Colloid Mill Research Articles

Preparation of Dispersed Particle Gel (DPG) through a Simple High Speed Shearing Method

Dispersed particle gel (DPG) has been first successfully prepared using cross-linked gel systems through a simple high speed shearing method with the aid of a colloid mill at room temperature. The gel microstructure and particle size were investigated by scanning electron microscope (SEM), transmission electron microscope (TEM), and dynamic light scattering (DLS) measurements. The results clearly show that the prepared DPG particles have highly uniformly spherical structures with an average size of 2.5 μm. A possible mechanism for the formation of DPG has been put forward and discussed in details. The high speed shearing method is considered to be the simple and rapid method for the preparation of DPG.

Visible-Light-Induced Photocatalyst Based on Cobalt-Doped Zinc Ferrite Nanocrystals

The present work reported the synthesis of visible-light-induced cobalt-doped zinc ferrite (Zn1-xCoxFe2O4) photocatalysts via a facile reduction–oxidation route, which involved rapid reduction of Fe3+ and Co2+ cations in colloid mill reactor, followed by oxidation of iron and cobalt nuclei and structural transformation under hydrothermal conditions. The structural and optical properties of materials were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and UV–vis diffuse reflectance spectra. The results indicated that metallic Co and Fe nuclei could be obtained by reduction in the colloid mill, and Zn1-xCoxFe2O4 nanocrystals with uniform size were successfully achieved. Furthermore, compared to ZnFe2O4, Zn1-xCoxFe2O4 samples (x = 0.03, 0.1, 0.2) exhibited enhanced photocatalytic activity in the degradation of methylene blue under visible light irradiation. Especially, the Zn0.8Co0.2Fe2O4 sample had the highest photocatalytic activity, which was mainly attributable to its smaller band edge. Since as-synthesized Zn–Co ferrites nanocrystals have the advantages of intrinsic chemical stability and magnetic property, it can be expected that they may have potential application in the field of industrial photodegradation of organic pollutants.

Preparation of <i>Grifola frondosa</i> Fermented Beverage without Preservatives

Purpose To prepare Grifola frondosa fermented beverage and study on its production process, ingredients and characteristics. Methods The following process was used to prepare Grifola frondosa fermented beverage: Grifola frondosa original strains →Strain activation →Inclined plane strain →Liquid spawn →Submerged fermentation →Fermentation broth with mycelium →Colloid mill grinding →High pressure homogenization →Homogenate →Add preservatives or not →Package → Sterilizing or not →Finished product. Grifola frondosa mycelium biomass was determined by Weight-Drying method. Total sugar content was measured by Phenol-sulfuric acid method. Reducing sugar content was measured by 3, 5-dinitrosalicylic acid (DNS) method. Protein content was measured by Coomassie brilliant blue method. The quality of Grifola frondosa fermented beverage was evaluated every 10 days from six areas: color, precipitation, transparency, aroma, taste and the bacteria growth situation. Results Mycelia biomass of Grifola frondosa fermentation product is 378.3 ± 7.21mg/100ml. The total sugar content is 1.8995 mg/ml, the reducing sugar content is 0.2539 mg/ml, and grifolan content is 1.6456 mg/ml, protein content 7.971μg/ml. The total number of colonies is 67 CFU/ml and no E. coli in Grifola frondosa fermented beverage, this comply with the requirements of the national food safety standard. The samples of Grifola frondosa fermented beverage without sterilized and preservatives placed at room temperature for 6 months are normal, and no bacteria growth. Conclusion The production process of Grifola frondosa fermented beverage is feasible. In the case without sterilization and preservatives, Grifola frondosa fermented beverage can be placed at room temperature for 6 months without deterioration and still maintain its characteristics of nutrient-rich, pure taste, clean and hygienic, with natural mushroom fragrant. This can provide a reference for the development of Grifola frondosa submerged fermentation products.

Synthesis of uniform Ni–Al layered double hydroxide via a novel reduction–oxidation route

Ni–Al layered double hydroxides (LDHs) were successfully synthesized through a novel reduction–oxidation route, which involved a rapid reduction of Ni2+ cations and nucleation in a colloid mill, followed by an oxidation of metallic nickel nuclei and structural transformation under hydrothermal conditions in the presence of sodium carbonate. The results indicated that the concentration of sodium carbonate and hydrothermal reaction temperature had important influence on the growth of LDH phase, and NiAl-LDH crystals with high crystallinity and good homogeneity could be achieved under the optimal conditions. The possible formation mechanism of a NiAl-LDH compound was proposed tentatively. The present work provided a new method for a scale-up synthesis of a variety of well-crystallized LDH materials.

Development of Processing Technology and Stability of Peanut Beverage

Objective: To study the processing technology and formula of peanut–tea beverage, and further provide reference for the plant protein beverage. Methods: The peanut was baked in the far-infrared oven, soaked with soft water containing 5% NaHCO3, rinsed and then cooked for 30 min, milled at 0.05 mm spacing grinding, filtered and finished peanut slurry. Tea leaves were extracted twice by water of 90°C. The two ingredients were combined with other supplement, refined by colloid mill, homogenized twice, followed by bottling, sealed, sterilization, cooled and other processing. In this study, the formula, stabilizers and additives by orthogonal experiments were investigated. Results: The peanut slurry and sugar were found to be major factors which affected the beverage’s quality. The formula was optimized when the content of peanut slurry, tea and sucrose reached 75 mL, 25 mL and 4 g especially in per 100 mL peanut-tea beverage. As single stabilizer, CMC-Na showed the most significant effect, and storage temperature was found to be better at room temperature than low temperature. Compared with single stabilizer, compound stabilizer was better. The optimal formula was CMC-Na 0.4 g/L, seaweed sodium 0.2 g/L, gelatin 0.8 g/L. Conclusion: The peanut-tea beverage, with unique flavor and rich nutrients, was a novel type of health plant beverage which was suitable for a large variety of people, and had a promising market.

Study on Optimization of Sugar Juice Clarification with Superfine Calcium Hydroxide

The lime milk was ground with colloid mill in which the particles became finer and modified with mechanical intensification. The results, after the lime milk was ground for 60s and then used to the clarification of sugar juice, showed that: the purity of the clarified juice increased 1.5~2.0 percentage points, the lime salts decreased 0.02 percentage point, the color value and the reducing sugar also went down.

Wet grinding characteristics of soybean for soymilk extraction

Wet grinding of hydrated soybean was carried out with mixer grinder, stone grinder and colloid mill which revealed that particle size had a profound effect on the protein recovery in the extracted milk with a maximum recovery of 89.3%. Greater reduction in particle size was achieved with mixer grinder (180 μm) with 5 min of grinding while reduction was not significant beyond 18 min (233 μm) in stone grinder. Specific energy consumption in colloid mill was only one-fourth of the mixer grinder while stone grinder required twice the energy. Although Kick’s, Rittinger’s and Bond’s laws could not be applied for total grinding duration, all the three classical laws were found suitable after the initial grain break-up period (2 min). Temperature and duration of thermal treatment given during hot extraction influenced protein recovery and viscosity of soymilk. The results suggest that colloid mill is a potential device for industrial scale operation.

Engineered morphologies of layered double hydroxide nanoarchitectured shell microspheres and their calcined products

CoFe IIFe III-layered double hydroxide (LDH) hollow spheres with two distinctly different hierarchical morphologies—flower-like and raspberry-like, involving edge-on and face-on oriented LDH platelets as building blocks, respectively—can be fabricated by tuning the rate of addition of NaOH solution in a coprecipitation process with sulfonated polystyrene spheres as a template. Ex situ pH-dependent microscopic observations of the formation of the flower-like LDH shells shows the details of non-classic nucleation and growth underlying the edge-on orientation. After calcination, the resulting CoFe 2O 4 materials retain the hierarchical morphology of the corresponding LDH precursor. The hollow CoFe 2O 4 spheres with raspberry-like morphology exhibit magnetic properties comparable to a reference material obtained by calcination of a conventional LDH powder precursor. Similar materials with tunable magnetic properties can be prepared by virtue of the flexibility in LDH layer composition. The CoFe IIFe III-LDH spheres with a raspberry-like morphology may be also be prepared by using a scalable procedure involving separate ultra-rapid nucleation and aging steps in a modified colloid mill reactor. The results reported here may open up the possibility of producing shell structures with controllable morphologies and properties on a large scale.

Novel Preparation Technology of SBS Modified Asphalt

Colloid mill or high-speed shearing mechanical is used in traditional preparation technology of SBS modified asphalt for the dispersion of SBS in matrix asphalt, which leads to the high equipment cost in production of SBS modified asphalt. The fractions oil of FCC slurry oil distillation with a high content of aromatics is a good swelling agent of SBS. The FCC distillation residual (FR) with high softening point can resolve the problem that penetration increased when the addition of swelling agent increased. SBS is pre-swelled by the heavier fractions from FCC slurry oil, and then it will be dispersed in the vacuum residuum (VR) by simple mechanical stirring to prepare SBS modified asphalt due to the perfect swelling effects in this work. The influences of different materials, distillation yield and ratio of FR to VR on the performance of SBS modified asphalt have been investigated. Fluorescence microscopy was applied to observe the different disperse images of SBS modified asphalt prepared by simple mechanical stirring and high speed shearing. The results indicated that the novel method can be used to prepare SBS modified asphalt with good performance and storage stability.

Grinding and cooking dry-fractionated corn germ to optimize aqueous enzymatic oil extraction

The many recent dry-grind plants that convert corn to ethanol are potential sources of substantial amounts of corn oil. This report describes an aqueous enzymatic extraction method to separate oil from dry-fractionated corn germ. The method is an extension of a method previously developed for wet-mill germ. Oil dispersed in lipid bodies throughout the germ was converted to oil droplets suspended in an aqueous solution and then to drops of oil large enough to be separated from the solution as a continuous, buoyant phase (free oil). A microwave oven was used to cook the germ to its highest temperature, just short of burning. Thereafter the germ was extracted using the method developed for wet-mill germ: mix the heated germ with water and cook it under pressure, followed by colloid milling and enzymatic digestion of the milled germ particles overnight. A foam fraction was removed from the digested dispersion by bubbling nitrogen through a short column connected to a mixing tank. The foam fraction was then centrifuged to separate free oil. An estimate of aqueous enzymatic extraction plant costs to extract 24 million kg of dry-fractionated germ per year [40 million gal/year ethanol], showed that income from the unrefined oil streams and a stream sending the rest of the germ to the fermentation process was roughly equal to the estimated operating cost, with an investment of $2.6 million. Recycle of the enzyme may reduce the estimated enzyme cost of $750,000/year.

Nanocrystalline zinc ferrite photocatalysts formed using the colloid mill and hydrothermal technique

Nanocrystalline zinc ferrite (ZnFe 2O 4) photocatalysts with different crystallite sizes prepared using the colloid mill and hydrothermal technique are reported. This synthetic approach involves a very rapid mixing of Fe 3+ cations with reducing agent and reduction process in a colloid mill reactor, followed by a slow oxidation of iron nuclei and structural transformation in a separate hydrothermal process. Material characterization has been presented by powder X-ray diffraction (XRD), chemical element analysis, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and UV–vis diffuse reflectance spectra. The results indicate that ZnFe 2O 4 nanocrystals with the uniform crystallite sizes have been obtained using in situ forming iron nuclei as the source of Fe. A possible formation mechanism of ZnFe 2O 4 nanocrystals was proposed. Furthermore, through photocatalytic investigation, these ZnFe 2O 4 nanocrystals displayed better abilities to photodecompose acid orange II azodye molecule under UV irradiation due to quantum confinement effect and high surface area structure, as compared to bulk ZnFe 2O 4 sample prepared by the conventional solid-state method. Since as-synthesized ZnFe 2O 4 nanocrystals have excellent chemical and thermal stabilities and exhibit good photocatalytic activities, it can be expected that they may have potential application in the field of industrial photo-degradation of organic azodye pollutants.

Foam Separation of Oil from Enzymatically Treated Wet‐Milled Corn Germ Dispersions

AbstractMore than 9 billion gallons of ethanol were produced in 2008, mostly from dry grind corn fermentation plants. These plants are a potential source of substantial amounts of corn oil, if an economical method of separating it can be developed. In this work, oil was separated from corn germ by aqueous enzymatic extraction (AEE). Batches of wet‐milled corn germ in water were preheated in a pressure cooker, ground in a colloid mill, and churned in a vertical column/mixing vessel system, after the addition of enzyme. Nitrogen gas was then bubbled through the column removing an overflowing foam fraction which was subsequently centrifuged to separate free oil. Using a newly commercialized enzyme complex it was found that 80% of the oil could be recovered using a w/w ratio of enzyme solution to germ of 1:80. The low dose and low price of the enzyme complex leads to a cost estimate of AEE of corn oil from germ, similar to the wet‐milled germ extracted, cost competitive with expelled oil (with the separation and drying of the foam protein), and feasible for commercialization in a dry grind plant retrofitted to separate germ.

Formulation and evaluation of pharmaceutically equivalent parenteral depot suspension of methyl prednisolone acetate.

The aim of the present study was to formulate and evaluate pharmaceutically equivalent injectable aqueous suspension for parenteral depot of methyl prednisolone acetate. Various aqueous suspensions were prepared by rapid stirring and colloid milling method. The prepared aqueous suspensions were subjected to particle size determination, sedimentation study, in vitro release studies (pH dependent dissolution study), and stability studies. The optimized formulation consisted of 4% w/w of methyl prednisolone acetate, 2.91% w/w of PEG-3350, 0.19% w/v of injection grade Tween-80, 0.68% w/w of monobasic sodium phosphate, 0.15% w/w of di-basic sodium phosphate, 0.91% w/v of benzyl alcohol, 0.32% w/w sodium meta bisulphate. The f2 value was calculated for innovator (DepoMedrol®, Batch No. MPH-0254) and optimized formulation at pH 6.8 and pH 7.4 phosphate buffers. The f2 values of 62.94 and 54.37 were obtained at pH 6.8 and pH 7.4 phosphate buffers respectively. The particle size ranged 23-27 μm at D value of 0.9 for both test and innovator product.

Facile Synthesis and Characterization of Cobalt Ferrite Nanocrystals via a Simple Reduction−Oxidation Route

In this paper, a facile synthetic route of cobalt ferrite nanocrystals with narrow size distribution was reported. The key feature of this method involved a very rapid mixing of reducible metal cations with sodium borohydride and simultaneous reduction in a colloid mill, which is followed by a slow oxidation in a separate hydrothermal treatment. The microstructural and magnetic characteristics of the materials were characterized by powder X-ray diffraction (XRD), chemical analysis, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDX), transmission electron microscopy (TEM), Mossbauer spectroscopy, and magnetometry. The results unambiguously indicated that the obtained products consisted of CoFe2O4 nanocrystals with good monodispersity and high stoichiometry and that, especially, a 9 nm sample exhibited room-temperature superparamagnetism. The formation mechanism of nanocrystals was proposed. It is believed that the extreme forces, to which ...

Investigation of the effects of mechanical post‐processing with a colloid mill on the texture properties of stirred yogurt

Texture properties of stirred low‐fat yogurt were investigated in terms of processing after fermentation. The yogurt gel was pumped through a colloid mill at two gap widths and various peripheral velocities of the rotor. The storage modulus and yield stress were measured after 1 day and after 3 weeks, and the occurrence of syneresis was noted. The main factor for the structural degradation in the shear gap was the mean peripheral velocity of the rotor, rather than the apparent shear rate. Syneresis is related to a certain level of the storage modulus. The yield stress correlated with the storage modulus.

Grinding characteristics and batter quality of rice in different wet grinding systems

Grinding characteristics of raw and parboiled rice were evaluated in various wet grinding systems, namely, mixer grinder, stone grinder and colloid mill. The duration of grinding had inverse effect on the particle size and direct impact on the starch damage as well as energy consumption in batch grinders. Stone grinder was the least energy efficient and specific energy consumption for grinding raw rice (160.6kJ/kg) was nearly twice as that of mixer grinder (74.9kJ/kg). Parboiled rice required longer duration of grinding compared to raw rice, consequently specific energy consumption was higher (∼220kJ/kg). All the three classical laws of grinding (Kick’s, Rittinger’s and Bond’s) seemed to be applicable while Rittinger’s law showed better suitability than the other two followed by Bond’s law. Predominant compressive forces involved in stone grinder reflected in higher starch damage in batter which was also evident in the micrographs. Parboiled rice slurry exhibited much greater viscosity than raw rice but both displayed non-Newtonian pseudoplastic behaviour.

Oil separation from wet-milled corn germ dispersions by aqueous oil extraction and aqueous enzymatic oil extraction

The many recent dry-grind plants that convert corn to ethanol are a potential source of substantial amounts of corn oil, if an economical method of separating it can be developed. Oil separation from corn germ by aqueous extraction (AE) was studied. Batches of 5–20% germ in a buffer solution were preheated in a pressure cooker, ground in a blender or colloid mill, churned in an incubator/shaker and centrifuged to separate a free oil fraction. The highest oil yields were obtained when the germ mass fraction was between 0.1 and 0.16. Addition of an enzyme solution to the ground germ suspension prior to churning, aqueous enzymatic extraction (AEE) gave an oil yield twice as high as the AE yield, carried out using similar conditions. Both types of extraction produced the most oil after a 122 °C cook followed by churning at 160 rpm and 70 °C. Oil yield increased linearly with dispersion loading, from 0.5 up to 1.0 g/cm 2 based on beaker cross-section (0.09–0.12 germ mass fraction). Over a several month period the germ used for the extractions became more difficult to extract, despite storage at 4 °C.

Development of Ni–Cu–Mg–Al catalysts for the synthesis of carbon nanofibers by catalytic decomposition of methane

This work presents the kinetics and characterization results of Ni–Cu–Mg–Al catalysts used for the synthesis of carbon nanofibers (CNFs) by catalytic methane decomposition (CCVD). Ni–Cu–Mg–Al-based lamellar double hydroxides (LDHs) were synthesized by the coprecipitation method using either a regular maturation stage or a colloid mill process. After calcination at 1073 K and reduction at 1023 K, the formation of alloyed Ni–Cu nanoparticles over a mixed MgO–MgAl 2O 4–NiAl 2O 4 support was observed. The kinetic study of CNF synthesis by CCVD of methane was carried out in a thermobalance operated as a differential reactor. Small proportions of Cu ( ⩽ 10 wt% ) were found to improve the activity and mainly the stability over time of Ni–Mg–Al catalysts. On the other hand, large proportions of Cu dramatically decrease the activity of the catalysts in terms of CNF yield. The catalysts were able to produce high-quality CNFs with a graphitic or turbostratic structure. The size of metal particles and the diameter of carbon filaments obtained depend on the catalyst composition (i.e., Ni:Cu ratio). The application of a kinetic model based on the growing mechanism of CNFs allows us to determine the influence of the operating conditions on the kinetic parameters.

Pilot Scale Processing of Red Flesh Guava RTS Beverage

Pilot scale studies on production of ready-to-serve (RTS) beverage from red flesh guava were done using 100 kg of the fruit. Pulp yield was more (73.68 %) in lye peeling than in hand peeling (58.68 %). RTS beverage was prepared by mixing fruit pulp with syrup to an optimum level of acidity and sugar, as standardized on a laboratory scale. Blending RTS beverage by using colloidal mill improved the colour, consistency and overall quality. From 100 kg of red flesh guava, 247 litres of RTS beverage could be obtained. The cost:benefit ratio and value addition from this process were worked out at 1.79 and Rs. 5.45/kg of fruit, respectively.

Chemineer's Greerco Colloid Mill refines coatings

Chemineer's Greerco Colloid Mill refines coatings