indicates that they could be used for both biological and environmental applications.

Effects of Heterogeneous Metals on the Generation of Persistent Free Radicals as Critical Redox Sites in Iron-Containing Biochar for Persulfate Activation

“…These results demonstrate the abundant presence of OFGs, which are beneficial to the hydrophilicity and dispersibility of the catalyst. Compared to PBC, extra organometal bonds (e.g., Fe–O bond) at 530 cm –1 were detected in iron-containing biochar, which proved the attachment of the metal particles to the biochar . In addition, the −CH 2 intensity at 1390 cm –1 in IBCs was lower than that in PBC, reflecting the fragmentation of aromatic rings and the reduction of amorphous phases .…”

“…Compared to PBC, extra organometal bonds (e.g., Fe−O bond) at 530 cm −1 were detected in iron-containing biochar, which proved the attachment of the metal particles to the biochar. 44 In addition, the −CH 2 intensity at 1390 cm −1 in IBCs was lower than that in PBC, reflecting the fragmentation of aromatic rings and the reduction of amorphous phases. 37 This conclusion was consistent with the results of Raman spectroscopy.…”

Synergistic Mechanism of Photocatalysis and Photo-Fenton by Manganese Ferrite and Graphene Nanocomposite Supported on Wood Ash with Real Sunlight Irradiation

“…It is possible to observe that when using 1 g/L of photocatalyst the peak of decolorization efficiency is reached at 60 min and is followed by a decline. Such behavior can be attributed to the obstruction of the pores on the surface of the material and also to its saturation [71][72][73]. However, the use of 0.25 g/L or 0.5 g/L of photocatalyst dose did not result in a significant increase in the efficiency of final decolorization of MB, as it was 94% and 95%, respectively.…”

“…Additionally, doubling the photocatalyst dose to 1 g/L, the MB removal efficiency It is possible to observe that when using 1 g/L of photocatalyst the peak of decolorization efficiency is reached at 60 min and is followed by a decline. Such behavior can be attributed to the obstruction of the pores on the surface of the material and also to its saturation [71][72][73].…”

Microtubular Nanoporous g-C3N4@Ag as an Efficient Photocarrier Transfer Agent and Visible Light-Harvesting for Photodegradation of Methylene Blue

“…However, these methods cannot eliminate all of the organic pollutants. 5,6 Therefore, the photodegradation of organic pollutants using photocatalysts under visible light conditions is a promising method for water treatment, due to its high performance for photodegradation of a wide range of non-degradable and toxic organic pollutants with simple and low-cost technology. 5,7,8 Today polymeric semiconductors due to appropriate band gaps and unique abilities for UV−vis light harvesting and effective use of solar energy are used a lot.…”