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Jia L, Lloyd MD, Lees MR, Huang L, Walton RI. Limits of Solid Solution and Evolution of Crystal Morphology in (La 1-xRE x)FeO 3 Perovskites by Low Temperature Hydrothermal Crystallization. Inorg Chem 2023; 62:4503-4513. [PMID: 36877753 PMCID: PMC10031561 DOI: 10.1021/acs.inorgchem.2c04325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
Abstract
The crystallization of a new series of A-site substituted lanthanum ferrite materials (La1-xREx)FeO3 was explored by the hydrothermal method at 240 °C, for rare earth (RE) = Nd, Sm, Gd, Ho, Er, Yb, and Y, with 0 ≤ x ≤ 1. The effect of elemental substitution on the morphological, structural, and magnetic properties of the materials was studied using high-resolution powder X-ray diffraction, energy dispersive spectroscopy (EDS) on the scanning electron microscope, Raman spectroscopy, and SQUID magnetometry. If the radius of the La3+ and the substituent ions is similar, such as for Nd3+, Sm3+, and Gd3+, homogeneous solid solutions are formed, with the orthorhombic GdFeO3-type structure, and a continuous evolution of Raman spectra with composition and distinct magnetic behavior from the end members. When the radius difference between substituents and La3+ is large, such as for Ho3+, Er3+, Yb3+, and Y3+, then instead of forming solid solutions, crystallization in separate phases is found. However, low levels of element mixing are found and intergrowths of segregated regions give composite particles. In this case, the Raman spectra and magnetic behavior are characteristic of mixtures of phases, while EDS shows distinctive elemental segregation. A-site replacement induces an evolution in the crystallite shape with an increasing amount of substituent ions and this is most evident for RE = Y from cube-shaped crystals seen for LaFeO3 to multipodal crystals for (La1-xYx)FeO3, providing evidence for a phase-separation-driven evolution of morphology.
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Affiliation(s)
- Lu Jia
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, P. R. China
| | - Matthew D Lloyd
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K
| | - Martin R Lees
- Department of Physics, University of Warwick, Coventry CV4 7AL, U.K
| | - Limin Huang
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, P. R. China
| | - Richard I Walton
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K
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Recent Advances in the Development of Novel Iron–Copper Bimetallic Photo Fenton Catalysts. Catalysts 2023. [DOI: 10.3390/catal13010159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Advanced oxidation processes (AOPs) have been postulated as viable, innovative, and efficient technologies for the removal of pollutants from water bodies. Among AOPs, photo-Fenton processes have been shown to be effective for the degradation of various types of organic compounds in industrial wastewater. Monometallic iron catalysts are limited in practical applications due to their low catalytic activity, poor stability, and recyclability. On the other hand, the development of catalysts based on copper oxides has become a current research topic due to their advantages such as strong light absorption, high mobility of charge carriers, low environmental toxicity, long-term stability, and low production cost. For these reasons, great efforts have been made to improve the practical applications of heterogeneous catalysts, and the bimetallic iron–copper materials have become a focus of research. In this context, this review focuses on the compilation of the most relevant studies on the recent progress in the application of bimetallic iron–copper materials in heterogeneous photo–Fenton-like reactions for the degradation of pollutants in wastewater. Special attention is paid to the removal efficiencies obtained and the reaction mechanisms involved in the photo–Fenton treatments with the different catalysts.
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Zhang T, Zhou P, Zhang L, Xia C, Xie M, Guo Q, Chen M, Yuan J, Li X, Xu Y. Construction lamellar BaFe 12O 19/Bi 3.64Mo 0.36O 6.55 photocatalyst for enhanced photocatalytic activity via a photo-Fenton-like Mo 6+/Mo 4+redox cycle. CHEMOSPHERE 2022; 307:135909. [PMID: 35940412 DOI: 10.1016/j.chemosphere.2022.135909] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 07/14/2022] [Accepted: 07/30/2022] [Indexed: 06/15/2023]
Abstract
The novel BaFe12O19/Bi3.64Mo0.36O6.55 composite materials were constructed as magnetically recyclable photo-Fenton-like degradation systems. The composite catalyst not only promoted the effective transfer of photo-generated electrons and improved the Mo6+/Mo4+ cycle consequent, but also activated hydrogen peroxide to generate oxidizing free radicals. BaFe12O19/Bi3.64Mo0.36O6.55-0.25 exhibited an outstanding degradation performance for tetracycline hydrochloride it is 1.3 times to Bi3.64Mo0.36O6.55. The thermal catalytic performance of the Bi3.64Mo0.36O6.55 monomer is similar to that of the BaFe12O19/Bi3.64Mo0.36O6.55 material without light. However, the removal rate of BaFe12O19/Bi3.64Mo0.36O6.55 material reaches 84.5% after 60 min with light, far exceeding that of Bi3.64Mo0.36O6.55 material. By way of the contrast experiment with light and without light, it is further demonstrated that interfacial interaction between BaFe12O19 and Bi3.64Mo0.36O6.55 acted a key role in the photocatalytic reaction system. It is also a good advantage that pollutants can be efficiently degraded without adjusting the pH. The characterization of photocurrent and X-ray photoelectron spectroscopy (XPS) also further proved the synergy between the two materials, which is useful to the separation of electrons and holes. The synergy ultimately improves the degradation performance. Besides, BaFe12O19/Bi3.64Mo0.36O6.55 can be easily separated by an external magnetic field after the photocatalytic activity reaction owing to BaFe12O19's magnetic properties. It provides a new research idea for the construction and iron-based heterogeneous Fenton-like system for magnetic degradation of antibiotics.
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Affiliation(s)
- Tingting Zhang
- School of Chemistry and Chemical Engineering, School of Pharmacy, School of Agricultural Equipment Engineering Institute of Agricultural Engineering, Jiangsu University, Zhenjiang, 212013, PR China.
| | - Puyang Zhou
- School of Chemistry and Chemical Engineering, School of Pharmacy, School of Agricultural Equipment Engineering Institute of Agricultural Engineering, Jiangsu University, Zhenjiang, 212013, PR China.
| | - Lingxiao Zhang
- School of Chemistry and Chemical Engineering, School of Pharmacy, School of Agricultural Equipment Engineering Institute of Agricultural Engineering, Jiangsu University, Zhenjiang, 212013, PR China.
| | - Changkun Xia
- School of Chemistry and Chemical Engineering, School of Pharmacy, School of Agricultural Equipment Engineering Institute of Agricultural Engineering, Jiangsu University, Zhenjiang, 212013, PR China.
| | - Meng Xie
- School of Chemistry and Chemical Engineering, School of Pharmacy, School of Agricultural Equipment Engineering Institute of Agricultural Engineering, Jiangsu University, Zhenjiang, 212013, PR China.
| | - Qiting Guo
- School of Chemistry and Chemical Engineering, School of Pharmacy, School of Agricultural Equipment Engineering Institute of Agricultural Engineering, Jiangsu University, Zhenjiang, 212013, PR China.
| | - Min Chen
- School of Chemistry and Chemical Engineering, School of Pharmacy, School of Agricultural Equipment Engineering Institute of Agricultural Engineering, Jiangsu University, Zhenjiang, 212013, PR China.
| | - Junjie Yuan
- School of Chemistry and Chemical Engineering, School of Pharmacy, School of Agricultural Equipment Engineering Institute of Agricultural Engineering, Jiangsu University, Zhenjiang, 212013, PR China.
| | - Xiang Li
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang, 212003, PR China.
| | - Yuanguo Xu
- School of Chemistry and Chemical Engineering, School of Pharmacy, School of Agricultural Equipment Engineering Institute of Agricultural Engineering, Jiangsu University, Zhenjiang, 212013, PR China.
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Soares JDO, Cavalcanti WEC, Torres MAM, Pergher SBC, De Oliveira FJVE, Braga TP. Synthesis, Characterization and Photocatalytic Activity of CoFe 2O 4/Fe 2O 3 Dispersed in Mesoporous KIT-6. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:3566. [PMID: 36296757 PMCID: PMC9611405 DOI: 10.3390/nano12203566] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 10/03/2022] [Accepted: 10/06/2022] [Indexed: 06/16/2023]
Abstract
The present work aimed to synthesize and characterize a solid based on CoFe2O4/Fe2O3-KIT-6 and evaluate its performance in the photocatalytic degradation of the remazol red ultra RGB dye. By analyzing XRD, N2 physisorption, and Mössbauer results, it was possible to identify that the desired CoFe2O4/Fe2O3 phase was achieved, which maintained its structural properties. The FTIR-pyridine indicated the presence of Lewis acid sites, while TPD-CO2 showed a large amount of weak basic sites. The band-gap energy indicated that the compound can be applied in photocatalytic degradation under UV/visible light, with the possibility of magnetic separation at the end of the reaction. The photocatalysis results indicated that there was complete degradation of the remazol red ultra RGB dye within 1 h of reaction. Despite the absence of H2O2, the combination of the proposed photocatalyst with the anatase phase (TiO2) showed significant improvements in the degradation process. The proposed mechanism for complete dye degradation indicated that a sequence of radical reactions is necessary, generating oxidant species such as •OH and the final products were CO2 and H2O.
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Affiliation(s)
- Johnatan de Oliveira Soares
- Instituto de Química Laboratório de Peneiras Moleculares (LABPEMOL), Instituto de Química, Universidade Federal do Rio Grande do Norte, Natal 59078-970, RN, Brazil
| | - Wesley Eulálio Cabral Cavalcanti
- Instituto de Química Laboratório de Peneiras Moleculares (LABPEMOL), Instituto de Química, Universidade Federal do Rio Grande do Norte, Natal 59078-970, RN, Brazil
| | - Marco Antonio Morales Torres
- Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, Natal 59078-970, RN, Brazil
| | - Sibele Berenice Castella Pergher
- Instituto de Química Laboratório de Peneiras Moleculares (LABPEMOL), Instituto de Química, Universidade Federal do Rio Grande do Norte, Natal 59078-970, RN, Brazil
| | - Fernando José Volpi Eusébio De Oliveira
- Instituto de Química Laboratório de Peneiras Moleculares (LABPEMOL), Instituto de Química, Universidade Federal do Rio Grande do Norte, Natal 59078-970, RN, Brazil
| | - Tiago Pinheiro Braga
- Instituto de Química Laboratório de Peneiras Moleculares (LABPEMOL), Instituto de Química, Universidade Federal do Rio Grande do Norte, Natal 59078-970, RN, Brazil
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Alarslan F, Frosinn M, Ruwisch K, Thien J, Jähnichen T, Eckert L, Klein J, Haase M, Enke D, Wollschläger J, Beginn U, Steinhart M. Reactive Additive Capillary Stamping with Double Network Hydrogel-Derived Aerogel Stamps under Solvothermal Conditions. ACS APPLIED MATERIALS & INTERFACES 2022; 14:44992-45004. [PMID: 36130011 DOI: 10.1021/acsami.2c11781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Integration of solvothermal reaction products into complex thin-layer architectures is frequently achieved by combinations of layer transfer and subtractive lithography, whereas direct additive substrate patterning with solvothermal reaction products has remained challenging. We report reactive additive capillary stamping under solvothermal conditions as a parallel contact-lithographic access to patterns of solvothermal reaction products in thin-layer configurations. To this end, corresponding precursor inks are infiltrated into mechanically robust mesoporous aerogel stamps derived from double-network hydrogels. The stamp is then brought into contact with a substrate to be patterned under solvothermal reaction conditions inside an autoclave. The precursor ink forms liquid bridges between the topographic surface pattern of the stamp and the substrate. Evaporation-driven enrichment of the precursors in these liquid bridges, along with their liquid-bridge-guided conversion into the solvothermal reaction products, yields large-area submicron patterns of the solvothermal reaction products replicating the stamp topography. For example, we prepared thin hybrid films, which contained ordered monolayers of superparamagnetic submicron nickel ferrite dots prepared by solvothermal capillary stamping surrounded by nickel electrodeposited in a second orthogonal substrate functionalization step. The submicron nickel ferrite dots acted as a magnetic hardener, halving the remanence of the ferromagnetic nickel layer. In this way, thin-layer electromechanical systems, transformers, and positioning systems may be customized.
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Affiliation(s)
- Fatih Alarslan
- Institut für Chemie neuer Materialien and CellNanOs, Universität Osnabrück, Barbarastr. 7, 49076 Osnabrück, Germany
| | - Martin Frosinn
- Institut für Chemie neuer Materialien and CellNanOs, Universität Osnabrück, Barbarastr. 7, 49076 Osnabrück, Germany
| | - Kevin Ruwisch
- Department of Physics, Universität Osnabrück, Barbarastr. 7, 49076 Osnabrück, Germany
| | - Jannis Thien
- Department of Physics, Universität Osnabrück, Barbarastr. 7, 49076 Osnabrück, Germany
| | - Tim Jähnichen
- Institute of Chemical Technology, Universität Leipzig, Linnéstraße 3, 04103 Leipzig, Germany
| | - Louisa Eckert
- Institute of Chemical Technology, Universität Leipzig, Linnéstraße 3, 04103 Leipzig, Germany
| | - Jonas Klein
- Institut für Chemie neuer Materialien and CellNanOs, Universität Osnabrück, Barbarastr. 7, 49076 Osnabrück, Germany
| | - Markus Haase
- Institut für Chemie neuer Materialien and CellNanOs, Universität Osnabrück, Barbarastr. 7, 49076 Osnabrück, Germany
| | - Dirk Enke
- Institute of Chemical Technology, Universität Leipzig, Linnéstraße 3, 04103 Leipzig, Germany
| | - Joachim Wollschläger
- Department of Physics, Universität Osnabrück, Barbarastr. 7, 49076 Osnabrück, Germany
| | - Uwe Beginn
- Institut für Chemie neuer Materialien and CellNanOs, Universität Osnabrück, Barbarastr. 7, 49076 Osnabrück, Germany
| | - Martin Steinhart
- Institut für Chemie neuer Materialien and CellNanOs, Universität Osnabrück, Barbarastr. 7, 49076 Osnabrück, Germany
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Ochmann M, Vrba V, Kopp J, Ingr T, Malina O, Machala L. Microwave-Enhanced Crystalline Properties of Zinc Ferrite Nanoparticles. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:2987. [PMID: 36080025 PMCID: PMC9457733 DOI: 10.3390/nano12172987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 08/24/2022] [Accepted: 08/25/2022] [Indexed: 06/15/2023]
Abstract
Two series of ZnFe2O4 mixed cubic spinel nanoparticles were prepared by a coprecipitation method, where a solution of Fe3+ and Zn2+ was alkalised by a solution of NaOH. While the first series was prepared by a careful mixing of the two solutions, the microwave radiation was used to enhance the reaction in the other series of samples. The effect of the microwave heating on the properties of the prepared particles is investigated. X-ray powder diffraction (XRD), 57Fe Mössbauer spectroscopy and magnetometry were employed to prove the cubic structure and superparamagnetic behavior of the samples. The particle size in the range of nanometers was investigated by a transmission electron microscopy (TEM), and the N2 adsorption measurements were used to determine the BET area of the samples. The stoichiometry and the chemical purity were proven by energy dispersive spectroscopy (EDS). Additionally, the inversion factor was determined using the low temperature Mössbauer spectra in the external magnetic field. The microwave heating had a significant effect on the mean coherent length. On the other hand, it had a lesser influence on the size and BET surface area of the prepared nanoparticles.
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Affiliation(s)
- Martin Ochmann
- Department of Experimental Physics, Faculty of Science, Palacký University Olomouc, 17. listopadu 1192/12, 779 00 Olomouc, Czech Republic
| | - Vlastimil Vrba
- Department of Experimental Physics, Faculty of Science, Palacký University Olomouc, 17. listopadu 1192/12, 779 00 Olomouc, Czech Republic
| | - Josef Kopp
- Department of Experimental Physics, Faculty of Science, Palacký University Olomouc, 17. listopadu 1192/12, 779 00 Olomouc, Czech Republic
| | - Tomáš Ingr
- Department of Experimental Physics, Faculty of Science, Palacký University Olomouc, 17. listopadu 1192/12, 779 00 Olomouc, Czech Republic
| | - Ondřej Malina
- Regional Centre of Advanced Technologies and Materials, Czech Advanced Technology and Research Institute (CATRIN), Palacký University Olomouc, Šlechtitelů 27, 779 00 Olomouc, Czech Republic
| | - Libor Machala
- Department of Experimental Physics, Faculty of Science, Palacký University Olomouc, 17. listopadu 1192/12, 779 00 Olomouc, Czech Republic
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Lachowicz D, Stroud J, Hankiewicz JH, Gassen R, Kmita A, Stepień J, Celinski Z, Sikora M, Zukrowski J, Gajewska M, Przybylski M. One-Step Preparation of Highly Stable Copper-Zinc Ferrite Nanoparticles in Water Suitable for MRI Thermometry. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2022; 34:4001-4018. [PMID: 35573108 PMCID: PMC9097161 DOI: 10.1021/acs.chemmater.2c00079] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 04/01/2022] [Indexed: 05/03/2023]
Abstract
Superparamagnetic ferrite nanoparticles coated with a polymer layer are widely used for biomedical applications. The objective of this work is to design nanoparticles as a magnetic resonance imaging (MRI) temperature-sensitive contrast agent. Copper-zinc ferrite nanoparticles coated with a poly(ethylene glycol) (PEG) layer are synthesized using a one-step thermal decomposition method in a polymer matrix. The resulting nanoparticles are stable in water and biocompatible. Using Mössbauer spectroscopy and magnetometry, it was determined that the grown nanoparticles exhibit superparamagnetic properties. Embedding these particles into an agarose gel resulted in significant modification of water proton relaxation times T 1, T 2, and T 2* determined by nuclear magnetic resonance measurements. The results of the spin-echo T 2-weighted MR images of an aqueous phantom with embedded Cu0.08Zn0.54Fe2.38O4 nanoparticles in the presence of a strong temperature gradient show a strong correlation between the temperature and the image intensity. The presented results support the hypothesis that CuZn ferrite nanoparticles can be used as a contrast agent for MRI thermometry.
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Affiliation(s)
- Dorota Lachowicz
- Academic
Centre for Materials and Nanotechnology, AGH University of Science
and Technology, 30-059 Krakow, Poland
| | - John Stroud
- Center
for the Biofrontiers Institute, University of Colorado Colorado Springs, 1420 Austin Bluffs Pkway, Colorado Springs, Colorado 80918, United States
| | - Janusz H. Hankiewicz
- Center
for the Biofrontiers Institute, University of Colorado Colorado Springs, 1420 Austin Bluffs Pkway, Colorado Springs, Colorado 80918, United States
| | - River Gassen
- Center
for the Biofrontiers Institute, University of Colorado Colorado Springs, 1420 Austin Bluffs Pkway, Colorado Springs, Colorado 80918, United States
| | - Angelika Kmita
- Academic
Centre for Materials and Nanotechnology, AGH University of Science
and Technology, 30-059 Krakow, Poland
| | - Joanna Stepień
- Academic
Centre for Materials and Nanotechnology, AGH University of Science
and Technology, 30-059 Krakow, Poland
| | - Zbigniew Celinski
- Center
for the Biofrontiers Institute, University of Colorado Colorado Springs, 1420 Austin Bluffs Pkway, Colorado Springs, Colorado 80918, United States
| | - Marcin Sikora
- Academic
Centre for Materials and Nanotechnology, AGH University of Science
and Technology, 30-059 Krakow, Poland
| | - Jan Zukrowski
- Academic
Centre for Materials and Nanotechnology, AGH University of Science
and Technology, 30-059 Krakow, Poland
| | - Marta Gajewska
- Academic
Centre for Materials and Nanotechnology, AGH University of Science
and Technology, 30-059 Krakow, Poland
| | - Marek Przybylski
- Academic
Centre for Materials and Nanotechnology, AGH University of Science
and Technology, 30-059 Krakow, Poland
- Faculty
of Physics and Applied Computer Science, AGH University of Science
and Technology, 30-059 Krakow, Poland
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Hydrothermal Synthesis of Iridium-Substituted NaTaO 3 Perovskites. NANOMATERIALS 2021; 11:nano11061537. [PMID: 34200843 PMCID: PMC8230512 DOI: 10.3390/nano11061537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/19/2021] [Accepted: 06/07/2021] [Indexed: 11/16/2022]
Abstract
Iridium-containing NaTaO3 is produced using a one-step hydrothermal crystallisation from Ta2O5 and IrCl3 in an aqueous solution of 10 M NaOH in 40 vol% H2O2 heated at 240 °C. Although a nominal replacement of 50% of Ta by Ir was attempted, the amount of Ir included in the perovskite oxide was only up to 15 mol%. The materials are formed as crystalline powders comprising cube-shaped crystallites around 100 nm in edge length, as seen by scanning transmission electron microscopy. Energy dispersive X-ray mapping shows an even dispersion of Ir through the crystallites. Profile fitting of powder X-ray diffraction (XRD) shows expanded unit cell volumes (orthorhombic space group Pbnm) compared to the parent NaTaO3, while XANES spectroscopy at the Ir LIII-edge reveals that the highest Ir-content materials contain Ir4+. The inclusion of Ir4+ into the perovskite by replacement of Ta5+ implies the presence of charge-balancing defects and upon heat treatment the iridium is extruded from the perovskite at around 600 °C in air, with the presence of metallic iridium seen by in situ powder XRD. The highest Ir-content material was loaded with Pt and examined for photocatalytic evolution of H2 from aqueous methanol. Compared to the parent NaTaO3, the Ir-substituted material shows a more than ten-fold enhancement of hydrogen yield with a significant proportion ascribed to visible light absorption.
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Loading Effect of Sol-Gel Derived Barium Hexaferrite on Magnetic Polymer Composites. NANOMATERIALS 2021; 11:nano11030558. [PMID: 33668079 PMCID: PMC7995991 DOI: 10.3390/nano11030558] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 02/08/2021] [Accepted: 02/18/2021] [Indexed: 11/29/2022]
Abstract
Solution–processing methods were investigated as viable alternatives to produce the polymer-bonded barium hexaferrite (BaM). BaM powders were first synthesized by using the sol-gel auto-combustion method. While the ignition period in two synthesis batches varied, the morphology of hexagonal microplates and nanorods, as well as magnetic properties, were reproduced. To prepare magnetic polymer composites, these BaM powders were then incorporated into the acrylonitrile-butadiene-styrene (ABS) matrix with a weight ratio of 80:20, 70:30, and 60:40 by using the solution casting method. Magnetizations were linearly decreased with a reduction in ferrite loading. Compared to the BaM loose powders and pressed pellet, both remanent and saturation magnetizations were lower and gave rise to comparable values of the squareness. The squareness around 0.5 of BaM samples and their composites revealed the isotropic alignment. Interestingly, the coercivity was significantly increased from 1727–1776 Oe in loose BaM powders to 1874–2052 Oe for the BaM-ABS composites. These composites have potential to be implemented in the additive manufacturing of rare-earth-free magnets.
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Sonophotocatalytic Degradation of Malachite Green by Nanocrystalline Chitosan-Ascorbic Acid@NiFe2O4 Spinel Ferrite. COATINGS 2020. [DOI: 10.3390/coatings10121200] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Statistics show that more than 700 thousand tons of dye are produced annually across the globe. Around 10–20% of this is used in industrial processes such as printing and dyeing, while about 50% of the dye produced is discharged into the environment without proper physicochemical treatment. Even trace amounts of dye in water can reduce oxygen solubility and have carcinogenic, mutagenic, and toxic effects on aquatic organisms. Therefore, before dye-containing wastewater is discharged into the environment, it must be properly treated. The present study investigates the green synthesis of nickel ferrite NiFe2O4 (NIFE) spinel magnetic nanoparticles (MNPs) via chemical coprecipitation of a solution of Ni2+/Fe3+ in the presence of a biopolymer blend of chitosan (CT) and ascorbic acid (AS). The magnetic nanomaterial was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy–energy dispersive X-ray analysis (SEM-EDX), transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV-Vis), differential scanning calorimetry (DSC), and vibrating-sample magnetometry (VSM). The material was further explored as a catalyst for the photocatalytic degradation of malachite green (MG) under visible light irradiation coupled with ultrasonic waves. The combination of 90 min of visible solar light irradiation with 6.35 W·mL−1 ultrasonic power at pH 8 resulted in 99% of the photocatalytic efficiency of chitosan-ascorbic acid@NIFE (CTAS@NIFE) catalyst for 70 mg·L−1 MG. The quenching of the photocatalytic efficiency from 98% to 64% in the presence of isopropyl alcohol (IPA) suggested the involvement of hydroxy (•OH) radicals in the mineralization process of MG. The high regression coefficients (R2) of 0.99 for 35, 55, and 70 mg·L−1 MG indicated the sonophotocatalysis of MG by CTAS@NIFE was best defined by a pseudo first-order kinetic model. The mechanism involves the adsorption of MG on the catalyst surface in the first step and thereby mineralization of the MG by the generated hydroxyl radicals (•OH) under the influence of visible radiation coupled with 6.34 W·mL−1 ultrasonic power. In the present study the application of photodegradation process with sonochemistry results in 99% of MG mineralization without effecting the material structure unlike happens in the case adsorption process. So, the secondary pollution (generally happens in case of adsorption) can be avoided by reusing the spent material for another application instead of disposing it. Thus, the ecofriendly synthesis protocol, ease in design of experimentation like use of solar irradiation instead of electric power lamps, reusability and high efficiency of the material suggested the study to be potentially economical for industrial development at pilot scale towards wastewater remediation.
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