Ferrous Sulfate Solution Research Articles

Recovery of niobium and titanium from low-grade niobium ores and the evaluation of Fe5Si3 alloy by-product as oxygen evolution reaction electrocatalysts

A low-grade ore containing 4 % niobium and 7 % titanium has been extracted from Bayan Obo tailing, but its potential has not been fully utilized. This study aims to recover the niobium and titanium elements from this low-grade ores in the form of their carbides. The process involves reducing niobium and titanium to (Nb,Ti)C through a carbothermal process. During this process, iron and silicon are also reduced to Fe-Si intermetallic compounds, allowing (Nb,Ti)C to diffuse into them. Subsequently, selective electrochemical oxidation is used to separate (Nb,Ti)C from the Fe-Si intermetallic compounds in an aqueous ferrous sulfate solution. The Fe-Si intermetallic compounds are first oxidized to the Fe3Si phase, and then to the Fe5Si3 phase in the solution with pH 0.35. The (Nb,Ti)C/matrix interfaces are identified as the preferred site of electrochemical pitting corrosion. By exploiting the electrochemical oxidation reaction of iron in the matrix, (Nb,Ti)C powders are separated along these interfaces. The by-products of this process are FeSi alloys, which are evaluated for their electrocatalytic properties in oxygen evolution reactions. It is found that the Fe5Si3 alloy by-product exhibits good electrocatalytic activity and kinetics in the oxygen evolution reaction, demonstrating its potential for practical applications.

From Waste to Wonder: Leveraging Rust Dyeing and Eco-Printing for Modern Sustainable Textiles

In rust dyeing, rusted objects are repurposed to transfer unique patterns and earthy tones onto fabric, transforming what might be considered waste into beautiful, sustainable works of art. This study investigates the combined effects of rust dyeing and eco-printing on different fabric types—cotton, modal, viscose, and polyester. Rust dyeing was performed using rusted iron nails to impart earthy tones of brown and orange to the fabrics. Following the dyeing process, eco-printing was carried out using Psidium guajava (guava) leaves that were pre-mordanted with a ferrous sulphate solution. The colourfastness, pattern quality, and overall appearance of the rust-dyed fabrics post eco-printing was assessed. Results revealed that rust dyeing produced distinct shades on each fabric type, with cotton and modal showing the most pronounced colour retention and eco-print detail. Viscose exhibited moderate colour absorption, while polyester showed limited dye adhesion and eco-print definition. The study concludes that while rust dyeing and subsequent eco-printing can effectively enhance the aesthetic qualities of natural and regenerated cellulosic fabrics, polyester's synthetic nature poses challenges in achieving vibrant and durable impressions. The findings provide insights into optimizing eco-printing techniques for diverse fabric types and contribute to the broader understanding of sustainable textile processes. By embracing the unpredictability of nature, artists and designers can create one-of-a-kind designs that reflect the textures, shapes, and hues found in the environment. These eco-friendly approaches not only reduce reliance on synthetic dyes but also transform everyday materials, often considered waste, into beautiful works of art.

Absorptive Capacity of Gingival Retraction Cords in Hemostatic Solutions: An In Vitro Study.

Background and Objectives: Gingival retraction is a critical pre-impression procedure in fixed prosthodontics, crucial for exposing tooth margins and ensuring accurate impressions for restorations like crowns and bridges. This study aimed to evaluate the absorptive capacity of different gingival retraction cords. Materials and Methods: Ninety samples each of Ultrapak (Ultradent, South Jordan, UT, USA) #00, braided cord, coreless thread, and monofilament thread (totaling 270 samples) were immersed in 0.9% NaCl, 10% aluminum chloride, and 12.7% ferrous sulfate solutions for 120, 300, and 1200 s. The liquid absorption capacity was measured using a gravimetric method, and the data were analyzed using an F-test, setting the significance threshold at p < 0.05. Results: The results revealed statistically significant differences in absorption, particularly for aluminum chloride and ferric sulfate (p < 0.001). Ultrapak demonstrated the highest absorption, followed by the coreless cotton thread, while the monofilament thread absorbed the least, especially at 1200 s. Conclusions: These findings indicate that Ultrapak's superior absorption could enhance moisture control during procedures, highlighting the importance of selecting an appropriate retraction cord for optimal clinical outcomes. Further research is needed to confirm these findings in a clinical setting.

Synergetic recycling of permanent magnet and Li-ion battery cathode material for metals recovery

Rare earth elements (REEs)-based (NdFeB) magnets and lithium−ion batteries (LIBs) are critical for a low−carbon economy. Their production depends on critical elements like REEs, Li, Co and Ni. Recycling of these products have been explored separately as a potential solution. Conventional methods for recycling NdFeB magnets and LIBs face challenges like high energy consumption, lengthy processing, excessive reagent usage, and waste generation. In this study, a novel synergetic recycling methodology is proposed to minimize these challenges. The idea is based on using waste ferrous sulfate solution generated during magnet leaching as a reducing and leaching reagent for battery recycling thereby eliminating the need for additional reagents for oxidation of iron in NdFeB and reduction of cathode material in LIBs. The magnet is leached in diluted H2SO4 at 70 °C followed by double sulfate precipitation for REEs with Na2SO4. The REE-depleted but acidic ferrous solution is then used for reductive leaching of cathode material at 90 °C. The overall recovery rates of REEs, Li, Co, Ni, and Mn in this process are >95%. The iron from magnet material is recovered as crystalline and easily-filterable iron compound that can be converted to goethite and used as a byproduct. This synergetic approach not only reduces reagent consumption and waste generation aligning with the principles of circular economy but also offers improved efficiency, resource conservation, and environmental sustainability.

Adsorption-coupled Fenton type reduction of bromate in water by high-yield polymer-derived ceramic-supported nano-zerovalent iron

Nano-zerovalent iron (nZVI) is a promising material for the removal of both organic and inorganic pollutants from contaminated water. This study investigates the potential of a novel composite of nZVI on a polymer-derived supporting ceramic (nZVI-PDC) synthesized via the liquid-phase reduction method for the simultaneous adsorption and Fenton-type reduction of bromate anion (BrO3−) in water. The nZVI nanoparticles were effectively anchored onto the PDC by impregnating high-yield carbon in a ferrous sulfate solution. The PDC facilitated the uniform dispersion of nZVI nanoparticles due to its multiple active sites distributed within mesocarbon cavities. The developed nZVI-PDC composite exhibited a high specific surface area of 837 m2 g−1 and an ordered mesoporous structure with a pore volume of 0.37 cm3 g−1. As an adsorbent, the nZVI-PDC composite exhibited a maximum adsorption capacity (qe) of 842 mg g−1 and a partition coefficient (KH) of 10.2 mg g−1 μM−1, as calculated by the pseudo-second-order model. As a catalyst, the composite demonstrated a reaction kinetic rate of 43.5 μmol g−1 h−1 within 6 h at pH 4, using a dosage of 60 mg L−1 nZVI-PDC and a concentration of 0.8 mmol L−1 H2O2. Comparatively, PDC exhibited a qe of 408 mg g−1, KH of 1.67 mg g−1 μM−1, and a reaction rate of 20.8 μmol g−1 h−1, while nZVI showed a qe of 456 mg g−1, KH of 2.30 mg g−1 μM−1, and a reaction rate of 27.2 μmol g−1 h−1. The modelling indicated that the nZVI-PDC composite followed pseudo-second-order kinetics. The remarkable removal efficiency of the nZVI-PDC composite was attributed to the synergistic effects between PDC and nZVI, where PDC facilitated charge transfer, promoting Fe2+ generation and the Fe3+/Fe2+ cycle. Overall, this work introduces a promising adsorption technology for the efficient removal of BrO3− from contaminated aqueous solutions, highlighting the significant potential of the nZVI-PDC composite in water purification applications.

Interfacially self-assembled Fe2O3 nanoparticles decorated kaolinite for high performance anti-bacterial and anti-cancerous agents

Nano-engineering of naturally occurring layered materials incorporates enhanced inherent properties for bionanotechnology. Here, kaolinite was treated with a concentrated aqueous ferrous sulfate solution at 100 °C for 1 h for surface modification. Therefore, interfacially self-assembled nanostructure of ferric oxide (Fe2O3) decorated kaolinite composites (FDKC) was fabricated from cationically (Fe2+) modified kaolinite (CMK) after calcinations at 680 °C. Characterized nanocomposites by ATR-IR, EDS, XRD and SEM were tested for antimicrobial activity and antibiofilm activity against Gram negative bacteria Escherichia coli (E. coli), Klebsiella spp (K. spp) and Salmonella typhi (S typhi), as well as Gram positive Staphylococcus aureus, while cytotoxic activity was observed against HeLa cell. CMK and FDKC showed significantly higher antimicrobial activity and biofilm destruction ability than virgin kaolinite (p < 0.05). Besides, FDKC showed the highest anticancer activity in HeLa cell at moderate concentration. The synergistic effect of nanocomposites would offer the modulation of enhanced electronic and physical properties from a simple technology to improve inherent antimicrobial activity and cell toxicity of kaolinite for targeted assay.

Acid Leaching of Uranium from Weathered Uraniferous Black Shale

This paper describes the chemical leaching of uranium from weathered black shale by using sulfuric acid(H2SO4) and acidic ferric sulfate (Fe2 (SO4)3 solutions as lixiviants. The black shale sample was radioactive in nature dueto the presence of uranium and its decay radio-isotope products like 226Ra, 214Pb and 214Bi. The γ-activity of natural 235Uwas 97.6 ± 1.34 Bq Kg-1. The shale sample showed 48±1% porosity with bulk density of 1.38 ± 0.015 g/ cm3. The mainminerals identified in the weathered shale sample were quartz, illite, microcline (K-feldspar), anorthite (Ca-feldspar),gypsum and hematite. A mixed layer illite-smectite phase at 10.8Å was also detected indicating the weathering of clayminerals present in the shale sample. The shale sample was polymetallic in nature and contained 0.005% U3O8, 0.24%V2O5, 0.038% NiO, 0.012% CuO, 0.037% CeO2 and 0.019% ZnO on dry matter basis. The shale sample was organiccarbon rich and contained 19.60% C, 1.25% N and 2.50% H, which indicated the presence of nitrogenous hydrocarboncompound(s). Uranium was present in the tetravalent oxidation state (U4+) in the shale matrix. A series of leachingexperiments were conducted in shake flasks and percolation column for uranium dissolution from black shale with andwithout acidic ferric sulfate solutions of pH 1.5 and pH 2.0 at 30±2 °C. Uranium leaching efficiency was mainly attributedto the concentrations of H2SO4 and Fe3+ ions in the leaching solutions. Uranium dissolution from the weathered blackshale mainly attributed to redox reaction of U4+ to U6+ with Fe3+ as an oxidant in acidic leaching environment.

Success Rates of Antibiotic Sterilization, Indirect Pulp Treatment, and Pulpotomy in the Management of Primary Teeth with Deep Carious Lesions.

A new concept of antibiotic sterilization has come into existence which can be used to sterilize the demineralized portion of the teeth with minimal or ultraconservative excavation of caries in deep dentinal carious lesions as an alternative for indirect pulp therapy (IPT) and pulpotomy to avoid further complications. This study was undertaken to compare the success rates of antibiotic sterilization, indirect pulp treatment, and pulpotomy in the management of primary teeth with deep carious lesion. Ninety teeth involving deep carious lesions approaching pulp in primary molars were selected and randomly divided into three groups containing 30 teeth. Group I was treated with antibiotic sterilization using 3Mix-MP paste, group II was treated with indirect pulp treatment using calcium hydroxide, and group III was treated with conventional pulpotomy using 15.5% ferric sulfate (FS) solution. Clinical and radiographic analysis of all three groups was performed at 1, 3, 6, 9, and 12 months to evaluate the success of treatment procedures using predetermined criteria. Pearson's Chi-squared test and McNemar test were used for statistical analysis. At the end of the 12-month follow-up period, the overall clinical and radiographic success was determined to be 96.3% for group I, 100% for group II, and 96.4% for group III. There were no statistically significant differences observed between the success of three groups, suggesting that either of the procedures can be adopted for the management of deep carious lesions approaching pulp in primary teeth. Antibiotic sterilization can be introduced as a newer modality in the management of deep carious lesions approaching pulp in primary teeth which is ultraconservative in nature and reduces the risk of pulp exposure in comparison with indirect pulp treatment and pulpotomy procedures. Saxena D, Garg N, Pathivada L, et al. Success Rates of Antibiotic Sterilization, Indirect Pulp Treatment, and Pulpotomy in the Management of Primary Teeth with Deep Carious Lesions. Int J Clin Pediatr Dent 2024;17(3):237-242.

Development of the method for obtaining and studying vitriol of the iron sulphate based on iron-containing wastes

Especially in recent years, a ferric sulfate solution has occupied the attention as a useful water treatment agent and, particularly, a ferric sulfate solution and a basic ferric sulfate solution have a quick sedimentation speed for the resulting flocs and show good deodorizing ability as compared with a water treatment agent of an aluminum type such as an aluminum sulfate solution and la basic aluminum chloride solution whereby they have been widely used as a water treatment agent for waste water from paper manufacturing industry, from food industry, from chemical industry, leather industry. The purpose and task of the research is to develop the technology for the production of iron sulfate salts. For this purpose used iron filings and sulfuric and hydrochloric acid acid were used for this purpose. Processes of dissolution of ferric waste in acid are well studied and are shown.

Sucrose, NaCl, and citric acid suppress the metallic sensation of FeSO4.

Metallic sensation is often described as unpleasant and can reduce acceptance of foods and beverages and compliance with medication. Masking and suppressing aversive sensations can help to improve acceptance of these products, with many successful strategies identified for bitterness. However, there are few studies investigating effective strategies for suppressing metallic sensation. This study aims to assess the effectiveness of mixture suppression to reduce the metallic sensation elicited from ferrous sulfate and examine whether individual differences in metallic sensation are associated with the effectiveness of suppression strategies. To achieve this, participants (n = 121) reported the intensity of suprathreshold concentrations of ferrous sulfate alone and in binary mixtures with three tastants, specifically, sucrose, citric acid, and sodium chloride. The results revealed that metallic sensation ratings were significantly lower for every binary mixture tested compared to ferrous sulfate presented in isolation. For 0.3mM ferrous sulfate, sucrose was identified to be the most effective compound in suppressing metallic sensation, followed by citric acid and sodium chloride. For the 1.0mM ferrous sulfate solutions, all tastants were equally effective at suppressing metallic sensation. In addition, there is a significant interaction between the perceived metallic intensity and the effectiveness of each strategy. These findings suggest that sucrose, citric acid, and sodium chloride have the potential to be effective in suppressing metallic sensation.

Corncob-Derived Sulfonated Magnetic Solid Catalyst Synthesis as Heterogeneous Catalyst in The Esterification of Waste Cooking Oil and Bibliometric Analysis

A corncob-derived magnetic solid acid catalyst was synthesized through the sulfonation method and an impregnation process, respectively. In the sulfonation process, the concentrated H2SO4 was utilized as an activation agent to obtain acidic properties. The solution of ferric sulphate-ferrous sulphate was utilized for impregnation to generate the magnetic behaviour of the material. The prepared magnetic acid solid catalyst had a high saturation magnetisation value of 16.48 emu/g and a total acidity of 1.43 mmol/g. The performance of the catalyst was evaluated in the esterification reaction of waste cooking oil. The best result presented 86.12% FFA conversion under reaction conditions of 5% catalyst loading and a 1:15 oil-to-methanol molar ratio at 60oC for 4 h. The catalyst was separated magnetically from the reaction solution and exhibited a good reusability with 61% remaining active after 5 consecutive cycles of reaction. This study resulted in a promising method to obtain magnetic-sulfonated carbon-based catalyst from corncob residue, and it is economical potentially and environmentally friendly for the esterification of low-quality feedstock for biodiesel production.

Dose response assessment of conventional Fricke: a relationship between UV-Visible and nuclear magnetic resonance techniques

Conventional Fricke is an aqueous ferrous sulfate solution that has been widely studied in the field of chemical dosimetry. The feasibility of its use has become attractive for high dose measurements that are of clinical interest in the field of radiotherapy and for industrial purposes, in the irradiation of blood bags and the sterilization of surgical material. The derivation of the absorbed dose of Fricke depends on the radiation-induced oxidation of iron (II) ions (Fe2+) present in the aqueous solution to iron (III) ions (Fe3+), which occurs after exposure to ionising radiation. In this paper, it is proposed to evaluate the dose response of the Fricke dosimeter using two different analytical techniques, ultraviolet-visible spectrophotometry (UV-Vis) and nuclear magnetic resonance spectroscopy (NMR). Twelve groups of samples were analysed in triplicate, irradiated with doses between 0 and 800 Gy, using a cobalt-60 source (60Co). The dose rate of Fricke dosimeters was evaluated against the practical values obtained. The different methods allowed an analytical correlation of the species of oxidised iron (Fe3+) using a linearity curve as a function of the applied radiation dose.

Comparison of sphalerite, djurleite, and chalcopyrite leaching by chemically and biologically generated ferric sulfate solutions

Ferric leaching, including the oxidation of sulfide raw materials of nonferrous metals in a ferric sulfate solution, is a well-known hydrometallurgical process that is widely applied in practice. Recent studies have indicated differences in the leaching kinetics of sphalerite concentrates when using solutions of ferric sulfate obtained by dissolving a commercial reagent or after bio-oxidation of iron-containing substrates by acidophilic chemolithotrophic microorganisms. In this research, the leaching of powder samples of natural zinc and copper sulfide minerals (sphalerite, djurleite, and chalcopyrite) was compared using two different solutions. The first one was an aqueous solution of a chemically pure ferric sulfate reagent, and the second solution contained ferric sulfate obtained via biooxidation of the chemically pure reagent of ferrous sulfate by an acidophilic bacterium Leptospirillum ferriphilum. The leaching solutions contained 10.1 g/L of ferric iron, pH 1.3. The experiments were carried out in batch mode in a mechanically stirred reactor. When using a solution of the chemical reagent of ferric sulfate, the level of dissolution of sulfide minerals was higher than in the case of the biological reagent: by 21.3% after 5 h (80 °C; 1% pulp density) for sphalerite, by 11.8% after 3 h (80 °C; 1% pulp density) for djurleite, and by 9.1% after 5 h (80 °C; 0.5% pulp density) for chalcopyrite. A comparison of the results of experiments with the biological reagent throughout from which microbial cells were preliminarily removed and the chemical reagent to which microbial cells were added confirmed the pivotal role of microbial cell lysis products in decreased efficiency of leaching with the biological reagent. Metabolomics analysis revealed several potential metabolites of L. ferriphilum involved in the observed negative effect on the leaching effectiveness, including nucleosides, alkaloids, and benzaldehydes. By contrast, the efficiency of zinc leaching from sphalerite was improved in the presence of metabolism products of L. ferriphilum in the first hours of the process.

Numerical modeling of radiation-induced reactions: Fricke dosimeter at 298 K, 198 K, and 77 K

The Fricke dosimeter is a widely used gamma radiation dosimetry system. The system is based on the detection of Fe2+ to Fe3+ oxidation in an aqueous solution of ferrous sulfate in sulfuric acid, exposed to ionizing radiation in the presence of oxygen. The system is formed by a series of highly dependent chemical reactions. We developed a numerical model of coupled differential equations based on the mass balance; each equation incorporates information about the formation and breakdown of each molecule, as well as a term that represents an external source of radiation. The numerical model can reproduce the behavior of the experimental data at room temperature. We proposed a correction factor to simulate the behavior of the dosimeter at temperatures of 198 K and 77 K, respectively, when the system is in a thermal bath of dry ice or liquid nitrogen. This model could support a variety of experimental challenges for radiation at low temperatures in different fields of industry and could have relevance for astrobiology problems by offering the possibility of simulating reactions in comets and other exoplanetary bodies.

AN ECO-FRIENDLY DYE FOR BATIK CLOTHES: A NATURAL DYE SOLUTION MADE OF MANGO SEEDS EXTRACT (Mangifera indica L.)

Waste pollution resulting from the production process of synthetic batik dyes is against the Sustainable Development Goals (SDGs) in the aspects of waste management systems and clean water. One effort to cut down the amount of pollution is the use of natural dyes for coloring batik clothes. This undertaking is not only healthy but also expected to bring in some added value economically, community empowerment, and intergenerational inheritance. This experimental research was carried out collaboratively between the Textile and Batik Craft Studio at the Indonesian University of Education, the Umymay Batik Studio, and the Yogyakarta Batik and Craft Center. A batik cloth was dyed 5 times with a mango seed extract solution as the dependent variable, then fixed with lime solution (Ca(OH)2) and Ferrous Sulfate solution (FeSO4.7H2O) as the independent variables. The dyed fabrics were tested for their colorfastness against washing and sun exposure. The results of the study: 1) The process of dyeing the batik cloth was performed through several stages, that is, by cutting the cloth with a canting stamp, dyeing the cloth, and fixing it with Ca(OH)2 and FeSO4.7H2O, the batik cloth fixed with Ca(OH)2 tended to be brown in color while the other one fixed with FeSO4.7H2O resulted in black; 2) The results of the Color Fastness Test against Washing at 40℃ on the batik cloth that has been dyed with mango seed extract fixed with Ca(OH)2 and FeSO4.7H2O were considered a good category with respective values of 4 on a scale of 5. Likewise, the results of the Color Resistance to Light: Day Light Ray Resistant Test Value with the fixation of Ca(OH)2 and FeSO4.7H2O was in the moderate category with a value of 3 each on a scale of 5. There should be a governmental policy to promote a green industry. As for batik artisans, they can utilize an eco-friendly alternative dye for batik clothes.

Strength and Environmental Behaviours of Municipal Solid Waste Incineration Fly Ash for Cement-Stabilised Soil

Many sandy soil foundations need to be solidified during traffic construction in Guangxi, China. Because it has a similar chemical composition as cement, municipal solid waste incineration fly ash (MSWIFA) can strengthen sandy soil. However, the chloride ions and heavy metals in MSWIFA may have a negative influence on the solidification of sandy soil. Thus, FA resource use faces great challenges. This study evaluates the feasibility of using MSWIFA to solidify sandy soil. The acetic acid buffer solution method was used in the leaching test to simulate the weak acid groundwater environment in the Guangxi karst landform. The effects of the treatment methods (washing with ferrous sulphate solution, pre-treatment of organics via chelation, and adding sugarcane ash) on the strength and environmental characteristics of fly ash cement-stabilised soil (FACS) are discussed in detail. The results indicate that the FACS unconfined compressive strength (UCS) decreased by 24.82–46.64% when 5% cement was replaced with FA. Sugarcane ash effectively improved the strength of FACS by more than 10%. The leaching concentrations of Zn and Cu in the FACS meet the concentration limit set by GB 16889-2008. The leaching concentrations of Cr and Pb after washing with 6% ferrous sulphate solution were reduced by more than 30%. Meanwhile, the FACS strength developed faster. Organic chelating agents solidified most heavy metals.

Biofortification of iron in rice (Oryza sativa) grown in acid soil of Assam, India

A pot experiment was conducted during 2019 under rain protected condition at Assam Agricultural University, Jorhat to know the effect of two different levels of soil iron (Fe) content on Fe content of rice tissues including grain (brown rice). Soils of initial DTPA extractable Fe content of 159.40±0.51 mg/kg was applied with 50 ppm Ferrous sulfate solution to increase the soil Fe content to 182.35±0.57 mg/kg. Two popular rice varieties, Ranjit and Mahsuri, and one traditional variety Kajoli Chakua were cultivated as winter rice under submerged condition in pots. There was no Fe toxicity symptom in the leaves for the plants grown at two different soil Fe content. At harvesting stage, the concentration of Fe in different tissues of rice were detected in the order: leaves&gt;husk&gt;grain. The Fe content of brown rice was significantly higher (&gt;100% than that of control) in plants grown in soils of higher Fe content. Significant variation in the Fe content of brown rice was observed according to its position on the rachis, being the highest at the top and the lowest at the bottom. Considering initial soil Fe status, application of Fe fertilizer of suitable concentration to the soil was found to be successful in biofortification of Fe in brown rice, leading to increase of Fe content depending on varieties.

Simple and facile synthesis of magnetic nanosheets by improved precipitation method

Magnetic nanosheets exhibit tremendous potential because of their unique properties. However, the methods commonly used to synthesize magnetic nanosheets have some problems, such as harsh reaction conditions, complex preparation processes, high cost, and low yield, which seriously restrict their development and application. In this study, the dripping speed of the ferrous sulfate solution was controlled by the syringe pump. At a lower reaction temperature, magnetic nanosheets with high saturation magnetization and regular morphology were synthesized by an improved precipitation method without templates and surfactants. The results showed that the lateral size and thickness of the magnetic nanosheets were 30–160 nm and 4.2–4.6 nm, respectively. The magnetic nanosheets were face-centered cubic Fe3O4 with ferromagnetic behavior at room temperature and could be separated from the liquid within 30 s under the external magnetic field. Moreover, the formation mechanism of magnetic nanosheets was also analyzed. Compared to other methods, this study provides a simple and facile method to synthesize magnetic nanosheets, which is suitable for large-scale and low-cost synthesis.

Higher Extrusion Temperature Induces Greater Formation of Less Digestible Type V and Retrograded Starch in Iron-Fortified Rice Grains But Does Not Affect Iron Bioavailability: Stable Isotope Studies in Young Women

BackgroundHot extrusion is widely used to produce iron-fortified rice, but heating may increase resistant starch and thereby decrease iron bioavailability. Cold-extruded iron-fortified rice may have higher bioavailability but has higher iron losses during cooking. Thus, warm extrusion could have nutritional benefits, but this has not been tested. Whether the addition of citric acid (CA) and trisodium citrate (TSC) counteracts any detrimental effect of high-extrusion temperature on iron bioavailability is unclear. ObjectivesOur aim was to assess the effects of varying processing temperatures on the starch microstructure of extruded iron-fortified rice and resulting iron solubility and iron bioavailability. MethodsWe produced extruded iron-fortified rice grains at cold, warm, and hot temperatures (40°C, 70°C, and 90°C), with and without CA/TSC at a molar ratio of iron to CA/TSC of 1:0.3:5.5. We characterized starch microstructure using small- and wide-angle X-ray scattering and differential scanning calorimetry, assessed color over 6 mo, and measured in vitro iron solubility. In standardized rice and vegetable test meals consumed by young women (n = 22; mean age: 23 y; geometric mean plasma ferritin: 29.3 μg/L), we measured iron absorption from the fortified rice grains intrinsically labeled with 57ferric pyrophosphate (57FePP), compared with ferrous sulfate (58FeSO4) solution added extrinsically to the meals. ResultsWarm and hot extrusion altered starch morphology from native type A to type V and increased retrograded starch. However, extrusion temperature did not significantly affect iron solubility or iron bioavailability. The geometric mean fractional iron absorption of iron from fortified rice extruded with CA/TSC (8.2%; 95% CI: 7.9%, 11.0%) was more than twice that from extruded rice without CA/TSC (3.0%; 95% CI: 2.7%, 3.4%; P < 0.001). ConclusionsHigher extrusion temperatures did not affect iron bioavailability from extruded rice in young women, but co-extrusion of CA/TSC with FePP sharply increased iron absorption independently from extrusion temperature. This trial is registered at www.clinicaltrials.gov as NCT03703726.

Remediation of Pear Iron Deficiency Chlorosis by Nanocellulose-iron Chelation and the Underlying Mechanism

Nanocrystal cellulose possesses a strong capability to chelate Fe due to its adsorptive properties. Iron deficiency chlorosis (IDC) is a mineral disorder that remarkably weakens pear photosynthesis, causing declines in plant yields and quality. Conventional methods for controlling IDC generally lack efficiency and overuse chemicals. Foliar application of nanocellulose (NC)-Fe chelate (NCFe) provides a new approach to remediate IDC in pear (Pyrus betulifolia). In this study, NC was prepared by acidic hydrolysis using 64 wt% H2SO4 at 45 °C for 45 minutes. NCFe was formulated based on the net charge density of NC and ferrous sulfate (FeSO4) solution. The nanoparticle properties were characterized by transmission electron microscopy (TEM), dynamic light scattering, and conductometry. Pyrus betulifolia seedlings were pre-etiolated in an improved Hoagland’s nutrient solution and treated with bicarbonate. Changes in chlorophyll content, active Fe content, and photosynthesis rate in NCFe-treated leaves were determined by SPAD values, spectrophotometry, and photosynthetic apparatus, respectively. Ferritin genes (PbFER) and pectin methylesterase genes (PbPME) were extracted from leaf tissue, and gene expression profiles were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR). The results showed that NCFe particles maintained a whisker-like morphology; the Z-average hydrodynamic diameter and zeta potential of NCFe measured by dynamic light scattering were 107.4 ± 3.0 nm and −9.7 ± 0.4 mV, respectively. When NCFe was prepared at a mixing ratio of 1:3000, the total chlorophyll content, active Fe content, and net photosynthetic rate of plant leaves were significantly enhanced by 23.8%, 65.9%, and 40.4% after 72 hours of treatment, respectively, compared with FeSO4 spraying. Importantly, NCFe treatment also significantly downregulated the expression of PbPME and upregulated the expression of PbFER, which are key genes regulating the active Fe content.