Superfine Powder Research Articles

Production of superfine green tea powder from processing wastes: Characterization of chemical composition and exploration of antimicrobial potential against Ralstonia solanacearum

“Green waste” derived from food or agro-industrial has been applied to remove pathogenic bacteria. Green tea waste is polyphenol rich green waste but barely been focused by researchers. We ground the green tea wastes into superfine powder at 4 °C. The median particle size of superfine green tea powder (SGTP) was 9.215 μm. The chemical composition of powder was analyzed by high performance liquid chromatography (HPLC), and was mainly consisting of gallic acid (GA), epigallocatechin gallate (EGCG), caffeine (CAF), and epicatechin gallate (ECG). In vitro experiment indicated that the SGTP significantly inhibited bacterial proliferation of plant pathogen Ralstonia solanacearum GMI1000 in a concentration-dependent manner. However, when the hrpB deletion mutant of GMI1000 was inoculated in medium supplemented with SGTP, the bacterial growth was barely affected. Furthermore, the SGTP significantly decreased the bacterial swimming motility. Scanning electron microscope (SEM) image exhibited that cell damage emerged when bacteria was exposed to medium supplemented with SGTP. Antibacterial activity was compared towards SGTP, tea polyphenol, and tea extract, which suggested that SGTP had potential to be a functional antimicrobial. Our approach of SGTP as antimicrobial would broaden the scope of green waste utilization in a greener, cost-effective, and sustainable approach in future.

Physicochemical properties and anthocyanin bioaccessibility of downy rose-myrtle powder prepared by superfine grinding

ABSTRACTThe downy rose-myrtle berry is regarded as a healthy food due to its high content of anthocyanin and other antioxidant phytochemicals. The berries are sometimes dried, ground into a powder and used as a natural food coloring agent or functional food additive. This study aimed to determine the physicochemical properties and anthocyanin bioaccessibility of superfine ground downy rose-myrtle powders. Compared with shear pulverized coarse particles, the superfine ground particles of berry powders had decreased bulk density and fluidity while improved water-holding capacity and solubility. In addition, the amounts of polyphenols and anthocyanins released from the superfine powders were significantly higher than those from coarse powders during in vitro gastrointestinal digestion. These results indicate that after superfine grinding treatment, downy rose-myrtle powder could serve as a potential resource of natural bioactive compounds for food and nutraceutical applications.

Segregation patterns and characteristics differences of superfine pulverized coal ground by three pulverizing systems

Comminution methods and segregation of coal powder are key factors affecting the characteristics of superfine pulverized coal. However, there are few articles available in this issue. In this paper, three representative pulverizing systems with diverse grinding patterns and gathering methods are selected to prepare superfine powder using the same raw coal. Afterwards, element analysis, approximate analysis, maceral determinations, surface area measurement and XPS tests are performed successively. The segregation tendencies and its influences on the coal powder are compared and discussed among three groups. Data of similar sizes in three groups receive special attentions. Based on the experiments, it is found that at the same conditions, vitrinite is easier to gain thorough crushing compared with inertinite. Due to the smaller sizes, vitrinite and ashes are prone to escape from the cyclone separator. Due to the high density, inertinite and ashes are apt to accumulate in the lower part of the coal pile. The maceral segregation imposes greater influences on the C-containing functional groups on the surfaces than the mechanochemical effects. The significances of this paper lie in figuring out the influences of grinding methods on properties and segregation patterns of superfine pulverized coal, which provide valuable references for industrial applications of this technology.

Removal of per- and polyfluoroalkyl substances using super-fine powder activated carbon and ceramic membrane filtration.

Contamination of drinking water sources with per- and polyfluoroalkyl substances (PFASs) is a major challenge for environmental engineers. While granular activated carbon (GAC) is an effective adsorbent-based treatment technology for long-chained PFASs, GAC is less effective for removal of short-chained compounds, necessitating a more complete treatment strategy. Super-fine powder activated carbon (SPAC; particle diameter <1 um) is potentially a superior adsorbent to GAC due to high specific surface area and faster adsorption kinetics. This study served to evaluate SPAC coupled with ceramic microfiltration (CMF) for PFAS removal in a continuous flow system. Comparison of PFAS mass loading rates onto SPAC and GAC to 10% breakthrough of PFASs using contaminated groundwater indicates that SPAC has nearly double the adsorption potential of GAC. Limitations reaching breakthrough for the SPAC system led to additional higher mass loading experiments where PFAS adsorption onto SPAC reached 2990 μg/g (for quantifiable PFASs), 480x greater than GAC and is thought to be a function of adsorbent size, pore content and PFAS chain length. Additional analysis of system performance through the application of liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QToF-MS) revealed the presence of additional PFASs in influent samples that were removed by the SPAC/CMF system.

Efficiency characterization of fire extinguishing compound superfine powder containing Mg(OH)2

To improve the fire extinguishing efficiency of existing dry powders, a new type of superfine dry powder was prepared using magnesium hydroxide as an additive. In our study, a thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to analyze the thermal decomposition of the synthesized powders. The temperature of thermal decomposition, weight loss, and other thermodynamic parameters of the fire extinguishing powders were analyzed to explain the performance advantages of the compound superfine powder. Through a small-scale fire experiment, the physical parameters of the extinguishing process—such as extinguish time, powder dosage, smoke concentration, and minimum extinguishing concentration—were quantified for the suppression of a diesel fire using the different powders; these parameters were used to evaluate the fire extinguishing capacity and toxic gas suppression ability of the powders. TGA demonstrated that the compound superfine powder decomposed more quickly and its thermal decomposition process was much shorter than those of the other powders. The DSC data indicated that the compound superfine powder could decrease the characteristic temperature at each stage and thus the powder absorbed the flame's heat more quickly and suppressed flame propagation. The fire extinguishing test demonstrated that the consumption of the three types of fire extinguishing powder decreased with an increase in the driving pressure, and the order of powder dosage was as follows: commercial dry powder > superfine powder > compound superfine powder. Similarly, the order of minimum extinguishing concentration was as follows: commercial dry powder > superfine powder > compound superfine powder. Furthermore, the compound superfine powder exhibited a greater capacity for controlling toxic and harmful gas emissions.

Вплив ультразвукового оброблення в кульовому млині на фазово-структурні характеристики високодисперсних порошкових сумішей міді з залізом і кобальтом

Вплив ультразвукового оброблення в кульовому млині на фазово-структурні характеристики високодисперсних порошкових сумішей міді з залізом і кобальтом

Sulfur Doped Lead Monoxide Superfine Powder Materials: Solid-State Synthesis, Characterization, Adsorption and Photocatalytic Property of Methylene Blue

Sulfur doped lead monoxide (S–PbO) superfine powder materials with high visible light-driven activity were successfully prepared by a simple solid-state reaction method at low temperature using sodium dodecyl benzene sulfonate (SDBS) as a template. The samples were characterized by X-ray powder diffraction, high resolution transmission electron microscopy/energy-dispersive X-ray spectroscopy, UV–Vis absorption spectra, infrared spectroscopy, X-ray photoelectron spectroscopy and N2 adsorption–desorption. The effect of feed ratio on the microstructure of materials, the doping mechanism of sulfur and the adsorption mechanism of methylene blue (MB) on the material surface were discussed. In addition, the intrinsic relationships among the material structure parameters, the photocatalytic degradation of MB under visible light irradiation and the stability of materials were investigated. The results show that the S element is successfully incorporated into the (111) crystal plane of the orthorhombic β-PbO lattice as a S(IV) and S(VI) at the assistance of SDBS. The content of sulfur has a certain regulatory effect on the energy gap of the orthorhombic PbO, and there is a positive correlation among the photocatalytic property of MB, the content of sulfur, and the lattice spacing of (111) and (310) crystal plane. The adsorption of MB mainly depends on the interaction between the surface active sites (S–O bond) and hydroxyl groups, and the adsorption relaxation time under different sulfur content. Under visible-light irradiation at room temperature within 60 min, the photocatalytic degradation (wt%) rate of MB (C0 = 50 mg/L) follows an order of S–PbO(S:Pb = 0.05:0.95) (97.8%) > S–PbO(S:Pb = 0.10:0.90) (90.6%) > S–PbO(S:Pb = 0.15:0.85) (83.5%) > S–PbO(S:Pb = 0.20:0.80) (72.3%) > PbO (48.2%). The holes (h+) and hydroxyl radicals (·OH) are the main active species during the photodegradation of MB solution for the S-doped PbO materials. The S-doped PbO materials are of a p-type indirect semiconductor, and the loss of lead is very little in the MB solution, it is feasible to the S-doped PbO powder materials as photocatalysts.

A supersonic target jet mill based on the entrainment of annular supersonic flow.

Jet mill is an apparatus that produces superfine powder and is widely used in various industries. In this work, a new supersonic target jet mill based on aerodynamic theory is presented according to the flow field of a traditional jet mill. An annular supersonic flow produced by an annular converging-diverging nozzle is used to entrain the central particle flow by the shear mechanism in this new supersonic target jet mill. Then, the particle beam concentrating in the flow center impacts the target with high kinetic energy after the entrainment of the supersonic flow. An apparatus of the annular supersonic target jet mill was created to validate the theoretical design. Two types of experiments were implemented to estimate its performance. The validation experiments confirmed that the gas speed in the collision chamber was approximately 600 m/s and the supersonic flow could deliver a kinetic energy of approximately 180 J/s to the particles. The particle size reduction of boroncarbide (B4C) and silica (Si) in the collision tests showed that the accelerated particles concentrated in the supersonic flow center collided on the targets precisely with high collision energy.

Powders with small microparticle size from Hedera helix and Scrophularia nodosa exhibited high preventive antioxidant activity against H2O2-induced oxidative stress in mouse primary spleen cells.

The purpose of this study was to examine the effects of powder particle size on the cytoprotective and antioxidant activity of Hedera helix (HH) and Scrophularia nodosa (SN), two medicinal plants more commonly known as ivy and figwort, against H2O2-induced oxidative stress in mouse primary spleen cells. Thus, the preventive effects of powders of 3 different granulometric classes (50-100μm, 100-180μm and 180-315μm) and those of the hydroethanolic (HE) extract from HH and SN on oxidative stress were compared by monitoring reactive oxygen species (ROS) formation, malondialdehyde (MDA) production, and the activity of enzymatic antioxidants including catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx). Results showed that pretreatment with the 3 fine powders from both plants generally offered to H2O2-exposed spleen cells, a protection against oxidative stress, highlighted by a significant decrease of both ROS formation and the level of MDA (p<0.001), and a significant increase of GPx activity (p<0.05). The two superfine powders (i.e. 50-100μm and 100-180μm), at 250μg/mL, were more effective in modulating all oxidative stress markers studied than both HE extracts (p<0.01), and the powder with the highest particular size (i.e., 180-315μm) (p<0.01). Compared to untreated cells, our results suggest that pretreatment with powders, in particular the superfine fractions, has relatively restored the levels of antioxidant-related enzymes including GPx, CAT and SOD. In summary, our results suggest differential effects between the 3 different fine powders studied, with the best cytoprotective and antioxidant activities being in favor of the superfine powders.

Observation of changes in the number of myocardial capillaries in rabbits after treatment of acute myocardial infarction by Tongxinluo superfine powder

OBJECTIVETo investigate the effects of Tongxinluo superfine powder on cardiac function, infarct size and the number of myocardial capillaries in a rabbit model of acute myocardial infarction. METHODSA total of 32 New Zealand white rabbits were randomly divided into four groups: sham operation group, model group, treatment group, and pre-treatment, the experiment of pre-treatment group was performed 6 weeks early than the treat) group, The four groups use a unified modeling technique. An acute myocardial infarction model was established through external application of 70% ferric chloride on the coronary artery. After 7 d, electrocardiogram, ultrasonography of cardiac function, micro-computed tomography, pathology and other data were collected. RESULTSIn the treatment and pre-treatment groups, ejection fraction, left ventricular short axis shortening rate, left ventricular end-systolic diameter and cardiac output significantly improved, the number of capillaries significantly increased, and infarct size significantly decreased. In addition, the results suggest that the value of intra-ventricular pressure and the situation of electrocardiogram also changed to different degrees with the increasing of treatment of cycle. CONCLUSIONTongxinluo superfine powder can protect the myocardium, improve the blood supply of the myocardium and reduce the degree of myocardial injury, during acute stage of myocardial infarction.

Steam jet mill—a prospective solution to industrial exhaust steam and solid waste

Bulk industrial solid wastes occupy a lot of our resources and release large amounts of toxic and hazardous substances to the surrounding environment, demanding innovative strategies for grinding, classification, collection, and recycling for economically ultrafine powder. A new technology for grinding, classification, collection, and recycling solid waste is proposed, using the superheated steam produced from the industrial exhaust steam to disperse, grind, classify, and collect the industrial solid waste. A large-scale steam jet mill was designed to operate at an inlet steam temperature 230-300°C and an inlet pressure of 0.2-0.6MPa. A kind of industrial solid waste fluidized-bed combustion ashes was used to grinding tests at different steam temperatures and inlet pressures. The total process for grinding, classification, and collection is drying. Two kinds of particle sizes are obtained. One particle size is d50 = 4.785μm, and another particle size is d50 = 8.999μm. For particle size d50 = 8.999μm, the inlet temperature is 296°C and an inlet pressure is 0.54MPa for the grinding chamber. The steam flow is 21.7t/h. The yield of superfine powder is 73t/h. The power consumption is 3.76kWh/t. The obtained superfine powder meets the national standard S95 slag. On the basis of these results, a reproducible and sustainable industrial ecological protocol using steam produced by industrial exhaust heat coupled to solid waste recycling is proposed, providing an efficient, large-scale, low-cost, promising, and green method for both solid waste recovery and industrial exhaust heat reutilization.

Submicron LaB6 powders with high purity prepared in large scale by salt-assisted combustion synthesis

LaB6 powders were synthesized in large scale by salt-assisted combustion synthesis (CS) with different NaCl diluent contents. The variety of phases, particle size and purity of the powders were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), and transmission electron microscope (TEM). With increase of NaCl content, the adiabatic combustion temperature of the reaction system linearly declines, the average particle size of leached products decreases, the impurity phases are easier to remove, and the products purity enhances obviously. When NaCl content is 40 wt%, the purity of the superfine powders of LaB6 is more than 98 wt%, and the average particle size is 380 nm.

Thermal analysis testing and natural radioactivity characterization of kaolin as building material

Kaolins are used in a multiplicity of industries because of unique physical and chemical properties. Relationships between thermal and radioactivity properties are discussed in its application as a building material. Super-fine kaolin powder with particle sizes about 30 μm was analyzed. Simultaneous TGA/DTA analysis was performed on powder samples at various heating rates in an argon atmosphere. Based on investigated thermal properties, it was concluded that dehydroxylation process can vary depending on the characteristics of starting material. The maximum degree of the dehydroxylation (DT) was obtained at the lowest rate of heating (DT = 60.79% for 10 °C min−1). With an increase in the heating rate, decline in DT value was observed. Based on comprehensive testing, it was identified that the degree of dehydroxylation does not drop below 50%. It was concluded that appointed experimental conditions seem sufficient admissible for obtaining degree of dehydroxylation (DT) higher than 50%. In order to safe use of kaolin as a building material from the standpoint of radiological safety, content of natural radionuclides was determined by gamma spectrometry.

A new data in the kinetic and thermodynamic analysis of non-isothermal decomposition of super-fine kaolin powder

Abstract Kinetic and thermodynamic analysis of non-isothermal decomposition of super-fine kaolin powder was examined. It was established that the decomposition process proceeds through liberation of adsorbed water, the loss of the water of hydration and dehydroxylation process, which produces highly disordered metakaolin. By applying the distributed reactivity approaches, it was found that dehydroxylation can be described with simultaneous two-parallel reactions model. By applying the Exner-Linert statistical method on estimated Eyring plots, the true isokinetic temperature was confirmed. The appearance of entropy – enthalpy compensation (EEC) showed the direct cause-and-effect relationship between these thermodynamic observables resulting by physically real factors such as the steric factors. It was shown that the phenomenon of true compensation effect arises from conformational (geometrical) changes, which occur during metakaolin formation.

Study on Preparation of C60 High Performance Concrete by Replacing Partial Cement with Superfine Phosphorus Slag Powder

This paper mainly studies the substitution effect of the superfine powder on cement after the use of superfine powder in concrete. The experiment shows that the superfine phosphor slag powder can significantly improve the performance of C60 high-performance concrete and has an important role in the retention value of 1h slump. The incorporation of superfine phosphorus slag powder can reduce the incorporation of gelled materials and reduce the quantity of the gelation materials by about 50kg when it meets C60 grade concrete strength. Compared with other mineral admixtures, ultrafine phosphorus slag powder can improve the durability of concrete and reduce the early cracking tendency of concrete in C60 high performance concrete. The C60 high performance concrete has the characteristics of good working and easy to crack, and has the technical and economic advantages of similar products in the market.

Experimental Study on Fire Extinguishing Properties of Compound Superfine Powder

Abstract In this paper, the existing fire extinguishing powder was improved with magnesium hydroxide as additive to prepare the compound superfine powder. And the fire extinguishing performance of the compound powder was tested by the modified cup-burner, being compared with the commercial dry powder and the superfine powder. The advantages of the compound superfine powder were explained from the aspects of minimum extinguishing concentration, temperature and extinguishing time. The experimental results showed that the minimum extinguishing concentration of compound superfine powder was much lower than the other two, and the temperature drop rate was greater in the process of suppressing flame. Although the compound superfine powder was slightly lower than the superfine powder in the average extinguishing time, the standard deviation results showed that the composite powder had better stability. In addition, the experimental results showed that the fray-out of flame was very fast and the time only accounted for 17.5% in the fire extinguishing process.

Physicochemical and antioxidant properties of hard white winter wheat (Triticum aestivm L.) bran superfine powder produced by eccentric vibratory milling

Hard white winter wheat (Triticum aestivm L.) bran was grinded by an eccentric vibratory mill below 30±0.5°C, and the effect of processing times (15, 20, 25 and 30 min) on the physicochemical and antioxidant properties of the superfine powder was investigated with disc-milled powder as control in the study. After vibratory milling treatment, the particle size of powder effectively reduced to a micron scale and the brightness increased, as well as the contents of soluble dietary fiber and phytic acid increased. Compared with the control, the eccentric vibratory milled bran powder showed higher values in bulk density (from 0.27 to 0.39g/mL), tapped density (from 0.31 to 0.76g/mL), water holding capacity (from 4.20 to 7.00g/g), swelling capacity (from 1.67 to 2.87g/g) and oil binding capacity (from 1.50 to 2.61g/g), while lower values in angles of repose and slide in the processing time sequence. Meanwhile, the thermal stability was enhanced. And the decreases of IC50 values for DPPH radical scavenging activity and ferrous ion-chelating activity suggested the improvement of antioxidant activity for bran superfine powder. The results indicated that the eccentric vibratory milled wheat bran superfine powder have various potential applications as food and pharmaceutical additives to improve the uniformity and/or to enhance functionalities of final products.

Identification and antioxidant activity of carotenoids from superfine powder of Rhodobacter sphaeroides

The interest in carotenoids from the natural-antioxidant point of view has recently risen sharply because of their substantial health benefits. Here, we report the identification and antioxidant activity of carotenoids extracted by superfine grinding from Rhodobacter sphaeroides 3757 which is a species of photosynthetic bacteria. After separation and purification by silica gel column chromatography and reversed-phase high performance liquid chromatography (RP-HPLC), the four major carotenoids from the superfine powder of R. sphaeroide 3757 were identified as bixin, hydroxyspheroidenone, 3,3¢,4¢-tetrahydrospirilloxanthin-20-al, and spheroidenone by reversed phase - high performance liquid chromatography - atmospheric pressure chemical ionization - mass spectrometry (RP-HPLC-APCI-MS). The antioxidant activity of the carotenoids extracted after superfine grinding of dry biomass of R. sphaeroide 3757 was higher than that after ultrasonic treatment. When the ratio solvent-to-solid was 30, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity, reducing power, and lipid peroxidation inhibitory activity of the extracts after superfine grinding were 74.0% ± 3.1%, 0.497 ± 0.022, and 77.6% ± 3.2%, respectively. By contrast, the extracts after ultrasonic treatment, these numbers were 61.0% ± 2.5%, 0.328 ± 0.014, and 55.2% ± 2.3%, respectively. These results indicate that carotenoids from R. sphaeroide 3757 show a significant antioxidant activity in vitro in a concentration-dependent manner, and that superfine grinding is the optimal extraction method. We hope to provide scientific guidance for commercial production of natural- antioxidant and functional food from carotenoids of R. sphaeroide.

Impact of pork collagen superfine powder on rheological and texture properties of Harbin red sausage.

Pig skin has cheap price, and easy to get. Pig skin-derived CSPs provide the potential to be used as a good filler and textured modifier available for high quality meat products, including Harbin red sausage.

Experimental studies on thermal analysis and explosion characteristics of superfine polystyrene powders

Recently, various superfine powders have been used in a wide range of applications in industrial production, but the research on the flammability and explosion characteristics of the organic powder is still under development. In this study, the thermal behaviors of superfine polystyrene (PS) powders were studied by using thermogravimetric analysis (TG). The results showed that the thermal degradation of micro-PS occurred in a two-step process, and the TG and DTG curves shifted to the higher-temperature zone when the particle size increased. Dust explosion test device series (MIE-D 1.2- and 20-L spherical explosion test device) were adopted to analyze the influence of sample concentration, particle size and ignition delay on various flammability characteristics of superfine PS powders, including minimum ignition energy (MIE), maximum explosion pressure (P max), maximum rate of pressure rise ((dP/dt)max) and lower explosive limit (LEL). The results revealed that the MIEs of different samples with different sizes (3, 5, 10, 15 and 20 μm) were 7.54, 9.73, 13.11, 15.42 and 19.29 mJ, respectively, while the corresponding LELs were 10, 10, 15, 25 and 25 g m−3, respectively. These two parameters (MIE and LEL) that characterize the possibility of dust explosion decrease with decreasing the particle size. The powders with sizes of 3, 5, 10 and 20 μm have P max values of 0.6406, 0.6277, 0.6066 and 0.5805 MPa, respectively, while the (dP/dt)max values are 89.318, 85.634, 82.073 and 80.577 MPa s−1, respectively. These two parameters (P max and (dP/dt)max) that characterize the severity of dust explosion increase with decreasing the particle size. This study shows the smaller the particle size, the higher the explosion possibility and higher the severity of superfine PS powders.