Iron Oxide Research Articles

Shifting to biology promotes highly efficient iron removal in groundwater filters

Rapid sand filters are established and widely applied technologies for groundwater treatment. In these filters, main groundwater contaminants such as iron, manganese, and ammonium are oxidized and removed. Conventionally, intensive aeration is employed to provide oxygen for these redox reactions. While effective, intensive aeration promotes flocculent iron removal, which results in iron oxide flocs that rapidly clog the filter. In this study, we operated two parallel full-scale sand filters at different aeration intensities to resolve the relative contribution of homogeneous, heterogeneous and biological iron removal pathways, and identify their operational controls. Our results show that mild aeration in the LOW filter (5 mg/L O2, pH 6.9) promoted biological iron removal and enabled iron oxidation at twice the rate compared to the intensively aerated HIGH filter (>10mg/L O2, pH 7.4). Microscopy images showed distinctive twisted stalk-like iron solids, the biosignatures of Gallionella ferruginea, both in the LOW filter sand coatings as well as in its backwash solids. In accordance, 10 times higher DNA copy numbers of G. ferruginea were found in the LOW filter effluent. Clogging by biogenic iron solids was slower than by chemical iron flocs, resulting in lower backwash frequencies and yielding four times more water per run. Ultimately, our results reveal that biological iron oxidation can be actively controlled and favoured over competing physico-chemical routes. The production of more compact and practically valuable iron oxide solids is of outmost interest. We conclude that, although counterintuitive, slowing down iron oxidation in the water before filtration enables rapid iron removal in the biofilter.

Random pore model insights into structural and operational parameters for hydrogen-based iron oxide reduction

The hydrogen-based direct reduction of iron oxide (DRI) provides a sustainable approach to cleaner ironmaking. In this research, for analyzing hydrogen-based DRI in pellet scale, the random pore model (RPM), the most sophisticated non-catalytic gas-solid model, is applied to determine the effects of structural parameters, including pore-size parameter (ψ), Thiele modulus (ϕ), and product layer resistance (β), along with operational parameters such as pressure, temperature, and gas composition. The PDE equations of RPM were solved numerically using the method of lines together with a finite-difference discretization in space. The effects of parameters ψ and ϕ were investigated, revealing that the reaction rate increases with larger pores and decreases with higher values of ϕ over length and time. Kinetics resemble the unreacted shrinking core model (USCM) for small particles, while pore structure dominates for large particles. Parameter determination is influenced by ϕ changes, shifting control from chemical kinetics to diffusion, with operating conditions impacting reaction rate enhancement. Investigations revealed that as ϕ increases from 0.454 to 1.454, a 6 % conversion gradient forms from the pellet center to the surface. Additionally, at 700°C, reducing the temperature by 100°C slows conversion by 15.45 minutes while increasing it accelerates conversion by 4.55 minutes.

A billion-year shift in the formation of Earth’s largest ore deposits

Banded iron formations (BIFs) archive the relationship between Earth's lithosphere, hydrosphere, and atmosphere through time. However, constraints on the origin of Earth's largest ore deposits, hosted by BIFs, are limited by the absence of direct geochronology. Without this temporal context, genetic models cannot be correlated with tectono-thermal and atmospheric drivers responsible for BIF upgrading through time. Utilizing in situ iron oxide U-Pb geochronology, we provide a direct timeline of events tracing development of all the giant BIF-hosted hematite deposits of the Hamersley Province (Pilbara Craton, Western Australia). Direct dating demonstrates that the major iron ore deposits in the region formed during 1.4 to 1.1 Ga. This is one billion to hundreds of millions of years later than previous age constraints based upon 1) the presence of hematite ore clasts in conglomerate beds deposited before ~1.84 Ga, and 2) phosphate mineral dating, which placed the onset of iron mineralization in the Province at ~2.2 to 2.0 Ga during the great oxidation event. Dating of the hematite clasts verified the occurrence of a ~2.2 to 2.0 Ga event, reflecting widespread, but now largely eroded iron mineralization occurring when the Pilbara and Kaapvaal cratons were proximal. No existing phosphate mineral dates overlap with obtained hematite dates and therefore cannot be related to hematite crystallization and ore formation. New geochronology conclusively links all major preserved hematite deposits to a far younger (1.4 to 1.1 Ga) formation period, correlated with the amalgamation of Australia following breakup of the Columbia supercontinent.

Investigation of superparamagnetic iron oxide nanoparticles in air environment for elevated saturation magnetization

Iron oxide nanoparticles have garnered interest for their unique properties and wide application areas. For applications, superparamagnetic nanoparticles are required so that they can be magnetized by an external magnetic field and rapidly demagnetize again when the field is removed. High saturation magnetization, Ms is also required for applications to provide easy magnetic control over separation and targeting. For magnetically controlled applications, superparamagnetic iron oxide nanoparticles with a high Ms are important. In this study, superparamagnetic iron oxide nanoparticles were co-precipitated under air atmosphere and the effects of alkali concentration, stirring rate and reaction time on the structural and related magnetic properties were investigated to obtain the high Ms for each parameter. According to the structural results, it is challenging to obtain magnetite nanoparticles under air atmosphere due to oxidizing effect. The increase of Ms values with the increase of alkali concentration may come from the phase of the samples although the crystal size of the nanoparticles is getting smaller. It can be said that there is an optimum stirring rate to obtain the highest Ms under air atmosphere rather than an uptrend/downtrend. The maximum Ms of 69.2 emu g−1 was obtained for superparamagnetic iron oxide nanoparticles synthesized at 700 rpm. With the increase of reaction time, magnetic size of the nanoparticles is observed to decrease in contrast with the increase of physical particle size. The maximum Ms value for the reaction time parameter is 67.3 emu g−1 at 15 min. Due to their high Ms values and superparamagnetic nature, the nanoparticles synthesized under study may find use in magnetic separation, water purification, and other related fields.

Studies on the thermal sensitivity of lung cancer cells exposed to an alternating magnetic field and magnesium-doped maghemite nanoparticles

BackgroundMagnetic fluid hyperthermia (MFH) represents a promising therapeutic strategy in cancer utilizing the heating capabilities of magnetic nanoparticles when exposed to an alternating magnetic field (AMF). Because the efficacy and safety of MFH treatments depends on numerous intrinsic and extrinsic factors, therefore, the proper MFH setups should focus on thermal energy dosed into the cancer cells.MethodsIn this study, we performed MFH experiments using human lung cancer A549 cells (in vitro) and NUDE Balb/c mice bearing human lung (A549) cancer (in vivo). In these two experimental models, the heat was induced by magnesium-doped iron(III) oxide nanoparticles coated with mPEG-silane (Mg0.1-γ-Fe2O3(mPEG-silane)0.5) when exposed to an AMF.ResultsWe observed that the lung cancer cells treated with Mg0.1-γ-Fe2O3(mPEG-silane)0.5 (0.25 mg·mL−1) and magnetized for 30 min at 14.4 kA·m−1 yielded a satisfactory outcome in reducing the cell viability up to ca. 21% (in vitro). The activation energy calculated for this field strength was estimated for 349 kJ·mol−1. Both volumetric measurements and tumor mass assessments confirmed by magnetic resonance imaging (MRI) showed a superior thermal effect in mice bearing human lung cancer injected intratumorally with Mg0.1-γ-Fe2O3(mPEG-silane)0.5 nanoparticles (3 mg·mL−1) and subjected to an AMF (18.3 kA·m−1) for 30 min four times at weekly intervals. Research demonstrated that mice undergoing MFH exhibited a marked suppression of tumor growth (V = 169 ± 94 mm3; p < 0.05) in comparison to the control group of untreated mice. The CEM43 (cumulative number of equivalent minutes at 43 °C) value for these treatments were estimated for ca. 9.6 min with the specific absorption rate (SAR) level ranging from 100 to 150 W·g−1.ConclusionsThe as-obtained results, both cytotoxic and those related to energy calculations and SAR, may contribute to the advancement of thermal therapies, concurrently indicating that the proposed magnetic fluid hyperthermia holds a great potential for further testing in the context of medical applications.Graphical

Bismuth Iron Oxide Catalysts for Efficient CO2 Electroreduction to Formate.

Renewable energy-driven electrocatalytic CO2 reduction reaction (CO2RR) over bismuth-based catalysts shows great promise for converting CO2 into formic acid and formate while closing the carbon cycle. Herein, we report a high-performance BiFeO3/Bi25FeO40 precatalyst, which delivers a formate partial current density of 359.8 mA cm-2 and a formate formation rate of 6.71 mmol h-1 cm-2 in a flow cell at -0.75 V versus reversible hydrogen electrode (vs RHE). Furthermore, it shows stable formate production for 88 h at -0.64 V vs RHE with a total current density of 160 mA cm-2. The impressive electrocatalytic performance toward CO2RR to formate is likely ascribed to the synergistic effect of single Bi atoms and bimetallic BiFe nanoparticles present in close proximity after in situ electrochemical reconstruction of the BiFeO3/Bi25FeO40 precatalyst. This work presents new insights into the development of highly efficient Bi-based catalysts for the CO2RR.

Biodegradable Magnetic Vesicles for Magnetic Hyperthermia Stimulated Drug Release

AbstractMagnetic nanomaterials have emerged as an effective drug‐delivery platform for targeted imaging and therapy. However, it remains challenging to fabricate biodegradable magnetic nanoparticles with controllable drug release behaviors and strong magnetic responsiveness. Here an asiaticoside‐loaded biodegradable magnetic vesicle is developed based on the self‐assembly of amphiphilic block copolymer tethered superparamagnetic iron oxide nanoparticles. Thanks to the collective properties, the magnetic vesicles show stronger magnetic responsiveness than individual nanoparticles. Additionally, the magnetic vesicles are dissociated within weeks owing to the biodegradable polymer backbone, which can significantly improve the long‐term biocompatibility of the nanomaterials. The asiaticoside‐loaded magnetic vesicles can readily release the payloads in an alternating magnetic field, likely due to the rising local temperature over the phase transition temperature of the polymers attached on nanoparticles. This work provides new insights into the design and construction of biodegradable magnetic nanomedicines for targeted drug delivery.

Effect of Different Shapes of Nanoparticles on Mixed Convective Nanofluid Flow in a Darcy-Forchhiemer Porous Medium

The nanofluid has diverse applications in industries, engineering, and medicine due to its greater thermal characteristics. However, various factors such as the shape and size of nanoparticles, the base fluid, the porous medium, the quadratic drag force, and the viscous dissipation have significant effects on the flow and heat transfer characteristics of nanofluids. Therefore, it is crucial to study the influence of these factors. In this paper, a theoretical investigation is conducted to analyze the mechanisms of thermal conductivities of different shapes of nanoparticles, such as platelet, cylinder, brick and blade on the mixed convective nanofluid flow in a vertical channel saturated with porous medium. Consider ethylene glycol and water as base fluids for the nanoparticles, including copper, aluminum oxide, titanium oxide, silver, and iron oxide. A thin, movable baffle plate of negligible thickness is inserted in the channel and made into double passages. To define the porous matrix, the Darcy-Brinkaman-Forchhiemer model is used, and to define the nanofluid, the Tiwari and Das model is used. Robin boundary conditions are considered for the channel flow. The differential transform method (DTM) is applied to solve non-linear governing equations with inertia, and the perturbation method is applied to solve the problem without inertia. Velocity and temperature cantors are shown graphically using MATLAB and MATHEMATICA. The obtained values by DTM and the perturbation method are well validated and shown graphically. The Nusselt number was evaluated and tabulated for all governing parameters. The objective of this article is to investigate the effect of nonspherical shapes of nanoparticles, the base fluid, the inertial forces of the porous medium, and the buoyancy force on the thermal characteristics of flow and heat transfer of nanofluids. The main findings of this problem are that the optimum velocity and temperature cantor are found for platelet-shaped water-based silver nanofluid.

Engineering Magnetic Extracellular Vesicles Mimetics for Enhanced Targeting Chemodynamic Therapy to Overcome Ovary Cancer.

Chemodynamic therapy (CDT), employing metal ions to transform endogenous H2O2 into lethal hydroxyl radicals (•OH), has emerged as an effective approach for tumor treatment. Yet, its efficacy is diminished by glutathione (GSH), commonly overexpressed in tumors. Herein, a breakthrough strategy involving extracellular vesicle (EV) mimetic nanovesicles (NVs) encapsulating iron oxide nanoparticles (IONPs) and β-Lapachone (Lapa) was developed to amplify intracellular oxidative stress. The combination, NV-IONP-Lapa, created through a serial extrusion from ovarian epithelial cells showed excellent biocompatibility and leveraged magnetic guidance to enhance endocytosis in ovarian cancer cells, resulting in selective H2O2 generation through Lapa catalysis by NADPH quinone oxidoreductase 1 (NQO1). Meanwhile, the iron released from IONPs ionization under acidic conditions triggered the conversion of H2O2 into •OH by the Fenton reaction. Additionally, the catalysis process of Lapa eliminated GSH in tumor, further amplifying oxidative stress. The designed NV-IONP-Lapa demonstrated exceptional tumor targeting, facilitating MR imaging, and enhanced tumor suppression without significant side effects. This study presents a promising NV-based drug delivery system for exploiting CDT against NQO1-overexpressing tumors by augmenting intratumoral oxidative stress.

Emulsion liquid membrane (ELM) enhanced by nanoparticles and ionic liquid for extracting vanadium ions from wastewater.

Emulsion liquid membrane (ELM) stands out as an extraction process that has drawn much attention due to its promising prospects in industrial wastewater treatment technology. Nevertheless, the pivotal challenge is to reach high membrane stability to overcome the obstacle of applying ELM at the industrial scale. In this study, ELM was boosted by using nanoparticles (superparamagnetic iron oxide (Fe2O3)) in the stripping phase (W1) and ionic liquid (1-methyl-3-octyl-imidazolium-hexafluorophosphate [OMIM][PF6) in the oil phase (O) for recovering/extracting vanadium from synthetic wastewater to near completion and at the same time enhancing emulsion stability to be appropriate for industrial application. The vanadium recovery/extraction percentage has been raised significantly in 3min to 99.6% when adding 0.01% (w/w) Fe2O3 NPs (20 to 50nm in size) in the internal phase (W1) and 5% (v/v) [OMIM]PF6 ionic liquid in the oil phase (O). Also, the emulsion stability was considerably improved, and the leakage percentage was reduced to 16% after 3days. The results of this study could be used in the future to remove additional heavy metal ions from industrial effluents.

Cytotoxic and radical activities of metal-organic framework modified with iron oxide: Biological and physico-chemical analyses

Metal-organic framework (MOF) modified with iron oxide, Fe3O4-MOF, is a perspective drug delivery agent, enabling magnetic control and production of active hydroxyl radicals, •OH, via the Fenton reaction. This paper studies cytotoxic and radical activities of Fe-containing nanoparticles (NPs): Fe3O4-MOF and its components – bare Fe3O4 and MOF (MIL-88B). Luminous marine bacteria Photobacteriumphosphoreum were used as a model cellular system to monitor bioeffects of the NPs. Neither the NPs of Fe3O4-MOF nor MOF showed cytotoxic effects in a wide range of concentrations (<10 mg/L); while Fe3O4 was toxic at >3·10−3 mg/L. The NPs of Fe3O4 did not affect the bacterial bioluminescence enzymatic system; their toxic effect was attributed to cellular membrane processes. The integral content of reactive oxygen species (ROS) was determined using a chemiluminescence luminol assay. Bacteria mitigated excess of ROS in water suspensions of Fe3O4-MOF and MOF, maintaining bioluminescence intensity closer to the control; this resulted in low toxicity of these NPs. We estimated the activity of •OH radicals in the NPs samples with physical and chemical methods – spin capture technology (using electron paramagnetic resonance spectroscopy) and methylene blue degradation. Physico-chemical interpretation of cellular responses is provided in terms of iron content, iron ions release and •OH radical production.

Eco-Friendly Mycogenic Synthesis of Iron Oxide Nanoparticles Using Volvariella volvacea and Unveiling its Potential as Antibiofilm and Anticancer Agents

Abstract This research explores the eco-friendly creation of functional, biocompatible nanomaterials through green chemistry, utilizing natural extracts over chemicals to produce metal and metal oxide nanoparticles. The study focuses on iron oxide nanoparticles synthesized with Volvariella volvacea (GIONP) and evaluates their physical, chemical, and biological traits, including their anticancer capabilities, against traditionally made IONPs (CIONP). GIONPs, confirmed by UV-visible spectroscopy and dynamic light scattering, showed enhanced stability and consistent size distribution. They also demonstrated smaller sizes via Fe-scanning electron microscopy analysis, and X-ray diffraction and Fourier transform infrared studies verified their crystalline structure and organic functional groups. Notably, GIONPs exhibited strong antioxidant properties, low toxicity to blood cells, promising for intravenous use, and greater antimicrobial and antibiofilm activities against various bacterial strains than CIONPs. The study revealed that both GIONPs and CIONPs exhibit a similar degree of toxicity towards MDA-MB 231 cancer cells. The internalization of GIONPs within these cells was verified through a Prussian blue assay and further supported by the concentration-dependent increase in intracellular iron levels post-treatment. These findings underscore the successful formulation of GIONPs that are not only biocompatible and eco-friendly but also capped with bioactive compounds, highlighting their promising applications in the field of biomedicine.

Unraveling iron oxides as abiotic catalysts of organic phosphorus recycling in soil and sediment matrices

In biogeochemical phosphorus cycling, iron oxide minerals are acknowledged as strong adsorbents of inorganic and organic phosphorus. Dephosphorylation of organic phosphorus is attributed only to biological processes, but iron oxides could also catalyze this reaction. Evidence of this abiotic catalysis has relied on monitoring products in solution, thereby ignoring iron oxides as both catalysts and adsorbents. Here we apply high-resolution mass spectrometry and X-ray absorption spectroscopy to characterize dissolved and particulate phosphorus species, respectively. In soil and sediment samples reacted with ribonucleotides, we uncover the abiotic production of particulate inorganic phosphate associated specifically with iron oxides. Reactions of various organic phosphorus compounds with the different minerals identified in the environmental samples reveal up to ten-fold greater catalytic reactivities with iron oxides than with silicate and aluminosilicate minerals. Importantly, accounting for inorganic phosphate both in solution and mineral-bound, the dephosphorylarion rates of iron oxides were within reported enzymatic rates in soils. Our findings thus imply a missing abiotic axiom for organic phosphorus mineralization in phosphorus cycling.

Geometry and Surface Area Optimization in Iron Oxide Nanoparticles for Enhanced Magnetic Properties

Geometry and Surface Area Optimization in Iron Oxide Nanoparticles for Enhanced Magnetic Properties

Ferrihydrite colloid-mediated transport of sulfamerazine in saturated porous media: Combined roles of rhamnolipid and solution pH

To date, there is still very little knowledge about the combined effects of typical biosurfactants and solution pH values on iron oxide colloid-mediated transport of sulfamerazine (SMZ, a typical sulfonamide antibiotic) in saturated porous media. Herein, the influences of rhamnolipid (a common biosurfactant in the environment) on SMZ mobility in the absence or presence of ferrihydrite (a model iron oxide) colloids in saturated quartz sand were explored. Generally, the rhamnolipid suppressed the transport of SMZ without ferrihydrite colloids owing to the bridging effect of this biosurfactant (i.e., rhamnolipid served as a bridging agent between SMZ and sand). Moreover, ferrihydrite colloids also inhibited SMZ mobility due to the deposition of colloid-associated SMZ. Surprisingly, the presence of rhamnolipid significantly influenced ferrihydrite colloid-mediated transport of SMZ, and this effect was highly dependent on the solution pH. Concretely, rhamnolipid enhanced the inhibitory effects of ferrihydrite colloids on SMZ transport at pH 5.0 because of the increased SMZ retention on the deposited colloids via the bridging effect of biosurfactant. At pH 7.0, the transport-inhibition effects of colloids were weakened by adding rhamnolipid, which was due to the colloid-associated SMZ transport and the promoting electrostatic repulsion between the free SMZ and sand/ the deposited colloids. Surprisingly, ferrihydrite colloids facilitated SMZ transport in the addition of rhamnolipid at pH 9.0. This phenomenon stemmed from the enhanced free SMZ mobility, the colloid-assisted mobility of SMZ, and the competitive deposition between SMZ– species and negatively charged colloids. Moreover, the two-site non-equilibrium model was performed to help interpret the controlling mechanisms for the synergistic effects of rhamnolipid and solution pH on colloid-mediated transport of SMZ. The outcomes of this study offer valuable knowledge about the functions of widespread biosurfactants in the environmental consequences of antibiotics in subsurface systems with iron oxide colloids.

Understanding Zinc Transport in Estuarine Environments: Insights from Sediment Composition

Sediments are sources and sinks of heavy metals in water, and estuaries are heavily influenced by human production and life. Therefore, it is of great significance to study the composition of estuarine sediments and the relationship between their components to understand the transport and transformation pathways of heavy metals in the environment. In this research, we investigated the characteristics and patterns of Zn adsorption by organic–inorganic composites, organic–clay mineral composites, and iron oxide–clay mineral composites in eight estuarine sediment samples from Dianchi Lake. The results show that both Langmuir and Freundlich isothermal models can describe the adsorption behaviour of the adsorbent better. The order of the adsorption capacity of the three groups of samples for zinc was organic–inorganic composites &gt; organic–clay mineral composites &gt; iron oxide–clay mineral composites. Through FTIR and XRD analyses, the adsorption of Zn2+ on the three groups of samples was dominated by electrostatic attraction and coordination adsorption, accompanied by the occurrence of ion exchange and co-precipitation. After FTIR semi-quantitative analysis, it was found that the source of the differences in the high and low Zn adsorption of the three types of samples may be mainly due to the content of phenolic functional groups in the organic matter. This may be related to the low redox site of the phenolic hydroxyl group, which, as an electron donor, is susceptible to electrostatic attraction and complexation with heavy metal cations. The organic–inorganic composite has a higher adsorption capacity for Zn when the ratio of the active fraction of organic matter to the free iron oxide content is 0.65–0.70. In this range, the organic matter can provide enough negative charge without making the sample surface too dense. Iron oxides can also activate the sample by providing sufficient contact between the clay minerals and the organic matter. When this ratio is too high or too low, it will be unfavourable for Zn adsorption.

Preparation of yttrium-90 resin microspheres based on SiO2-Fe3O4 nanomaterials and analysis of their biodistribution

This study reports the development and evaluation of yttrium-90 (90Y) radiolabeled silica-coated iron oxide (SiO2-Fe3O4) resin microspheres for potential theranostic application in cancer radiation therapy. Iron oxide nanoparticles of average diameter 29.7 nm were synthesized via optimized co-precipitation and displayed superparamagnetic behavior ideal for MRI. Aminosilane surface functionalization enabled covalent conjugation of 1 mmol/g DTPA/DOTA chelators for labeling 2 mCi 90Y per 150 μg nanoparticles with 92 % efficiency when incubated for 45 mins at pH 5.5 and 50°C. In vitro stability assays in buffers and human serum showed excellent 90Y retention (>95 %) up to 48 hours. In vivo biodistribution in Wistar rats revealed extended nanoparticle circulation half-life of 5.2 hours and peak exposure of 22.4 %ID/g compared to rapid clearance of unconjugated 90Y chloride within 1 hour. Complete renal recovery by 72 hours and minimal bone accumulation (<2 %) proves in vivo stability and biocompatibility of the 90Y-radiolabeled theranostic platform.

Hydrothermal alteration and elemental mass balance for the Surda Copper Deposit, Singhbhum Shear Zone, Eastern India: Implications for both copper and magnetite-apatite mineralization

This paper explores the geological relationships, mineralogical, and geochemical characteristics, and quantitative elemental mass balance constraints of the hydrothermal alteration zones within the uraniferous Surda copper deposit in the Singhbhum Shear Zone in eastern India, which is affiliated with an iron oxide copper-gold system. Five distinct alteration zones are identified: a proximal potassic (biotitization) zone containing magnetite- apatite; a central chloritization zone containing copper, uranium, gold, and magnetite; distal silicification (quartz) and albitization zones; and a transitional chlorite-sericitization zone. Evidence suggests these zones originated from mafic precursors linked to a subduction zone. Magnetite mineralization shows both magmatic (δ 18 O +2.0 to +4.8 ‰) and hydrothermal (δ 18 O +0.4 to +0.6 ‰) signatures. Hydrothermal magnetite-apatite formed at temperatures of 440° to 550°C, with continued crystallization at lower temperatures (280° to 360°C) concurrent with copper sulfide and uranium precipitation from an Fe-rich, isotopically heavy fluid (δ 34 S + 4.55 to + 9.66‰). Major elements (Ca, Na, Mg) and some minor and rare earth elements decrease from weakly-altered mafic rocks to late alteration zones, reflecting the breakdown of Ca-bearing hornblende, biotite and plagioclase. Potassium decreases from early to late alteration zones due to mineral transformations. Mass-balanced geochemical data align with hydrothermal alteration mineral assemblages, indicating processes like mineral dissolution, element absorption, and sulfide behavior. Overall, the study highlights the complex hydrothermal alteration processes shaping the Surda copper deposit and provides insights into ore formation mechanisms.

Ball milling boosted magnetic cotton husk-derived biochar adsorptive removal of oxytetracycline and ciprofloxacin from water

Oxytetracycline (OTC) and ciprofloxacin (CIP) contamination have caused serious risks to human health, and modified biochar is considered as a potential adsorbent for their removal. The typical agricultural waste of cotton husk was used as the feedstock, then was combined with γ-Fe2O3 and ball milling to innovatively synthesize nano zero-valent iron (nZVI) supporting magnetic cotton hush-derived biochar (Fe2O3@BMBC) by reductive calcination. Fe2O3@BMBC performed excellent adsorption performance with a maximum adsorption capacity for OTC (266.7 mg·g−1) and CIP (83.36 mg·g−1), and its adsorption capacity was 1.6 and 2.3 times that of cotton husk biochar (BC). Characterization analysis showed that Fe2O3@BMBC contained abundant oxygenated functional groups (e.g., -OH, C = O and Fe–O) and its surface was covered by diverse iron oxides. The high magnetization sensitivity of Fe2O3@BMBC guaranteed that it was easily to be separated by a magnet. Oxygenated functional groups (e.g., -OH, C = O and Fe–O) participated in the adsorption process, and solution pH significantly affected the adsorption behaviour, and pseudo-second-order model and Freundlich model better fitting the kinetics and isotherms data. These results confirmed that π-π conjugation, H-bonding, Fe–O complexation and electrostatic interactions contributed to the greater adsorption capacity of Fe2O3@BMBC. Ethanol + ultrasound could efficiently regenerate the used Fe2O3@BMBC and maintain its sustainable adsorption performance for OTC and CIP. Additionally, Fe2O3@BMBC performed a good environmental security in a wide pH range (from 3 to 11) in view of the low leaching risk of Fe.Graphical

Impact of Iron Oxide on Anaerobic Digestion of Frass in Biogas and Methanogenic Archaeal Communities’ Analysis

With the increasing prominence of the global energy problem, socioeconomic activities have been seriously affected. Biofuels, as a renewable source of energy, are of great significance in promoting sustainable development. In this study, batch anaerobic digestion (AD) of frass (swine manure after bioconversion by black soldier fly larvae) and co-digestion with corn straw after the addition of iron oxide (Fe3O4) nanoparticles is investigated, as well as the start-up period without inoculation. The biochemical methane potential of pure frass was obtained using blank 1 group and after the addition of various sizes of Fe3O4 nanoparticles for 30 days period, and similarly, the digestion of frass with straw (blank 2) and after the addition of various sizes of Fe3O4 nanoparticles for 61 days period. The results showed that the average gas production was 209.43 mL/gVS, 197.68 mL/gVS, 151.85 mL/gVS, and 238.15 mL/gVS for the blank, ~176 nm, ~164 nm, and ~184 nm, respectively. The average gas production of frass with straw (blank 2) was 261.64 mL/gVS, 259.62 mL/gVS, 241.51 mL/gVS, and 285.98 mL/gVS for blank 2, ~176 nm, ~164 nm, and ~184 nm, respectively. Meanwhile, the accumulated methane production of the ~184 nm group was 2312.98 mL and 10,952.96 mL, respectively, which significantly increased the biogas production compared to the other groups. The methanogenic results of the frass (30 days) indicated that Methanocorpusculum, Methanosarcina, and Methanomassiliicoccus are the important methanogenic species in the AD reactor, while the microbial diversity of the ~184 nm group was optimal, which may be the reason for the high gas production of ~184 nm.