Irregular Particles Research Articles

An Efficient SPH Framework for Modeling Binary Granular Mixtures and Implications for Granular Flows

ABSTRACTA two‐way coupling numerical framework based on smoothed particle hydrodynamics (SPH) is developed in this study to model binary granular mixtures consisting of coarse and fine grains. The framework employs updated Lagrangian SPH to simulate fine grains, with particle configurations updated at each time step, and total Lagrangian SPH to efficiently model coarse grains without updated particle configurations. A Riemann solver is utilized to introduce numerical dissipation in fine grains and facilitate their coupling with coarse grains. To enhance computational efficiency, a multiple time‐stepping scheme is initially applied to manage the time integration coupling between coarse and fine grains. Several numerical experiments, including granular column collapse, low‐speed impact craters, and granular flow impacting blocks, are conducted to validate the stability and accuracy of the proposed algorithm. Subsequently, two more complex scenarios involving a soil–rock mixture slope considering irregular coarse particle shapes, and bouldery debris flows on natural terrain, are simulated to showcase the potential engineering applications. Finally, a detailed analysis is performed to evaluate the computational efficiency advantages of the present approach. The findings of this study are consistent with previous experimental and numerical results, and the implementation of a multiple time‐stepping scheme can improve computational efficiency by up to 600%, thereby providing significant advantages for large‐scale engineering simulations.

Suffusion of irregular concave gap-graded sand with resolved CFD-DEM

The complex morphologies of particles are a crucial factor influencing suffusion in gap-graded granular soils. However, the micro-mechanism of soil suffusion composed of irregular concave particles remains unclear. To this end, a systematic numerical simulation that considers particle concavity and aspect ratio is performed with the resolved discrete element method (DEM) and computational fluid dynamics (CFD) approach. The macro responses of suffusion of particles with varying morphologies, e.g., cumulative eroded particle mass and sample profile, are revealed and interpreted from a microscopic view, e.g., particle rotation, coordination number, and moment. It is found that the rotation of irregularly shaped particles during suffusion requires overcoming the moment applied by the surrounding particles. Particles with bigger contact force or irregularity require a higher moment to be overcome, thus significantly increasing their suffusion resistance. Irregularly shaped particles can adjust their orientation to reduce the moment and drag force applied to them. At the same aspect ratio, particles with larger concavity are more likely to interlock with each other, with increasing the coordination number of the soil packing and shrinking the pore channel for particle migration. A shape parameter considering both concavity and aspect ratio is finally proposed to characterise the influence on suffusion.

Study of the residual stress distribution in SiCp/Al composites under thermal cycling conditions

In this study, a three-dimensional random representative volume element model was constructed using the finite element method combined with Python script to investigate the residual stress distribution in SiCp/Al composites with varying volume fractions, particle shapes, and particle size under thermal cycling conditions. The model has two different particle morphologies: spheres and irregular polygons. The results show that the irregular polygonal SiC particles exhibit higher residual stresses than spherical particles before and after thermal cycling due to their complex load transfer pathways and higher stress concentration at particle corners, which makes them more consistent with the characterization of SiCp/Al composites under practical application conditions. As the volume fraction of SiC particles increases, the particle spacing decreases, hindering the release of thermal stresses through plastic deformation. Notably, the relief rate of residual stress reached 53% in the 12 vol% SiCp/Al composites, with the stress decreasing from 698 MPa to 328 MPa after 50 thermal cycles. In contrast, the reduction rate for 18 vol% composites is only 13% after thermal cycling. Furthermore, compared to larger particles (7.3 µm, 8.9 µm), the smaller particles (4.3 µm, 5.9 µm) exhibit a more uniform stress distribution and lower thermal stresses before and after thermal cycling. Consequently, our work provides a significant theoretical basis for the design and application of SiCp/Al composites, especially for the application of materials under extreme temperature changes.

Co/Er2O3/C ternary nanocomposites derived from cobalt/erbium Prussian blue analogs for efficient microwave absorption

This study presents the synthesis of Er[Co(CN)6], a Prussian blue analog (ErCo-PBA) with varied morphology, fabricated by modulating the solvent ratio between C2H6O and H2O. This approach leverages the solubility characteristics of K3[Co(CN)6] and the consequential influence of C2H6O on the crystal growth. When the solvent ratios are 1:8, 8:1, and 1:1, the resulting ErCo-PBA precursors nanorods, irregular particles, and spindle-shaped particles, respectively. After annealing, these precursors in an Ar environment allowed the Co/Er2O3/C derivatives to retain the morphology of the precursor well. Electromagnetic parameters testing revealed that Co/Er2O3/C-1 exhibits superior electromagnetic wave-absorbing (EMWA) performance among the synthesized derivatives with an effective absorption bandwidth of 5.1 GHz at 1.85 mm and a minimum reflection loss of −56.7 dB at 2.9 mm. The incorporation of Er2O3 is an effective method for adjusting and optimizing the electromagnetic parameters of materials, thereby enhancing the EMWA performance of Co/Er2O3/C composite. This study highlights the potential of rare-earth oxide/Co/C composites, synthesized through direct annealing rare-earth metal–organic frameworks, as an absorber and are promising candidate to achieve high-efficiency electromagnetic wave absorption.

Study on micromechanical behavior and energy evolution of granular material generated by latent diffusion model under rotation of principal stresses

In this study, advanced image processing technology is used to analyze the three-dimensional sand composite image, and the topography features of sand particles are successfully extracted and saved as high-quality image files. These image files were then trained using the latent diffusion model (LDM) to generate a large number of sand particles with real morphology, which were then applied to numerical studies. The effects of particle morphology on the macroscopic mechanical behavior and microscopic energy evolution of sand under complex stress paths were studied in detail, combined with the circular and elliptical particles widely used in current tests. The results show that with the increase of the irregularity of the sample shape, the cycle period and radius of the closed circle formed by the partial strain curve gradually decrease, and the center of the circle gradually shifts. In addition, the volume strain and liquefaction strength of sand samples increase with the increase of particle shape irregularity. It is particularly noteworthy that obvious vortex structures exist in the positions near the center where deformation is severe in the samples of circular and elliptical particles. However, such structures are difficult to be directly observed in sample with irregular particles. This phenomenon reveals the influence of particle morphology on the complexity of the mechanical behavior of sand, providing us with new insights into the understanding of the response mechanism of sand soil under complex stress conditions.

Osteoinductively Functionalized 3D-Printed Scaffold for Vertical Bone Augmentation in Beagle Dogs.

To evaluate the efficacy of 3D-printed scaffolds that were osteoinductively functionalized with a bone morphogenetic protein 2 (BMP-2)-incorporated biomimetic calcium phosphate particles (BMP-2-inc. BpNcCaP)/hyaluronic acid (HA) composite gel in vertical bone augmentation in beagle dogs. Four Beagle dogs were used in this study. Three months after the extraction of 1st, 2nd, 3rd, and 4th premolars at both sides of the lower jaws of Beagle dogs, one or two critical-size vertical bone defects (4 mm vertical bone defect without buccal and lingual bone) on each sidewere surgically created. The defects were randomly subjected to the following groups: (1) Control (without bone-defect-filling materials); (2) 3D scaffold; (3) BMP2-inc. BpNcCaP/HA-functionalized 3D scaffold. Six weeks post-surgery, samples were harvested and subjected to micro-CT and histomorphometric analyses. The struts of the BMP2-inc. BpNcCaP/HA-func. 3D scaffold were covered by a thick layer of cemented irregular particles with an average pore size at 327 ± 27 μm. The BpNcCaP/HA-func. 3D scaffold group bore significantly higher bone volume, bone volume fraction, trabecular number, trabecular thickness, bone mineral density, connectivity density, and bone volumes in three directions (mesiodistal, buccolingual, and apicocoronal) when compared with the groups of Control and 3D scaffold. Moreover, the BMP2-inc. BpNcCaP/HA-func. 3D scaffold group bore significantly lower trabecular separation and exhibited significantly higher bone-to-scaffold contact percentage and newly formed bone area percentage within pores in comparison with 3D scaffold. BMP2-inc. BpNcCaP/HA-func. 3D scaffold dramatically enhanced vertical alveolar bone augmentation, which suggests a promising application potential of BMP2-inc. BpNcCaP/HA-func. 3D scaffold in dental clinic.

Synthesis and characterization of bacterial cellulose composite with graphite and TiO2-ZnO: structural and functional analysis

This research aims to synthesize and characterize a bacterial cellulose (BC)-based composite with graphite and TiO2-ZnO as reinforcement materials using ex-situ synthesis with CTAB as a surfactant. FTIR and SEM-EDS analysis revealed interactions between the matrix and the reinforcement materials, as well as irregular particle distribution in the BC/G-TiO2-ZnO composite. The addition of graphite to BC significantly increased the conductivity of the composite, while the addition of TiO2-ZnO had the opposite effect. The mechanical properties of the composite exhibited an inverse relationship with the conductivity parameter. Swelling tests indicated that pH and the addition of CTAB influenced the swelling behavior of the BC-based composite. The results of this study provide a strong foundation for the development of potential applications in the fields of electronics and pollutant filtration. The synthesis of this composite aims to harness the unique properties of BC, graphite, and TiO2-ZnO, creating a multifunctional material with potential uses in flexible electronics, sensors, biocompatible conductive materials, and advanced filtration systems.

Determining the priority control sources of heavy metals in the roadside soils in a typical industrial city of North China

Heavy metals (HMs) in roadside soils (RS) are closely related to urban ecosystem and human health, but priority control sources and eco-health risks of HMs remain unclear. We explored pollution sources of HMs using positive matrix factorization (PMF), scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS), and random forest (RF), and assessed their source-specific eco-health risks. The combination of PMF, SEM-EDS and RF indicated that pollution sources of HMs were coal combustion (27.99 %), construction materials (30.15 %), and traffic emissions (41.86 %). SEM-EDS revealed RS particles were identified by a combination of physical (spherical, porous rounded, crustal flake, crustal rounded and irregular particles) and elemental surface characteristics (O, C, Si, Al, Fe, Ca, Mg, K, Zn, Cu, and Mn). RF highlighted road network density, residential density, and industrial density had significant importance influence on pollution sources. Approximately 72.35 % of soil samples were at a low ecological risk with traffic emissions being the major contributor. Non-carcinogenic risks had a minimal effect, but carcinogenic risks were at a cautionary level with coal combustion being the highest contributor. Overall, coal combustion and traffic emissions were regarded as priority control sources of HMs. These findings provided effective guidance for soil pollution prevention and risk control.

Can mussel shell waste optimize cement and air lime mortars hygrothermal performance?

Mussel shells used as aggregates for mortars have flaky and irregular particles, which significantly increases the pore volume. This leads to the identification the microstructure of mussel shell mortars as a light and porous composite, which could have good hygrothermal properties. In the present study, the density and thermal properties are assessed on cement and air lime mortars, each with three replacement percentages of replacement of conventional sand by mussel shell sand (25 %, 50 % and 75 %), are evaluated and compared with their respective baselines (0 % replacement). Thermal conductivity measurements are also carried out on different loose fractions of the mussel shell aggregate to understand the behaviour of this material without binder matrix. Finally, adsorption and desorption cycles at 80 % and 50 % relative humidity are carried out on loose aggregate fractions and on the eight mortars. The results are very positive for the mussel shell mortars, as it can be concluded that the use of mussel shell aggregates improves the thermal performance and the potential moisture buffering capacity of both cement and air-lime coating mortars.

Polarization optical properties of suspended particles measurement in water by a polarized Scheimpflug lidar system.

The polarization optical properties of suspended particles in water play a pivotal role in numerical simulation or real water medium detection. Polarized multi-wavelength oceanic lidar provides an effective method for characterizing the size, shape, and concentration of suspended particles. In this paper, we present a concise and effective optical approach to measure the information in the polarization of the lidar signal with 0°, 45°, 90°, and 135° polarization angles of suspended particles by laboratory experiments based on polarized Scheimpflug lidar system. This work uses typical suspended particles with different sizes and shapes as tracer particles to analyze particulate polarization information. Experiments with spherical or irregular silicon dioxide particles show that these particles can be effectively distinguished by analyzing the polarization optical properties of the backward scattering light. The laboratory system can classify suspended particles and may serve as a shipborne oceanic lidar or be used with submersibles.

La-Al modified Fe3O4 adsorbent for adsorption performance and mechanism of low P concentration in water

Adsorbents of LaAl hydroxide (oxygen) species have been widely used for removal of phosphate (P) from water, but fewer studies were conducted on the removal of low P concentration. This study firstly fabricated a new composite material of LaAl modified Fe3O4 by co-precipitation method applied for removal of low P concentration in water. Results showed that the optimal adsorbent performance was at a La/Al molar ratio of 2:1 and an optimum dosage of 0.1 g/L. P removal was >99 % with a low initial P concentration (2 mg/L), and the residual P was only 0.02 mg/L. La2-Al@Fe3O4 adsorbent was an irregular magnetic particle with a large specific surface area of 101.35 m2/g. Adsorption process primarily involved chemisorption and formation of multiple adsorption layers. The maximum adsorption capacity was 71.75 mg/g when the initial P concentration was 50 mg/L. Meanwhile, it showed good adsorption performance at pH 4.0–9.0, exhibited notable selectivity for P despite competing ions such as Cl−, HCO3−, SO42−, and NO3−, and was influenced by coexisting citric acid and humic acid. Also, La2-Al@Fe3O4 showed good reproducibility and maintained 85.6 % of the original adsorption capacity after five adsorption and desorption cycles. Additionally, P concentration could be reduced to below 0.02 mg/L in actual water, and La2-Al@Fe3O4 was friendly to the water environment based on the toxicity analysis of Chlorella vulgaris. The adsorption mechanism of P by La2-Al@Fe3O4 mainly involved electrostatic adsorption and ligand exchange. This novel adsorbent shows great potential for application in low P concentration water treatment.

Experimental and Numerical Investigations of Tensile Properties of SiC Particle‐Reinforced Composites

In this study, experiments and finite element modeling (FEM) are performed to study the tensile mechanical properties of SiC particle‐reinforced 6061 Al‐matrix composites (SiCp/6061Al) at various volume fractions (VFs) of SiCp. The Young's modulus, yield strength, and tensile strength of SiCp/6061Al display an overall upward trend with the increment of the VF of SiCp. The fracture analysis results demonstrate that the fracture of SiCp/6061Al is a hybrid of matrix fracture, reinforcement fracture, and interface debonding. An algorithm is developed to construct the mesostructure of particle‐reinforced composites, based on the random sequential absorption algorithm. The VFs of the particles of the representative volume element (RVE) model constructed using the novel algorithm are as high as 42%. The tensile mechanical properties of SiCp/6061Al are predicted by replacing the irregular particle reinforcements in SiCp/6061Al with spherical particles in the RVE model. Comparisons reveal that the stress–strain curves obtained via experiment and FEM are highly consistent in the elastic‐plastic stage, which verifies the effectiveness and rationality of the novel algorithm.

Enhancement of the photodegradation performance towards methylene blue and rhodamine B using AgxSn1–xO2 nanocomposites

In the present study, the structural properties, as well as the photodegradation performance of methylene blue (MB) and rhodamine B (Rh B) using hydrothermal synthesized AgxSn1–xO2 (0 ≤ x ≤ 1) nanocomposites were studied. The study was investigated using various techniques including EDS, XRD, FE-SEM, HR-TEM, photoluminescence spectroscopy, N2 adsorption-desorption, GC-MS, and a double-beam spectrophotometer. The tetragonal SnO2 phase dominates, while the cubic Ag2O phase appears at larger x ratios (x ≥ 0.5). The crystallite and particle sizes were slightly raised for a low Ag ratio but dramatically increased for higher x ratios. Different morphologies emerge depending on the composition, such as spherical and irregular particles for x = 0 and 1, sheet-like morphology for x = 0.05, 0.2, and 0.4, and worm-like morphology for x = 0.5. The maximum surface area was calculated using the BET method to be 358 and 354 m2/g for x = 0.2 and 0.4, respectively. The direct optical band gap depends on the x ratio and the crystallite size and equals 3.95 eV and 3.70 eV for x = 0 and x = 1, respectively. The synthesized AgxSn1–xO2 composites demonstrated excellent photodegradation efficiency (η) towards MB and Rh B. The majority of compositions had high η towards MB and the highest value of 99.6 % was attained using Ag0.4Sn0.6O2 under the UV–visible irradiation for 1.5 h. Also, synthetic composites demonstrated efficient photodegradation of Rh B, particularly for higher Ag content (η = 94.4 % at x = 0.5). The catalysts revealed acceptable reusability and stability, and the degraded products were studied using the GC-MS technique with a proposed mechanism of degradation. The improvement in photodegradation of MB and Rh B dyes can be attributed to an increase in surface area, as well as the development of shape and optical characteristics.

Effective removal of Pb(II) ions using Fe3O4/MgO adsorbent: A comprehensive study  

The effective removal of heavy metal ions, particularly Pb(II), from contaminated water sources remains a pressing environmental concern. This study explores the potential of Fe3O4/MgO nanocomposites as an efficient adsorbent for selective Pb(II) removal. The Fe3O4/MgO nanocomposite was synthesized using a controlled sol-gel method and characterized using various techniques. X-ray diffraction (XRD) analysis confirmed the presence of cubic MgO and cubic Fe3O4. Pb(II) adsorption induced a crystallographic transformation, forming hexagonal Mg(OH)2 crystals, indicating interaction with the adsorbent. Scanning Electron Microscope (SEM) analysis revealed pyramid-like and irregular crystal morphologies. Pyramid-like structures provided a larger surface area and active sites for effective Pb(II) interaction, while irregular crystal particles, representing magnetic Fe3O4, contributed to stability and dispersibility. Vibrating sample magnetometer (VSM) results confirmed superparamagnetic behaviour with a saturation magnetization of 32.02 emu g-1, indicating potential for magnetic separation and recovery in various wastewater treatment applications. Adsorption experiments utilized optimized conditions: an initial concentration of 600 mg L-1, adsorbent dosage of 0.25 g L-1, pH of 7, and 120 minutes of reaction time. The Fe3O4/MgO nanocomposite exhibited exceptional performance with a remarkable 99.98% removal efficiency and a high adsorption capacity of 2399.44 mg g-1. These impressive results underscore the outstanding adsorption potential of the nanocomposite. Adsorption kinetics followed the pseudo-second-order model (R2 = 0.99), confirming suitability for Pb(II) removal. The Freundlich model indicated a heterogeneous surface with different adsorption sites. Overall, the Fe3O4/MgO nanocomposite exhibits potential as a cost-effective, environmentally friendly adsorbent for removing Pb(II) ions, providing a promising solution for water purification and environmental remediation.

Tuning the magnetocaloric and structural properties of La0.67Sr0.28Pr0.05Mn1–xCoxO3 refrigeration materials

Abstract The structural, magnetic and magnetocaloric properties of perovskite manganites La0.67Sr0.28Pr0.05Mn1−x Co x O3 (x = 0.05, 0.075 and 0.10) (LSPMCO) are investigated. LSPMCO crystallizes as a rhombohedral structure with R-3c space group. As the Co content increases, the cell volume expands, the Mn–O–Mn bond angle reduces and the length of the Mn–O bond increases. The samples show irregular submicron particles under a Zeiss scanning electron microscopy. The particle size becomes larger with increasing doping. The chemical composition of the samples is confirmed by x-ray photoelectron spectroscopy (XPS). The ferromagnetic (FM) to paramagnetic (PM) phase transition occurs near the Curie temperature (T C), and all transitions are second-order phase transitions (SMOPT) characterized by minimal thermal and magnetic hystereses. Critical behavior analysis indicates that the critical parameters of LSPMCO closely align with those predicted by the mean-field model. The T C declines with Co doping and reaches near room temperature (302 K) at x = 0.075. The maximum magnetic entropy change ( − Δ S M max ) at x = 0.05 is 4.27 J/kg⋅K, and the relative cooling power (RCP) peaks at 310.81 J/K. Therefore, the system holds significant potential for development as a magnetic refrigeration material, meriting further professional and objective evaluation.

Computed tomography-driven analysis of particle breakage using a coupled FDM–DEM approach

This study proposes a refined approach for simulating the mechanical behavior of soils under high stress by integrating the finite difference method–discrete element method (FDM–DEM) with in situ experiment. This novel framework incorporates advanced technologies such as flexible membrane and X-ray computed tomography (CT) to enhance the predictive capabilities of the simulation with physical insight. The FDM–DEM model adeptly simulates irregular particle shapes, capturing their interactions and the dynamics of particle breakage. The use of flexible membrane within the model further enriches this approach by enabling the capture of deformation responses in granular materials during shearing. Moreover, the adoption of CT technology facilitates continuous optimization of the simulation process. Validation through in situ experiments has confirmed the model’s effectiveness. The ability of the model to predict areas of high stress concentration—and their correlation with observed particle breakage patterns—underscores the utility of the enhanced FDM–DEM framework as a robust predictive tool for understanding the behavior of granular materials under shearing.

Synthesis and Characterization of LaMnO3 Prepared by Hydrothermal Synthesis Method

Abstract LaMnO3 powders were prepared by hydrothermal synthesis method by varying citric acid to metal ions. The ratio of citric acid to metal ions is one of the parameters that have an affect on purity of LaMnO3 prepared by hydrothermal method. It is necessary to control the parameter to obtain the good quality of the final product of LaMnO3. LaMnO3 with variation molar ratio of citric acid to metal ion (CA/M) of 0, 1 and 4 were prepared. To determine the morphology, crystall structure, and phase composition, the powders were characterized by Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and X-Ray Diffraction (XRD) techniques. The obtained results revealed that the morphology of sample CA/M = 0 has rod-like shape, CA/M = 1 was in the formed of irregular fine particles that stuck together and formed agglomerates, while the spherical morphology with various diameters were formed in the sample CA/M = 4. The XRD analysis demonstrated that sample CA/M = 1 had a single phase while in sample CA/M = 0 and CA/M = 4 others phase were detected such as La (OH)3 and La2O3. There was a change in crystall structure of the LaMnO3 phase in each sample due to the presence of citric acid. The peaks position in sample CA/M = 0, 1, dan 4 exhibit orthorhombic, rhombohendral and cubic structure with space group of Pnma, R -3c and Pm-3m respectively.

The influence of ball milling conditions on the powder characteristics and sintering densification of Mo[sbnd]Cu alloy

Mechanical alloying was utilized to produce Mo-30Cu(wt%) composite powder. The effects of milling conditions on the powder characteristics and sintering densification were investigated. The morphological evolution during the mechanical alloying process can be categorized into four stages: 1-individual Mo and Cu particles, 2-coexistence of Mo particles and blocky MoCu composite particles, 3-coarse irregular composite particles, and 4-refined near-spherical composite particles or lamellar MoCu composite particles, depending on whether process control agent (PCA) is added. The mechanical alloying degree of the MoCu composite powder was deepened gradually from stage 1 to 4, which is influenced by the ball milling parameters. As the milling speed and milling time increase, the lattice strain and the alloying degree of the MoCu composite powders increase while the grain size of molybdenum particles decreases, which is conducive to accelerating the sintering density. Among these ball milling parameters, an elevated milling speed notably accelerates the mechanical alloying process and the sintering density. Under the milling speed of 600 r/min, ball to powder ratio (BPR) of 10:1, and milling time of 4 h, the grain size, lattice strain, and average particle diameter of the composite powder were measured to be 48.4 nm, 0.247 %, and 21.04 μm, respectively, with the particle morphology being nearly spherical. The sintered density of the MoCu composite reached 98.1 %, larger than the other composites.

Optimization of Ultrasonic-Assisted Extraction, Characterization and Antioxidant and Immunoregulatory Activities of Arthrospira platensis Polysaccharides.

This study aimed to enhance the ultrasonic-assisted extraction (UAE) yield of seawater Arthrospira platensis polysaccharides (APPs) and investigate its structural characteristics and bioactivities. The optimization of UAE achieved a maximum crude polysaccharides yield of 14.78%. The optimal extraction conditions were a liquid-solid ratio of 30.00 mL/g, extraction temperature of 81 °C, ultrasonic power at 92 W and extraction time at 30 min. After purification through cellulose DEAE-52 and Sephadex G-100 columns, two polysaccharide elutions (APP-1 and APP-2) were obtained. APP-2 had stronger antioxidant and immunoregulatory activities than APP-1, thus the characterization of APP-2 was conducted. APP-2 was an acidic polysaccharide consisting of rhamnose, glucose, mannose and glucuronic acid at a ratio of 1.00:24.21:7.63:1.53. It possessed a molecular weight of 72.48 kDa. Additionally, APP-2 had linear and irregular spherical particles and amorphous structures, which contained pyranoid polysaccharides with alpha/beta glycosidic bonds. These findings offered the foundation for APP-2 as an antioxidant and immunomodulator applied in the food, pharmaceutical and cosmetic industries.

Extraction and Characterization of Chitosan from Snail Shells (Achatina fulica)

Background: Chitosan due to biodegradable and non-toxic characteristics has versatile applications. Extraction and characterization of Chitosan from Snail Shells In January, 2023 Achatina fulica was performed. Methods: A chemical process involving demineralization and deproteinization was utilized to extract 2000g Chitin from Achatina fulica shells. To produce chitosan, the chitin was subjected to deacetylation. The chitosan was subsequently characterized using Fourier Transform Infrared spectroscopy, X-ray diffraction, and Scanning Electron Microscopy. The physicochemical charactristics and mineral compositionswere investigated and the data were analyzed using the Statistical Package for Social Sciences (SPSS) software version 20.0. Results: The chitosan obtained from the process was 75%. It exhibited a Degree Of Deacetylation of 82.31%, a molecular weight of 2.65×105 g/mol, an intrinsic viscosity of 1,007.2 mg/g, and a solubility of 70%. The pH value of chitosan in acetic acid solution was recorded at 6.38, with a solubility of 70%. The proximate analysis revealed moisture, ash, fat, protein, crude fiber, and carbohydrate contents of 0.32, 0.72, 2.01, 0.13, 0.15, and 96.67%, respectively.The mineral analysis revealed sodium, potassium, calcium, magnesium, phosphorus, iron, and zinc concentrations of 32.10, 21.80, 721, 288.60, 123.75, 41.77, and 8.48 mg/g, respectively. X-ray diffraction analysis identified the region characterized by the presence of calcite and calcium phosphate, indicating residual minerals in the extracted chitosan, which contribute to its crystalline structure. Fourier Transform Infrared spectroscopy demonstrated functional groups such as amino and hydroxyl groups, whereas Scanning Electron Microscopy reported an irregular particle size with rough surfaces and a microfibrillar crystalline structure. Conclusion: The current investigation has the potential to promote the sustainable use of a locally abundant yet underutilized resource, assisting in waste reduction and creation of innovative bioactive materials which could be applied in food preservation, pharmaceuticals, and medical devices.