Fe₃O₄ Nanoparticles Synthesized from Waste Iron Dust for Sunlight-Boosted Photodegradation of Nitrophenols and Their Mixtures

Abstract

Here, we describe a simpler-sustainable approach for fabricating photo-active magnetite nanoparticles (Fe 3 O 4 -NPs) using an almost inert waste material known as red-colored iron oxide dust (IOD). The synthesized heterogeneous catalyst Fe 3 O 4 -NPs showed photoactivity in the presence of sunlight and was used for photodegradation of a higher concentration (∼1000 mg L −1 ) of noxious nitrophenols and their mixtures in an aqueous medium. Kinetic studies, including control tests, have been performed to compare the photocatalytic performance of Fe 3 O 4 -NPs vs IOD in sunlight and artificial bulb light. The half-life and percentage of photodegradation strongly suggest that sunlight influences the faster rate of photodegradation of nitrophenols and their mixtures. Radical trapping experiments were performed to identify the reactive active species responsible for the photodegradation, and the results support the significant involvement of hydroxyl radicals along with holes. Further, the real-life assessment of Fe 3 O 4 -NPs as a photocatalyst was explored by checking its photodegradation capability in industrial wastewater and soil samples via the external spiking of nitrophenols. Moreover, the results are compared with two commercially available samples of Fe 3 O 4 , which showed almost comparable results, and in the case of trinitrophenol (TNP) and the mixture, synthesized Fe 3 O 4 -NPs showed slightly better results. The quantitative studies of green chemistry metrics and DOZN software-based calculations supported the greener and more sustainable process of the present method for the synthesis of Fe 3 O 4 -NPs.

Melamine–Formaldehyde Polymer-Based Nanocomposite for Sunlight-Driven Photodegradation of Multiple Dyes and Their Mixture

“…To further ensure the dye degradation related to breaking of the complex structure of organic dyes, comparative 1 H NMR spectra of the control dyes and their mixture compared to their corresponding photodegraded products are shown in Figures a–f and S5 and S6. The 1 H NMR spectra indicate that most of the proton signals of these six organic dyes (MB, JG, IC, CV, EBT, and RhB) lie in the aromatic region and few signals in the aliphatic region. , However, after the photodegradation, the 1 H NMR spectra of their corresponding photodegraded product do not show any proton signals in the aromatic region like the signals they showed in their control samples, although the emergence of few new low-intensity peaks in the aliphatic region, which is due to the fragmentation of the aromatic hydrocarbon into aliphatic hydrocarbons, Figures and S6. The 1 H NMR spectra of the mixture of dyes were also recorded.…”

“…The photodegradation of all the six dyes follows the pseudo-first-order kinetics, confirmed by linearly fitted data with a good regression coefficient value. The following pseudo-first-order reaction equation has been used to calculate the photodegradation rate. ln ( C 0 C t ) = k t where C 0 (initial) and C t (at time t ) represent the concentrations and k is the rate constant of pseudo-first-order kinetics. The plot of ln ( C 0 / C ) vs time shows that the degradation of dyes follows pseudo-first-order kinetics, supported by fitting the experimental data in the Langmuir–Hinshelwood model (with R 2 > 0.95). , The slope of the linearly fitted curve is the rate constant of photodegradation of an individual dye for pseudo first order reaction.…”

3D Porous MoS2-Decorated Reduced Graphene Oxide Aerogel as a Heterogeneous Catalyst for Reductive Transformation Reactions

“…Additionally, reduction pathways explored in the present report were found to be sustainable and greener, as supported by the “DOZN” score , (Supporting Information, Section 2) and Green matrix calculation (Supporting Information, Section 3). , …”

Structural and optical properties of silver supported α-Fe2O3nanocomposite fabricated bySaraca asocaleaf extract for the effective photo-degradation of cationic dye Azure B

“…Several effective approaches were investigated for this purpose. [27][28][29][30] The technique used to prevent the short lifetime of photogenerated (e − -h + ) pairs and decrease its band gap energy is to incorporate various types of metal into the surface of iron oxide nanoparticles. These techniques can signicantly boost the separation rate of photogenerated charge carriers in semiconductor materials, which will raise the efficiency of the photocatalytic process.…”