Monodisperse Spheres Research Articles

Size-selective characterization of porous media via tortuous network analysis

Particle migration through gels, glasses, and other porous media provides selectivity, storage, and delivery of macromolecules and other particles that are critical to biological cell function, drug delivery, and water filtration. Modeling migration rates of solvent-borne colloids through such materials is thus essential in understanding and engineering the structure-transport relationship. However, most of these materials comprise an amorphously structured porous network not amenable to analytical modeling. Approaches to overcoming this challenge typically bypass interrogating the porous network by abstracting it away via mean-field models or by interrogating the solid features for a coarse estimate of porosity. While such approaches reduce analytical complexity significantly, resulting models cannot reveal interconnectedness of the void network, size-specific permeability, or insight into migration mechanisms. Other approaches aim to extract a network of void paths by approximating a medium as packing of monodisperse spheres and using traditional Voronoi decomposition, giving results that are accurate only when the constituent particles are monodisperse but strongly overpredict the passable size when the medium is made up of size-polydisperse particles, as is the case for colloidal gels, additive manufacturing, soil sediment, to name some examples. We use radical Voronoi decomposition to establish a network backbone of the porous microstructure, which accurately represents morphology for any degree of constituent polydispersity. We present an algorithm for endowing this network with the accurate size and shape and, from it, systematically deducing size-specific accessible branches. The result is a detailed permeability model for porous media of arbitrary microstructure that reveals material morphology, material phase, and size-specific permeability.

Synthesis of an Ethylenediamine-Modified Hypercrosslinked Polymer and its Preliminary Study for Antipyrine and Pamabrom Extraction

Emerging contaminants (EC) are naturally occurring or synthetic chemicals that may enter the environment and cause adverse effects to aquatic and human health. EC consist of pharmaceuticals, pesticides, organic chemicals and personal care products that present in water sources at low concentrations (μg/L), hence, they are not widely monitored in the environment. Pharmaceuticals contain biologically-active components that pollute water courses. These generally originate from human waste or the uncontrolled release of residues from chemical plants. The removal of pharmaceutical compounds from water can be carried out using polymeric materials with high specific surface areas and good selectivity due to the presence of accessible active functional groups. In the present work, the synthesis and characterizations of microspheres, acrylonitrile-co-divinylbenzene-80-co-vinylbenzylchloride(AN-co-DVB-80-co-VBC) terpolymers with weak-anion-exchange (WAX) character and high porosity have been successfully carried out. The polymeric microspheres were synthesized by precipitation polymerization and subsequently hypercrosslinked (HXL) via a Friedel-Crafts reaction. The HXL terpolymer was then chemically modified with 1,2-ethylenediamine (EDA) to incorporate diamine functional groups, which improved the selectivity of the HXL microspheres towards polar compounds. Fourier Transform-Infrared (FT-IR) spectra of the EDA-modified HXL terpolymer showed that the nitrile groups derived from AN units were utilized due to the presence of diamine groups along the polymeric chains, indicating that the chemical modification was successful. The microanalysis showed that the chlorine content of the polymer was significantly decreased after hypercrosslinking, indicating that the reaction was successful. The nitrogen content increased after chemical modification with EDA, indicating successful chemical modification of the microspheres. The polymers were in the form of spherical monodisperse polymer microspheres with mean particle diameters of ~7.00 μm. The highest observed specific surface areas (SSAs) of the HXL terpolymer and EDA-modified HXL terpolymer were 2,274 m²/g and 503 m²/g, respectively. The microspheres were utilized to extract the pharmaceutical compounds antipyrine and pamabrom from aqueous solution using the dispersive solid phase extraction (DSPE) method. The extraction analysis was carried out by Gas Chromatography–Mass Spectrometry (GC-MS). The influence of adsorbent dosage, extraction time and elution time were studied to evaluate the performance of the adsorbent in the extraction of antipyrine and pamabrom from aqueous solution. It can be concluded that EDA-modified HXL poly(AN-co-DVB-80-co-VBC) was more favourable towards the extraction of antipyrine, which had a maximum extraction efficiency (EE%) of 95%, compared to that of pamabrom (maximum EE% of 54%).

Enzymatic mediated modification of gum Arabic by curcumin oxidation products: Physicochemical and self-assembly study

Gum Arabic (GA) is a polysaccharide widely used in industry as an emulsifier and encapsulating agent. Nevertheless, its physicochemical properties can be largely improved. The objective of this study was then to modify its structure to improve its functionalities or to provide new ones. To do so, a heterogeneous catalysis process using a laccase and a phenolic compound, curcumin, in aqueous solution was performed. The laccase allowed the oxidation of curcumin, which was then able to be grafted onto the polymer. Therefore, this environmentally friendly process allowed the modification of GA with curcumin oxidation products (OXP) by creating ester bonds between GA and OXP. The molecular mass of GA was largely increased after functionalization. This product contained two fractions of approximately ∼1.165 × 108 g.mol−1 and ∼5.057 × 106 g.mol−1. All these modifications impacted greatly the polymer properties such as its thermal behaviour, with a significant decrease of its glass transition, its hydrophilicity and its hygroscopicity. They also brought antioxidant properties to the modified GA. Moreover, the modification led interestingly to the spontaneous formation of spherical monodisperse micrometric particles in water.

Effect of spatial filter features on local heat transfer coefficients obtained from particle-resolved simulations of a flow through a fixed random array of rigid spherical particles

We use Particle-Resolved (Direct Numerical) Simulation (PR-DNS or PRS) to investigate momentum and heat transfer in the incompressible flow of a Newtonian fluid through a fixed bed of mono-disperse spheres. We perform a set of simulations with various porosities ranging from 0.5 to 0.9, Reynolds numbers ranging from 18 to 72 and Prandtl numbers ranging from 1 to 5 and analyze computed results. All cases are hence in the moderately convection dominated thermal regimes, i.e., Peclet numbers from 18 to 360. We locally average fluid flow data around particles using different filters centered at each particle mass center and we study the effect of the mathematical form of the filter as well as of the filter support size on the particle Nusselt number distribution. While both mathematical form and support size have a limited effect on the average particle Nusselt number, the width of the distribution, i.e., the standard deviation, is strongly influenced by the filter support size. This observation has important consequences for the derivation of new transfer coefficient models that incorporate information about the actual particle microstructure and attempt to estimate the transfer coefficient fluctuations for a given average local porosity.

Experimental and numerical investigations on the local wall heat transfer coefficient in a narrow packed bed with spheres

Packed beds are used at the laboratory scales to model and understand the phenomena of water flow through soil and rocks. The behaviour of local wall heat transfer coefficient with randomised packing of mono-dispersed spheres is examined in the present study. Under steady-state conditions, the high-resolution local wall temperature data is obtained by placing the infrared (IR) camera in close proximity to the test section. The local wall heat transfer coefficient is computed using the measured bulk fluid temperature, local wall temperature data and applied heat flux. Physical and numerical experiments were conducted for the narrow bed to particle diameter ratio of 1.25 using random packing of mono-dispersed (impermeable) glass spheres (diameter 6 mm) in order to be able to recreate similar geometry for numerical simulations of fluid flow and heat transfer. An attempt is made for recreation of the experimental narrow bed geometry by using the technique of method of gaps and computational fluid dynamics simulations were performed. The results of simulations are presented in appropriate velocity vectorial plots and flow stream lines revealing complex 3D mixing patterns inside void spaces of the narrow bed. Local variations of wall heat transfer coefficient are found along the packed bed and the numerical simulations of fluid flow and heat transfer reveal interesting complex flow patterns inside the bed.

Nanospatial Charge Modulation of Monodispersed Polymeric Microsphere Photocatalysts for Exceptional Hydrogen Peroxide Production.

Photocatalysis offers a sustainable strategy for hydrogen peroxide (H2 O2 ) production, which is an essential oxidant and emerging energy carrier in modern chemical industry. The development of polymer-based photocatalysts to produce H2 O2 has great potential but is limited by lower efficiency due to the limitation of light utilization and the low charge separation efficiency. Herein, a series of monodispersed mesoporous resorcinol-formaldehyde resin spheres (MRFS) are reported with a rational designed spatial charge distribution, exhibiting wide light absorption with a solar-to-chemical conversion (SCC) efficiency of 1.1%. Surface photovoltage microscopy (SPVM) measurements unraveled the charge separation in nanospace with uneven distribution of donor (D) and acceptor (A) sites. A density functional theory (DFT) calculation elucidated the origin of photogenerated electrons and holes. Moreover, MRFS demonstrates photocatalytic water oxidation ability. The findings in this work open a new avenue for the development of porous polymeric photocatalysts toward highly efficient solar energy conversion.

Critical numerical analysis of quasi-two-dimensional silo-hopper discharging

We present a critical comparative analysis between numerical and experimental results of quasi-two-dimensional silo and hopper flows. In our approach, the Discrete Element Method was employed to describe a single-layer mono-disperse sphere confined by two parallel walls with an orifice at the bottom. As a first step, we examined the discharge process, varying the size of the outlet and the hopper angle. Next, we set the simulation parameters fitting the experimental flow rate values obtained experimentally. Remarkably, the numerical model captured the slight non-monotonic dependence of the flow rate with the hopper angle, which was detected experimentally. Additionally, we analyzed the vertical velocity and solid fractions profiles at the outlet numerically and experimentally. Although numerical results also agreed with the experimental observations, a slight deviation appeared systematically between both approaches. Finally, we explored the impact of the system’s confinement on this process, examining the consequences of particle-particle and particle-wall friction on the system macroscopic response. We mainly found that the degree of confinement and particle-wall friction have a relevant impact on the outflow dynamics. Our analysis demonstrated that the naive 2D approximation of this 3D flow process fails to describe it accurately.

Synthesis of monodisperse and high-purity α-Si3N4 powder by carbothermal reduction and nitridation

Carbothermal reduction-nitridation method is an effective means for synthesizing Si3N4 powder. Herein, spherical monodisperse silica was used as silicon source. The effects of reaction temperature, nitrogen flow rate and Si3N4 seeds content on the products were studied. It was found that high-purity α-Si3N4 (>99.0 wt%) was synthesized from C/SiO2 = 3:1 at 1400 °C, reaction time of 6 h and nitrogen flow rate of 800 ml/min. The powder, with an average size of 0.5 μm, showed good dispersity and regular morphology because spherical monodisperse silica could be completely coated with carbon. The more contact sites between SiO2 and C, the higher concentration of SiO(g) would be produced in the initial stage. It also indicated that the nucleation rate of α-Si3N4 increased, thereby inhibiting the formation of an agglomerate phase and suppressing the grain growth of α-Si3N4. Furthermore, higher nitriding temperature and Si3N4 seeds content both decreased the grain size and increased β-Si3N4 content. The forming mechanism of non-agglomerated and submicron-sized α-Si3N4 was clarified.

Fabrication of Fe3O4@PVA microspheres by one-step electrospray for magnetic resonance imaging during transcatheter arterial embolization

Magnetic resonance imaging (MRI) has attracted increasing attention as a feasible alternative or adjunctive imaging modality for X-ray digital subtraction angiography because of the high tissue resolution and non-ionization radiation. In this study, a one-step electrospray method was developed to fabricate PVA microspheres encapsulated with in situ synthesized Fe3O4 nanoparticles. Fe3O4@PVA microspheres were mono-dispersed black spheres with a wide range of sizes (262–958 µm). The in situ-synthesized Fe3O4 nanoparticles were used as the contrast agent of MRI and the cross-linkers of PVA matrixes for the embolization purpose. In vivo evaluation of renal arteries of normal rabbits showed that Fe3O4@PVA microspheres had good embolic effect and enhanced capability of MRI. In vitro and in vivo biosafety assessment confirmed that Fe3O4@PVA microspheres had favorable biocompatibility. The DOX-loaded Fe3O4@PVA microspheres showed a typical drug-sustained release profile. These results suggest that the prepared DOX-loaded Fe3O4@PVA microspheres have the function of MRI, embolotherapy and chemotherapy. We expect our study could provide a simple and useful approach for the systematic design, fabrication, and application of a new type of magnetic microspheres as a triple-functional embolic agent for the development of MRI-guided TACE. Statement of significanceDue to the low tissue resolution and hazardous ionization radiation of X-ray digital subtraction angiography, it is beneficial to study MR imaging embolic microspheres for the development of MRI-guided TACE. In this study, a one-step electrospray method was firstly developed to fabricate PVA microspheres encapsulated with in situ synthesized Fe3O4 nanoparticles. Then, chemotherapeutic agent (DOX), contrast media of MRI (Fe3O4) and embolic agent (PVA matrix) were combined together in one body (DOX-loaded Fe3O4@PVA microspheres) to achieve the triple effects of chemotherapy, MR imaging and embolization. This triple-functional embolic agent offers potential for the future development of MRI-guided TACE.

Single-projection reconstruction technique for positioning monodisperse spheres in 3D with a divergent x-ray beam

The measurement of the position of single-sized spheres in 3D from a single, divergent, radiographic projection is addressed in the present study with the development of a novel method. Generally speaking, the location of the shadow cast by a single sphere on a detector defines a source-detector ray; the position of the particle along this ray is identified by the strong prior knowledge of its radius and the size of the shadow. For a dense assembly of equal-sized particles whose projections overlap, a novel Fourier transform based technique is introduced to give a first 3D determination of the particle centres. The uncertainty of this measurement is calculated from synthetic data with a known noise distribution. A further refinement of this measurement is performed based on the minimisation of the projection residual. The combined approach is validated both on synthetic data, and on real radiographs of a glass bead packing. The effect of noise on the measurement uncertainty is evaluated. The technique is made available to the community in the open source python package radioSphere.

Selenite bioreduction and biosynthesis of selenium nanoparticles by Bacillus paramycoides SP3 isolated from coal mine overburden leachate

A native strain of Bacillus paramycoides isolated from the leachate of coal mine overburden rocks was investigated for its potential to produce selenium nanoparticles (SeNPs) by biogenic reduction of selenite, one of the most toxic forms of selenium. 16S rDNA sequencing was used to identify the bacterial strain (SP3). The SeNPs were characterized using spectroscopic (UV–Vis absorbance, dynamic light scattering, X-ray diffraction, and Raman), surface charge measurement (zeta potential), and ultramicroscopic (FESEM, EDX, FETEM) analyses. SP3 exhibited extremely high selenite tolerance (1000 mM) and reduced 10 mM selenite under 72 h to produce spherical monodisperse SeNPs with an average size of 149.1 ± 29 nm. FTIR analyses indicated exopolysaccharides coating the surface of SeNPs, which imparted a charge of −29.9 mV (zeta potential). The XRD and Raman spectra revealed the SeNPs to be amorphous. Furthermore, biochemical assays and microscopic studies suggest that selenite was reduced by membrane reductases. This study reports, for the first time, the reduction of selenite and biosynthesis of SeNPs by B. paramycoides, a recently discovered bacterium. The results suggest that B. paramycoides SP3 could be exploited for eco-friendly removal of selenite from contaminated sites with the concomitant biosynthesis of SeNPs.

Controlled Biosynthesis of ZnCdS Quantum Dots with Visible-Light-Driven Photocatalytic Hydrogen Production Activity.

The development of visible-light-responsive photocatalysts with high efficiency, stability, and eco-friendly nature is beneficial to the large-scale application of solar hydrogen production. In this work, the production of biosynthetic ternary ZnCdS photocatalysts (Eg = 2.35–2.72 eV) by sulfate-reducing bacteria (SRB) under mild conditions was carried out for the first time. The huge amount of biogenic S2− and inherent extracellular proteins (EPs) secreted by SRB are important components of rapid extracellular biosynthesis. The ternary ZnCdS QDs at different molar ratios of Zn2+and Cd2+ from 15:1 to 1:1 were monodisperse spheres with good crystallinity and average crystallite size of 6.12 nm, independent of the molar ratio of Cd2+ to Zn2+. All the ZnCdS QDs had remarkable photocatalytic activity and stability for hydrogen evolution under visible light, without noble metal cocatalysts. Especially, ZnCdS QDs at Zn/Cd = 3:1 showed the highest H2 production activity of 3.752 mmol·h−1·g−1. This excellent performance was due to the high absorption of visible light, the high specific surface area, and the lower recombination rate between photoexcited electrons and holes. The adhered inherent EPs on the ZnCdS QDs slowed down the photocorrosion and improved the stability in photocatalytic hydrogen evolution. This study provides a new direction for solar hydrogen production.

Local crystalline order features in disordered packings of monodisperse spheres

A new tetrahedral structure model was developed for disordered sphere packings, including not only regular tetrahedron (T), but also quartoctahedron (Q) and bcc simplex (B), the tetrahedral building blocks in fcc, hcp and bcc crystal structures, respectively. Both geometric frustrated configurations and local configurations associated with crystalline order in disordered packings can be comprehensively characterized. It is found that with increasing packing fraction, the population of T, Q, and B increases. Moreover, the crystal-type local configurations formed by face-adjacent T, Q and B increases as packing fraction increases, which is more prevalent than the geometric frustrated ones formed by face-adjacent T. In addition, as packing fraction increases, the local density of irregular simplexes is found to increase more quickly than regular ones, playing more important roles in the density increase in disordered packings. These structure features are found to be intrinsic in the jammed random sphere packings with different friction coefficients, which is independent of interparticle friction and only determined by the packing fraction. Our findings provide new understanding for the structural nature of disordered packings and the underlying structural basis of the random close packing.

An Overview of the Lagrangian Dispersion Modeling of Heavy Particles in Homogeneous Isotropic Turbulence and Considerations on Related LES Simulations

Particle tracking is a competitive technique widely used in two-phase flows and best suited to simulate the dispersion of heavy particles in the atmosphere. Most Lagrangian models in the statistical approach to turbulence are based either on the eddy interaction model (EIM) and the Monte-Carlo method or on random walk models (RWMs) making use of Markov chains and a Langevin equation. In the present work, both discontinuous and continuous random walk techniques are used to model the dispersion of heavy spherical particles in homogeneous isotropic stationary turbulence (HIST). Their efficiency to predict particle long time dispersion, mean-square velocity and Lagrangian integral time scales are discussed. Computation results with zero and no-zero mean drift velocity are reported; they are intended to quantify the inertia, gravity, crossing-trajectory and continuity effects controlling the dispersion. The calculations concern dense monodisperse spheres in air, the particle Stokes number ranging from 0.007 to 4. Due to the weaknesses of such models, a more sophisticated matrix method will also be explored, able to simulate the true fluid turbulence experienced by the particle for long time dispersion studies. Computer evolution and performance since allowed to develop, instead of Reynold-Averaged Navier-Stokes (RANS)-based studies, large eddy simulation (LES) and direct numerical simulation (DNS) of turbulence coupled to Generalized Langevin Models. A short review on the progress of the Lagrangian simulations based on large eddy simulation (LES) will therefore be provided too, highlighting preferential concentration. The theoretical framework for the fluid time correlation functions along the heavy particle path is that suggested by Wang and Stock.

Permeability and the Ergun Equation as a Basis for Permeability Measurements of Metallic Foams and Wire Meshes

This paper concerns a method and a test set-up to measure the permeability of plates of metal foams and sets of wire meshes used to control flows in fluid filters and other flow systems designed to yield constant velocity distributions over large cross sections of flows. The method is based on permeability considerations using the Ergun equation to describe the pressure losses of packages of mono-dispersed spheres. One correlation is suggested for the permeability k over the entire range of mean velocities U0. A suitable measuring set-up was designed, built and used to measure the permeability of plates of metallic foams and sets of wire meshes. The specific objective of the present investigation was to provide permeability data for combined sets of wire meshes with flow properties that are mainly characterized by the wire meshes with the smallest mesh size. A method of data presentation is suggested that clearly illustrates the ranges of laminar and turbulent flows through the wire meshes. The results are compared with those for technical porous plates. The suggested presentation of the results indicates that the general features of the flows through porous plates of metal foams and wire meshes are the same.

Stationary Phases for Capillary Gas Chromatography Obtained on the Basis of Hypercrosslinked Polystyrenes

Capillary columns with previously or in situ synthesized super-crosslinked polystyrene phases are prepared. It has been shown that columns with stationary phases based on presynthesized hypercrosslinked polystyrenes, spherical monodisperse particles, or “nano-sponges,” despite their microporous structure, show insufficient kinetic efficiency and selectivity in the separation of light hydrocarbons. Higher kinetic efficiency was observed in columns where the hypercrosslinked polystyrene phase was synthesized directly in the column, although the porosity structure of this phase remains unknown. All columns with hypercrosslinked polystyrene stationary phase have good thermal stability, with no observed chemical destruction and physical aging at temperatures up to 250°C.

Preparation of nanosilica from sugarcane bagasse ash for enhanced insecticidal activity of diatomaceous earth against two stored-products insect pests

Nanosilica was prepared from sugarcane bagasse ash (SCBA) and used as additive to the diatomaceous earth (DE). Nanosilica was characterized using laser light scattering (LS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD). Nanosilica has uniform spherical shape and monodisperse distribution with particle diameters of ∼100 nm. The insecticidal activity of silica nanoparticles (SNPs), Mamaghan DE, Mamaghan DE plus 15% SNPs and Mamaghan DE plus 20% SNPs was determined against adults of Tribolium confusum Jacquelin du Val. and Rhyzopertha dominica (F.) at the rate of 400 ppm. Nanosilica enhanced the insecticidal activity of Mamaghan DE, and after 14 d of exposure the adult mortality was more than 86% and 95% for T. confusum and R. dominica when SNPs were added to the DE, respectively.

Bacillus megaterium-Mediated Synthesis of Selenium Nanoparticles and Their Antifungal Activity against Rhizoctonia solani in Faba Bean Plants.

Rhizoctonia root-rot disease causes severe economic losses in a wide range of crops, including Vicia faba worldwide. Currently, biosynthesized nanoparticles have become super-growth promoters as well as antifungal agents. In this study, biosynthesized selenium nanoparticles (Se-NPs) have been examined as growth promoters as well as antifungal agents against Rhizoctonia solani RCMB 031001 in vitro and in vivo. Se-NPs were synthesized biologically by Bacillus megaterium ATCC 55000 and characterized by using UV-Vis spectroscopy, XRD, dynamic light scattering (DLS), and transmission electron microscopy (TEM) imaging. TEM and DLS images showed that Se-NPs are mono-dispersed spheres with a mean diameter of 41.2 nm. Se-NPs improved healthy Vicia faba cv. Giza 716 seed germination, morphological, metabolic indicators, and yield. Furthermore, Se-NPs exhibited influential antifungal activity against R. solani in vitro as well as in vivo. Results revealed that minimum inhibition and minimum fungicidal concentrations of Se-NPs were 0.0625 and 1 mM, respectively. Moreover, Se-NPs were able to decrease the pre-and post-emergence of R. solani damping-off and minimize the severity of root rot disease. The most effective treatment method is found when soaking and spraying were used with each other followed by spraying and then soaking individually. Likewise, Se-NPs improve morphological and metabolic indicators and yield significantly compared with infected control. In conclusion, biosynthesized Se-NPs by B. megaterium ATCC 55000 are a promising and effective agent against R. solani damping-off and root rot diseases in Vicia faba as well as plant growth inducer.

Optical and Morphology Properties of the Magnetite ( Fe3O4) Nanoparticles Prepared by Green Method

Magnetite nanoparticles have been synthesized by a green method. For this process, ferricchloride hexahydrate, ferrouschloride tetrahydrate (2/1 molar ratio) solution was mixed with different amounts of carob leaves extract and NaOH solution was added to get pH(2, 5,8 and 11) heated for 30 min at (30,60,80 and 100) °C . In this report, a description was introduced for the synthesis of Fe304 nanoparticles (NPs) in order to obtain the optimum (pH8 ,temperature and amount of extract) that have small particle size MNPs. The magnetite nanoparticles were characterized by UV-Vis absorption spectroscopy, through Field emission scanning electron microscopy (FESEM) and Atomic Force Microscope (AFM). In UV-Vis spectroscopy, the absorbance of surface plasmon resonance (SPR) of magnetite nanoparticles synthesized with different parameters, were observed a single visible peak located in the range of (290-519) nm and it was related to spherical monodisperse, peak shifts to shorter wavelength (blue shift) with change parameter. FESEM images confirm the Fe304 NPs synthesized with different parameters were spherical shaped and lower than 50 nanoscale. AFM images of magnetite nanoparticles with different parameter. It is observed that each nucleus magnetite Nanoparticles is spherical in geometry

Synthesis of carbon dots@Fe3O4 and their photocatalytic degradation properties to hexaconazole

The CD@Fe3O4 photocatalysts were synthesized via hydrothermal synthesis method. The CD@Fe3O4 particles were synthesized using Fe3O4 as the core and using citric acid and ethylenediamine as a raw material, which were heated to 200 °C for 4 h. The synthesized fluorescent CD@Fe3O4 was characterized by HR-TEM, IR and fluorescence spectrophotometer. The HR-TEM results showed CD and Fe3O4 nanoparticles were uniform, mono-dispersed sphere or hemisphere particles with an average size of approximately 3 nm, and particle size of CD@Fe3O4 were mainly in range of 20–30 nm. XRD results showed the nanoparticles mainly belonged to Fe3O4 and CD@Fe3O4, which made recycling our photocatalysts possible due to the magnetic performance. On daylight lamp, the half-life of hexaconazole in CD@Fe3O4 photocatalysts was about 4 days, and it is lower than half-life (over 100 days) of hexaconazole without CD@Fe3O4 photocatalysts.