Wet Milling Research Articles

THE EFFECT OF BARIUM SUBSTITUTION WITH COMBINATIONS OF RARE EARTH ON PERMANENT MAGNETIC SURFACE MORPHOLOGY BASED ON BARIUM HEXAFERRITE

The development of hard magnets today is progressing very rapidly. Developing hard magnets based on rare earth metals becomes a severe problem when the raw materials are not readily available. The chosen solution is to replace oxide-based permanent magnets with small amounts of rare earth metals substituted to improve their magnetic properties. This study synthesized a permanent magnet oxide based on barium hexaferrite doped with lanthanum and cerium atoms. In the synthesis of this material, a mechanical wet milling technique is used to obtain a single-phase permanent magnetic Ba1-β-γLaβCeγFe12O19 system with composition (β = 0 - 0.5 and γ = 0 - 0.1). The precursors are weighted according to their stoichiometric composition. Each mixed composition was milled by high energy milling (PW 1000 in the mixer/mill) at a milling speed of 1000 rpm using steel balls with an average diameter of 12 mm. Grinding conditions included a ball-to-powder weight ratio of 2:1, milling time 5 hours, then compacted with 7000 Psi pressure and sintered at 1200oC for 2 hours. The surface morphology and microstructure of the resulting sample particles were observed using scanning electron microscopy (SEM) with the SEM JEOL JED 305 brand. The characterization results show that the particles are hexagonally homogeneous in shape with particle sizes in the range of 1000-2000 nm for β = 0 and γ = 0 (without doping). In general, the four samples with varying concentrations of doping ions La3+ and Ce4+ showed homogeneous hexagonal structures but smaller particle sizes than pure barium hexaferrite. The sample particle sizes ranged from 500-1000 nm for β = 0.02 and 300-1000 nm for β = 0.04.

Fatty Acid Release and Gastrointestinal Oxidation Status: Different Methods of Processing Flaxseed.

Flaxseed has been recognized as a superfood worldwide due to its abundance of diverse functional phytochemicals and nutrients. Various studies have shown that flaxseed consumption is beneficial to human health, though methods of processing flaxseed may significantly affect the absorption and metabolism of its bioactive components. Hence, flaxseed was subjected to various processing methods including microwaving treatment, microwave-coupled dry milling, microwave-coupled wet milling, and high-pressure homogenization. In vitro digestion experiments were conducted to assess the impact of these processing techniques on the potential gastrointestinal fate of flaxseed oil. Even though more lipids were released by the flaxseed at the beginning of digestion after it was microwaved and dry-milled, the full digestion of flaxseed oil was still restricted in the intestine. In contrast, oil droplets were more evenly distributed in wet-milled flaxseed milk, and there was a greater release of fatty acids during simulated digestion (7.33 ± 0.21 μmol/mL). Interestingly, wet-milled flaxseed milk showed higher oxidative stability compared with flaxseed powder during digestion despite the larger specific surface area of its oil droplets. This study might provide insight into the choice of flaxseed processing technology for better nutrient delivery efficiency.

Innovative ionic liquid pretreatment followed by wet disk milling treatment provides enhanced properties of sugar palm nano-fibrillated cellulose

In order to accommodate the increased demand for innovative materials, intensive research has focused on natural resources. In pursuit of advanced substances that exhibit functionality, sustainability, recyclability, and cost-effectiveness, the present work attempted an alternative study on cellulose nanofibers derived from sugar palm fiber. Leveraging an innovative approach involving ionic liquid (IL) pre-treatment, bleaching, and wet disc mill technique, nano-fibrillated cellulose (NFC) was successfully obtained from the sugar palm fiber source. Remarkably, 96.89% of nanofibers were extracted from the sugar palm fiber, demonstrating the process's efficacy and scalability. Further investigation revealed that the sugar palm nano-fibrillated cellulose (SPNFC) exhibited a surface area of 3.46 m2/g, indicating a significant interface for enhanced functionality. Additionally, the analysis unveiled an average pore size of 4.47 nm, affirming its suitability for various applications that necessitate precise filtration. Moreover, the surface charge densities of SPNFC were found to be −32.1 mV, offering opportunities for surface modification and enhanced interactions with various materials. The SPNFC exhibit remarkable thermal stability, enduring temperatures of up to 360.5 °C. Additionally, the isolation process is evident in a significant rise in the crystallinity index, escalating from 50.97% in raw fibers to 61.62% in SPNFC. These findings shed light on the vast potential and distinct features of SPNFC, opening the path for its application in a wide array of industries, including but not limited to advanced materials, biomedicine, and environmental engineering.

Feasibility of Non-Remanufactured Waste Bottle Glass as Supplementary Cementitious Material

Theoretically, glass can be recycled entirely, but there are several requirements for remanufacturing. For the first time, this work studied industrial bottle waste glass (WG), which cannot be used to remanufacture new glass as a cement replacement for concrete applications. Wet and dry milling treatments were performed to reduce the particle size of WG and remove fibre and plastic contaminants. The different waste glasses treated were characterised by chemical, physical, and morphological analysis. Afterwards, mortar-level studies followed, using raw WG and wet-milled WG (AGWG) as a 10% Portland cement replacement. Mechanical and several durability indicators were assessed. WG and AGWG incorporation improved mortar performance against water capillary absorption, chloride ingress, and alkali–silica reaction. The unfavourable effect, namely, mechanical strength loss on glass-modified mortars, was mainly due to fibre contaminants observed by SEM on WG and AGWG samples. Even though wet milling reduced the amount and length of the fibre contaminants, it still did not guarantee adequate mechanical strength for the mortar. Thus, additional or alternative treatments, such as thermal treatments, must be explored.

Agar aerogel powder particles for future life science applications: fabrication and investigations on swelling behavior and cell compatibility

The use of bio-based raw materials in the manufacture of customized aerogels has increased significantly over the last decade. Combining the advantages of biopolymer sustainability and lower costs when producing aerogels in particulate form, agar aerogel particles were fabricated in this study. They were prepared by successive thermal gelation, ethanol solvent exchange, wet milling and supercritical CO2 assisted drying. The particles still maintain high porosity (~ 1.0 cm3 g−1) and high specific surface areas (210–270 m2 g−1). The stability in wound fluid substitutes, liquid holding capacity, and cytocompatibility of these agar-based aerogel particles may make them an advantageous wound-dressing matrix that can be further customized for particular applications by adding wound-active/reactive substances, such as antibiotics, antioxidants, immunoreactive drugs or growth factors.Graphical abstract

Co-spray dried inhalable composite powders of ciprofloxacin and alginate oligosaccharide as anti-biofilm therapy

The treatment of chronic respiratory infections caused by biofilm formation are extremely challenging owing to poor drug penetration into the complex biofilm structure and high drug resistance. Local delivery of an antibiotic together with a non-antibiotic adjuvant to the lungs could often enhance the therapeutic responses by targeting different bacterial growth pathways and minimizing drug resistance. In this study, we designed new inhalable dry powders containing ciprofloxacin (CIP) and OligoG (Oli, a low-molecular-weight alginate oligosaccharide impairing the mucoid biofilms by interacting with their cationic ions) to combat respiratory bacterial biofilm infections. The resulting powders were characterized with respect to their morphology, solid-state property, surface chemistry, moisture sorption behavior, and dissolution rate. The aerosol performance and storage stability of the dry powders were also evaluated. The results showed that inhalable dry powders composed of CIP and Oli could be readily accomplished via the wet milling and spray drying process. Upon the storage under 20 ± 2 °C/20 ± 2 % relative humidity (RH) for one month, there was no significant change in the in vitro aerosol performances of the dry powders. In contrast, the dry powders became non-inhalable following the storage at 20 ± 2 °C/53 ± 2 % RH for one month due to the hygroscopic nature of Oli, which could be largely prevented by incorporation of leucine. Collectively, this study suggests that the newly developed co-spray-dried powders composed of CIP and Oli might represent a promising and alternative treatment strategy against respiratory bacterial biofilm infections.

Nano-micron soda residue as green nucleation seeding additive for silicate cement

Soda residue (SR) is a kind of by-product by the ammonia-alkali process in the soda ash production, which contains calcium components, such as calcium sulfate and calcium chloride. In this work, the feasibility of using SR as an accelerating additive for Portland cement (PC) was investigated. Wet milling method was used to prepare nano-micron SR seed with D50 of 246 nm. A binary system of PC and SR seed was designed, and its compressive strength, hydration kinetics and microstructure were studied. Results showed that the 12-hour compressive strength of PC was greatly increased by 1.69 times when the dosage of SR seed was 6%. This improvement was attributed not only to the nucleation seeding and filling effect of the SR seed, but also to the presence of pre-dissolved chlorine and sulfate ions from SR particles. Furthermore, the pore volume was reduced by more than 16%, the critical pre radius was decreased by 86.3%, and the gel pore content was 2.3 times that of reference group, indicating a high microstructure refinement and gel binding contribution of SR seed.

Emulsification Characteristics of Insoluble Dietary Fibers from Pomelo Peel: Effects of Acetylation, Enzymatic Hydrolysis, and Wet Ball Milling.

To improve the application potential of pomelo peel insoluble dietary fiber (PIDF) in emulsion systems, acetylation (PIDF-A), cellulase hydrolysis (PIDF-E), and wet ball milling (PIDF-M) were investigated in this paper as methods to change the emulsification properties of PIDF. The impact of the methods on PIDF composition, structure, and physicochemical properties was also assessed. The results demonstrated that both acetylation modification and cellulase hydrolysis could significantly improve the emulsification properties of PIDF. The emulsions stabilized with PIDF-A and PIDF-E could be stably stored at 25 °C for 30 d without phase separation at particle concentrations above 0.8% (w/v) and had higher storage stability: The D4,3 increments of PIDF-A- and PIDF-E-stabilized emulsions were 0.98 μm and 0.49 μm, respectively, at particle concentrations of 1.2% (w/v), while the storage stability of PIDF-M-stabilized emulsion (5.29 μm) significantly decreased compared with that of PIDF (4.00 μm). Moreover, PIDF-A showed the highest water retention capacity (21.84 g/g), water swelling capacity (15.40 mL/g), oil retention capacity (4.67 g/g), and zeta potential absolute (29.0 mV) among the PIDFs. In conclusion, acetylation modification was a promising method to improve the emulsifying properties of insoluble polysaccharides.

Numerical Investigation of a Novel Grinding Device for the One-Pot Production of Ferromagnetic Nanoparticles

The use of nanoparticles (NPs) in industrial applications is consistently increasing given their peculiar properties compared to bulk precursor materials. As a result, there is a growing need to develop alternative technical strategies for the synthesis of such NPs using processes that are not only environmentally friendly but also easy and inexpensive to implement on an industrial scale. In this regard, a novel approach has recently been proposed for the safe and sustainable production of metal NPs directly from a bulky solid by magnetically driven low-energy wet milling, which overcomes the limits of applicability to ferromagnetic materials through a unique device configuration. In the present contribution, the understanding of this alternative configuration is deepened by computational investigation. Discrete Element Method (DEM) simulations were used to model the dynamics of the system, highlighting the role of the various parameters involved in the setup and operation of the process. The collisions between grinding and primary particles are analyzed in terms of frequency, impact angle, and energy. Comparing the results with the standard device configuration, the general trend is preserved, though collisions at higher impact angle and energy are also detected.

High Volumetric Energy Density LiFePO4/C Cathode Materials Synthesized by Dodecyl Polyglucoside-Assisted Glucose-Polyethylene Glycol Composite Carbon Source

Abstract High volumetric energy density LiFePO4/C cathode materials were synthesized by wet ball milling, spray drying, and carbothermal reduction method using glucose and polyethylene glycol (PEG) as composite carbon sources and dodecyl polyglucoside (C12APG) as a milling aid. With the introduction of C12APG during the ball milling process, the prepared cathode materials have uniform particle size (100-200 nm in diameter) and regular primary particle morphology. In addition, PEG substitutes part of glucose as a carbon source, resulting in low carbon content and high graphitization of residual carbon after high-temperature calcination. The prepared LiFePO4/C cathode materials have a high powder compaction density (2.68 g cm-3) and excellent electrochemical performance (discharged capacities of 161.2 and 141.7 mAh g-1 at 0.2 C and 5 C, and cycle retention of 98.6% for 100 cycles at 1 C/1 C). This LiFePO4/C composite was assembled into 14500-type cylindrical batteries with a compaction density of 2.62 g cm-3 for the positive electrode. The volumetric energy densities of the positive electrode were 1135.18 Wh L-1 and 918.16 Wh L-1 at 0.2 C and 5 C, respectively.

Xylanases and high-degree wet milling improve soluble dietary fibre content in liquid oat base

The growth of plant-based food and drink substitutes has led to increased interest in oat-based milk substitute as a dairy milk alternative. Conventional liquid oat base (LOB) production results in a fibre-rich insoluble by-product and loss of valuable macronutrients. This study investigates the use of xylanase enzymes to release insoluble arabinoxylan (AX) fibre and employs different degrees of milling in the LOB manufacturing process, with the aim to reduce insoluble waste and simultaneously increase soluble dietary fibre in oat-based milk substitutes. The combination of decreased mill gap space from 1 to 0.05 mm and addition of GH10 xylanase, resulted in a homogenous LOB product and solubilization of all available AX. Potential prebiotic arabinoxylooligosaccharides of DP3-7 from GH10 hydrolysis were identified using HPAEC-PAD and MS analysis. These findings demonstrate the value of utilizing xylanases and fine-milling in LOB manufacturing, offering a sustainable approach to maximize health benefits of oat-based beverages.

Correction: Liao et al. A Comparison of the Fine-Grinding Performance between Cylpebs and Ceramic Balls in the Wet Tumbling Mill. Minerals 2022, 12, 1007

In the original publication [...]

Milled graphitic nanoparticle toughened epoxy composites via increased resistance to in-plane crack propagation

Fascinating features of 2D-based carbon materials like graphene have drawn increasing attention to fulfill the desire to enhance the fracture toughness of epoxy composites. However, challenges remain to improve their dispersibility in polymers and increase interaction ability. Thus, work is needed to synthesize alternative cost-effective 2D carbon nanofillers capable of delivering consistent performance as a reinforcer to monitor the fracture toughness of the epoxy composites. The present study demonstrates transforming graphite to ball-milled graphite (BMG) via an effective high-energy wet ball milling process. Herein a noteworthy size reduction is achieved for the BMG ranging from ∼217 to 227 nm. Microscopic investigation spotted an exfoliated 3D networked graphite nanosheet with nanopores. These BMGs were functionalized to attach amine-based silane moieties and were incorporated into the epoxy network. Consequently, even at higher loading levels, they showed their astonishing capability to enhance the crack far field resistance of nanocomposite resulting in significantly improved fracture toughness and energy to ∼2.31 MPa m1/2 and ∼11.30 kJ/m2, respectively. Improvement is ascribed to the better dispersing ability of BMG, which provides a consistent strong interfacial interaction with the epoxy network to modulate material resistance to fracture. Such environmentally friendly nanofillers must be industrially acceptable for synthesizing durable epoxy nanocomposite systems and can be utilized to prepare structural composites.

Controlling sintering temperature for biphasic calcium phosphate scaffolds using submicron hydroxyapatite slurries for LCD 3D printing

Liquid crystal display (LCD)-based 3D printing, a precise and surface-smooth technology, has found widespread use in dentistry due to its exceptional precision and surface quality. This research endeavors to create a scaffold through 3D printing using bone graft materials, specifically addressing the challenge of molding bone graft powders to fit defect areas in dental surgery. Our approach involved developing biphasic calcium phosphate (BCP) scaffolds by regulating the sintering temperature of an HA-based green body. Initially, by using wet ball mill technology, HA slurries with 30 %, 40 %, and 50 % HA content by weight were prepared and exhibited viscosities below 0.15 Pa s. Subsequently, these slurries were 3D printed via an LCD-based VP printer. The utilization of submicron-sized HA particles played a critical role in maintaining slurry stability and preventing sedimentation during the printing process. We investigated sintering temperatures of 1100 °C, 1200 °C, and 1300 °C, discovering that submicron-sized HA particles enabled precise alignment of the decomposition temperature with the typical HA sintering range. Consequently, we achieved the production of BCP scaffolds with adjustable properties by tuning the sintering temperature. Subsequent analysis delved into scaffold shrinkage, mechanical characteristics, degradation behavior, and biological responses. Among the sintered scaffolds, the 50 % HA slurry printed and sintered at 1200 °C exhibited the highest compressive strength. The cell viabilities of these sintered scaffolds consistently met the ISO 10993-5 standard, affirming their biocompatibility. Moreover, the biological responses of MG63 cells demonstrated that the sintered scaffolds not only exhibited cytocompatibility but also facilitated strong cell attachment and proliferation. Furthermore, scaffolds sintered at 1300 °C containing TCP showed the formation of a layer of HA with plate-like structures due to ion-induced precipitation, indicating their bioactivity. In conclusion, this study highlights the promising potential of LCD-based VP 3D printing technology for ceramic slurries, with clear implications for clinical applications in bone tissue engineering.

MODELING OF PARTICLE WET MILLING IN A STIRRED TANK USING CFD/PBE COUPLED APPROACH

Many industrial processes involve grinding and milling operations to produce powders of well-controlled particle size distribution. Improving these processes requires researchers to consider particle-particle interactions, breakage, aggregation, and in the case of wet milling, hydrodynamics. The purpose of this study is to develop a numerical model, accounting for these mechanisms, with the final goal to guide the design of an optimal process. Computational fluid dynamics is coupled with a population balance model. The hydrodynamics of the multiphase flow is predicted using the multifluid Euler approach, whereas the class method is considered to solve the population balance equation. A theoretical definition of the breakage functions, based on hydrodynamics inside the tank, is proposed. The results show that breakage is highly heterogeneous inside the tank and that particle breakage frequency allows researchers to evaluate milling efficiency.

Waste Water Management in Wet Coffee Processing Mills and their Impact on the Water quality status of Gidabo River and its Tributaries, Southern Ethiopia.

The Gidabo River and its tributaries are the main sources of water for more than 1,584,646 inhabitants. It is an important source of water for the surrounding rural communities for various uses such as domestic, irrigation, livestock watering, fishing, and recreation. The river is the main tributary of Lake Abaya. The present study was designed to investigate the water quality status of the Gidabo River and its tributaries for domestic and aquatic life. To assess the water quality status, water samples were collected in monthly intervals for a period of 3 months from September to November (coffee processing time), 2022. Arc GIS 9.3, 3 DEM, and spreadsheet were used to analyze the data collected from SRTM (Shuttle Radar Thematic Mapper, 90 m) and field observation. Of all the water quality parameters analyzed; turbidity, BOD5, DO, COD, pH, Ni, Fe, NO3 -, and PO4 3- were higher than the recommended limits of national and international standards for aquatic life. Based on the Weighted Arithmetic Mean (WAM), Water Quality Index (WQI) calculations of the River, WQI value of the river ranges between 34.83 and 54.31 in different reaches of the watershed which is classified under bad category. The wet coffee processing industry which is the main sources of contamination in the watershed uses 63 L of processing water to produce 1 kg of green coffee beans. Traditional lagoons, with an average hydraulic retention time (HRT) of 1.99 days, are the most common methods of treating wastewater. The river is at higher risk from harmful anthropogenic activities in the watershed and requires urgent monitoring and mitigation to prevent further degradation.

Morphological studies of single crystal Alumina fabricated by wet milling method

Morphological studies of single crystal Alumina fabricated by wet milling method

Rebamipide nanocrystal with improved physicomechanical properties and its assessment through bio-mimicking 3D intestinal permeability model.

This study investigated the formulation and characterization of rebamipide nanocrystals (REB-NCs) to enhance the solubility and permeability of rebamipide, an anti-ulcer medication known for its low aqueous solubility and permeability, classified as BCS class IV. Employing high-pressure homogenization and wet milling techniques, we successfully achieved nanonization of rebamipide, resulting in stable nanosuspensions that were subsequently freeze-dried to produce REB-NCs with an average particle size of 223 nm. Comprehensive characterization techniques, including Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and differential scanning calorimetry (DSC) confirmed the crystalline nature of the nanocrystals and their compatibility with the selected excipients. The saturation solubility study revealed a remarkable three-fold enhancement in PBS pH 7.4 compared to rebamipide API, indicating the effectiveness of the nanocrystal formulation in improving drug solubility. Furthermore, 3D in-vitro permeability assessments conducted on Caco-2 cell monolayers demonstrated an noticeable increase in the permeability of REB-NCs relative to the pure active pharmaceutical ingredient (API), highlighting the promise of this formulation to enhance drug absorption. The dissolution profile of the nanocrystal tablets exhibited immediate release characteristics, significantly outperforming conventional formulations in terms of the dissolution rate. This research underscores the potential of nanomilling as a scalable, environment-friendly, and less toxic approach to significantly enhance the bioavailability of rebamipide. By addressing the challenges associated with the solubility and permeability of poorly water-soluble drugs, our outcome offers insightful information into developing efficient nanomedicine strategies for enhancing therapeutic outcomes.

Synthesis of fine Na-type zeolite grains from coal fly ash and the assessment of the adsorption capability of lead ions from aqueous solutions

Fine Na-type zeolite grains (ZE) were prepared by dry milling treatment (D-ZE) or wet milling treatment (W-ZE).

Nanocrystal-chitosan particles for intra-articular delivery of disease-modifying osteoarthritis drugs

Osteoarthritis is the most common chronic joint disease and a major health care concern due to the lack of efficient treatments. This is mainly related to the local and degenerative nature of this disease. Kartogenin was recently reported as a disease-modifying osteoarthritis drug that promotes cartilage repair, but its therapeutic effect is impeded by its very low solubility. Therefore, we designed a unique nanocrystal-chitosan particle intra-articular delivery system for osteoarthritis treatment that merges the following formulation techniques: nanosize reduction of a drug by wet milling and spray drying. The intermediate formulation (kartogenin nanocrystals) increased the solubility and dissolution rates of kartogenin. The final drug delivery system consisted of an easily resuspendable and ready-to-use microsphere powder for intra-articular injection. Positively charged chitosan microspheres with a median size of approximately 10 µm acted as a mothership drug delivery system for kartogenin nanocrystals in a simulated intra-articular injection. The microspheres showed suitable stability and a controlled release profile in synovial fluid and were nontoxic in human synoviocytes. The cartilage retention skills of the microspheres were also explored ex vivo using cartilage. This drug delivery system shows promise for advancement to preclinical stages in osteoarthritis therapy and scale-up production.