Mechanochemical Treatment Research Articles

Mechanochemical Treatment for the Extraction of Lithium from Hard Rock Minerals: A Comprehensive Review

Mechanochemical Treatment for the Extraction of Lithium from Hard Rock Minerals: A Comprehensive Review

Antibacterial action of novel zeolite-based compositions depends upon doping with Ag(+) and Сu(2+) cations

Recently, there is a growing interest to exploration of sorption and catalytic properties of solid nanomaterials, in particular natural zeolites, as well as to study of their antimicrobial effects with the aim of potential using them as a principal component of disinfection and degassing remedies. The purpose of this work was to study the antimicrobial action of compositions based on the Transcarpathian clinoptilolite (CL) doped with Ag+ and Сu2+ cations or Ag microparticles (MPs). These compositions were subjected to mechanochemical modification in ethanol medium and with the addition of plant (Actinidia arguta) extract used as an antioxidant. Mechanochemical treatment (MChT) of all forms of CL MPs led to their grinding which caused better contact of CL with bacterial cells, while an increased content of larger pores improved their access to the active sites on the surface of the CL MPs. Treatment of CL samples with metallic silver used as a dopant with the help of the extract of Actinidia arguta plant did not increase the antibacterial activity regardless of treatment time. Treatment of AgNO3 with ethanol slightly increased the antibacterial action of the CL MPs towards Gram-positive bacteria and decreased it towards Gram-negative bacteria. The CL samples doped with copper and treated with ethanol and plant (Actinidia arguta) extract demonstrated comparable toxic action towards Bacillus subtilis regardless of grinding conditions. While such a treatment caused a significant decrease in the antibacterial activity towards Staphylococcus aureus and Pseudomonas aeruginosa strains, compared to the action of samples that were not treated with that plant extract. To address the potential biochemical mechanisms of the antibacterial action of the created zeolite-based compositions, their influence on generation of the reactive oxygen species (ROS) was studied using diphenylpicrylhydrazyl (DPH) fluorescent dye. Most versions of the CL composites demonstrated time-dependent antioxidant effect comparable with the effect of the ascorbic acid used as a positive control. Thus, the ROS generation is not the mechanism that is responsible for the antibacterial action of the created CL-based compositions. Probably, that action is explained by the peculiarities of interaction of doped CL microparticles with the surface of the bacterial cells. Keywords: antimicrobial action, clinoptilolite-based compositions, doping with Ag+ and Сu2+ cations, physicochemical treatment

Formation of Bio-based Derived Dicalcium Silicate Ceramics via Mechanochemical Treatment: Physical, XRD, SEM and FTIR Analyses

Beta-dicalcium silicate plays an important role in modern technology, but its tendency for polymorphic transformation results in the dusting phenomenon, is a major challenge. Therefore, mechanochemical treatment is used to reduce the particle size to retain the stability of the polymorph. In this study, pure dicalcium silicate ceramics of β-monoclinic structure with P 121/c1 space group were synthesized using calcium oxide and silicate powders derived from calcined eggshells and rice husks, respectively. The powders were mixed in a 2:1 molar ratio by mechanochemical treatment and heat-treated in the air at temperatures ranging from 900°C to 1100°C for 2 h. The results reveal that pure betadicalciumsilicate formed at 1100°C without adding stabilizers. The properties of the pristine and sintered bodies were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM). SEM revealed that the grain and pore sizes increase with rising sintering temperatures. FTIR spectra indicate the existence of Si-O bonds in -4 4 SiO tetrahedrons on all the samples. The sample sintered at 1000°C attains the lowest bulk density (1.2463 g/cm3), whereas the apparent porosity is the highest (62.5%). The reason for this trend is due to the decomposition of carbonate into CO2 gas. The densification onset for the sample sintered at 1100°C as the bulk density rises and grain size achieves 6.06 μm. This study further explains the effect of sintering temperatures on the physical, structural, and morphological properties of Ca2SiO4 which would also be useful for further optimization of its use.

High-Temperature SHS Heat Insulators Based on Pre-Activated Mineral Raw Materials

In this paper, the results of the technological combustion of SHS heat insulators based on mineral origins are presented. It is shown that after mechanochemical treatment of minerals—diatomite—the kinetic characteristics of the combustion process change, providing targeted formation of the phase composition, structure, and properties of the SHS composite. A positive effect of using various modifiers during the MCT of diatomite—the activation of the combustion process—was established. The selection of modifiers provides an increase in the strength of the synthesized SHS composites as a result of the formation of aluminate compounds in the synthesis products, and a decrease in thermal conductivity to 0.157 W/m*K due to the formation of the ultraporous structure of the samples.

Mechanochemical Synthesis, Characterization and Reactivity of a Room Temperature Stable Calcium Electride.

A new calcium-based Room temperature Stable Electride (RoSE), K[{Ca[N(Mes)(SiMe3)]3(e-)}2K3] (2), is successfully synthesized from the reaction of a calcium tris-amide, [Ca{N(Mes)(SiMe3)}3K] (1) (Mes = 2,4,6-trimethylphenyl), with potassium under mechanochemical treatment. The dimeric structure of K[{Ca[N(Mes)(SiMe3)]3(e-)}2K3] is calculated using ab initio random structure searching (AIRSS) methods. This shows the existence of highly localized anionic electrons (e-) and suggests poor electrical conductance, as confirmed via electroconductivity measurements. The two anionic electrons in 2 are strongly antiferromagnetically coupled, thus in agreement with the largely diamagnetic response from magnetometry. Reaction of 2 with pyridine affords 4,4'-bipyridine, while reaction with benzene gives C-H activation and formation of a calcium hydride complex, [K(η6-C6H6)4][{Ca[N(Mes)(SiMe3)](H)}2K3] (3). Computational DFT analysis reveals the crucial role played by the ligand framework in the stabilization of this new Ca-hydride complex.

Si-P-Cu internally bonded anode: An innovative strategy for low-cost and high-performance pseudocapacitive Li-ion storage

Maintaining the structural integrity of silicon and phosphorus anodes during the Li+ insertion and extraction cycles poses a significant challenge. Inspired by the natural process of plant roots anchoring into soil, we present a simple yet effective method for integrating a SiP anode into the copper current collector. This approach involves subjecting readily available and cost-effective micrometre-sized silicon particles (50–150 μm) and red phosphorus to mechanochemical treatment. Subsequently, the resulting Si/P composite is coated onto copper foil and subjected to annealing treatment, resulting in the formation of an integrated structure, incorporating Cu3Si, Cu3P, and P-doped Si, firmly established within the copper current collector. The electrode obtained (BM-Si@P/Cu-350), promoted by a crosslinked (polyimide) PI binder, outperforms not only the ball-milled Si and red P but also the same electrode in which the annealing process is absent (BM-Si@P/Cu-100). During the mechanochemical treatment, red P acts as both the doping agent and a lubricant, facilitating the grinding of the Si particles into P-doped Si particles in the range of predominantly 200–300 nm; while during the thermal treatment, Si plays a key role in preventing excessive interaction between the P and the Cu current collector. Instead, a tailored rooting of the active material into the current collector is achieved through the formation of Cu3P and Cu3Si phases, not only increasing the mechanical stability of the electrode to endure volume changes during cycling and limit developing cracks, but also enhancing the electrical conductivity of the system. This article suggests a simple and potentially low-cost strategy for the utilization of highly available micrometre-sized silicon and red-P for Li-ion storage applications.

Unleashing the antitumor power of cyclophosphamide by arabinogalactan and aptamer conjugation

Cyclophosphamide (CPA) (2-oxo-2-di(β-chloroethyl)amino tetrahydro-2,1,3-phosphoxazine) is an alkylating cytostatic compound with a broad spectrum of antitumor activity. Despite its efficacy, the clinical application of CPA is hindered by the significant occurrence of adverse side effects. To address these limitations, a promising approach involves the mechanochemical treatment of CPA with arabinogalactan (AG) to facilitate the dispersion of the drug within the AG matrix. AG stands out from other polymers due to its uniformity, low molecular weight, water solubility, and ability to form drug conjugates, thereby enhancing their therapeutic potency. Moreover, AG possesses immune-modulating properties that have the potential to counteract the immunosuppressive effects induced by CPA. By means of mechanical treatment, we successfully obtained CPA-AG complexes with a CPA:AG ratio of 1:10. These complexes were further modified with As42 aptamers that specifically target Erlich ascites cells. Aptamers, a novel class of oligonucleotide ligands obtained through SELEX technology, possess high affinity and specificity for binding to various receptors. An ascitic form of Ehrlich carcinoma was chosen as an in vitro and in vivo tumor model due to its notable drug resistance. In vitro and in vivo evaluations were conducted to compare the antitumor activity of both the CPA-AG and CPA-AG-As42 complexes with pure CPA. In vitro experiments revealed that the CPA-AG complex displayed superior antitumor activity compared to pure CPA, leading to complete tumor cell death primarily through necrosis. Notably, no toxic effects were observed with the CPA-AG and CPA-AG-As42 complexes, and they significantly prolonged the lifespan of tumor-bearing mice by more than 3.5 times. Histological studies further supported the antitumor efficacy of these complexes. These results underscore the potential of utilizing CPA-AG mechanocomposites, functionalized with aptamers, for the targeted delivery of CPA to tumors.

Highly Porous Nitrogen and Phosphorus Dual-Doped Carbon with Increased Phosphorus Content As an Efficient Oxygen Reduction Electrocatalyst

Highly porous nitrogen and phosphorus dual-doped carbon (NPC) was synthesized using acetylene black as a carbon source in two steps: (1) solid–gas mechanochemical treatment to prepare nitrogen-doped carbon (NC), (2) heat treatment to dope the NC with phosphorus. X-ray photoelectron spectroscopy and N2 gas adsorption analysis revealed that the solid–gas mechanochemical treatment using a ball mill incorporated nitrogen atoms into the carbon network and increased the pore volume and surface area. Furthermore, the resulting NC exhibited enhanced reactivity with ammonium dihydrogen phosphate, which was used as a phosphorus source, upon heat treatment. The phosphorus content in NPC synthesized by two-step mechanochemical and heat treatments reached 1.91 at%, a 14-fold increase compared to that of phosphorus-doped carbon synthesized by heat treatment. The NPC exhibited higher electrocatalytic activity for the oxygen reduction reaction than NC, suggesting that the additional phosphorus doping into NC can improve its electrocatalytic performance.

Anthelmintic efficacy of Fenbendazole and Niclosamide suspensions obtained by liquid phase mechano-chemical treatment

The purpose of the research is to study the anthelmintic efficacy of suspensions based on a combined solid dispersion of Fenbendazole and Niclosamide.Materials and methods. Mechanochemistry methods were used to prepare suspensions of Fenbendazole (FBZ) and Niclosamide (NSM) substances, in particular, liquid phase grinding of substances with additives (licorice extract, polyvinylpyrrolidone (PVP)) in water or in aqueous sodium carboxymethylcellulose (NaCMC) solution. The grinding was conducted in LE-101 roller mill at energy intensity of 1 g for 1 hour at a roll rotation speed of 60–70 rpm. The resulting suspension samples of combined FBZ and NSM dispersions were studied for cestodocidal activity on a laboratory model of hymenolepiosis of white mice that were infected at a dose of 200 infective Hymenolepis nana eggs per animal.Results and discussion. The 100% efficacy of a combined NaCMC-based drug suspension containing FBZ 13 mg and NSM 130 mg in 1 g of suspension was achieved at a dose of 20 mg/kg of NSM and 2 mg/kg of FBZ. The suspension based on licorice extract, NaCMC, and dioctyl sulfosuccinate sodium salt containing FBZ 18.6 mg and NSM 186 mg in 1 g of suspension at the same dose, i.e. 20 mg/kg of NSM and 2 mg/kg of FBZ showed 71.43% efficacy against H. nana. The suspension based on licorice extract and NaCMC containing FBZ 24.6 mg and NSM 246 mg in 1 g of suspension at the same dose showed a 62.0% effect against H. nana. The activity of the basic drug, the FBZ and NSM suspension was 28.58% at this dose without using mechano-chemical treatment.

β-starch amorphization via mechanochemical treatment and the molecular weight dependence of the drug release of milled amorphous starch gel-matrix tablets

The effect of mechanochemical treatments on the swelling of potato-derived-β-starch gel-matrix tablets and their drug release from the gel-matrix were investigated based on drug release and hydrogel formation kinetics. The X-ray powder diffraction peak intensity of starch decreased after ball milling; the starch changed to an amorphous state after more than 60 min of milling and its viscosity increased. Gel matrix tablets containing various milled starches and low- or medium-molecular-weight drugs (theophylline: TH or atorvastatin calcium: ATC) were prepared via compression. Drug release and swelling rates of the gel-matrix tablets were measured using in-vitro drug release tests and X-ray computed tomography imaging. The TH-containing gel-matrix tablet exhibited different swelling and drug release rates from those containing ATC, depending on the drug physicochemical properties. The drug release and swelling profiles of the gel-matrix tablets were analyzed using Korsmeyer-Peppas, Higuchi, and pseudo-second-order reaction equations. The swelling processes of both the TH and ATC gel-matrix tablets followed non-Fick's law, such as pseudo-second-order kinetics. Therefore, the drug release processes of the TH and ATC gel-matrix tablets simultaneously depend on swelling and trans-matrix diffusion phenomena. The results showed that molecular weight: TH < ATC; solubility: TH > ATC; wetting property: TH > ATC; therefore, the swelling and drug release rates of the gel matrix tablets containing TH were greater than those containing ATC. These rates were significantly influenced by the physicochemical properties of the active pharmaceutical ingredients.

Mechano-chemical, high-consistency activation of kraft pulp in deep eutectic solvent of choline chloride and urea

Deep eutectic solvents (DESs) offer an appealing green medium for the activation of cellulose fibres to promote their swelling, reactivity, hydrolysis, disintegration, and solubility for further processing. Typically, DES treatments are carried out below 5 wt% consistency even though a higher solids content could enhance the fibre activation and reduce the solvent consumption. In this work, a high-consistency (HC) mechano-chemical activation of bleached softwood kraft pulp was elucidated using a simultaneous fibre treatment with DES of choline chloride-urea and a sigma-type kneader or a twin-screw extruder at a solids content of 15–35 wt% and 30 wt%, respectively. Both HC treatments efficiently triggered fibre swelling, which was indicated by an increase in the fibre width, and loosened the cell wall structure which was indicated by an increase in the mesopore volume. Mechano-chemical HC processing generated fibre fines and external fibrillation, while the molecular-level structural alteration or changes in chemical composition were minor; the intrinsic viscosity and the crystallinity of the pulp remained at their initial level and only a small amount of xylan was dissolved. Overall, HC treatment in a twin-screw extruder caused notably more severe morphological changes in the fibres than batch treatment in a sigma-type kneader. Thus, the mechano-chemical HC treatment with DES provides an industrially relevant technology for cellulose modification and opens possibilities to enhance heterogeneous cellulose modification processes in which the highly available surface area of pulp is a key parameter.

Comprehensive Investigation of the Crystal Structure of Cation-Disordered Li3VO4 as a High-Rate Anode Material: Unveiling the Dichotomy between Order and Disorder.

This study investigates mechanochemical synthesis and cation-disordering mechanism of wurtzite-type Li3VO4 (LVO), highlighting its promise as a high-performance anode material for lithium-ion batteries and hybrid supercapacitors. Mechanochemical treatment of pristine LVO using a high-energy ball mill results in a "pure cation-disordered" LVO phase, allowing for meticulous analysis of cation arrangement. The X-ray and neutron diffraction study demonstrates progressive loss of order in LVO crystal with increasing milling duration. High-resolution transmission electron microscopy reveals disrupted lattice fringes, indicating cationic misalignment. Pair-distribution function analysis confirms loss of cation arrangements and the presence of short-range order. Combination of these multiple analytical techniques achieves a comprehensive understanding of cation regularity and clearly demonstrates order/disorder dichotomy in cation-disordered materials, ranging from short (<8 Å) to middle-long range (8-30 Å), using an integrated superstructure model of the cation-disordered LVO crystals. Electrochemical testing reveals that mechanochemically treated LVO exhibits superior rate capability, with a 70% capacity retention at a high current density of 50C-rate. Lithium diffusion coefficient measurements demonstrate enhanced lithium-ion mobility in the mechanochemically treated LVO, attributed to cation-disordering effect. These findings provide valuable insights into mechanochemical cation-disordering in LVO, presenting its potential as an efficient anode material for lithium-ion-based electrochemical energy storage.

Synthesis-Dependent Structural and Magnetic Properties of Monodomain Cobalt Ferrite Nanoparticles

This research examines the structural and magnetic properties of monodomain cobalt ferrite nanoparticles with the formula (Co1−xFex)A[Fe2−xCox]BO4. The particles were synthesized using various methods, including coprecipitation (with and without ultrasonic assistance), coprecipitation followed by mechanochemical treatment, microemulsion, and microwave-assisted hydrothermal techniques. The resulting materials were extensively analyzed using X-ray diffraction (XRD) and magnetic measurements to investigate how different synthesis methods affect the structure and cation distribution in nanoscale CoFe2O4. For particles ranging from 15.8 to 19.0 nm in size, the coercivity showed a near-linear increase from 302 Oe to 1195 Oe as particle size increased. Saturation magnetization values fell between 62.6 emu g−1 and 74.3 emu g−1, primarily influenced by the inversion coefficient x (0.58–0.85). XRD analysis revealed that as the larger Co2+ cations migrate from B- to A-sites (decreasing x), the lattice constants and inter-cation hopping distances increase, while the average strength of super-exchange interactions decreases. This study establishes a connection between the magnetic properties of the synthesized samples and their structural features. Importantly, this research demonstrates that careful selection of the synthesis method can be used to control the magnetic properties of these nanoparticles.

Study of Conversion of Waste LFP Battery into Soluble Lithium through Heat Treatment and Mechanochemical Treatment

Study of Conversion of Waste LFP Battery into Soluble Lithium through Heat Treatment and Mechanochemical Treatment

Mechanochemical room-temperature lead reduction: Elucidating the mechanism from structural evolution and electrochemical insights

Mechanochemistry has rapidly advanced as an effective method for recovering metals from hazardous wastes due to its mild reaction conditions, while understanding the underlying mechanisms remains a significant challenge. This work investigates the mechanochemical reduction of lead compounds using iron powder at room temperature, focusing on physicochemical properties and electrochemical performance. Notable transformations were observed in the crystal structures, morphologies, and thermal stability of PbSO4 and PbCl2. Electrochemical tests indicated enhanced redox reactivity, decreased reduction potential, and reduced charge transfer impedance after mechanochemical treatment. Additionally, the reduction of PbSO4 proved more challenging than PbCl2 under the same conditions. Our findings provide valuable insights into the management of toxic lead waste and improve the understanding of the mechanochemical effects on redox reactions, with important implications for environmental applications.

Study of antibacterial effects of Transcarpathian clinoptilolite compositions modified in different chemical ways

Background. Natural clinoptilolite (CL) meets most of the requirements for the multifunctional mineral nanomaterials. It is considered biologically neutral and non-toxic. CL is the only representative of natural zeolites that has been approved for use in medical practice and food industry. Antibacterial activity of Transcarpathian clinoptilolite was shown to be enhanced via its modification using thermal, chemical and mechanochemical treatments. The natural form of this mineral contains a significant concentration of surface silanol (-OH) groups. An increase in the efficiency of zeolite-based materials in terms of biological activity can be achieved by means of thermal and chemical treatments, replacement of cations in the exchange complex, doping with heavy metal cations, or mechanochemical treatment. Materials and Methods. FTIR spectroscopy, Electronic spectroscopy, Particle size distribution, IR spectroscopy, Crystal structure and morphology, Measurement of antibacterial activity. Results. Intact and thermally modified CL was shown to exhibit weak antibacterial effect, while its mechanical modification led to an enhanced activity. It was established that H-form of clinoptilolite demonstrated higher efficiency in inhibiting the growth of Gram-positive bacteria, compared to the Na-form of the clinoptilolite, but their effect on growth of Gram-negative bacteria was insignificant. Such an activity was accompanied by an increase in the specific surface area and porosity that promoted better contact with bacteria. Conclusions: Different samples of CL had dissimilar effect on specific types of bacteria. Intact CL has a weak antibacterial activity of inhibiting growth of microorganisms, while thermal, chemical, and mechanical modifications of the CL structure differentially increased such an activity. The H-form of CL inhibited the growth of Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis) more effectively compared to the Na-form of CL. However, H-form of CL has a weak effect on growth of the Gram-negative bacteria (Pseudomonas aeruginosa, Pseudomonas fluorescens).

Amorphization of β-tricalcium phosphate particles by mechanochemical treatment

Increasing the amounts of calcium and phosphate ions released in vivo by β-tricalcium phosphate (β-TCP) may enhance its osteogenic activity for bone repair and regeneration. Planetary ball milling of β-TCP powder using acetone and 1-mm-diameter zirconia beads reduced the average particle size of the powder to ∼ 0.4 µm within 120 min and converted most of the crystals to an amorphous phase of calcium orthophosphate. Immersing the treated powder in a tris-HCl buffered solution of pH 7.4 for 24 h at 37 °C dissolved calcium and phosphate ions with several times the yield from that of the original β-TCP powder. This approach is expected to be useful for preparing composite materials with an enhanced therapeutic effect on living tissues.

Influence of mechanochemical treatment and oxygen inhibited layer on the adhesion of self-adhesive resin cement to bulk-fill composite resin

Influence of mechanochemical treatment and oxygen inhibited layer on the adhesion of self-adhesive resin cement to bulk-fill composite resin

Mechanochemical synthesis of fluoride-ion conducting glass and glass–ceramic in ZrF4–BaF2 binary system

Fluoride glasses in the binary system ZrF4–BaF2 were prepared via mechanochemical treatment. The glass-forming region of the ZrF4–BaF2 system obtained using the mechanochemical method was wider than that obtained using the conventional melt-quenching method. The glass–ceramic 60ZrF4·40BaF2 (mol%) sample was obtained by heat treatment and shows a higher conductivity of 1.2 × 10–6 S cm−1 at 200 °C than the pristine glass. This study revealed that mechanochemical treatment was effective for the synthesis of fluoride glasses.

Ultra-fast mechanochemical strategy to obtain stable colloidal dispersions of MWCNT in hydrophilic media: Never has been so easy

In this paper, we present a new protocol that allows the dispersion of multi-wall carbon nanotubes (MWCNT) in the form of stable colloids in a hydrophilic medium up to concentrations of ca. 0.06 % (w/w). The strategy involves using a combination of mechanochemical treatment and surfactants. In this study, we processed MWCNTs with surfactants in a ball mill without using any solvents. The mechanochemical treatment consists of processing mixtures of MWCNTs (0.35 g) with different surfactants (4.5 g of CTAB, 3.6 g of SDS and 4.5 g of F127 as cationic anionic and neutral surfactants, respectively) in a ball mill for only 20 min at 300 rpm. The resulting black powder is then used directly to prepare dispersions in hydro-alcoholic media, which maintain colloidal stability for at least 25 days. Although various strategies for dispersal have been proposed in the literature, many involve time-consuming and multi-step processes with low yields. The MWCNTs modified non-covalently using our protocol are synthesised in a single step with a 100 % yield without any loss of reagents. MWCNT have shown potential in many emerging applications of great interest. Its use necessarily implies the achievement of a good dispersion in different solvents, and this aspect, in the case of hydrophilic media, still does not have a satisfactory answer. The absence of solvent during the mechanochemical treatment is the key aspect of our strategy. This small change represents a significant improvement. We demonstrate the outstanding stability of the obtained suspensions and the preservation of the nano-/microstructure of the MWCNTs, which remains unaltered during their preparation. Furthermore, using environmentally friendly solutions for dispersion makes this protocol a Green Chemistry approach.