Effect Of Fe3O4 Nanoparticles Research Articles

Nano Fe3O4 improved the electron donating capacity of dissolved organic matter during sludge composting

The effect of Fe3O4 nanoparticles (Fe3O4 NPs) on the electron transfer process in aerobic composting systems remains unexplored. In this study, we compared the electron transfer characteristics of DOM in sludge composting without additives (group CK) and with the addition of 50 mg/kg Fe3O4 NPs additive (group Fe). It was demonstrated that the electron transfer capacity (ETC) and electron donating capacity (EDC) of compost-derived DOM increased by 13%–29% and 40%–47%, respectively, with the addition of Fe3O4 NPs during sludge composting. Analyzing the composition and structure of DOM revealed that Fe3O4 NPs promoted the formation of humic acid-like substances and enhanced the aromatic condensation degree of DOM. Correlation analysis indicated that the increase in EDC of DOM was closely associated with the phenolic group in DOM and influenced by quinone groups and the degree of aromatization of DOM. The higher EDC and the structural evolution of DOM in group Fe reduced the bioaccessibility of Cu, Cr, Ni, Zn. This study contributes to a deeper understanding of the redox evolutionary mechanism of DOM in sludge composting and broadens the application of iron oxides additives.

Curing process, mechanical property and thermal stability of acrylic polyurethane/Fe2O3 nanocomposite coatings

The effect of Fe2O3 nanoparticles (NPs) on the curing and properties of acrylic polyol HSU 1168 based coating were investigated. The SEM images showed that Fe2O3 NPs with the content £ 2 wt.% were dispersed regularly in the polymer matrix. The obtained results indicated that Fe2O3 NPs slowed down the curing process of acrylic polyol coating. Without nanoparticles, the neat HSU 1168 based coating has completely cured after 96 hours, whereas in the presence of 2 wt.% Fe2O3 NPs in coating matrix it needed 120 hours for a full curing. In addition, the relative hardness of nanocomposite coating has reduced with increasing the Fe2O3 NPs content. Without nanoparticles, the relative hardness of neat acrylic polyol coating was 0.88, whereas it was 0.75 when 4 wt.% Fe2O3 NPs was added into the coating matrix. Besides, incorporation of Fe2O3 NPs into the acrylic polyol coating also enhanced its abrasion resistance and impact resistance with 2 wt.% Fe2O3 NPs being the best content (i.e. 200 kG.cm of impact resistance and 408.8 L/mil of abrasion resistance). On the other hand, incorporation of Fe2O3 NPs into the coating matrix improved its thermal stability. The starting temperature for degradation of nanocomposite coating (with 2 wt.% Fe2O3 NPs) was 15 oC higher than that of the neat coating (without nanoparticles)

The effects of Fe2O3 nanoparticles on catalytic function of human acetylcholinesterase: size and concentration role.

Fe2O3 NPs can enter cells quickly, pass through the blood-brain barrier and interact with macromolecules. These materials are widely used in different fields, so their risk assessment is among the most critical issues. Acetylcholinesterase (AChE) is a cholinergic enzyme in central and peripheral nervous systems. In this work, the possible effects of Fe2O3 NPs on the structure and catalytic activity of AChE were investigated using circular dichroism (CD), surface plasmon resonance (SPR), and fluorescence spectroscopies. The outcomes demonstrated that 5 nm Fe2O3 NPs inhibit AChE activity through mixed mechanism. While 50 nm Fe2O3 NPs caused an enhancement in the catalytic activity up to 60 nM. However, higher concentrations of Fe2O3 NPs (above 60 nM) hindered the enzyme activity via mixed mechanism. Fluorescence analysis showed that NPs can quench the fluorescence intensity of AChE that refer to conformational changes. Furthermore, CD results showed that Fe2O3 NPs can reduce the α-helix and β-sheet contents of the enzyme and decrease the stability of AChE. Also, the SPR data analysis showed that the affinity between AChE and Fe2O3 NPs decreased with rising temperature. After treatment with Fe2O3 NPs, the catalytic activity of AChE was assessed in HepG2 cell lines, and the results confirmed the inhibitory effects of Fe2O3 NPs on AChE activity in vivo. These findings provide helpful information about the impact of Fe2O3 NPs on the structure and function of AChE and could offer new insights into the risk assessment of the medical application of nanoparticles.

Preparation, Characterization, and Lubrication Performances of Water-Based Nanolubricant for Micro Rolling Strips.

Water-based nanolubricants are widely used in rolling processes due to their unique characteristics. As a common additive, nanoparticles could significantly improve the tribological properties of the lubricant. However, the effect of the physical properties of the particles on the anti-friction behavior is unclear. In this study, the effect of Fe3O4 nanoparticles as an additive for the prepared lubricant is studied. The tribological properties of Fe3O4 water-based nanolubricant are examined using a tribometer and a scratch meter. The absorption energy is calculated using the molecular dynamic simulation method, and the best parameters for the preparation of the nanolubricant are obtained. The developed nanolubricant is used in the rolling process. The results show that the processing quality of samples is promoted and the tribological properties of water-based lubricant can be significantly promoted by an Fe3O4 nanoparticle additive. An economical and environmentally friendly method is presented through which the water-based Fe3O4 nanolubricant can be prepared for the replacement of oil-based lubricant in cold rolling strips.

Effects of Fe3O4 nanoparticles and nano hydroxyapatite on Pb and Cd stressed rice (Oryza sativa L.) seedling

Nowadays, Lead (Pb) and Cadmium (Cd) contamination in rice is an important worldwide environmental concern. Fe3O4 nanoparticles (Fe3O4 NPs) and Nano hydroxyapatite (n-HAP) are promising materials to manage Pb and Cd contamination. This study systematically investigated the effect of Fe3O4 NPs and n-HAP on Pb and Cd stressed rice seedlings’ growth, oxidative stress, Pb and Cd uptake and subcellular distribution in roots. Furthermore, we clarified the immobilization mechanism of Pb and Cd in the hydroponic system. Fe3O4 NPs and n-HAP could reduce Pb and Cd uptake of rice mainly through decreasing Pb and Cd concentrations in culture solution and combining with Pb and Cd in root tissues. Pb and Cd were immobilized by Fe3O4 NPs through complex sorption processes and by n-HAP through dissolution-precipitation and cation exchange, respectively. On the 7th day, 1000 mg/L Fe3O4 NPs reduced the contents of Pb and Cd in shoots by 90.4% and 95.8%, in roots by 23.6% and 12.6%, 2000 mg/L n-HAP reduced the contents of Pb and Cd in shoots by 94.7% and 97.3%, in roots by 93.7% and 77.6%, respectively. Both NPs enhanced the growth of rice seedlings by alleviating oxidative stress and upregulating glutathione secretion and antioxidant enzymes activity. However, Cd uptake of rice was promoted at certain concentrations of NPs. The subcellular distribution of Pb and Cd in roots indicated that both NPs decreased the percentage of Pb and Cd in the cell wall, which was unfavorable for Pb and Cd immobilization in roots. Cautious choice was needed when using these NPs to manage rice Pb and Cd contamination.

Toxicity of iron-based nanoparticles to Nannochloropsis oculata: effects of Fe2O3-NPs on oxidative stress and fatty acid composition

ABSTRACT The growing application of nanotechnology has led to the release of nanoparticles in aquatic ecosystems. Thus, investigating the effect of nanoparticles on microalgae, as the primary producers of the food chain, is an important issue. The present study was conducted to examine the toxicity mechanisms of α- Fe2O3 nanoparticles (Fe2O3-NPs) dominated by oxidative stress in Nannochloropsis oculata. The accumulation of Fe2O3-NPs on the cell surface of N. oculata and in f2 medium was observed in SEM images and DLS analysis, respectively. EDX graph and TEM images also showed the presence of NPs in N. oculata. There was an increase of H2O2 and MDA content and growth inhibition was also elevated in N. oculata exposed to Fe2O3-NPs. Further, Fe2O3-NPs application caused a noticeable enhancement of non-enzymatic antioxidants (carotenoids, phenolic compounds and PUFAs) and APX activity, while the content of SFAs and MUFAs as well as the activity of CAT and PPO were reduced as a result of Fe2O3-NPs stress. Overall, the activation of defence mechanisms was not effective in N. oculata and treatment with concentrations of more than 50 mg l−1 Fe2O3-NPs could induce oxidative stress in this microalga.

Effect of Fe3O4 nanoparticles on magnetic xerogel composites for enhanced removal of fluoride and arsenic from aqueous solution

Fe3O4 magnetic xerogel composites were prepared by polycondensation of resorcinol (R)–formaldehyde reaction via a sol–gel process in an aqueous solution through varying the molar ratio of Fe3O4 nanoparticles (MNPs), catalyst (C), and water (W) content. MNPs were obtained by co-precipitation (MC), oxidation of iron salts (MO), or solvothermal synthesis (MS). Both MNPs and magnetic xerogels were examined regarding the performance of arsenic and fluoride removal in a batch system. The MC-based MNPs had higher adsorption capacities for both fluoride (202.9 mg/g) and arsenic (3.2 mg/g) than other MNPs in optimum conditions. The X-ray diffraction, Fourier transform infrared spectroscopy, and energy-dispersive X-ray spectroscopy confirmed that Fe was composed into the polymeric matrix of magnetic xerogels that contained 0.59%–4.42% of Fe with a molar ratio of MNPs (M) to R between 0.01 and 0.10. With low R/C and optimum M/R ratios, an increase in the surface area of magnetic xerogels affected the fluoride and arsenic adsorption capacities. The magnetic xerogel composites with the MC-based MNPs prepared at a fixed R/C ratio (100) and at different R/W (0.05–0.06) and M/R (0.07–0.10) ratios had a high arsenic removal efficiency of 100% at an As(V) concentration of 0.1 mg/L and pH of 3.0. The maximum adsorption capacities of magnetic xerogels were approximately five times higher than those of the xerogels without MNP composites. Therefore, Fe3O4 nanoparticles enhanced the adsorption of arsenate and fluoride. The variations of alkaline catalyst and water content significantly affected the resulting properties of textural and surface chemistry of magnetic xerogel composites.

Effect of Fe3O4 nanoparticles on microbial diversity and biogas production in anaerobic digestion of crude glycerol

This study investigated the effects of citrate-coated Fe3O4 nanoparticles in the anaerobic digestion of crude glycerol, the main by-product of the biodiesel industry. Fe3O4 nanoparticles were synthesized by the coprecipitation method and Scanning Electron Microscopy (SEM) characterized it. The method designed for synthesis produced stable Fe3O4 nanoparticles with diameters about 20 nm. Duplicate of anaerobic batch reactors (500 mL) were used for assessing the influence of Fe3O4 nanoparticles in four assays performed at 37 °C. The reactors were filled with anaerobic granular sludge; crude glycerol (25.0 g COD L−1); buffer solution; citrate-coated Fe3O4 nanoparticles suspension (0.2 g L−1; 0.4 g L−1 and; 0.8 g L−1 and a control without Fe3O4 nanoparticles); deionized water up to 250 mL. There were increases of 49.8%, 28.5% and 26.0% in the accumulated production of CH4 and 25.7%, 17.1% and 20.0% in the maximum rate of CH4 production in assays supplemented with 0.2, 0.4 and 0.8 g L−1 of Fe3O4 nanoparticles, respectively, in relation to control reactors. It was also observed a substantial increase on relative abundance of Bacteria and Archaea Domains, specially Bacteroides, Clostridiales, Methanomicrobiales and Methanosarcinales orders, after anaerobic digestion supplemented with Fe3O4 nanoparticles. The addition of Fe3O4 nanoparticles could improve the anaerobic digestion of crude glycerol, optimizing bacterial and archaeal communities enhancing the CH4 production.

Effect of Fe3O4 nanoparticles on magneto-responsive shape memory behavior of polyurethane-carbon nanotube nanocomposites

Effect of Fe3O4 nanoparticles on magneto-responsive shape memory behavior of polyurethane-carbon nanotube nanocomposites

Effects of Fe3O4 nanoparticles on anaerobic digestion enzymes and microbial community of sludge

ABSTRACT Fe3O4 nanoparticles (NPs) have potential effects on the anaerobic digestion of excess sludge. The effects of different concentrations of Fe3O4 NPs (0, 100, 200, 400 and 600 mg/L) on enzymes and microorganisms in anaerobic digestion were studied to explore the mechanism of the effect of Fe3O4 NPs on anaerobic digestion. The results showed that 100, 200 and 400 mg/L Fe3O4 NPs could promote anaerobic digestion, and 200 mg/L Fe3O4 NPs had the most obvious promoting effect. The activities of protease, cellulase, dehydrogenase, acetic kinase and coenzyme F420 in the 200 mg/L Fe3O4 NPs group reached 120 U/mg VS, 71.75 U/g VS, 135 U/mL, 94 mol/L, 1.37 umol/g VSS, respectively, which were 3.8, 1.5, 1.2, 1.2 and 1.6 times of the blank group, respectively. However, when the concentration of Fe3O4 NPs reached 600 mg/L, the activities of cellulase, dehydrogenase and acetic kinase were lower than those of the blank group, and anaerobic digestion was inhibited. The above conclusions can also be confirmed by high-throughput sequencing. The abundance of longilinea and ornatilina in the 200 mg/L Fe3O4 NPs group was 8.8% and 4.1% respectively, and methanthrix abundance was 69%, which was more conducive to decomposition acetic acid into CH4.

Bio-inspired smart surface to achieve controllable locomotion through adjustable anisotropic friction

Anisotropic friction generated by microstructured surfaces is crucial for performing functions such as directional locomotion and adhesion in biological systems. Hence, an epoxy-based shape memory polymer (SMP) incorporating Fe3O4 nanoparticles is used in this study to create a smart surface with oriented structures to mimic anisotropic friction and exploit human-developed controllable locomotion systems. Applying the specific properties of the epoxy-based SMP, fast switching friction can be achieved by adjusting the topography and stiffness of the microstructures on the surface. In addition, the photothermogenesis effect of Fe3O4 nanoparticles induces changes in the asymmetric topography and stiffness on the SMP surface under the irradiation of near-infrared (NIR) light, thereby inducing a rapid switching of the friction force. Furthermore, a microbot is created to demonstrate remotely controlled locomotion, such as unidirectional and round-trip movements, and braking by switching the friction force under NIR light. These results are promising for the design of new intelligent surfaces and interfaces; additionally, they may facilitate the investigation of biological structures and processes.

Magnetite nanoparticles as a promising non contaminant method to control populations of fruit flies (DIPTERA: Tephritidae)

“True fruit flies” belong to the family Tephritidae. Among them, the Mediterranean fruit fly (Medfly) Ceratitis capitata (Wiedemann) is the most economically important agricultural pest insect in the world. Anastrepha fraterculus (Wiedemann) is the South American fruit fly and represents a serious problem for countries of America. Both species share hosts fruits. Traditionally the control of fruit flies bases on the use of pesticides with chemical components. Due to their massive use to crops, pesticides are associated to environmental pollution and toxicity in mammals. An emerging technology is the use of nanomaterials with pesticidal activity or for the delivery of pesticides. The present paper reports: a) the synthesis of iron oxide (magnetite) nanoparticles and b) the effects of Fe3O4 nanoparticles during the development of the tephritid flies C. capitata and A. fraterculus. We sampled guava fruits to recover immature stages of fruit flies. Magnetite nanoparticles Fe3O4 were synthesized by co-precipitation of Fe (III) and Fe (II). We suspended doses of 100, 200 and 400 µg/ml of magnetite nanoparticles in water and we added the suspensions to larval medium. NPs are spherical with a medium diameter of 11 ± 2 nm and unimodal size distribution. During larval-pupal development, we checked out difficulties in the capacity to complete the natural biological cycle. Only 40% of larvae feeded in medium 400 μg / ml Fe3O4 NPs were able to continue their life cycle, in contrast to 92% of the control. Application of iron oxide (or magnetite) nanoparticles to larval food resulted in larvae toxicity expressed as dose-dependent lethality

Molecular dynamics simulation of water-based Ferro-nanofluid flow in the microchannel and nanochannel: Effects of number of layers and material of walls

Due to the increasing development of nanotechnology and its wide applications, the flow of a nanofluid in a duct is also optimal geometric construction of ducts in the fabrication and production of various ducts to increase efficiency in nanofluid behavior are essential. In this paper, by using the molecular dynamics (MD) simulation process, the effect of Fe3O4 nanoparticles on the behavior of water-based fluid is investigated. Physical parameters such as total temperature, potential energy, fluid, nanofluid density profiles, fluid velocity, nanofluid profiles, and fluid and nanofluid temperature profiles are reported. Also, the effect of the number of layers and wall material on fluid flow is investigated. Therefore, the channel wall material in the following simulations will be considered as platinum, copper, and iron. Over time, the temperature of atomic structures reaches 300 K, which indicates the temperature stability in the simulated atomic structures. The results show that by increasing the number of wall layers in nanochannels and similar microchannels, interactions between fluid particles and walls increase. As these interactions increase, the accumulation of fluid particles in the vicinity of the channel walls increases, which increases the density of the shelves adjacent to the channel walls. Also, by changing the microchannel material from copper to iron and platinum, the number of interactions between particles in the present structures increases. This increase in the number of interactions between the particles present in the microchannel wall and the base fluid causes the maximum density to be observed in the platinum microchannel.

Effect of Fe3O4 nanoparticles on the performance of anaerobic digestion through electrochemical analysis

ABSTRACT In view of the high cost and complex operation of the traditional chemical method for the determination of the anaerobic digestion (AD) process, this study investigated the feasibility of using electrochemistry analysis to determine the effect of Fe3O4 nanoparticles (NPs) on the AD process. The quantity of electric charge of Fe3O4 NPs modified graphite electrode in sodium acetate electrolyte was higher than that of graphite electrode. The addition of Fe3O4 NPs was beneficial to improve the electrochemical activity of the electrode. On this basis, enzymes and microorganisms were extracted from anaerobic reactors containing different concentrations of Fe3O4 NPs to make electrodes respectively to further investigate the effects of Fe3O4 NPs on enzyme and microbial activities in AD. The electrochemical analysis results of the enzyme electrodes and microbial electrodes showed that the quantity of electric charge produced by the group of 200 mg/L Fe3O4 NPs was the highest. The cumulative biogas production of 200 mg/L Fe3O4 NPs was 809 mL/g VS, and better than other groups. These results showed that 200 mg/L Fe3O4 NPs was the best dosage, and the electrochemical analysis has higher sensitivity in the AD detection.

Stimulatory Effect of Fe3O4 Nanoparticles on the Growth and Yield of Pseudostellaria heterophylla via Improved Photosynthetic Performance

Nanomaterials have recently been used as growth stimulants to promote the production of crops in saline-alkali through root application. However, if applied through leaves, little is known about the effect of Fe3O4 nanoparticles (NPs) on the root growth and yield, especially for medicinal crops. To fill this gap, a single factor experiment was conducted to explore the effects of Fe3O4 NPs on growth, yield, the dry matter distribution, chlorophyll content, photosynthetic characteristics, chlorophyll fluorescence parameters, and polysaccharide content of Pseudostellaria heterophylla by foliar spraying under field conditions. Fe3O4 NPs (20–50 mg·L–1) significantly promoted growth, the dry matter distribution of root and root tuber yield per unit area. Fe3O4 NPs enhanced net photosynthetic rate (Pn) by increasing chlorophyll content. And Fe3O4 NPs increased the daily mean and peak value of Pn, and alleviated the phenomenon of “midday depression” by improving nonstomatal limitation. Chlorophyll fluorescence parameters indicating that Fe3O4 NPs promoted the photochemical activity of PSII and alleviated photoinhibition by enhancing the photochemical use of excess excitation energy. Gray correlation analysis showed that Fe3O4 NPs enhanced the adaptability of P. heterophylla photosynthesis to high temperatures and strong light. Of note, Fe3O4 NPs enhanced the polysaccharide content of the root tuber. Phytotoxic effect was recorded at high NPs (100 mg·L–1) doses. Collectively, Fe3O4 NPs could promote performance of P. heterophylla by improving photosynthetic performance, enhancing its adaptability to the environment, and increasing the distribution ratio of photosynthates to the underground part.

Effect of Fe3O4 nanoparticles on seed germination in tobacco.

Many studies on the toxicity of nanoparticles (NPs) have reported different levels of toxicity for various types of NPs. This study aimed to examine the morpho-ultrastructural impact of iron oxide (Fe3O4) NPs on seed germination in tobacco (Nicotiana tabacum var. Turkish) using different sizes and concentrations of nanoparticles. Seeds were allowed to germinate in the presence of (Fe3O4) NPs of three different sizes (5, 10, and 20 nm) at three different concentrations 3, 10, and 30 mg/L for each size. Seeds were assessed using light and transmission microscopy. Radical lengths and seed germination rate were significantly affected (positively or negatively) in all NPs-treated seeds compared to control seeds. The radical lengths in 5 nm-treated seeds (30 mg/L concentration) and 10 nm-treated seeds (10 and 30 mg/L concentrations) were significantly shorter than control seeds. In contrast, the radical lengths in 10 nm-treated seeds (3 mg/L concentration) and 20 nm-treated seeds (10 mg/L concentration) were significantly longer than control seeds. Most NPs-treated seeds exhibited significant higher seed germination except for seeds treated with 5 nm NPs (3 mg/L concentration). Moreover, thick and thin micrographs of radicles and leaflets of 5 nm NPs-treated seeds (30 mg/L concentration) and 10 nm NPs (30 mg/L concentration) showed structural and ultrastructural deformation. Thus, these findings confirm that the toxicity and the bioaccumulation of (Fe3O4) NPs were size and concentration dependent.

Effects of Fe2O3 nanoparticles on extracellular polymeric substances and nonylphenol degradation in river sediment

In this study, the impact of Fe2O3 nanoparticles (nFe2O3) on microbial extracellular polymeric substances (EPS) and nonylphenol (NP) degradation in sediment were investigated. The results showed that the addition of nFe2O3 lowered the degree of EPS overproduction and the amount of polysaccharides and proteins secreted in NP contaminated sediment. Particularly, the secretion of colloidal EPS (C-EPS) lowered significantly (P < 0.05), and the content of tyrosine-like, tryptophan-like, and soluble microbial by-product-like substances in C-EPS also decreased, leading to a lower aromaticity, humification, and hydrophobicity of C-EPS. Furthermore, with lower C-EPS content in water, NP was adsorbed to sediment more easily, and the weakened toxic effect of NP to bacteria as well as a higher proportion of organic matter degrading microbes stimulated NP degradation. These findings revealed the vital role of nFe2O3 in alleviating NP toxicity to microbes and reducing NP ecological risk in aquatic environments.

Effect of Fe₃O₄ Nanoparticles on Magnetorheological Properties of Flake-Shaped Carbonyl Iron Water-Based Suspension

To analyze the effect of magnetite Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> disk-shaped nanoparticles with flake-shaped microparticles in water-based magneto rheological (MR) suspension, the rheological properties were studied using a parallel plate rheometer. The morphology, crystallinity, and magnetic property of the prepared MR suspensions were examined by field emission scanning electron microscopy (FESEM), X-ray diffraction, and vibrating sample magnetometer, respectively. In the presence of a magnetic field, micron-sized carbonyl iron (CI) particles lead to form a robust columnar structure with Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> nanoparticles and enhanced the magnetorheological performances. The magnetorheological performances of MR suspensions were examined in shear rate, shear strain, and shear stress testing sweep modes with and without a magnetic field. It was observed that adding the 1 wt% of Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> , the magnetorheological performance of MR suspension enhanced. The MR fluid with CI/Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> nanoparticle mixture showed significantly higher shear viscosity and shear stress and yielded stresses than pure CI-based MR fluid. The yield stresses were higher in the shear rate sweep mode than strain and stress sweep testing modes.

Fe3O4 nanoparticles and Rhizobium inoculation enhance nodulation, nitrogen fixation and growth of common bean plants grown in soil

The effects of Fe3O4 nanoparticles (NPs) and Rhizobium inoculation on nodulation, nitrogen fixation and plant growth of common bean (cv. Red Guama, Phaseolus vulgaris) plants were investigated in growth chambers. Plants were exposed to: Fe3O4 NPs (2000 mg/L) (T1), Rhizobium inoculation (T2) and Fe3O4 NPs + Rhizobium inoculation (T3); non-treated plants were considered as controls. Harvested 35-day-old treated plants showed improved symbiotic performance including increased nitrogenase activity (51.2–90.7%), nodule leghaemoglobin (44.8–80.9%) and iron content (83.4–84.2%), number of active nodules per plant (58.7–122%) and nodule dry weight (40.2–70.6%). This resulted in enhanced symbiotic nitrogen fixation,and increased shoot (26.5–50.2%) and root (24.1–48.2%) total nitrogen content in treated plants in comparison with the controls. The best result was obtained using treatment T3. Furthermore, Fe3O4 NPs were taken up by bean plants in treatments T1 and T3, and these accumulated in their organs, including in nodules. All treatments led to an increase in root (51.9–79.8%) and shoot (27.5–52.7%) lengths, in leaf area (10.9–16.8%) and in root (10.1–17.8%), stem (9.8–12.7%) and leaf dry weight (8–17.3%) compared to control plants. Thus applied treatments have the potential to improve common bean plant growth through enhancement of nodulation and nitrogen fixation during vegetative growth.This study also provides strong evidence that the presence Fe3O4 NPs in nodules improves the symbiotic performance between Rhizobium (leguminosarum CF1 strain) and the common bean plant, due to enhanced nodulation and nitrogen fixation.

Improvement of CO2 absorption by Fe3O4/water nanofluid falling liquid film in presence of the magnetic field

AbstractCarbon dioxide is considered as the main greenhouse gas responsible for climate change. Absorption of CO2 by liquid phase has gained attention as a means of mitigating environmental challenges. In this study, the effect of Fe3O4 nanoparticles on the CO2‐water mass transfer coefficient was experimentally evaluated in the presence and absence of a magnetic field. The absorption experiments were carried out in a falling liquid film absorber system in laminar and turbulent flow regimes. Fe3O4/water nanofluid was used in 0.001‐0.05 vol% concentrations. The results show that adding Fe3O4 nanoparticles to water increases the mass transfer coefficient (MTC), and that it increases with an increase in nanofluid concentration. For a concentration of 0.05 vol% nanofluid, the MTC was improved 111% and 13.7% in the turbulent and laminar flow regimes, respectively. The mass transfer coefficient of CO2 in water and effective mass transfer coefficient in nanofluid were increased up to 10% and 29% in the presence of a parallel alternative magnetic field, respectively.