Pretreatment Temperature Research Articles

Optimizing Hempcrete Properties Through Thermal Treatment of Hemp Hurds for Enhanced Sustainability in Green Building

This study examines the effects of the thermal pre-treatment of hemp hurds on the physical, mechanical, and thermal properties of hempcrete, evaluating its potential as a sustainable building material. Hemp hurds were pre-treated at various temperatures (120–280 °C) and characterized by proximate analysis, CHNS elemental analysis, and thermogravimetric analysis (TGA). The resulting hempcrete samples were analyzed for density, water absorption, compressive strength, and thermal conductivity. Three different hempcrete formulations, with varying lime:hemp proportions, were analyzed. The findings indicate that higher pre-treatment temperatures lead to reduced density and water absorption across all formulations. Formulations containing a higher hemp hurd content had lower densities but higher water absorption values. Compressive strength increased consistently with the pre-treatment temperature, suggesting that higher temperatures enhance matrix bonding and structural rigidity, and with the lime content. However, thermal conductivity also rose with pre-treatment, with only the composition containing the highest hemp hurd content maintaining the optimal insulation threshold (0.1 W/mK). This suggests a trade-off between compressive strength and insulation performance, influenced by the balance of hemp hurd and lime content. These findings underscore the potential of thermal pre-treatment to tailor hempcrete properties, promoting its application as a durable, moisture-resistant material for sustainable building, though the optimization of hurd–lime ratios remains essential.

Exploring the Potential of Pangasius Catfish Oil as a Base Oil for Nanoemulsion Products: Optimization and Characterization

Pangasius catfish, also known as striped catfish, is a high-fat fish compared to other freshwater fish like snakehead fish and carp. The oil extracted from this fish contains unsaturated and polyunsaturated fatty acids that are beneficial for health. The quality of the oil is affected by the extraction method, especially the preliminary heating temperature for the extraction. Pangasius catfish oil contains omega-3 fatty acids (EPA and DHA) that have the potential to inhibit inflammation, hyperpigmentation, accelerate skin healing for topical applications, and act as a skin permeation enhancer and oil base for nanoemulsion due to its high oleic acid content. In this research, an experimental design was conducted on pangasius catfish oil extraction using the pressing method to optimize predetermined parameters using Response Surface Methodology (RSM). The factors considered for optimization included the quantity of water and extraction temperatures, with water content ranging from 50% to 150% (w/v) and extraction temperatures ranging from 25°C to 55°C. These ranges were intended to yield results and characterization values of oxidation parameters are tested according to the International Fish Oil Standard (IFOS) through tests including Acid Value (AV), Peroxide Value (PV), Anisidine Value (p-AnV), and Total Oxidation (TOTOX). Subsequently, the optimal conditions were confirmed to obtain the best fish oil results, which were achieved at 1.5 times the amount of pre-treatment water and a pre-treatment temperature of 55°C. The pangasius catfish oil obtained from the confirmation of optimal conditions is used as a raw material for producing nanoemulsions. The D-Optimal Mixture Design of Design Expert approach is utilized to formulate the nanoemulsion. The nanoemulsion formula containing 0.5% pangasius catfish oil was determined as the optimal formula according to the range of physical characteristics of the referenced nanoemulsion preparations with a desirability value of 0.974. This study has demonstrated the potential utility of pangasius catfish oil as a prominent base oil in nanoemulsion products.

The Activation of Oxygen Species on the Pt/CeO2 Catalyst by H2 for NO Oxidation

The Pt/CeO2 catalyst has attracted significant attention due to its exceptional performance in NO oxidation. This study comprehensively examines the effects of calcination temperature and H2 pretreatment on the structure and activity of the Pt/CeO2 catalyst. Experimental findings indicate that the calcination temperature significantly affects the catalyst’s redox performance, thereby modulating its efficacy in NO oxidation reactions. H2 pretreatment facilitates the creation of oxygen vacancies on the catalyst, assisted by the reduction in PtOx to Pt, enhancing the formation of activated oxygen and thereby improving NO oxidation. This study offers valuable insights into the design and optimization of Pt/CeO2 catalysts for environmental applications, particularly in the development of exhaust gas after-treatment technologies.

Catalytic oxidation of CO over CuO@TiO2 catalyst: The relationship between activity and adsorption performance

AbstractThe emission of CO toxic gases seriously endangers environmental safety and human health. At present, the use of catalysts for catalytic oxidation of CO has become the mainstream research direction. In this study, CuO@TiO2 catalysts with different ratios were prepared by solvent hydrothermal method, and the effects of reaction pretreatment temperature and other factors on the catalytic oxidation performance of CO were investigated. The experimental results show that the catalyst can achieve 100% conversion of CO at 115°C under the condition of pretreament at 350°C for 2 h. This excellent performance is due to the uniform distribution of the active component on the surface of the TiO2 support, and the large pore structure constructed by the solvent hydrothermal method enhances the adsorption and activation of CO. This work provides an idea for the preparation of CO oxidation catalysts.

Dehydrated Food Waste and Leftover for Trench Composting

The growing global population has a persistently negative impact on the economy and ecology due to food waste. This topic has recently received much attention from around the world. For both homes and the food processing industry, recycling food waste is crucial to waste management. This study aims to show how dehydrated food scraps and leftovers can be used as raw materials for trench compost to enhance soil quality and reduce leachate and greenhouse gas emissions. The results showed that the pre-treatment and air temperature significantly affected the finished trench compost products’ EC, pH, and nutrient content. Pretreated dried leftover at 80°C after trench compost was found to have the highest value of CNH, S (36.53%), and micronutrients (0.103404%) when compared to micronutrients in the final product of pre-treatment dried leftover at 80<i>℃</i> after trench compost that was (0.057273%). Dehydrated leftovers from trench compost were thought to have nutrient content that would improve soil quality, slow decomposition, and reduce odor, thus enabling more frequent trash collection.

Impact of filtration at elevated temperature and solvent pre-treatment on crosslinked polyvinylidene difluoride and polyimide solvent-resistant nanofiltration membranes

The high temperature filtration performance of crosslinked polyvinylidene difluoride (XL-PVDF) and polyimide (XL-PI) membranes in solvent-resistant nanofiltration (SRNF) applications was studied. The membranes were tested in four industry-relevant, apolar solvents (toluene, xylene, chloroform, and n-butyl acetate) over a temperature range from 25 °C to 80 °C. The temperature effect on membrane performance was evaluated using a polar probe molecule (5,10,15,20-tetrakis(3,5-di-tert-butyl phenyl)porphyrin (TBPP), 1064 Da), showing that permeance increased with rising temperature due to the anticipating reduced solvent viscosity and enhanced flexibility of the membrane polymer chains. This effect varied clearly between the two polymer systems. After the high-temperature filtration, room-temperature (RT) filtrations demonstrated stable retention in xylene, BuOAc, and toluene, but a decrease in chloroform The membranes exhibited excellent long-term stability, retaining their quasi-intact filtration performance over a full week of operation. To investigate the impact of a pre-filtration solvent treatment, Sudan black (SB)/chloroform filtrations were done before and after exposure to toluene, xylene, BuOAc, and chloroform. Quite surprisingly, such solvent treatment resulted in a polymer-specific impact: an increased permeation for XL-PVDF and a decreased permeation for XL-PI. Retentions were constant for XL-PVDF but slightly increased for XL-PI. Overall, both membrane types showed excellent thermal and solvent stability, but the impact was very different.

Mo2Ti2C3TX MXene performance in catalytic CO2 hydrogenation and its promotion with single Pt atoms

Mo2Ti2C3Tx MXene materials, bare or loaded with strongly anchored single Pt atoms, were investigated using various methods, including STEM, XPS, XAS and DFT calculations. Upon Pt impregnation, the delaminated Mo-rich MXene surface undergoes partial oxidation, which is reversed by an H2 thermal treatment at 400 °C. The optimized MXene shows high catalytic activity for CO2 hydrogenation to CO and smaller amounts of methane and methanol. Around and above the pretreatment temperature of 400 °C, the MXene is gradually defunctionalized from O- and F-containing groups and depleted in carbidic carbon, leading to deactivation. Single Pt atoms are cationic after impregnation, and reduce upon H2 treatment, filling surface Mo vacancies. Pt addition increases the MXene activity, in particular by facilitating H2 dissociation, but has little effect on the single-atom catalyst selectivity and on the rate dependence upon reactant partial pressures. The lowest Pt loading leads to the highest turnover frequency, indicating that the MXene surface sites are key to CO2 activation.

Enhancing organic matter dissolution and microbial community structure in waste activated sludge using thermal-alkali-rhamnolipid pretreatment: Focus on thermal optimization

This study investigated the impact of pretreatment temperature on the dissolution of organic matter in sludge pretreated with alkaline rhamnolipid and its subsequent effect on the microbial community structure during anaerobic fermentation. The findings revealed that when the pretreatment temperature reached 80 °C, the maximum concentration of SCOD is 5008.89 mg/L, which is 4 times higher than that achieved at room temperature. Three-dimensional fluorescence parallel factor analysis indicated that increasing the pretreatment temperature significantly enhanced the degree of humification of sludge DOM and reduced the ratio of protein-like and fulvic acid in the sludge. The 16S rRNA gene-based analyses revealed that the relative abundance of Bacteroidetes was highest at 80 ℃ (11.14 %), and continued to increase as fermentation time progressed. This study highlights the critical role of temperature in the three-factor pretreatment of sludge, demonstrating that higher pretreatment temperatures not only accelerate the acid production rate during anaerobic fermentation but also enhance overall acid production.

Enhancing reed cellulose conversion to glucose with octyl glucoside and tea saponin pretreatment

Low pretreatment temperatures are beneficial for enhancing the activity of both soluble lignin and lignin in pretreated solids. To achieve high-activity lignin and a higher glucose yield at a lower lignin removal rate and reduced enzymatic loading, the synergistic effects of octyl glucoside and tea saponin during low-temperature ammonia‑oxygen pretreatment and enzymatic hydrolysis were explored. Utilizing a moderated lignin extraction at 38 %, with pretreatment at 110 °C, and enriched with 1 % octyl glucoside and 0.06 g/g tea saponin, the biochemical conversion was galvanized. This manifested in an enzymatic hydrolysis efficiency of 96 % and a glucose yield in excess of 85 % at an enzyme loading of 5 FPU/g of pretreated-solids. Conversely, the lignin removal rate without surfactants was 26 %, resulting in 70 % hydrolysis efficiency even at a higher enzyme loading of 15 FPU/g of pretreated-solids. In order to minimize the pretreatment temperature and enzyme load as much as possible without affecting the efficiency of enzymatic hydrolysis and glucose yield, the goal of this research is to investigate the roles of octyl glucoside in the pretreatment process and tea saponin in the enzymatic hydrolysis process. This study provides a new approach for refining lignocellulosic biomass.

Enhanced enzymatic hydrolysis of corn stover by γ-valerolactone pretreatment and the characteristics of enzymatic residues

Efficient pretreatment methods are crucial for the generation of fermentable sugars from the renewable lignocellulose. In this study, γ-valerolactone (GVL), a biomass-derived green solvent, was used to fractionate corn stover (CS). The impact of different additives on the enzymatic hydrolysis and pretreatment of CS within the GVL/water system was carefully investigated. The results demonstrate that the use of H2SO4-assisted GVL/H2O (80:20, w/w) pretreatment at mild conditions successfully facilitates the depolymerization of CS, thereby improving the cellulase accessibility. Furthermore, by increasing the GVL pretreatment temperature to 160 °C with 100 mM H2SO4 addition, the pretreated CS led to nearly 100 % of hydrolysis yield at 2 % (w/v) solid load. Finally, the thermogravimetric analysis (TGA) was performed to evaluate the thermal decomposition characteristics of untreated CS and enzymatic residues based on the H2SO4-assisted GVL/H2O pretreatment. The results indicate that the enzymatic residues had two depolymerization stages from 200 °C to 500 °C with a final residual mass of 22.73 %, which was higher than that of untreated CS (20.56 %). Overall, this study provides an efficient lignocellulose pretreatment for fermentable sugars production and valorization of enzymatic residues.

Effects of cold seawater pre-treatments on induction of early sexual maturation and sperm production in European eel (Anguilla anguilla)

To induce sexual maturation in captivity, eels rely on hormonal treatments, but this process is costly and time-consuming. As an alternative, different types of conditioning, also referred as pre-treatment, have been assessed to ease hormonal treatment response. Recent studies have shown that migrating eels experience a wide range of temperatures, varying from 12 °C at night to as low as to 8 °C during the day. Therefore, this study evaluates the effects of low-temperature (10 °C) seawater pre-treatments of different durations (2 and 4 weeks) on male eel reproduction. The eye, gonadosomatic and hepatosomatic indexes from control (without thermic seawater pre-treatment) and pre-treated fish were measured. Blood and testis samples were also collected for sex steroid and histology analysis, respectively. Eels pre-treated for 2 weeks demonstrated increased progestin levels, comparing with the control group. Eels pre-treated for 4 weeks showed significantly higher gonadosomatic index and elevated androgens and estradiol levels in comparison with the remaining groups. In eels pre-treated for 2 and 4 weeks, there was an increase in the proportion of spermatogonia type B cells compared to undifferentiated spermatogonia type A, a differentiation process that was not observed in the control group. Cold seawater pre-treatment induced early sexual maturation, including steroid production, which consequently stimulated biometric changes and increased spermatogonia differentiation. Following the pre-treatments, eels started receiving standard hormonal treatment (with recombinant human chorionic gonadotropin at 20 °C). Pre-treated males started to spermiate earlier than the control group. In some treatment weeks, pre-treated individuals registered higher values of sperm density, motility, and kinetic parameters. Moreover, an economic evaluation was carried out relating the investment made in terms of hormone injections with the volume of high-quality sperm obtained from each experimental group. The low temperature pre-treatments demonstrated their economic effectiveness in terms of hormone treatment profitability, increasing the production of high-quality sperm in the European eel. Thus, this in vivo study suggests that cold seawater pre-treatment may increase sensitivity to the hormone applied during standard maturation treatment.

Carbon Dioxide Adsorption over Activated Biocarbons Derived from Lemon Peel.

The rising concentration of CO2 in the atmosphere is approaching critical levels, posing a significant threat to life on Earth. Porous carbons derived from biobased materials, particularly waste byproducts, offer a viable solution for selective CO2 adsorption from large-scale industrial sources, potentially mitigating atmospheric CO2 emissions. In this study, we developed highly porous carbons from lemon peel waste through a two-step process, consisting of temperature pretreatment (500 °C) followed by chemical activation by KOH at 850 °C. The largest specific surface area (2821 m2/g), total pore volume (1.39 cm3/g), and micropore volume (0.70 cm3/g) were obtained at the highest KOH-to-carbon ratio of 4. In contrast, the sample activated with a KOH-to-carbon ratio of 2 demonstrated the greatest micropore distribution. This activated biocarbon exhibited superior CO2 adsorption capacity, reaching 5.69 mmol/g at 0 °C and 100 kPa. The remarkable adsorption performance can be attributed to the significant volume of micropores with diameters smaller than 0.859 nm. The Radke-Prausnitz equation, traditionally employed to model the adsorption equilibrium of organic compounds from liquid solutions, has been shown to be equally applicable for describing the gas-solid adsorption equilibrium. Furthermore, equations describing the temperature dependence of the Radke-Prausnitz equation's parameters have been developed.

Selective conversion of spent cracking catalyst to faujasite-structured zeolites

Current recycling strategies for spent catalyst in Fluid Catalytic Cracking (FCC) focus on valuable rare-earth elements (REE) and sometimes include a reuse of spent materials by down-cycling, which hinders a circular economy. Herein, a new procedure for the selective conversion of spent FCC catalysts to FAU-type zeolite without secondary crystalline phases such as sodalite, zeolite P or zeolite A is reported. The steps include a leaching process of REE, followed by thermal activation with sodium hydroxide and acid treatment to get an aluminum-rich feed. The synthesis of FAU-type zeolites with varying Si/Al ratios uses the aluminum-rich catalyst feed and commercial water glass. The experiments show that incorporation of silicate from water glass into the zeolite structure is limited to zeolite products with Si/Al ratio ≤ 2.0. It indicates a flocculation of silicates in higher concentration in competition to the crystallization process of FAU-type zeolites. This is reinforced by the resulting crystals, covered and surrounded with small particles with morphology of silica. Moreover, a clear differentiation between zeolite Y and zeolite X is possible from materials properties with the definite evidence of a mixed phase. The kinetics of feed dissolution and incorporation of impurities, alumina and silica are controlled by the pre-treatment temperature, duration and silicon source. This enables flexible adjustment of the aluminum re-use from spent FCC catalyst, the amount of foreign elements (Fe, Ni, V), phase purity, Si/Al ratio, specific surface area and thermal stability of the final zeolite product. Structural and textural data of the resulting zeolites reveals high crystallinity > 80 %, Si/Al ratios of 1.6–2.0, and specific surface areas up to 780 m2/g.

Alkali pretreatment-assisted catalytic pyrolysis of waste cellulose acetate for selective preparation of levoglucosenone

With the increasing demand for cellulose acetate (CA) in industrial and daily applications, the disposal of its waste has emerged as an environmental concern. In this study, a novel and sustainable method for value-added utilization of waste CA was proposed, which involved NaOH pretreatment and subsequent catalytic pyrolysis using phosphoric acid-activated carbon (PAC) to prepare levoglucosone (LGO). The effects of pretreatment temperatures and NaOH concentrations on the physicochemical characteristics of CA were thoroughly investigated. Furthermore, the pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) experiments were conducted to methodically assess the impacts of both pretreatment and pyrolysis conditions on the production of LGO. The results indicated that NaOH pretreatment could effectively hydrolyze the ester bonds in CA, leading to the removal of acetyl groups and a decrease in thermal stability. At a pretreatment temperature of 40 °C, a NaOH concentration of 0.5 mol/L, a catalyst/sample ratio of 1/3, and a pyrolysis temperature of 400 °C, the LGO yield could reach 11.52 wt%, much higher than that obtained from catalytic pyrolysis of CA (2.70 wt%). This study provides an efficient method for treating waste CA and demonstrates its potential for conversion into high-value chemicals, laying a solid foundation for the green recycling of waste plastics.

Thermostatic microwave-assisted pretreatment of corn stover at atmospheric pressure to enhance saccharification

A large amount of corn stover waste is produced from processing industries. In this study, the thermostatic microwave-assisted alkali pretreatment (TMAAP) of corn stover at atmospheric pressure was investigated to improve the utilization rate. The optimized conditions include pretreated time, NaOH concentration, temperature, initial power, and solid-liquid ratio. The pretreated corn stover samples for the enzymatic hydrolysis were studied on the crystallinity, surface microstructural changes, functional group changes and compositional analysis. The results showed cellulose recovery and lignin removal in the solid residue reached 87.39 % and 87.59 %, respectively when the corn stover was subjected for 45 min at a microwave reactor with an initial 600 W, 100 °C and 5 % NaOH. After TMAAP, the enzyme hydrolysis efficiency of the corn stove reached 85.40 %, which was higher than that of the untreated (59.96 %). The experiment can be carried out at atmospheric pressure without strict conditions. The techno-economic analysis predicts revenue of 22.82 USD by processing 100 kg of waste corn stover combined with enzyme cost analysis. To conclude, glucose (26.37 kg) and xylose (1.19 kg) were produced from corn stover (100 kg, 39.31 % glucan, 17.34 % xylan, 23.60 % lignin). The results can give insights into establishing an efficient alkali pretreatment of corn stove waste to produce glucose.

Effect of heat treatment on charge states, thermophysical and mechanical properties of polypropylene doped with ZrO2 nanoparticles

Charge states, thermophysical and mechanical properties of polypropylene doped with zirconium oxide nanoparticles, and their changes during heat treatment at temperatures 60 °C, 100 °C, and 140 °C are studied. The methods used are thermal stimulated depolarization (TSD), scanning differential calorimetry (SDC), and mechanical life assessment. It is shown that with an increase in the concentration of the filler, the intensity of the TSD peaks increases up to 3 vol.%. A further increase in concentration leads to a decrease in the intensity of the peaks. The activation energy of charge release from traps, temperature of maximum of the peaks, and the magnitude of the accumulated charge in the traps have also maximal value at nanoparticle concentration of 3 vol.%. The study of charge characteristics of the nanocomposite with concentration of 3 vol.% after heat treatment shows that the intensity of TSD peaks, the temperature of peak maxima, and the activation energy of charge release increase with increasing pretreatment temperature. The magnitude of the charge accumulated in traps has a maximal value at treatment temperature of 140 °C owing to the increase in the number of traps. The melting point of the composite is 149.38 °C and shifts to 146.88 °C after heat treatment at 140 °C. It indicates that the high temperature of heat treatment leads to partial destruction of polymer chains, leading to a decrease in the critical melting temperature. The mechanical durability of PP + 3%ZrO2 nanocomposite decreases with increase in pretreatment temperature.

Copper leaching from ultrasonically treated milled waste printed circuit boards: investigation of parameters optimization and kinetics.

Waste printed circuit boards (WPCBs) encompass abundant metals (gold, silver, and copper), along with other harmful materials including brominated epoxy resins, plastics, and heavy metals (lead, mercury, and cadmium). Direct burning and landfilling of WPCBs may cause severe health issues and impair the environment. Therefore, sustainable treatment of WPCBs is necessary to recover valuable metals and remove hazardous materials before disposal. The present work investigates the separation of copper-rich metallic fractions from the WPCBs by the combination of hammer milling and ultrasonic irradiation. Initially, discarded mobile phone PCBs are pre-processed and shortened into 1 × 1 cm2. Downscaled WPCBs are fed into the hammer mill to obtain the fine ground powder. The Powdered WPCBs are further processed through ultrasonic treatment to acquire metal-rich fraction. XRD, SEM-EDS, and ICP/AAS analysis revealed that the current technique can efficiently separate the metal-rich fraction without using toxic solvents. Results show the enhancement of copper fraction from 42.73 to 87 wt. % after ultrasonic treatment of WPCBs ground powder. Further, nitric acid leaching has been implemented to metal-rich fractions, and the parameters have been optimized for copper leaching with the assistance of response surface methodology (RSM) of the design of experiments (DOE). Quantitative dissolution (98.96%) of copper occurred using 3.5M nitric acid within 3h at 30°C with 50 GPL pulp density and 500rpm agitation speed. Finally, the kinetics of the leaching process were studied to conform the kinetics model. Moreover, the activation energy for diffusion (19.075kJ/mole) and reaction kinetics model (13.29kJ/mole) has also been calculated. The low energy consumption due to room temperature pre-treatment and effective leaching ensures the industrial feasibility of the proposed process.

Effect of Drying Methods and Temperature on Physical Properties of Spine Gourd (Momordica dioica Roxb.)

The present investigation entitled “Effect of Drying Method and Temperature on Physical Properties of Spine Gourd (Momordica dioica Roxb.)” was conducted at the Post Harvest Technology Laboratory, Department of Horticulture, Rajasthan College of Agriculture and Department of Processing and Food Engineering, College of Technology and Engineering, MPUAT, Udaipur, Rajasthan during August to December, 2023. The study consisted of 4 different drying methods (sun drying, tray drying, heat pump drying and fluidized bed drying), pretreatment (water blanching) and different temperatures (50°C, 60°C and 70°C). The experimental design used for this study was completely randomized design with three replications. The various physical observations were also recorded after drying. Among different types of drying methods and temperatures, water blanched and dried at 60°C tray dryer was found best with maximum dehydration ratio (0.174) and recovery % (17.43).

Preparation of BN Nanoparticle with High Sintering Activity and Its Formation Mechanism.

Hexagonal boron nitride (h-BN) nanoparticles have attracted increasing attention due to their unique structure and properties. However, it is difficult to synthesize h-BN nanoparticles with uniform spherical morphology due to their crystal characteristic. The morphology control by tuning their precursor synthesis is a promising and effective strategy to solve this problem. Especially, the treatment temperature of precursors plays an important role in the morphology and surface area of h-BN nanoparticles. Herein, h-BN nanoparticles with different morphologies were synthesized via regulating the treatment temperature of precursors. The result shows that treatment temperature will affect the microstructure and state of precursor and further influence the morphology of h-BN products. Benefiting from the unique structure, the h-BN obtained using 250 °C precursors shows higher specific surface area (61.1 m2 g-1) than that of 85 °C (36.5 m2 g-1) and 145 °C (27.9 m2 g-1). h-BN products obtained using 250 °C precursors show higher specific surface area than that of 85 °C and 145 °C. The optimal condition for obtaining high-quality spherical h-BN is the pretreatment temperature of 250 °C and sintering temperature of 1300 °C. Importantly, compared with commercial h-BN nanoparticles, the synthesized h-BN nanoparticles show more uniform structure and larger specific surface area, indicating that sintering activity will be greatly improved. Furthermore, the reaction pathway and formation mechanism of h-BN was revealed by DFT calculations. The result shows that the five stationary states and five transition states exist in the reaction pathway, and the energy barrier can be overcome at high temperatures to form a ring h-BN. In view of its simplicity and efficiency, this work is promising for designing and guiding the synthesis of h-BN nanoparticles with uniform morphology.

Study on micro-arc oxidation coating of copper pretreated at high temperature

Micro-arc oxidation (MAO), also known as plasma electrolytic oxidation (PEO), is a surface treatment technology widely used in valve metals. As a widely used non-valve metal, copper is generally not easy to prepare MAO coating on its surface. In this paper, from the principle of MAO, the black coating was successfully prepared on the surface of pure copper by using high temperature pretreatment method and MAO technology, and the surface morphology and composition of the coating are characterised in detail. Friction experiments show that the MAO coatings formed by copper after high-temperature pretreatment at 300 °C have better wear resistance. The water contact angle test and electrochemical experiments show that the 300 °C sample has a higher water contact angle and excellent corrosion resistance. This study expands the surface treatment method of copper and provides a new idea for MAO technology in the surface treatment of other non-valve metals.