Synthesis, characterization, and evaluation of antibacterial activity of transition metal oxyde nanoparticles

Nanoparticles (NPs) have a wide range of applications in various areas. For health application, cytotoxicity tests are used to ensure its efficiency and safety. In this paper, ZnFe₂O₄, CoFe₂O₄, Zn_0.5Co_0.5Fe₂O₄ NPs were synthesized, characterized and their antibacterial properties were evaluated. The Sol-Gel method was used to synthesize the NPs. Their electronic and crystallographic structures were characterized by Fourier Transform Infrared Spectroscopy Analysis (FTIR), X-ray fluorescence (XRF), X-Ray Diffraction (XRD), and Transmission Electron Microscopy (TEM). To perform the antibacterial evaluation, ferrites were dispersed through nanoemulsion to prevent the crystals from accumulating together. Then the evaluation was performed through microdilution in a 96-well plate and diffusion in agar disc in contact with 3 different strains of Staphylococcus aureus and Escherichia coli. It demonstrated that the Sol-Gel method was efficient to synthesize NPs with suitable sizes for health application. All synthesized NPs showed the inhibition of bacterias with different concentrations used.

Do Iron Oxide Nanoparticles Have Significant Antibacterial Properties?

The use of metal oxide nanoparticles is one of the promising ways for overcoming antibiotic resistance in bacteria. Iron oxide nanoparticles (IONPs) have found wide applications in different fields of biomedicine. Several studies have suggested using the antimicrobial potential of IONPs. Iron is one of the key microelements and plays an important role in the function of living systems of different hierarchies. Iron abundance and its physiological functions bring into question the ability of iron compounds at the same concentrations, on the one hand, to inhibit the microbial growth and, on the other hand, to positively affect mammalian cells. At present, multiple studies have been published that show the antimicrobial effect of IONPs against Gram-negative and Gram-positive bacteria and fungi. Several studies have established that IONPs have a low toxicity to eukaryotic cells. It gives hope that IONPs can be considered potential antimicrobial agents of the new generation that combine antimicrobial action and high biocompatibility with the human body. This review is intended to inform readers about the available data on the antimicrobial properties of IONPs, a range of susceptible bacteria, mechanisms of the antibacterial action, dependence of the antibacterial action of IONPs on the method for synthesis, and the biocompatibility of IONPs with eukaryotic cells and tissues.

Do Iron Oxide Nanoparticles Have Significant Antibacterial Properties?

The use of metal oxide nanoparticles is one of the promising ways for overcoming antibiotic resistance in bacteria. Iron oxide nanoparticles (IONPs) have found wide applications in different fields of biomedicine. Several studies have suggested using the antimicrobial potential of IONPs. Iron is one of the key microelements and plays an important role in the function of living systems of different hierarchies. Iron abundance and its physiological functions bring into question the ability of iron compounds at the same concentrations, on the one hand, to inhibit the microbial growth and, on the other hand, to positively affect mammalian cells. At present, multiple studies have been published that show the antimicrobial effect of IONPs against Gram-negative and Gram-positive bacteria and fungi. Several studies have established that IONPs have a low toxicity to eukaryotic cells. It gives hope that IONPs can be considered potential antimicrobial agents of the new generation that combine antimicrobial action and high biocompatibility with the human body. This review is intended to inform readers about the available data on the antimicrobial properties of IONPs, a range of susceptible bacteria, mechanisms of the antibacterial action, dependence of the antibacterial action of IONPs on the method for synthesis, and the biocompatibility of IONPs with eukaryotic cells and tissues.

Bactericidal and Virucidal Activities of Biogenic Metal-Based Nanoparticles: Advances and Perspectives

Much progress has been achieved in the preparation and application of engineered nanoparticles (NPs) in the field of medicine, mainly for antibacterial and antiviral applications. In the war against bacteria and viruses, besides traditional antibiotics and antiviral drugs, metal-based nanoparticles, such as silver (AgNPs), copper (CuNPs), copper oxides (CuO-NPs), iron oxide (FeO-NPs), zinc oxide (ZnO-NPs), and titanium oxide (TiO2-NPs) have been used as potent antimicrobial agents. These nanoparticles can be synthesized by traditional methods, such as chemical and physical routes, or more recently by biogenic processes. A great variety of macro and microorganisms can be successfully used as reducing agents of metal salt precursors in the biogenic synthesis of metal-based NPs for antimicrobial activity. Depending on the nature of the biological agent, NPs with different sizes, aggregation states, morphology, surface coatings and charges can be obtained, leading to different antimicrobial effects. Considering the drug resistance to traditional therapies, the development of versatile nanomaterials with potent antimicrobial effects is under intensive investigation. In this sense, this review presents and discusses the recent progress in the preparation and application of metal-based nanoparticles biogenically synthesized for antibacterial and antivirus applications. The strength and limitations are critically discussed.

Scraps to superior anodes for Li-ion batteries: Sustainable and scalable upgrading of waste rust

The abundant iron rust of no value generated from industrial scraps presents environmental problem and burden. Chemical etching and related methods deployed to convert rust into α-Fe₂O₃ nanoparticles, however, have serious shortcomings namely higher chemical consumption and generation of secondary pollution. In an unprecedented illustration, herein the intercalation of ammonium bicarbonate (ABC) as a gaseous bubble template into bulky iron rust is described; formation of ammonium iron carbonate hydroxide hydrate and the reduction of particle size using a simple ball milling method followed by calcination is accomplished. The salient features of ABC, optimization of ratios (rust: ABC), and the ideal calcination temperature were optimized for attaining desirable properties of meso-α-Fe₂O₃ NPs. The electrode obtained at 500 °C delivered a superior reversible capacity of 1,055 mAh g^-1 at 1 A g^-1 over 100 cycles, which is comparable to the best performance reported for meso-α-Fe₂O₃ NPs. The superior electrochemical performance is ascribed to the porous nature of meso-α-Fe₂O₃ NPs maximizing the surface area, ensuring good charge transfer kinetics and enhanced pseudocapacitive contribution. Thus, we believe that the high-energy ball milling (HEBM) process represents a novel route for the scalable recycling of iron rust scraps for promoting the sustainable production of lithium-ion batteries.

Influence of nanoscale micro-nutrient α-Fe2O3 on seed germination, seedling growth, translocation, physiological effects and yield of rice (Oryza sativa) and maize (Zea mays)

In the present study, nanoscale micronutrient iron (α-Fe₂O₃) has been prepared via co-precipitation using marine macro alga Turbinaria ornata. The nanoscale micronutrient iron has been used as priming agent for enhancing seed germination, seed quality, uptake, translocation, physiological effects and yield level of rice and maize crops. The physico-chemical characterization techniques results showed the successful preparation of nanoscale micronutrient iron. Seeds primed with nanoscale micronutrient iron at 25 mg/L significantly enhanced the seed germination and seedling parameters in comparison with conventional hydro-priming. ROS production in germinating nano-primed seeds of rice and maize enhanced the seed germination better than the conventional hydro-priming. Uptake and distribution of nanoscale micronutrient iron in rice and maize seedlings were studied using HR-SEM & ICP-MS analysis. Foliar application of low concentration (10 mg/L) nanoscale micronutrient iron under field conditions significantly increased the chlorophyll content, yield attributes of rice and maize crops.

One-pot green synthesis of iron oxide nanoparticles from Bauhinia tomentosa: Characterization and application towards synthesis of 1, 3 diolein

The green synthesis of NPs through plant extracts can be a modest, one-pot alternative synthesis to the conventional physical or chemical method. The prime focus of this study is to produce MNPs by the reducing effect of Bauhinia tomentosa leaf extract, and it was immobilized in porcine pancreatic lipase (PPL). Synthesized NPs were characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and Raman spectroscopy, UV-Vis Spectrometry, Thermogravimetry, and Differential Scanning Calorimeter (DSC), Zeta potential test, VSM, BET and Fourier Transform Infrared Spectroscopy (FTIR). The effect of process parameters was studied, about the efficiency of immobilization are enzyme stability, the extent of enzyme reusability, its separation from products, the activity of immobilized enzyme, recovery, and its loss. Finally, the immobilized lipase was used for the synthesis of 1,3-diolein using enzyme-mediated esterification of oleic acid and glycerol. Under optimized condition (reaction temp-55 [Formula: see text]C; molar ratio-2.5:1; pH-7) diolein yield was achieved to be 94%. Therefore, this work was further used for the industrial production of 1,3-diacylglycerol since a perfect enzyme-catalyzed process was observed.

Evaluation of Fe-Mg Binary Oxide for As (III) Adsorption-Synthesis, Characterization and Kinetic Modelling

Nanotechnology has received much attention in treating contaminated waters. In the present study, a facile co-precipitation method was employed to synthesize a novel iron and magnesium based binary metal oxide using a stoichiometrically fixed amount of FeNO₃·9H₂O and MgNO₃·6H₂O in a proportion of molar concentration 1:1 and was later evaluated in removing As (III) from contaminated waters. Characterization of the prepared nanomaterial was done using X-ray diffraction (XRD), scanning electron microscopy (SEM), Energy Dispersive X-ray Analysis (EDAX) and ultraviolet–visible spectrophotometry (UV-VIS). Experimental studies on batch scale were carried out, examining the effect of varying initial concentrations of metal, adsorbent dosage, application time and initial pH on removal efficiency. Arsenic removal increased on increasing adsorbent dosage (0.1–1 g/L) but trend reversed on increasing initial arsenic concentration attaining q_max of 263.20 mg/g. Adsorption was quite efficient in pH range 4–8. Freundlich fitted better for adsorption isotherm along with following Pseudo-2nd order kinetics. The reusability and effect of co-existing ions on arsenic adsorption, namely SO₄²⁻, CO₃²⁻ and PO₄³⁻ were also explored with reusability in 1st and 2nd cycles attained adsorptive removal up to 77% and 64% respectively. The prepared nano-adsorbent showed promising results in terms of high arsenic uptake (q_max of 263.20 mg/g) along with facile and cost-effective synthesis. Thus, the co-precipitation technique used in this work is a simple one step procedure without any use of any precursor as compared to most of the other procedures used for synthesis.

Antibacterial Activity of Positively and Negatively Charged Hematite (α-Fe2O3) Nanoparticles to Escherichia coli, Staphylococcus aureus and Vibrio fischeri

In the current study, the antibacterial activity of positively and negatively charged spherical hematite (α-Fe2O3) nanoparticles (NPs) with primary size of 45 and 70 nm was evaluated against clinically relevant bacteria Escherichia coli (gram-negative) and Staphylococcus aureus (gram-positive) as well as against naturally bioluminescent bacteria Vibrio fischeri (an ecotoxicological model organism). α-Fe2O3 NPs were synthesized using a simple green hydrothermal method and the surface charge was altered via citrate coating. To minimize the interference of testing environment with NP's physic-chemical properties, E. coli and S. aureus were exposed to NPs in deionized water for 30 min and 24 h, covering concentrations from 1 to 1000 mg/L. The growth inhibition was evaluated following the postexposure colony-forming ability of bacteria on toxicant-free agar plates. The positively charged α-Fe2O3 at concentrations from 100 mg/L upwards showed inhibitory activity towards E. coli already after 30 min of contact. Extending the exposure to 24 h caused total inhibition of growth at 100 mg/L. Bactericidal activity of positively charged hematite NPs against S. aureus was not observed up to 1000 mg/L. Differently from positively charged hematite NPs, negatively charged citrate-coated α-Fe2O3 NPs did not exhibit any antibacterial activity against E. coli and S. aureus even at 1000 mg/L. Confocal laser scanning microscopy and flow cytometer analysis showed that bacteria were more tightly associated with positively charged α-Fe2O3 NPs than with negatively charged citrate-coated α-Fe2O3 NPs. Moreover, the observed associations were more evident in the case of E. coli than S. aureus, being coherent with the toxicity results. Vibrio fischeri bioluminescence inhibition assays (exposure medium 2% NaCl) and colony forming ability on agar plates showed no (eco)toxicity of α-Fe2O3 (EC50 and MBC > 1000 mg/L).

Synthesis of new chitosan Schiff base and its Fe2O3 nanocomposite: Evaluation of methyl orange removal and antibacterial activity

New chitosan Schiff base (3EtO-4OH/Chit) and its 3EtO-4OH/Chit/Fe₂O₃ nanocomposite were synthesized and characterized by FTIR, ¹H NMR, XRD, TGA, DSC and SEM. The result confirmed the preparation of 3EtO-4OH/Chit and its 3EtO-4OH/Chit/Fe₂O₃ nanocomposite. The efficiency of the prepared catalysts was studied for the methyl orange (MO) removal from aqueous solution. The effect of adsorbent dose and contact time on the removal of dye has been studied. Their antibacterial activities were considered against two Gram positive (S. aureus and B. cereus) and two Gram negative (E. coli and P. aeruginosa) bacteria and the results showed that the activity of the 3EtO-4OH/Chit/Fe₂O₃ is excellent and is more than chitosan and 3EtO-4OH/Chit. Thermogravimetry studies shows that the weight loss stages and the residual value at 600 °C are different for the two compounds. DSC curve of the title compounds 3EtO-4OH/Chit and 3EtO-4OH/Chit/Fe₂O₃ is different from each other. The reason for this difference could be due to the presence of iron oxide nanoparticles in 3EtO-4OH/Chit/Fe₂O₃.

The Comparison between Magnetite Nanoparticles Co-Precipitated by Different Bases and Their Effects on Human Cells

The superparamagnetic magnetite nanoparticles were synthesized through co-precipitation method by using a strong base such as sodium hydroxide or a weak base such as ammonium hydroxide. The magnetite co-precipitated by ammonium hydroxide (MA) has different properties than the magnetite co-precipitated by sodium hydroxide (MS). The cytotoxicity effects of MA and MS on the breast cancer cells and normal hepatocytes cells were studied. The magnetite nanoparticles with two ways were characterized by using Vibrating Sample Magnetometer. X-ray fluorescence, Dynamic Light Scattering, Zeta Potential, pH changes, Wide-angle X-ray Diffraction, Fourier Transforms Infrared spectroscopy, MTT assay test and High-Resolution Transmission electron microscopy. The results showed that the final pH of MA and MS were 5 and 7.5, respectively. MA nanoparticles have salts which act as weak oxidizing agent and they were exposed to oxidation at high temperature and lost their magnetic property. They have a cytotoxic effect against breast cancer cells and normal hepatocytes cells more than the MS.

A review of green methods for phyto-fabrication of hematite (α-Fe2O3) nanoparticles and their characterization, properties, and applications

The aim of the current work is the introduction of a quick and simple literature survey about the bio-fabrication of the Alpha Hematite nanoparticles (α-Fe₂O₃) using the plant extracts green method. The survey manifested the utilities of the environmentally friendly biosynthesis methods via extracting different plant species, some of its important physicochemical properties, various instrumental analysis characterization tools, and potential applications.

New Perspectives on Iron-Based Nanostructures

Among all minerals, iron is one of the elements identified early by human beings to take advantage of and be used. The role of iron in human life is so great that it made an era in the ages of humanity. Pure iron has a shiny grayish-silver color, but after combining with oxygen and water it can make a colorful set of materials with divergent properties. This diversity sometimes appears ambiguous but provides variety of applications. In fact, iron can come in different forms: zero-valent iron (pure iron), iron oxides, iron hydroxides, and iron oxide hydroxides. By taking these divergent materials into the nano realm, new properties are exhibited, providing us with even more applications. This review deals with iron as a magic element in the nano realm and provides comprehensive data about its structure, properties, synthesis techniques, and applications of various forms of iron-based nanostructures in the science, medicine, and technology sectors.

Nano-micronutrients [γ-Fe2O3 (iron) and ZnO (zinc)]: green preparation, characterization, agro-morphological characteristics and crop productivity studies in two crops (rice and maize)

Nanotechnology based fertilizer production possessing the desired chemical composition, can improve plant nutrition and may reduce the environmental impact and enhance the plant productivity.

Antibacterial efficacy of green synthesized α-Fe2O3 nanoparticles using Sida cordifolia plant extract

The aim of the work is to synthesize iron oxide (α-Fe2O3) nanoparticles using Sida cordifolia plant extract along with evaluation of its antibacterial activity. The presence of phytochemicals in Sida cordifolia methanolic plant extract was investigated by HPTLC and LC-MS/TOF. The probable mechanism for formation of α-Fe2O3 nanoparticles in mediation with plant extract was demonstrated. The green synthesized iron oxide nanoparticles (α-Fe2O3 NPs) were characterized by using X-ray diffraction, scanning, and transmission electronic microscopy, TG-DTA, FTIR, and UV spectroscopy. The crystallite size of prepared α-Fe2O3 nanoparticles estimated via Debye-Scherrer formula and Williamson-Hall plot was around 20 nm which is in accordance with particle size in TEM images. The S. cordifolia mediated iron-oxide nanoparticles (α-Fe2O3 NPs) hold potent antibacterial activity against various gram positive and gram negative bacteria.

The removal of arsenic from arsenic-bearing groundwater in In-situ and Ex-situ environment using novel natural magnetic rock material and synthesized magnetic material as adsorbent: A comparative assessment

The removal of arsenic from groundwater is an important issue for environmental safety and human health. Research focused on the comparative assessment of arsenic removal from arsenic-bearing groundwater and arsenic-containing-synthetic water (2 mg/L) using natural magnetic material (NMM) (rock) and synthesized magnetic material (SMM) by Bacillus pasteurii and humic acid. The arsenic-bearing groundwater (97.56 ± 0.05 μg/L) exceed the WHO limit (10 μg/L) of arsenic concentration for drinking water. The NMM contains dominantly magnetite, hematite, ferrihydrate, coesite, quartz, and stishovite. The NMM of natural rock exhibited the existence of iron (6.25-8.86% Fe₃O₄), which is widespread and important component in sedimentary rocks. The investigation on vibrating sample magnetometers (VSM) of NMM and SMM demonstrated the typical magnetization properties, which can be separated after arsenic removal process. The thermogravimetric analysis (TGA) of SMM displayed the existence of organic matter decomposition during particle synthesis. The TEM and SEM exhibited the nanoparticle particle formation within the range of 10-39 nm (10-20 nm particle Fe₃O₄ through B. pasteurii). FTIR spectrum (before and after removal of arsenic) indicated the existence and binding nature in between arsenic and iron. >90% of arsenic was removed from arsenic-bearing groundwater using Fe₃O₄, Fe₃O₄ (N₂-Environment), Fe₃O₄ with humic acid, and Fe₃O₄ with B. pasteurii after 25 min, 8 min, 13 min and 120 min, respectively. In case of NMM in Site-A, the arsenic removal was observed very fast as 85-87% within 30 s, whereas 95-99%, 93-95% and 88-91% removal detected using the sample of Site-A, Site-B, and Site-C respectively, after 120 min at natural pH (8.31 ± 0.05) of arsenic-bearing groundwater. Thus, NMM, (ecofriendly green material), can be applicable for arsenic removal from arsenic-bearing groundwater.

A green approach for the synthesis of α-Fe2O3 nanoparticles from Gardenia resinifera plant and it's In vitro hyperthermia application

The Gardenia, traditional medicinal plant used from ancient time to increase appetite and other medicinal uses has been employed for the synthesis of superparamagnetic α-Fe₂O₃ nanoparticles (NPs). The plant extracts unveiled its bifunctional nature through the reducing ferric ions by phenolic groups and capping nature through the –OH bonding over the NPs surface. The prepared NPs exhibits α-Fe₂O₃ phase among iron oxides and spherical morphology with an average size around 5 nm. The magnetic measurements proved the superparamagnetic behavior of NPs with non-saturating M_S value of 8.5 emu/g at room temperature (300 K). Further, the hyperthermia study reveals, the NPs achieved a temperature of 40 °C and 43 °C within 6 min and reaches up to 43 °C and 45 °C within 10 min only for 5 μg/mL and 10 μg/mL concentrations respectively. Based on the heating profile of NPs, the SAR values (167.7 Oe, 300 MHz) calculated and are found to be around 62.75 W/g and 24.38 W/g for 5 μg/mL and 10 μg/mL NPs concentrations respectively. Subsequently, these have been used for toxicity assays, which presented enhanced cytotoxic effects on human mesenchymal cells lines proving them as a potential candidate for the biomedical applications.

Fabrication and a detailed study of antibacterial properties of α-Fe2O3/NiO nanocomposites along with their structural, optical, thermal, magnetic and cytotoxic features

Nanomaterials have specific properties which are uncommon in their bulk counterparts. Because of these unique characteristics, nanotechnology has been explored for various applications by the scientific community and it can play a crucial role in providing solutions of current major healthcare problems. In the present work, we describe the fabrication of a novel inorganic alternative of traditional antibiotics, which can effectively counter the pathogenic bacteria including multi drug resistant bacterial strains. For this purpose, nanocomposites of Fe/Ni oxide with different molar concentrations of nickel have been prepared via wet-chemical approach along with the α-Fe₂O₃ and NiO nanoparticles. The bactericidal efficiency of the prepared samples were tested against pathogenic strains of B. subtilis, S. aureus, E. coli and S. typhi using two distinct methods. In addition to this, structural, physical and chemical properties of the nanomaterials were studied using XRD, TEM, EDAX, Raman, VSM and TGA-DTA. Also, the cytotoxicity of synthesized samples was assessed using MTT assay against human cell lines MCF-10A (normal) and MCF7 (cancer).

Study of synthesis, structural, optical and magnetic characterizations of iron/copper oxide nanocomposites: A promising novel inorganic antibiotic

This paper reports the development of inorganic nanoparticles based novel antibiotic. Inorganic nanoparticles have the potential of being used as bactericidal agent due to their effective antimicrobial activity, colloidal aqueous stability and comparatively low toxic profile. Among them, iron oxide and copper oxide were chosen for this study because of the nascent bactericidal properties of both iron and copper. In this work, along with the pure samples of iron oxide and copper oxide nanoparticles, hybrid magnetic nanocomposites of iron oxide and copper oxide with varying molar concentrations of copper precursor were produced by wet-chemical approach. Structural, physical and chemical properties of the prepared samples were investigated using spectroscopic and microscopic techniques like XRD, SEM, TEM, EDAX, Raman, VSM and TGA-DTA. The antibacterial activity of the samples were established against pathogenic strains of bacteria E. coli, B. subtilis, S. aureus and S. typhi by using two different methods. The prepared nanomaterials were very adequate to combat the bacterial growth and their bactericidal efficiency was comparable to the commercial antibiotic gentamycin. Thus these non-toxic hybrid nanocomposites can be used as the potential antibiotic to counter the diseases caused by normal and multi drug resistant pathogenic bacterial strains.

Functionalized biochar derived from heavy metal rich feedstock: Phosphate recovery and reusing the exhausted biochar as an enriched soil amendment

This paper provides a circular win-win approach for recycling rhizofiltration biomass into multifunctional engineered biochar for various environmental applications (e.g. phosphate recovery) with a potential reuse of the exhausted biochar as an enriched soil amendment. Functionalized biochars were derived from the disposals of water hyacinth (Eichhornia crassipes) plants grown in synthetic contaminated water spiked with either Fe²⁺ (Fe-B), Mn²⁺ (Mn-B), Zn²⁺ (Zn-B) or Cu²⁺ (Cu-B) comparing with the original drainage water as a control treatment (O-B). The in-situ functionalization of biochar via the inherently heavy metal-rich feedstock produced homogenous organo-mineral complexes on biochar matrix without environmental hazards (e.g. volatilization or chemical sludge formation) associated with other post-synthetic functionalization methods. Physicochemical analyses (SEM-EDS, XRD, FTIR, BET and zeta potential (ζ)) confirmed the functionalization of Fe-B, Zn-B and Cu-B due to organo-mineral complexes formation, maximizing specific surface area, lowering the electronegativity, originating positively charged functional groups, and thus improving the anion exchange capacity (AEC) comparing with O-B. In contrary, physicochemical characteristics of Mn-B was in similarity with those of O-B. Phosphate recovery by the functionalized biochar was much greater than that of the unfunctionalized forms (O-B and Mn-B). Precipitation was the dominant chemisorption mechanisms for phosphate sorption onto biochar compared to other mechanisms (ion exchange, electrostatic attraction and complexation with active functional groups). The exhausted biochar showed an ameliorating effect on the low water and nutrient supply potentials of sandy soil, and thus improved fresh biomass yield and nutritional status of maize seedlings with some restrictions on its high micronutrient content.

Antibacterial applications of α-Fe2O3/Co3O4 nanocomposites and study of their structural, optical, magnetic and cytotoxic characteristics

Owing to their multiple mechanisms of bactericidal activity, inorganic metal oxides and hybrid metal oxide nanocomposites may serve as a new class of effective disinfectants. Among metal oxide nanoparticles, iron oxide nanoparticles exhibit minimal or no cytotoxicity to human cells with very efficient bactericidal properties over a wide spectrum of bacteria. This paper presents the very first report on antibacterial properties of novel nanocomposites of iron oxide and cobalt oxide nanoparticles against pathogenic bacterial strains B. subtilis, S. aureus, E.coli and S. typhi. The enhanced bactericidal activity of the Fe/Co oxide nanocomposite was the result of synergistic effect of iron oxide and cobalt oxide nanoparticles. The nanocomposites were synthesized using co-precipitation route with increasing cobalt content in the sample and further characterized using XRD, TEM, Raman and VSM to investigate structural, optical and magnetic properties of the prepared nanocomposites, respectively. Also, the prepared nanocomposites were highly biocompatible and found non-toxic to human cell line MCF7.

Iron nanostructured catalysts: design and applications

This review is focused on the recent advances in the design of iron nanostructures and their catalytic applications.

Formation of iron oxide nanoparticles for the photooxidation of water: Alteration of finite size effects from ferrihydrite to hematite

Iron oxide nanoparticles represent a promising low-cost environmentally-friendly material for multiple applications. Especially hematite (α-Fe2O3) nanoparticles demonstrate great possibilities in energy storage and photoelectrochemistry. A hydrothermal one-pot synthesis can be used to synthesise hematite nanoparticles. Here, the particle formation, nucleation and growth of iron oxide nanoparticles using a FeCl3 precursor over time is monitored. The formation of 6-line ferrihydrite seeds of 2-8 nm which grow with reaction time and form clusters followed by a phase transition to ~15 nm hematite particles can be observed with ex situ X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman and UV/Vis spectroscopy. These particles grow with reaction time leading to 40 nm particles after 6 hours. The changes in plasmon and electron transition patterns, observed upon particle transition and growth lead to the possibility of tuning the photoelectrochemical properties. Catalytic activity of the hematite nanoparticles can be proven with visible light irradiation and the use of silver nitrate as scavenger material. The generation of elementary silver is dependent on the particle size of iron oxide nanoparticles while only slight changes can be observed in the oxygen generation. Low-cost nanoscale hematite, offers a range of future applications for artificial photosynthesis.

Fabricating an anionic polyacrylamide (APAM) with an anionic block structure for high turbidity water separation and purification

Ultraviolet (UV)-initiated template polymerization (UTP) was used as a feasible strategy to prepare a novel anionic polyacrylamide (APAM) with a microblock structure.