Production Of Crystals Research Articles

Effects of organic pollutants on struvite crystallization kinetics and the molecular mechanism of inhibition on crystal growth

The abilities of improving phosphorus (P) resources sustainability and reducing water eutrophication make struvite crystallization technology attract increasing interest in wastewater treatment, but struvite crystallization process may be affected by various impurities in wastewater. In this study, the effects of nine representative ionic surfactants including three types (anionic, cationic and zwitterionic) on crystallization kinetics and product quality of struvite were investigated, and the influencing mechanism was further probed. The results demonstrated that anionic surfactants significantly inhibit crystal growth so as to reduce crystal size especially in a-axis direction, change crystal morphology and decrease P recovery efficiency, and also lead to a slight decline in product purity. In contrast, cationic and zwitterionic surfactants have no obvious influence on the formation of struvite. A series of experimental characterizations and molecular simulations collectively revealed that the inhibition of crystal growth by anionic surfactants is attributed to the adsorption of anionic surfactant molecules on struvite crystal surface and subsequent blockage of active growth sites. The binding ability of surfactant molecules with the Mg2+ exposed on struvite crystal surface was highlighted to be the most essential factor determining the adsorption behavior and adsorption capacity. Anionic surfactants with stronger binding ability with Mg2+ have more intense inhibitory effect, but a large molecular volume of anionic surfactants will weaken the adsorption capacity on crystal surface so as to reduce the inhibitory effect. Contrastively, cationic and zwitterion surfactants without binding ability with Mg2+ have no inhibitory effect. These findings enable us to have a clearer understanding of the impact of organic pollutants on struvite crystallization and make a preliminary judgment on the organic pollutants that may have the ability to inhibit the crystal growth of struvite.

A Feasible Route for Preparation of Calcium Sulfate Whiskers from FGD Gypsum via Filtrate Recycle under Hydro-Thermal Conditions

Calcium sulfate whiskers (CSWs) were synthesized using purified flue-gas desulfurization (FGD) gypsum as raw materials using a hydrothermal method, where the filtrate was recycled back to the reaction slurry. The study investigated the impact of pH and Cu2+ concentration in the reaction solution with or without reagent compensation. The effects of cycle number on the crystal morphology, phase structure, and productivity of the hydrothermal products were also examined. The findings indicate that the crystal morphology and quality of the CSWs deteriorated as the cycle number increased due to a rise in pH and a decrease in Cu2+ concentrations in the reaction solution without reagent compensation. However, adding a specific amount of H2SO4 and CuCl2 to the slurry with filtrate recycle maintained the long fibrous shape of the hydrothermal products for up to seven cycles while also increasing their productivity from 73.7% to 86%. Regardless of reagent compensation, the cycle number of filtrate significantly affected the crystal morphology of the hydrothermal products, but it had no impact on their phases.

CREATION OF COMPOSITE SCINTILLATORS WITH A SHORT DECAY TIME

To date, LuAG:Ce crystals are one of the most common scintillators, since they have been known for a long time and there are technologies for mass production of large-volume crystals. However, the scintillation properties of such crystals can be improved by creating mixed crystals with the replacement of some ions by others. In this work, composite scintillators based on the grown LuYAG:Ce inorganic crystals were produced. For the obtained samples, studies of optical transmission, luminescence, light output, and decay time were carried out. The optimal conditions and sizes of crystalline grains for the creation of composite scintillators have been determined.

Recovering electrical energy from forward osmosis process through amorphous silicon oxide crosslinked vanadium pentoxide-reduced graphene oxide membrane

Forward osmosis (FO) is a promising technology for energy-efficient water treatment but suffers from the drawback of reverse solute flux which often results in energy loss. Recent research has been directed toward reducing energy consumption and improving efficiency in the FO process. However, there remains a significant gap in utilization the inevitable reverse solute flux. Our study introduces an innovative approach to minimize energy consumption by transforming this reverse solute flux into sustainable electricity. Here, we fabricated membranes using two-dimensional flakes of vanadium pentoxide (VO) and reduced graphene oxide (r-GO) and cross-linked with amorphous silicon oxide (aSiO). The optimized VO-aSiO-rGO membrane showcases a remarkable ability to recover nearly 26% of the power applied for liquid pumping, exhibiting a significant advancement in the FO process. The membrane also outperforms commercial CTA-based FO membranes by achieving superior water fluxes (∼45 L/m2.h) and low specific reverse salt fluxes (SRSF) (∼0.13 g/L), indicating its superior separation efficiency for concentration applications. Moreover, the VO-aSiO-rGO membrane demonstrated stable performance with a water flux of 28.5 L/m2.h over 40 h of continuous operation. Additionally, it successfully generated output voltage and current values up to 293 mV and 32.2 µA, respectively, with a 106 fold salinity gradient, leading to a power density of ∼ 4.72 W.m−2. The study also explored energy-recovering possibilities and crystal production in realistic scenarios using different concentrations of tea as the feed solutions. The results of this work not only address the critical gap in the efficient use of energy in the FO process but also provide a significant breakthrough towards sustainable and efficient water treatment technologies with integrated energy recovery systems.

Crystal facet-dependent product selectivity of CO2 reduction reaction on indium revealed by first-principles calculations

Electrochemical CO2 reduction reaction (CO2RR) is a realistic way to achieve carbon neutrality which is essential to mitigate climate change and energy shortage. By using density functional theory based first-principles calculations in this work, we studied the mechanisms of CO2RR to formic acid (HCOOH), carbon monoxide (CO), and hydrogen (H2) on 6 indium (In) crystal surfaces, namely (101), (002), (111), (110), (211) and (100), and explored the crystal facet-dependent product selectivity. Based the surface energies calculated for the 6 In surfaces, the Wulff shape of In particle was constructed with 4 surface, namely In (101), (211), (002), and (111). By calculating the Gibbs free energies along 4 reaction pathways for the 3 products of CO2RR, it was shown that the 6 In surfaces favor either HCOOH or H2, rather than CO. Especially, the In (101) which dominates the Wulff shape shows good product selectivity for HCOOH, which is in accordance with the result of a recent experiment. Furthermore, the In (110) was predicted as a competitive candidate surface for CO2RR to HCOOH, but largely ignored before.

Prevalence, attachment ability and strength of the biological control agent Bacillus thuringiensis on tomato.

Bacillus thuringiensis (Bt) is commonly used as a biological control agent (BCA) to control insect pests in edible plant production and can as such be introduced into the food chain of fresh produce. Using standard food diagnostics Bt will be detected and reported as presumptive B. cereus. Tomato plants are often sprayed with Bt biopesticides for insect control, thus these Bt BCAs can also reach the tomato fruits and persist until consumption. In this study, vine tomatoes from the retail in Belgium (Flanders) were investigated for the occurrence and residual numbers of presumptive B. cereus and Bt. Of 109 tomato samples, 61 (56%) were tested positive for presumptive B. cereus. Of the presumptive B. cereus isolates (n=213) recovered from these samples, 98% were identified as Bt by the production of parasporal crystals. Further quantitative real-time PCR assays on a subselection of Bt isolates (n=61) showed that 95% of Bt isolates were indistinguishable from Bt biopesticide strains that are approved to be used on crops in the EU. Furthermore, the attachment strength of tested Bt biopesticide strains showed easier wash-off properties if using the commercial Bt granule formulation than the unformulated lab-cultured Bt or B. cereus spore suspensions.

Effects of different seed forms on crystal size distribution for seeded batch crystallization process

The effects of different seed forms on crystal product distribution are presented for optimizing crystal size distribution (CSD) in the case of seeded batch cooling crystallization process. Three different seed distributions and quality are introduced as variable parameter for CSD control of seeded batch crystallization process via simulation in Matlab software. Similar implementation is conducted in the experimental study using the same operating conditions and parameters. Cubic cooling profile is adapted as the temperature profile for potash alum crystallization system due to its ability to control secondary nucleation. The experimental data obtained from laboratory works are validated the simulation results from Matlab where good agreement has been achieved. In terms of mean crystal size of the final CSD, the seed profile with 0.29 standard deviation labelled Sieved Seed 2, produces the best seed profile for seeded batch potash alum crystallization process because it has the largest size of crystals at mean crystal size of 500 μm grown from 90 μm of seed crystals. However, considerable fine crystals at mean crystal size of 30 μm are also obtained indicating trade-off between large size of crystals and fine crystals are needed. In conclusion, this work highlights the effects of different seed quality in terms of distribution and shape on crystal size distribution as one of the important quality specifications in crystallization process and demonstrates narrow distribution of seed crystals as recommendation on the best seed quality for producing desired CSD.

Towards net zero emissions, recovered silicon from recycling PV waste panels for silicon carbide crystal production

The high rate of PV adaptation around the world requires a strategy for recovery of the materials from PV waste panels and a circular market development. In particular, the silicon recovered from the PV cells can be used in different applications. A valuable acquisition is to refine the recovered silicon at metallurgical grade to a high level of purity namely electronic grade silicon which in conjunction with graphite can be the raw material for silicon carbide crystal production. Based on a comprehensive and critical review of the latest research and development of relevant technologies, a manufacturing process is proposed to increase the usage of renewable resources, reduce the energy consumption and CO2e emissions. The recovered silicon from recycling PV waste can reduce the CO2e emissions to a third of what is involved in the current carbothermic reduction of quartz in an induction furnace. Based upon the thorough evaluation of available evidence, a continuous coupled process is envisaged where the upgraded metallurgical grade silicon from recycling PV waste undergoes further vacuum and gas refining to the electronic grade silicon. Then the purified liquid silicon enters a vertical Bridgeman furnace for silicon carbide crystal production through a bottom seeded solution growth process. Considering the silicon melting point at 1410 °C, omitting a solidification/ meting step after vacuum/gas refining leads to energy and material saving. The continuous method can reduce the CO2e emissions up to 75% compared with the current silicon carbide production through Acheson process.

Effect of replacing M (M=Cu, Zn) with Fe on the properties of high entropy (MgCoNiZnCu)O

Fe substitution of Cu or Zn in the high-entropy powder (MgCoNiCuZn)O was realized with a hydrothermal method. The effects of different substitution amounts on the crystal structure, product morphology and electrochemical properties of high entropy (MgCoNiCuZn)O were determined with X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEMEDS) and electrochemical methods. The results showed that when Zn was replaced by 0.05 mol of Fe at 160 ℃ for 12 h or 900 ℃ for 3 h, all of the Fe entered the high entropy rock salt structure and cooperated with Cu2+ to provide more channels for the removal/insertion of Li+, thus improving the electrochemical performance. The discharge capacity was 631.5 F/g at 0.1 A/g, and the capacity retention rate was 89% after 500 cycles.

Paleoproterozoic East Pana Layered Intrusion (Kola Peninsula, Russia): Geological Structure, Petrography, Geochemistry and Cu-Ni-PGE Mineralization

The East Pana intrusion is a part of the Paleoproterozoic Fedorova–Pana complex (FPC), which belongs to the group of Fennoscandian layered mafic–ultramafic massifs. This article discusses the magmatic stratification of the East Pana intrusion, as well as Cu-Ni and platinum-group elements (PGE) mineralization (PGE zones A, B and C) in its various parts with a total length of more than 20 km, including the East Chuarvy PGE deposit. Based on the whole-rock data on the distribution of major, trace, and ore-forming elements, it is assumed that PGE zone A belongs to the main ore–magmatic system of the FPC, while PGE zones B and C belong to the minor ore–magmatic systems. At the same time, additional magmatic injection played an important role in the formation of economic Cu-Ni-PGE mineralization (PGE zone B), characterized by high PGE concentrations and moderate palladium enrichment. On the normalized distribution spectra of trace elements, the crystallization products of this injection (Gabbronorite Zone 2) have a positive Zr-Hf anomaly, which distinguishes it from host rocks with an anomaly of the opposite sign (Gabbronorite Zone 1, Gabbro Zone). It is assumed that this portion of magma was intruded as a sill of crystal mush, the fractionation of which at depth led to its enrichment with residual liquid.

Crystallisation and characterisation of muscle proteins: a mini-review.

The techniques of X-ray protein crystallography, NMR and high-resolution cryo-electron microscopy have all been used to determine the high-resolution structure of proteins. The most-commonly used method, however, remains X-ray crystallography but it does rely heavily on the production of suitable crystals. Indeed, the production of diffraction quality crystals remains the rate-limiting step for most protein systems. This mini-review highlights the crystallisation trials that used existing and newly developed crystallisation methods on two muscle protein targets - the actin binding domain (ABD) of α-actinin and the C0-C1 domain of human cardiac myosin binding protein C (cMyBP-C). Furthermore, using heterogenous nucleating agents the crystallisation of the C1 domain of cMyBP-C was successfully achieved in house along with preliminary actin binding studies using electron microscopy and co-sedimentation assays .

Production of detector grade CdZnTe crystal with VGF furnace by analyzing segregation of Zn and In

Production of CdZnTe crystals for radiation detector applications through Bridgman and Vertical Gradient Freeze (VGF) techniques is challenging in many aspects. Due to the structural characteristics of CdZnTe, it is not possible to obtain a large single crystalline ingots from the melt growth technique. In addition, the segregation of dopants and Zn decrease the yield significantly. In order to achieve detector-grade CdZnTe crystals, zinc segregation behavior should be fully understood, and optimum dopant concentration (In) should be determined. In this work, indium-doped Cd0.9Zn0.1Te single crystals grown via the Vertical Gradient Freeze (VGF) technique were compared in terms of dopant segregation, defect concentration, electron mobility, and electrical resistivity. It is observed that Zn segregates towards the tip of the ingot while In segregates towards the heel. Zn segregation coefficient is calculated as 1.35 while In segregation coefficient is found to be 0.4 for the VGF method. The variation of Zn throughout the ingot and excessive In dopant concentration degraded the detector performance. CdZnTe crystals having In doping concentrations of more than 5 ppm were unresponsive to gamma radiation. (µτ)e of VGF-grown crystals in METU Crystal Growth Laboratory is calculated as 4–5 × 10−4 cm2/V.

Studying the Properties of Molecular Sites Produced from Gels Containing Layered 2D Silicoalumophosphates with Different SiO<sub>2</sub>/Al<sub>2</sub>O<sub>3</sub> Ratio

Abstract—Crystallization of molecular SAPO-41 sieves from gels containing layered 2D silicoaluminophosphates with various SiO2/Al2O3 molar ratios (from 0.1 to 0.3). The effect of the presence of layered phases in gels on the chemical and phase composition, acid properties, and the characteristics of the porous structure of their crystallization products has been established. A method for the synthesis of SAPO-41 of high phase purity and degree of crystallinity is proposed. The catalytic properties in the hydromeasurement of n-hexadecane prepared on the basis of the obtained molecular sieves of Pt-containing catalytic systems have been studied.

A possible origin of the lunar spinel-bearing lithologies as told by the meteorite NWA 13191

Abstract Pink spinel anorthosite (PSA) and pink spinel troctolite (PST) are two lunar lithologies known to contain Mg-rich spinel. PSA rich in spinel and lacking mafic minerals, was detected by the visible and near-infrared reflectance spectroscopy. PST clasts were found in returned lunar samples and meteorites. NWA 13191 is a recently approved lunar meteorite that contains a large amount of spinel-bearing clasts and provides an opportunity to discuss its origin. Sixty-four spinel-bearing clasts were studied in this research. These clasts are dominated by anorthitic feldspars (20.8–80.9 vol%, An90.9–96.8), mafic-rich and aluminum-rich glass (14.7–72.1 vol%) quenched from a melt, and spinels (0.19–5.18 vol%). Forty-nine of these clasts appear to have unusually low modal abundances of mafic silicates (avg. olivine ± pyroxene, 1.87 vol%), which distinguishes them from known spinel-bearing lunar samples (e.g., PST). The spinel compositions (avg. Mg# = 90.6, Al# = 97.4) and mafic minerals contents are basically consistent with those of PSA. The absorption characteristics of glass in the reflection spectrum are not obvious, so it is not clear if the PSA contains melt. The simulated crystallization experiment clearly shows that it contains a large amount of melt at the spinel crystallization stage. These phenomena provide experimental and sample evidence for the existence of glass in the lunar spinel-bearing lithologies. NWA 13191 records the highest known bulk Mg# (avg. 89.8), and the spinel records the highest Al# (98.8) and Mg# (93.1) of lunar samples to date. The chemical properties of spinel-bearing clasts in NWA 13191 are consistent with the slightly REE-enriched and alkali-poor Mg-suite rocks, such as PST, magnesian anorthosites (MANs), and olivine-enriched Mg-suite rocks. These phenomena and previous simulated crystallization experiments indicate that a Mg-Al-rich melt may be produced by impact melting of Mg-rich anorthosite precursors. The spinel is a metastable crystallization product along with plagioclase and vitric melt near the Moon’s surface. This realization provides observational evidence for previous simulated crystallization experiments and theoretical speculations.

Petrogenesis and geochemical evidence from early Jurassic intrusive rocks and their implications for subduction of the Paleo-Pacific Plate in the Yanbian area, Northeast China

Subduction of the Paleo-Pacific Plate plays a key role in the Early Jurassic magmatism evolution in the Yanbian area, Northeast China. In this paper, zircon U–Pb ages, whole-rock geochemical, and Sr–Nd–Hf isotopic compositions are presented. The Early Jurassic gabbros, diorite enclaves, granodiorites, and granites ages range from 183 to 189 Ma. They are characterized by enrichment in large-ion lithophile elements and depletion in high-field strength elements. The gabbros are classified as low- and medium-K tholeiitic, granodiorites and granites are high-K calc-alkaline I-type, and diorite enclaves are calc-alkaline transitional series. The gabbros have zircon εHf(t) values of 6.81–9.89, whole-rock 87Sr/86Sr(i) = 0.7043–0.7044, and εNd(t) from 2.72 to 2.80. The diorite enclaves have zircons with εHf(t) values of 8.26–12.80, whole-rock 87Sr/86Sr(i) = 0.7051, and εNd(t) from 0.96 to 1.09. The granodiorites and granites have zircon εHf(t) values of 7.59–12.87, whole-rock 87Sr/86Sr(i) = 0.7042–0.7066, and εNd(t) from 2.33 to 2.61. These data indicate that gabbroic magmas were derived from partial melting of a depleted mantle wedge metasomatized by subduction-related fluids. The basaltic magma underplated and heated the juvenile crust, whereas the granodiorites and granites might be the product of fractional crystallization of a mixture of basaltic and felsic magmas or derived from partial melting of the juvenile lower crust. Our data constrain the petrogenesis of these Early Jurassic intrusive rocks which are attributed to subduction of the Paleo-Pacific Plate beneath Eurasia continent in northeastern China.

Molecular Assembly and Nucleation Kinetics during Nucleation of 3,5-Dinitrobenzoic Acid.

As one of the most important processes in the process of crystallization, nucleation determines the physicochemical properties of the crystal products. The mechanism of nucleation has not been sufficiently understood due to the complexity of the molecular assembly process. In this work, a rigid molecule of 3,5-dinitrobenzoic acid (DNBA) was selected as the model compound to investigate the connection between nucleation kinetics and solution chemistry and to investigate the mechanism of nucleation. The nucleation induction period was determined by the nonrandom method, and the parameters including interfacial energy γ and collision frequency f0C0 were calculated. FTIR, NMR, and MS were used to analyze the existing form of DNBA molecules in solutions. It was found that the solute exists in the form of monomer, multimers, and solvates in different solvents. Besides, molecular simulation and calculation were also used to investigate the intermolecular interactions of DNBA in different solvents, and the relationship between the molecular existing form and the nucleation kinetics was revealed. Finally, a possible nucleation mechanism of DNBA molecules in solution was proposed.

Formation of calcareous deposits in the tidal zone and its effect on cathodic protection

Using the wire beam electrode technique, electrochemical impedance spectroscopy, energy-dispersive X-ray spectroscopy, the formation of calcareous deposits in a tidal zone and its effects on the corrosion and protection of Q235 steel under cathodic protection were studied. Results showed that the production of aragonite CaCO3 crystals significantly reduced from the immersion zone to the high-tide zone, the protective performance of the deposited layer weakened, and the corrosion of the metal intensified. In the immersion zone, the cathodic protection current density decreased, and the potential shifted negatively, indicating that the protection performance of the deposited layer was enhanced and the metal was effectively protected. In the tidal zone, the deposited layer was stratified, and the porosity of the deposited layer increased by dry-wet cycling. During flood tide, the cathodic reaction is accelerated near the waterline, which promotes the corrosion of the metal and the loss of the sacrificial anode under water.

Gallium isotopic constraints for the origin of the Earth-Moon system

Comparatively heavy isotopic compositions of moderately volatile elements (MVE) in lunar rocks have been advocated to reflect the loss of light isotopes during devolatilization processes from the Moon. In this study we present new gallium (Ga) isotope data for lunar highland rocks, with a focus on the Ferroan Anorthosite Suite (FAS). These are commonly thought to be direct crystallization products from the late lunar magma ocean (LMO) and should contain the majority of the Ga inventory of the Moon. As such, FAS rocks are crucial for identifying the processes that drove Ga isotope fractionation as well as for inferring the Ga isotopic composition of the bulk Moon.Our data reveal that FAS samples have a range in δ71Ga from −0.27 to 0.22‰ and are generally isotopically light in Ga compared to other lunar lithologies, but straddle values typical of terrestrial rocks. Although Ga is defined as an MVE, these Ga isotope variations do not correspond with concentrations of more volatile elements, indicating that Ga isotope variations in the FAS are not primarily controlled by devolatilization processes. Instead, the Ga isotopic compositions of bulk FAS rocks broadly correlate with the composition of plagioclase, with the calcium content of plagioclase decreasing as Ga becomes isotopically heavier. This suggests that fractionation of Ga isotopes in FAS rocks was caused by the preferential incorporation of isotopically light Ga into plagioclase during the later solidification stages of the LMO. The progressive crystallization and extraction of plagioclase forces the residual melt towards increasingly heavier Ga isotope ratios, corroborating similar conclusions derived from correlations between δ71Ga and Eu* in the mare basalt suite.Using Ga isotope partitioning calculations, we demonstrate that an isotope fractionation coefficient between plagioclase and coexisting melt of −0.3 to -0.4‰ could explain the observed range of δ71Ga values in FAS, mare basalt suite rocks, and KREEP. These calculations allow for a first order estimate of the Ga isotopic composition of the bulk silicate Moon prior to plagioclase fractionation and suggest it was close to the composition of the bulk silicate Earth. This would imply that the Moon did not lose a substantial fraction of its Ga inventory during accretion, consistent with new constraints from Rb-Sr isotope systematics that indicate the Moon's volatile deficit was primarily inherited from Theia. In conjunction with the overlap in non-mass-dependent isotope ratios, these collective observations could be reconciled if Theia and the proto-Earth formed in similar regions of the inner Solar System that were already volatile-depleted.

Lemongrass Powder in Bio-Bs Effervescent Formulation of Lombok Island Local Isolate on Viability and Amount of Bacillus Sphaericus Toxin Crystal Protein for Control of Anopheles sp. Larvae

Bio Formula – BS effervescent (Bio- Bacillus sphaericus) is an Effervescent powder-shaped formula that is easy to use by the public. Lombok's local effervescent bio-BS isolated formula has a weakness in terms of smell. The results from the literature search that fragrant lemongrass has a distinctive smell and can kill Aedes aeygpti, but scientific data has not been obtained about the ability of fragrant lemongrass to kill Anopheles Sp in the form of larvae and mosquitoes. The study aimed to find out the effect of the combination formulation of Bio-BS Effervescent local isolate Lombok Island with the addition of lemongrass powder for viability and the amount of toxin crystal protein Bacillus sphaericus. This research method is exploratory and experimental in the laboratory with the design of Post Test Only Control Group Design. The study used six treatment formulations. Samples of Anopheles sp larvae research in Batu Layar lagoon, West Lombok regency and pelur lagoon in Peringgesela, East Lombok regency and from the results of colonization of larvae. The independent Variable is a combination formulation of Bio-BS Effervescent isolated locally from Lombok Island with the addition of fragrant lemongrass powder. The dependent variable is the mortality of Larvae Anophels Sp, Viability of B. Sphaericus, and Amount of Toxin Protein Production of B. Sphaericus. The larvae death rate, the concentration of cells/endospores, and the number of repeats in each container are then tabulated and analyzed using Probit Analysis with the help of MINITAB 16 software. B. sphaericus viability data and the amount of endospore toxin protein crystal production were descriptively analyzed.

Study on Preparation, Structures, and Properties of Carbon based Magnetic Ferrite Nanofibers

Ferrite nanofibers with magnetic properties are a type of functional nanomaterials developed in recent years. Compared with common bulk materials, magnetic nanofibers are of great interest in research due to their characteristics including lightweight, large specific surface area, unique magnetism and magnetocrystalline anisotropy. In this study, Polyvinyl alcohol (PVA) was used as carrier, and magnetic α-Fe2O3/C nanofibers was prepared by electrospinning method, hydrothermal synthesis and high-temperature calcination. Then, the chemical structure, micromorphology, thermal properties, crystallization products and dye adsorption properties of the magnetic composite nanofibers were characterized by FT-IR, SEM, DSC, XRD and UV-Vis. The results show that: α-Fe2O3 is well coated on the surface of PVA-based fiber carrier, and magnetic α-Fe2O3/C nanofibers have three-dimensional (3D) tubular structures. Nanofibers have a single phase structure, and α-Fe2O3 nanoparticles on the the fiber surface are well crystallized and close-packed. Magnetic α-Fe2O3/C nanofibers can achieve the fast adsorption of methylene blue, and the dye removal rate can reach 78.3% at the time of 150 min.