Large Particle Size Distribution Research Articles

Co-sintering of a ceramic-metal bilayer: Coupled experimental, analytical and numerical approaches

The co-sintering behavior of a ceramic-metal bilayer is carefully investigated. This bilayer is composed of a gold film deposited by screen-printing on a silica-based low-temperature cofired ceramic (LTCC) layer. First, behaviors of both materials in free sintering are finely characterized. LTCC exhibits a viscous flow sintering mechanism, whereas the densification mechanism of gold is controlled by grain boundary diffusion (with an identified apparent activation energy of 101 ± 15 kJ mol−1). Free sintering of gold is also marked by a two-step densification process due to its large bimodal particle size distribution. A methodology is proposed to estimate gold viscosity at high temperatures directly from raw experimental data in free sintering, without performing dedicated mechanical characterizations. Based on the constitutive laws identified for LTCC and gold materials, analytical and numerical models of the bilayer co-sintering process are built. During co-sintering, stresses generated by densification kinetic mismatch between gold and LTCC are progressively relaxed by camber phenomenon. Calculated evolutions of camber in co-sintering are compared to curvature monitoring by ombroscopy. Finite element simulation in 3D fits well with the experimental data, whereas the analytical solution strongly underestimates camber rates. This shows that the simplified numerical approach suggested here leads to a robust numerical model, faithfully describing thermomechanical interactions occurring in co-sintering within the ceramic-metal bilayer.

Regulation of tea polyphenols in gluten-glucose Maillard reaction: Evaluation and analysis

Maillard reaction plays an important role in the flavour and color of some food. However, the excessive occurrence of Maillard reaction may affect the quality and safety of food. In this study, a simulated Maillard system composed of gluten and glucose was established to evaluate and analyze the regulatory role of tea polyphenols (TP) in it. The addition of tea polyphenols alleviated excessive browning of the Maillard reaction and significantly inhibited the accumulation of fructosamine and late glycosylation end products in the system. Based on the analysis of laser particle sizer and atomic force microscope, the large particle size distribution and aggregation structure of the Maillard reaction products in the tea polyphenol group disappeared. Further experiments showed that with the addition of tea polyphenols, the free radicals content in the system decreased, while the amount of reaction substrates increased. It was also shown that tea polyphenols effectively inhibited the isomerism of glucose to fructose and affected the content of free sulfhydryl and free amino groups in the system. The results indicated that tea polyphenols can regulate the Maillard reaction between gluten and glucose, which gives it the potential for application in the field of bakery and thermally processed foods.

Study of a Copper Oxide Leaching in Alkaline Monosodium Glutamate Solution

Oxide copper minerals are commonly extracted via acidic leaching, using acids such as H2SO4, HCl, or HNO3. These strong acids are the most widely used because of their high dissolution kinetics. However, their main concern is the high acid consumption because copper oxide deposits contain large amounts of acid-consuming gangue. This paper proposes using an alternative aqueous alkaline monosodium glutamate (MSG) system to leach copper oxide minerals. Tenorite (CuO) was used as the copper oxide mineral under study. The influence of process variables (such as temperature and glutamate concentration) and kinetics of this system on copper leaching from tenorite were studied. The results showed that temperature has a significant effect on copper dissolution rates. Increased temperature from 15 °C to 60 °C enhanced the copper extraction from 9.1% to 97.7% after 2 h. Leaching kinetics were analyzed using the shrinking core model (SCM) under various conditions, indicating that the leaching rate presented a mixed control. This method, however, fails to describe leaching for broad particle sizes due to its requirement for single-sized solid grains. This study demonstrated that a large particle size distribution in tenorite supported a successful extension of the SCM for leaching it from mixed glutamate solutions. The activation energy for the 15–60 °C temperature range was calculated to be 102.6 kJ/mol for the chemical control.

Multiple interaction electron beam powder bed fusion for controlling melt pool dynamics and improving surface quality

Low surface quality of fabricated parts and long processing times are two commonly stated reasons against a more wide-spread adoption of electron beam powder bed fusion (PBF-EB) as a commercially viable manufacturing technique. Aside from the large particle size distribution (45–150 µm) of processed powders, the surface roughness, limited structural resolution and process instabilities are attributed to unwanted dynamics of the melt pool, like spattering, balling, evaporation and melt pool displacement. As a result, a contouring step using slow but stable melting parameters is usually added to the process to improve surface quality, leading to increased processing times.In this study, we demonstrate how the surface quality can be improved by supplying the energy for melt pool formation over multiple, timely separated interactions. To investigate the effect of this multiple interaction processing (MIP), series of single line melt structures with increasing number of interactions were fabricated, characterized and corresponding thermal diffusion simulations performed. The experimental results show how MIP allows to lower surface roughness of melted structures through a reduction of spattering, balling and melt pool displacement during processing, while our simulation model identifies these benefits to be caused by a significant reduction in surface temperature and thus evaporation, with increasing number of interactions for melt pool formation. Our model further demonstrates, how a relatively simple, computationally inexpensive and thus scalable thermal diffusion model is capable of providing valuable information about thermal conditions during melt pool formation. Lastly, we introduce a few simple equations to calculate appropriate MIP parameters for any kind of scan strategy.

Potential Optimization of Industrial Waste as an Alternative Material for Composite Filler in Brake Pad Manufacturing – A Review

This study investigates the sustainable utilization of fly ash, palm slag and Cement By-Pass Dust (CBPD) waste as alternative materials for environmentally friendly brake pad development. These waste materials, with compositions similar to Asbestos, historically used in brake pad composites, present an eco-conscious solution. Integrating industrial waste in brake pad production offers substantial environmental benefits, technological progress, and commercial advantages. The compaction value and particle size distribution significantly impact brake pad mechanical properties. Adjusting these factors is crucial for meeting desired mechanical property requirements. A large particle size distribution enhances material density and hardness poses challenges in maintaining performance stability at high temperatures despite good recovery values. This paper highlights the potential of waste materials for sustainable brake pad development and underscores the need for careful optimization for high-temperature stability.

Trace Silicon Determination in Biological Samples by Inductively Coupled Plasma Mass Spectrometry (ICP-MS): Insight into the Volatility of Silicon Species in Hydrofluoric Acid Digests for Optimal Sample Preparation and Introduction to ICP-MS

A method for the determination of trace levels of silicon from biological materials by inductively coupled plasma mass spectrometry (ICP-MS) has been developed. The volatility of water-soluble silicon species, hexafluorosilicic acid (H2SiF6), and sodium metasilicate (Na2SiO3) was investigated by evaporating respective solutions (50 µg/mL silicon) in HNO3), nitric acid + hydrochloric acid (HNO3 + HCl), and nitric acid + hydrochloric acid + hydrofluoric acid (HNO3 + HCl + HF) at 120 °C on a hot-block to near dryness. The loss of silicon from H2SiF6 solutions was substantial (>99%) regardless of the digestion medium. Losses were also substantial (>98%) for metasilicate solutions heated in HNO3 + HCl + HF, while no significant loss occurred in HNO3 or HNO3 + HCl. These results show that H2SiF6 species were highly volatile and potential losses could confound accuracy at trace level determinations by ICP-MS if digestates prepared in HF are heated to eliminate HF. Among the various matrices comprising major elements, sodium appeared to be effective in reducing silicon loss from H2SiF6 solutions. Excess sodium chloride (NaCl) matrix provided better stability, improving silicon recoveries by up to about 80% in evaporated HF digestates of soil and mine waste samples, but losses could not be fully prevented. To safely remove excess acids and circumvent the adverse effects of excess HF (e.g., risk of high Si background signals), a two-step digestion scheme was adopted for the preparation of biological samples containing trace silicon levels. A closed-vessel digestion was performed either in 4 mL of concentrated HNO3 and 1 mL of concentrated HCl or 4 mL of concentrated HNO3, 1 mL of concentrated HCl and 1 mL of concentrated HClO4 on a hot plate at 140 °C. Digestates were then evaporated to incipient dryness at 120 °C to remove the acids. A second closed-vessel digestion was carried out to dissolve silicates in 0.5 mL of concentrated HNO3 and 0.5 mL of concentrated HF at 130 °C. After digestion, digestates were diluted to 10 mL. The solution containing about 5% HNO3 and 5% HF was directly analyzed by ICP-MS equipped with an HF-inert sample introduction system. The limit of detection was about 110 µg/L for 28Si when using the Kinetic Energy Discrimination (KED) mode. The method was used to determine silicon in various plant and tissue certified reference materials. Data were acquired for 28Si using KED and standard (STD) modes, and 74Ge and 103Rh as internal standard elements. There was not any significant difference between the accuracy and precision of the results obtained with 74Ge and 103Rh within the same measurement mode. Precision, calculated as relative standard deviation for four replicate analyses, varied from 5.3 (tomato leaves) to 21% (peach leaves) for plant and from 2.2 (oyster tissue) to 33% (bovine liver) for tissue SRM/CRMs. Poor precision was attributed to material heterogeneity and the large particle size distribution. An analysis of lung tissue samples from those with occupational exposure to silica dust revealed that tissues possessed substantial levels of water-soluble silicates, but the most silicon was present in the particulate matter fraction.

Effect of Molecular Architecture of Surface-Active Organosilicon Macromers on Their Colloidal Properties in Relation to Heterophasic Radical Polymerization of Styrene and Methyl Methacrylate

The effects of the molecular architecture of water-insoluble organosilicon polymerizable surfactant macromers (SAMs) on their colloidal-chemical characteristics and on their efficiency in heterophase radical polymerization of styrene and methyl methacrylate were studied. It was shown that despite considerable differences in the structure of three synthesized oligomers (linear α,ω-dipropylmethacrylatepolydimethylsiloxane with a number of repeated siloxane units n = 20—l-SAM; branched γ-methacryloxypropyl containing dimethylsiloxane oligomer—b-SAM; and “spherical” oligo-(γ-methacryloxypropyl)silsesquioxane—s-SAM), the colloidal-chemical characteristics (interfacial tension, layer thickness, adsorption, etc.) were rather similar. In particular, they all form “thick” multimolecular adsorption layers on the toluene–water interphase. All three SAMs were shown to act as effective colloidal stabilizers in heterophase radical polymerization of styrene and methyl methacrylate, which resulted in one-step preparation of large (0.5–1.5 µm) polymer particles with narrow particle size distribution. The obtained results are consistent with the published data on the use of water-insoluble polymerizable oligomers of various chemical structures on the heterophase radical polymerization. The use of these colloidal stabilizers may be considered as an effective way to obtain stable suspensions with large particles and narrow particle size distribution.

Further study on particle size, stability, and complexation of silver nanoparticles under the composite effect of bovine serum protein and humic acid.

Silver nanoparticles (AgNPs) are widely used due to their unique antibacterial properties and excellent photoelectric properties. Wastewater treatment plants form a pool of AgNPs due to the social cycle of wastewater. During biological treatment processes, the particle size and stability of AgNPs change. We studied the particle size changes and stability of silver nanoparticles in the presence of bovine serum albumin (BSA) and humic acid (HA). The experimental results indicated that silver nanoparticles can complex with the functional groups in BSA. For AgNP-BSA composites, as the BSA concentration increases, the size of the silver nanoparticles first decreases and then increases. AgNPs can combine with the amide, amino, and carboxyl groups in HA. As the concentration of HA increases, the particle size and large particle size distribution of AgNPs increase. This increasing trend is more obvious when the HA concentration is lower than 20 mg L-1. When HA and BSA exist at the same time, HA will occupy the adsorption sites of BSA on the surface of AgNPs, and the AgNP-HA complex will dominate the system. This study aims to provide key operational control strategies for the process operation of wastewater treatment plants containing AgNPs and theoretical support for promoting water environment improvement and economic development such as tourism.

Hydrophobic agglomeration flotation of fine cassiterite induced by kerosene and sodium oleate

In this study, the effect of kerosene and sodium oleate (NaOL) on inducing hydrophobic agglomeration flotation of fine cassiterite was investigated through the micro-flotation tests, particle size distribution and morphological analysis, zeta potential and contact angle measurements. The results indicated that adding kerosene before NaOL could obtain a higher recovery than adding NaOL before kerosene. The agglomerates induced by adding kerosene before NaOL was dense and regular in structure with larger particle size distribution and stronger surface hydrophobicity, which jointly contributed to its higher flotation recovery. Furtherly, the extended DLVO theory calculation was carried out to explain the agglomeration behaviour of fine cassiterite under different reagents. The results convinced that under the reaction of NaOL before kerosene or kerosene before NaOL, hydrophobic interaction and sufficient kinetic energy input were necessary to form agglomerates, and the attraction effect between cassiterite particles under the reaction of kerosene before NaOL was the strongest.

Microwave irradiation of corn kernels: Effects on structural, thermal, functional and rheological properties of corn flour

The current study investigated the impact of microwave treatment on the physicochemical properties of corn kernels. Three microwave powers (2, 3, 4 W/g) and three treatment times (2, 3, 4 min) were used to treat the corn kernels. The findings indicate that heat treatment increased gelatinization temperature and gelatinization enthalpy. Moreover, relative crystallinity was reduced by 17.89% in the microwave-treated flour in comparison to untreated samples, and alterations were observed in the protein secondary structure, ordered structure, and functional properties of corn flour. Microwave treatment caused the darkening of the sample and a larger particle size distribution. Higher radiation times and microwave powers exhibited more intensive treatment outcomes. Rheological tests indicated that the elastic and viscous moduli of the microwave treated corn gels were higher than those of the control group, and their large-amplitude oscillatory shear curves exhibited a strain-weak strain overshoot (type III). The results of this study suggest that microwave treatment can potentially be utilized as a technique to regulate the technical functional properties and viscoelasticity of corn flour.

A probability model for predicting the transport efficiency in vertical pipes considering the particle size distribution

Improving transport efficiency is one of the core issues in the field of deep-sea mining. Slip velocities have strong effects on the transport efficiency of deep-sea mineral nodules in the hydraulic conveying process. The present work proposes a probability model for predicting the transport velocity and efficiency, which can reflect the influence of different particle size distribution of large particles. By comparing with a numerical simulation, experimental data and empirical models, the proposed model is well verified and demonstrates advantages in accuracy. To acquire further knowledge of the optimal transport efficiency and the predominant factors, such as the volumetric concentration, the pipe diameter and the mixture velocity, effects of various parameters are explored in detail through the present model, including the medium particle diameter, the average dry solid production, the operating power, the particle density, and the fluid density. Furthermore, four general-purpose optimization algorithms, including the global search (GS), the MultiStart (MS), the pattern search (PS) and the genetic algorithm (GA), are combined to obtain the optimal transport efficiency and compared in an application study. The proposed model provides an efficient tool to fast optimize the transport efficiency of mineral nodules in hydraulic conveying pipes. • Probability model to predict velocity considering particle size distribution • Complete procedure to obtain optimal efficiency and corresponding variables • Four general-purpose optimization algorithms compared for hydraulic conveying • Superior prediction accuracy validated by experimental data and empirical models • Efficient tool to fast optimize transport efficiency of conveying mineral nodules

2D Hierarchical NiMoO4 Nanosheets/Activated Carbon Nanocomposites for High Performance Supercapacitors: The Effect of Nickel to Molybdenum Ratios.

Supercapacitors have the potential to be used in a variety of fields, including electric vehicles, and a lot of research is focused on unique electrode materials to enhance capacitance and stability. Herein, we prepared nickel molybdate/activated carbon (AC) nanocomposites using a facile impregnation method that preserved the carbon surface area. In order to study how the nickel-to-molybdenum ratio affects the efficiency of the electrode, different ratios between Ni-Mo were prepared and tested as supercapacitor electrodes, namely in the following ratios: 1:1, 1:2, 1:3, 1:4, and 1:5. X-ray diffraction, X-ray photoelectron spectroscopy, FESEM, HRTEM, and BET devices were extensively used to analyze the structure of the nanocomposites. The structure of the prepared nickel molybdates was discovered to be 2D hierarchical nanosheets, which functionalized the carbon surface. Among all of the electrodes, the best molar ratio between Ni-Mo was found to be 1:3 NiMo3/AC reaching (541 F·g-1) of specific capacitance at a current density of 1 A·g-1, and 67 W·h·Kg-1 of energy density at a power density of 487 W·Kg-1. Furthermore, after 4000 repetitive cycles at a large current density of 4 A·g-1, an amazing capacitance stability of 97.7% was maintained. This remarkable electrochemical activity for NiMo3/AC could be credited towards its 2D hierarchical structure, which has a huge surface area of 1703 m2·g-1, high pore volume of 0.925 cm3·g-1, and large particle size distribution.

The Influence of Particle Size and Hydrate Formation Path on the Geomechanical Behavior of Hydrate Bearing Sands

Determining the geomechanical properties of hydrate-bearing sands (HBS), such as strength and stiffness, are critical for evaluating the potential for the economic and safe recovery of methane gas from HBS reservoirs. To date, results from numerous independent laboratory studies on synthesized HBS have shown that strength and stiffness are largely influenced by hydrate saturation, the method adopted for hydrate formation, and to a lesser extent, the confining stresses applied during testing. However, a significant scatter is observed in the data even when these conditions are similar. These include recent studies on natural HBS where sands with larger particle size distribution (PSD) exhibited higher strengths despite lower hydrate saturation. To investigate the impact of PSD, and the role that specific hydrate formation conditions might impose, on the strength and stiffness of HBS, a series of laboratory tests were carried out on sand specimens formed with different particle size distributions and utilizing different approaches for forming gas saturated HBS. The laboratory apparatus included a resonant column drive head to measure the small-strain stiffness of the specimen during hydrate formation, and subsequent drained compressional shearing to capture the stress-strain response of the HBS. Results indicate that the PSD significantly affects both the stiffness evolution (during hydrate formation) and peak strength at failure after formation compared to the effect of the methodology adopted for hydrate formation. These observations improve our understanding of the geomechanical behavior of laboratory-synthesized HBS and allow more robust relationships to be developed between them and natural HBS. This may aid in the development of economic and safe methane gas production methods to help realize the energy resource potential of HBS reservoirs.

Snowfall Microphysics Characterized by PARSIVEL Disdrometer Observations in Beijing from 2020 to 2022

Accurate snowfall forecasting and quantitative snowfall estimation remain challenging due to the complexity and variability of snow microphysical properties. In this paper, the microphysical characteristics of snowfall in the Yanqing mountainous area of Beijing are investigated by using a Particle Size and Velocity (PARSIVEL) disdrometer. Results show that the high snowfall intensity process has large particle-size distribution (PSD) peak concentration, but the distribution of its spectrum width is much smaller than that of moderate or low snowfall intensity. When the snowfall intensity is high, the corresponding Dm value is smaller and the Nw value is larger. Comparison between the fitted μ−Λ relationship and the relationships of different locations show that there are regional differences. Based on dry snow samples, the Ze−SR relationship fitted in this paper is more consistent with the Ze−SR relationship of dry snow in Nanjing, China. The fitted ρs−Dm relationship of dry snow is close to the relationship in Pyeongchang, Republic of Korea, but the relationship of wet snow shows greatly difference. At last, the paper analyzes the statistics on velocity and diameter distribution of snow particles according to different snowfall intensities.

Heat-induced aggregation of subunits/polypeptides of soybean protein: Structural and physicochemical properties

To reveal the nature of thermal aggregation of soybean protein at subunit level, structure and physicochemical properties of αα'- and β-subunits isolated from β-conglycinin, acidic polypeptide, and basic polypeptide from glycinin, as well as β-conglycinin and glycinin, were characterized before and after heat treatment. The transmission electron microscopy (TEM) images showed that β-conglycinin, αα'-subunits and acidic polypeptide formed regular thermal aggregates, which exhibited high solubility, high ζ-potential value, and small particle size. While glycinin, β-subunit, and basic polypeptide aggregated to insoluble clusters with large particle size distribution. The results of size exclusion chromatography and non-reducing electrophoresis showed that the disulfide bond was the important force in stabilizing the protein conformation of thermal aggregates in β-conglycinin, glycinin, and their isolated subunits/polypeptides but β-subunit. The results of surface hydrophobicity and intrinsic fluorescence spectra showed that the thermal aggregations of β-subunit and basic polypeptide were mainly driven by hydrophobic interactions.

Exploration of process optimization for recovery of sodium and ammonium sulfate crystals from vanadium precipitation wastewater

In this paper, we have studied vanadium precipitation wastewater in two stages of the fractional crystallization process. In order to extract sodium sulfate and ammonium sulfate products with large particle size and uniform particle size distribution from the rear end vanadium precipitation wastewater and to realize the resource reuse of vanadium precipitation wastewater, the effects of various operating parameters (seeding amount, evaporation rate, stirring rate, growing time) on the particle size and particle size distribution of sodium sulfate and ammonium sulfate products were investigated. Better separation and crystallization conditions of sodium sulfate and ammonium sulfate were obtained. The optimized crystallization conditions of sodium sulfate are: the addition amount of ammonium sulfate seeding with a particle size of 40 μm is 1.17 %, the evaporation rate is 100 mL/h, the stirring rate is 80 rpm, the crystal growth time is 60 min, and the main particle size M.S. value of sodium sulfate crystals is 242.23 μm; The optimized crystallization conditions of ammonium sulfate were as follows: the addition amount of sodium sulfate seeding with a particle size of 80 μm was 0.68 %, the evaporation rate was 160 mL/h, the stirring rate was 150 rpm, and the crystal growth time was 30 min. The M.S. value of the final ammonium sulfate crystal was 880 μm.

Role of active slip systems induced with holmium impurity in Bi-2212 ceramics on mechanical design performance and morphological properties

Effect of Ho/Bi partial replacement in Bi2.1-xHoxSr2.0Ca1.1Cu2.0Oy (Bi-2212) superconductors on the fundamental structural, morphological and mechanical performance properties are investigated by Scanning Electron Microscopy (SEM) and Vickers hardness (Hv) measurement techniques. Crystallinity quality and surface morphology including the microcrystal coalescence orientations, grain alignment distributions, microscopic structural problems, microvoids, internal defects, uniform surface view, porosity and particle growth distribution are visually examined with the aid of SEM. Basic mechanical performance and characteristic features of Bi/Ho substituted Bi-2212 superconducting ceramics (0.00 ≤ x ≤ 0.10) are also determined with Vickers tests conducted at various loads intervals 0.245–2.940 N. Experimental findings show that the characteristic features enhance seriously in case of x = 0.01 due to refinement of crystallinity quality and slip systems. Thus, the optimum Ho concentration presents the highest mechanical fracture strength to the load applied as a result of better uniform surface appearance and grain orientations, well-connected flaky layers, larger particle size distribution and denser structure, confirmed by the SEM investigations. Namely, much more load is required to accelerate the dislocation movement and crack propagation to the terminal velocity for critical size growth. The fracture predominantly takes place in the transcrystalline regions and hence the propagations are easily controlled with the optimum Ho dopant ions. On the other hand, the increase in the Ho ions in Bi-2212 structure induces the crack-initiating defects for new stress concentration sites. In conclusion, the permanent and non-recoverable deformations appear at even lower indentation test loads. All samples present indentation size effect feature depending on the dominant character of elastic recovery mechanism. Further, original hardness parameters are semi-empirically analyzed in the plateau limit regions using mechanical modelling approaches for the first time. Based on the analyses, Hays–Kendall model exhibits the closest results to the experimental findings.

Influence of Non-Rubber Components on the Properties of Unvulcanized Natural Rubber from Different Clones.

Natural rubber from different Hevea braziliensis clones, namely RRIM600, RRIT251, PB235 and BPM24, exhibit unique properties. The influences of the various fresh natural rubber latex and cream concentrated latex on the non-rubber components related properties were studied. It was found that the fresh natural rubber latex exhibited differences in their particle size, which was attributed to the non-rubber and unique signature of clones which affect various properties. Meanwhile, the cream concentrated latex showed the protein contents, surface tension, and color of creamed latex to be lower than the fresh natural latex. However, TSC, DRC, viscosity, particle size and green strength of concentrated latex were found to be higher than the fresh natural latex. This is attributed to the incorporation of HEC molecules. Also, the rubber particle size distribution in the RRIM600 clone exhibited a large particle size and uniform distribution, showing good mechanical properties when compared to the other clones. Furthermore, the increased green strength in the RRIM600 clone can be attributed to the crystallization of the chain on straining and chain entanglement. These experimental results may provide benefits for manufacturing rubber products, which can be selected from a suitable clone.

Green fabrication of iron nanoparticles decorated with amine functionality for the remediation of lead ions from aqueous solutions

Eco-friendly iron nanoparticles (FeNP) were synthesized by utilizing a natural plant extract as a reducing and stabilizing agent. To further enhance the affinity of the nanoparticles toward heavy metals, N-[3-(Trimethoxysilyl)propyl]ethylenediamine (DA) was attached to the surface of FeNP by two different techniques, namely post-synthesis (grafting) and one-pot synthesis to produce FeNP-DA-G, and FeNP-DA-P, respectively. The three samples were characterized by TEM, SEM, TGA, UV, FT-IR, DLS, and BET analysis. The FT-IR spectra confirmed the capping rule of the plant extract in addition to the existence of the OH groups that are important for the reduction step. The DLS analysis supported the capping effect of the plant extract by showing a much larger particle size distribution than the one obtained by TEM. Both SEM and TEM images indicated irregular shape particles with a tendency to aggregate for FeNP and some larger spherical particles and broader particle size distribution for FeNP-DA-G, while FeNP-DA-P images showed more spherical particles with narrow size distribution and a tendency to aggregation. The successful formation of the nanoparticles was also confirmed via UV spectra, while the successful attachment of the DA to the surface of FeNP-DA-G and FeNP-DA-P was confirmed by EDS analysis. BET analysis showed a drastic decrease in both surface area and pore volume of FeNP-DA-G compared to FeNP and FeNP-DA-P, which is related to the blockage of the pores after attaching DA. The three samples were tested for the adsorption of lead ions from aqueous solutions. Both equilibrium and kinetic properties of the adsorption process were investigated and compared. The results generally suggested that the best sample concerning the removal of lead ions was FeNP-DA-P, followed by FeNP, and finally FeNP-DA-G.

Development of encapsulated sage extract powder: Inter-comparison with commercially available powder for physical properties and metabolites composition

Encapsulated Salvia officinalis L. powder (SESP) was developed from extract obtained by supercritical fluid extraction (SFE), and it was compared with commercial sage powder of hydro-distillation extract (HESP). The optimised conditions of 30 MPa at 50 °C for laboratory scale SFE extraction were found to generate the highest yield at 40.96 ± 0.84%. The conditions were later applied in the upscaled extraction, which yielded about 30.10 ± 1.33% extract. Large particle size distribution at 118.46 ± 6.63 µm for SESP was notified as compared to 66.80 ± 1.50 µm for HESP. Outcomes of crystallographic analysis demonstrated that abundant metabolites from various groups existed in both powders. About 25 and 43 metabolites were identified by Gas Chromatography-Mass Spectrometry (GC–MS) in HESP and SESP, respectively. In HESP, organic acids were found to be the major group identified, while terpenoids were the largest group found in SESP.