Manganese zinc ferrite nanoparticles as efficient catalysts for wet peroxide oxidation of organic aqueous wastes

Recent trends in magnetic spinel ferrites and their composites as heterogeneous Fenton-like catalysts: A review

In recent years, there has been a growing interest in utilizing spinel ferrite and their nanocomposites as Fenton-like catalysts. The use of these materials offers numerous advantages, including ability to efficiently degrade pollutants and potential for long-term and repeated use facilitated by their magnetic properties that make them easily recoverable. The remarkable catalytic properties, stability, and reusability of these materials make them highly attractive for researchers. This paper encompasses a comprehensive review of various aspects related to the Fenton process and the utilization of spinel ferrite and their composites in catalytic applications. Firstly, it provides an overview of the background, principles, mechanisms, and key parameters governing the Fenton reaction, along with the role of physical field assistance in enhancing the process. Secondly, it delves into the advantages and mechanisms of H2O2 activation induced by different spinel ferrite and their composites for the removal of organic pollutants, shedding light on their efficacy in environmental remediation. Thirdly, the paper explores the application of these materials in various Fenton-like processes, including Fenon-like, photo-Fenton-like, sono-Fenton-like, and electro-Fenton-like, for the effective removal of different types of contaminants. Furthermore, it addresses important considerations such as the toxicity, recovery, and reuse of these materials. Finally, the paper presents the challenges associated with H2O2 activation by these materials, along with proposed directions for future improvements.

Emerging Trends in Zinc Ferrite Nanoparticles for Biomedical and Environmental Applications

Over the last few decades, the application of nanoparticles (NPs) gained immense attention towards environmental and biomedical applications. NPs are ultra-small particles having size ranges from 1 to 100 nm. NPs loaded with therapeutic or imaging compounds have proved a versatile approach towards healthcare improvements. Among various inorganic NPs, zinc ferrite (ZnFe2O4) NPs are considered as non-toxic and having an improved drug delivery characteristics . Several studies have reported broader applications of ZnFe2O4 NPs for treating carcinoma and various infectious diseases. Additionally, these NPs are beneficial for reducing organic and inorganic environmental pollutants. This review discusses about various methods to fabricate ZnFe2O4 NPs and their physicochemical properties. Further, their biomedical and environmental applications have also been explored comprehensively.

Synthesis of MFe2O4/CNS (M = Zn, Ni, Mn) Composites Derived from Rice Husk by the Hydrothermal-Microwave Method for Remediation of Paddy Fields

In this research work, MFe2O4/CNS was prepared using the hydrothermal–microwave method. The influence of cations (M) toward functional groups of composites and their performance in pesticide degradation were studied. Rice husk was pyrolyzed hydrothermally (200 °C, 6 h) and by microwave (800 W, 40 min). Each product was mixed with MCl2 (Zn, Ni, Mn), FeCl3, KOH, and water, and calcined (600 °C, 15 min) to obtain a composite. Characterization by XRD confirmed the MFe2O4/CNS structure. The FTIR spectra of the composites showed different band sharpness related to C-O and M-O. A mixture of dried paddy farm soil, composite, BPMC (buthylphenylmethyl carbamate) pesticide solution (0.25%), and H2O2 solution (0.15%) was kept under dark conditions for 48 h. The solution above the soil was filtered and measured with a UV-Vis spectrophotometer at 217 nm. Applications without the composite and composite–H2O2 were also conducted. The results reveal that dark BPMC degradation with the composite was 7.5 times larger than that without the composite, and 2.9 times larger than that without the composite–H2O2. There were no significantly different FTIR spectra of the soil, soil–BPMC, soil–BPMC-H2O2, and soil–BPMC-H2O2 composite and no significantly different X-ray diffractograms between the soil after drying and soil after application for pesticide degradation using the composite.

Unravelling the cooperative role of lattice strain on MnO2/TiO2 and MnO2/ZnO catalysts for the fast decomposition of hydrogen peroxide

The rate of decomposition of hydrogen peroxide was directly correlated with lattice strain, as derived from strain calculations.

Chromium-zinc ferrite nanocomposites for the catalytic abatement of toxic environmental pollutants under ambient conditions

Catalytic abatement of 4-chlorophenol, 2,4-dichlorophenol and 2,4-dichlorophenoxy acetic acid in water was investigated by peroxide oxidation over chromium substituted zinc ferrite nanocomposites at ambient conditions. The structural and chemical properties of composites synthesized by sol-gel auto combustion method was studied by X-ray diffraction, Fourier Transform Infra-Red spectroscopy, Transmission Electron Microscopy, surface area, X-ray Fluorescence spectroscopy, Temperature Programmed Reduction and Desorption techniques. Complete removal of 4-CP, DCP and 2,4-D was achieved within 60, 75 and 90min with 96.7/90.5%, 93.88/77.23% and 88.55/62.1% of COD/TOC removal respectively at 298K and 343K. Influence of reaction variables including reaction temperature, oxidant concentration, substrate concentration, catalyst dosage and its composition on the removal efficiency was studied. Kinetic study revealed that wet peroxide oxidation followed a first order kinetic model with rate constant and activation energy of 3.5×10^-2min^-1/10.7kJ/mole, 9.5×10^-3min^-1/12.9kJ/mole and 2.29×10^-2min^-1/17.7kJ/mole respectively for 4-CP, DCP and 2,4-D. The results of five consecutive catalytic runs from X-ray diffraction, Brunauer Emmet Teller surface area and leaching studies from Atomic Absorption Spectrophotometry (AAS) revealed the excellent stability of the catalyst. Scavenging effect of n-butanol on hydroxyl radical indicated a heterogeneous free radical mechanism.