Carbon Particles Research Articles

Improvement and prediction of particles emission from diesel particulate filter based on an integrated artificial neural network

Diesel Particulate Filter (DPF) stands out as a highly effective device for mitigating emissions in engines. To enhance DPF regeneration performance, the numerical model and the GA-BP neural network model are developed, which delves into the impacts of velocity, temperature, oxygen mass fraction, and particles size on particulate conversion. The results show that conversion rate of carbon particles can be elevated by increasing the oxygen mass fraction and inlet velocity. Specifically, the conversion rate demonstrates a remarkable improvement of 37.41% at Tin = 600 K, de = 5 μm, Vin = 10 m/s, and mO2 increased from 0.01 to 0.04. Additionally, conversion rates are increased as the size of the carbon particles gradually reduced. Besides, a GA-BP neural network is deployed to analyze and predict the numerical results of 1818 sets of DPFs under different operating conditions. From the analysis and prediction of 132 data sets, and it is discerned that a high state of contamination transformation can be achieved at Tin = 525 K, de = 5 μm, Vin = 12 m/s and mO2 = 0.04. This demonstrates the significance of judiciously selecting boundary conditions for realizing effective regenerative emission reduction.

Performance of concrete superficially treated with nano-modified coatings under sulfuric acid exposures

Protection of concrete surface layer is crucial for preserving serviceability and durability of concrete structures during their service life. Chemical attack by sulfuric acid is an aggressive exposure, commonly causing significant damage to concrete elements such as buildings' foundations and basement walls, buildings and structures affected by acid rain, industrial facilities, and wastewater treatment facilities. Hence, this study endeavored to evaluate the performance of nano-modified composites as surface treatments for concrete under severe chemical exposures. Nano-calcium carbonate and nano-clay particles were dispersed at different dosages (0, 2.5, and 5% by mass) in the neat coatings: vinyl ester (membrane-forming polymer) and silane (hydrophobic agent). Moreover, an amorphous colloidal silica (SiO2>50%) was also used as a superficial treatment for concrete. These coatings were applied to concrete specimens with water-to-binder ratios (w/b) of 0.40 (representing good quality/low penetrability concrete treated for prohibition of deterioration) and 0.60 (representing deteriorated/high penetrability concrete in need for rehabilitation). the wettability and initial transport characteristics of the coated concrete specimens were determined. In addition, the durability of superficially treated concrete specimens was examined under two aggressive exposures: full submergence in a 5% (by volume) sulfuric acid solution, and 5% sulfuric acid solution combined with wetting-drying cycles. During both exposures, the deterioration of concrete specimens was observed by visual inspection and quantified in terms of mass change. Furthermore, the damage mechanisms and coatings’ performance were studied by microstructural, mineralogical, and thermal analyses. The overall results showed that vinyl ester and vinyl ester nanocomposites significantly improved the durability of concrete specimens by an average of around 64% relative to that of the silane and silane nanocomposites; hence, they are recommended for field applications.

Wood-converted porous carbon decorated with MIL-101(Fe) derivatives for promoting photo-Fenton degradation of ciprofloxacin.

In response to the escalating concerns over antibiotics in aquatic environments, the photo-Fenton reaction has been spotlighted as a promising approach to address this issue. Herein, a novel heterogeneous photo-Fenton catalyst (Fe3O4/WPC) with magnetic recyclability was synthesized through a facile two-step process that included in situ growth and subsequent carbonization treatment. This catalyst was utilized to expedite the photocatalytic decomposition of ciprofloxacin (CIP) assisted by H2O2. Characterization results indicated the successful anchoring of MIL-101(Fe)-derived spindle-like Fe3O4 particles in the multi-channeled wood-converted porous carbon (WPC) scaffold. The as-synthesized hybrid photocatalysts, boasting a substantial specific surface area of 414.90 m2·g-1 and an excellent photocurrent density of 0.79 μA·cm-2, demonstrated superior photo-Fenton activity, accomplishing approximately 100% degradation of CIP within 120 min of ultraviolet-light exposure. This can be attributed to the existence of a heterojunction between Fe3O4 and WPC substrate that promotes the migration and enhances the efficient separation of photogenerated electron-hole pairs. Meanwhile, the Fe(III)/Fe(II) redox circulation and mesoporous wood carbon in the catalyst synergistically enhance the utilization of H2O and accelerate the formation of •OH radicals, leading to heightened degradation efficiency of CIP. Experiments utilizing chemical trapping techniques have demonstrated that •OH radicals are instrumental in the CIP degradation process. Furthermore, the study on reusability indicated that the efficiency in removing CIP remained at 89.5% even through five successive cycles, indicating the structural stability and excellent recyclability of Fe3O4/WPC. This research presented a novel pathway for designing magnetically reusable MOFs/wood-derived composites as photo-Fenton catalysts for actual wastewater treatment.

Preparation of activated carbon/iron oxide/chitosan electrodes for symmetric supercapacitor using electrophoretic deposition: A facile, fast and sustainable approach

In this research, electrophoretic deposition (EPD) was employed to prepare a porous composite film (ACF electrode) consisting of 90 wt% activated carbon particles, 10 wt% iron oxide nanoparticles, and a chitosan as binder in a facile, fast, and sustainable manner. This micro-mesoporous composite film, with a thickness of ∼45 µm and a surface area of ∼208.1 m2g−1, was coated on a stainless steel substrate. The SEM and TEM investigations proved the homogeneous distribution of carbon microparticles and iron oxide nanoparticles in the deposit, while the EDX, XRD, Raman spectroscopy, and XPS confirmed the chemical composition. ACF electrodes were also used in a symmetric two-electrode cell configuration with a sandwiched gel polymer electrolyte - PVdF(HFP)-PC-Mg(ClO4)2 and revealed a specific capacitance of ∼54.4 F g−1, along with satisfactory energy and power density of ∼4.7 Wh kg−1 and 1.2 kW kg−1, respectively, and excellent electrochemical stability up to ∼10,000 cycles (with merely 8.5% decay by the 5000th cycle). Obtained results confirmed the stability of the used system and its possible application in the field of energy storage and conversion.

The effect of dispersion degree of calcium carbonate particles in polyvinyl chloride matrix on the mechanical properties of composites

By establishing representative volume units of polyvinyl chloride (PVC) matrix composites filled with calcium carbonate (CaCO3) particles with different agglomeration degrees, finite element simulation analysis is conducted to predict the degree of improvement of the mechanical properties of the CaCO3/PVC composites by the dispersion degree of calcium carbonate particles. When the agglomeration coefficient is 0.4, the stress concentration phenomenon of the CaCO3/PVC composites is the weakest, and the stress distribution of the entire CaCO3/PVC composites is relatively uniform. At the same time, the reinforcement effect of the CaCO3/PVC composites’s stiffness is also the best, increasing by 13.8%.

Black Carbon along a Highway and in a Residential Neighborhood during Rush-Hour Traffic in a Cold Climate

Short-term exposure to ultra-fine Black Carbon (BC) particles produced during incomplete fuel combustion of wood and fossil fuel has been linked to respiratory and cardiovascular diseases, hospitalizations and premature deaths. The goal of this research was to assess traffic-related BC in a cold climate along an urban highway and 300 m into an adjacent residential neighborhood. BC was measured with an aethalometer (MA350, Aethlabs) along the main traffic artery in geothermally heated Reykjavík, the capital of Iceland (64.135° N–21.895° W, 230,000 inhabitants). Stationary monitoring confirmed that traffic was the dominant source of roadside BC in winter, averaging 1.0 ± 1.1 µg/m3 (0.6 and 1.1 µg/m3 median and interquartile range; 28,000 vehicles/day). Inter-day variations in BC were primarily correlated to the atmospheric lapse rate and wind speed, both during stationary and mobile campaigns. During winter stills, BC levels surpassed 10 µg/m3 at intersections and built up to 5 µg/m3 during the afternoon in the residential neighborhood (adjacent to the highway with 43,000 vehicles/day). The BC penetrated deeply into the neighborhood, where the lowest concentration was 1.8 µg/m3 within 300 m. BC concentration was highly correlated to nitrogen dioxide (r > 0.8) monitored at the local Urban Traffic Monitoring site.

Effectiveness of activated zeolite adsorber in decreased soot emission and increased oxygen concentration from combustion smokes of polyvinyl chloride plastic

Polyvinyl Chloride plastic waste is becoming an increasingly urgent global environmental issue. Combustion PVC plastic waste can have significant negative impacts on human health. To overcome these problems, this research was conducted by utilizing zeolite as an adsorbent for PVC combustion smokes. The research methodology is zeolite activation, adsorber design and gas adsorption process through dry adsorption method which is the core of this research. This study will evaluate oxygen concentration and soot emissions. Before being given a zeolite adsorbent, the oxygen concentration produced in PVC combustion smokes was only 17.2% with high soot levels as evidenced by the blackened smoke color. Furthermore, after being given an adsorbent in the form of activated zeolite as much as 283.5 grams, the oxygen concentration produced increased significantly to 20.9% followed by a decrease in soot emission levels as evidenced by changes in the color of whitened smoke. Based on the test results related to the increase in oxygen concentration and the decrease in soot emission levels, it can be concluded that activated zeolite has a high effectiveness in carrying out the PVC combustion smoke adsorption process by producing particles of carbon and oxygen within the normal threshold in the air.

Enzyme-Based Cleanup Fluid Effective for High-Temperature Filter-Cake Removal

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 214628, “Enzyme-Based Cleanup Fluid for High-Temperature Filter-Cake-Removal Applications,” by Ali A. Al-Taq, SPE, Hussain A. Al-Ibrahim, SPE, and Ali A. Alsalem, SPE, Saudi Aramco, et al. The paper has not been peer reviewed. _ Enzyme-based cleanup fluids are preferred for filter-cake-removal applications, especially in horizontal wells, because of several advantages compared with conventional cleanup fluids, including low reactivity, less corrosivity, more-positive environmental impact, and, ultimately, homogeneous filter-cake-removal coverage. Most enzyme-based cleanup fluids are limited to low temperatures. In the complete paper, the authors describe extensive laboratory work conducted to evaluate an enzyme-based/in-situ generated organic acid cleanup fluid for a water-based mud at a temperature of 250°F. Experimental Work Before describing their experimental methods, the authors provide a literature review in the complete paper detailing cleanup or removal of filter-cake damage, natural cleanup, acids and oxidizers, enzymes, enzyme-breaker systems, and factors influencing performance of enzyme breakers. The drill-in fluids used to perform the high-pressure/high-temperature (HP/HT) filter press tests were laboratory and field samples. The field samples were obtained from Well A. XC-polymer, starch, and PAC-L polymers were used in the drilling-fluid formulation to control fluid loss and to increase its viscosity. Potassium hydroxide was added to adjust the pH of the drilling fluid. Potassium chloride (KCl) was used to mitigate fines migration and clay swelling. Fine and medium calcium carbonate particles were used as weighting materials. Equipment used in the experiments included HP/HT filter-press cells, see-through cells, and a pendant-drop instrument. The inductively coupled plasma (ICP) technique was used to measure the concentration of calcium in the spent acid samples. Filter-cake solids before and after the reaction took place were analyzed using X-ray diffraction (XRD) and X-ray fluorescence (XRF) techniques. The concentrations of spent acid samples were measured by acid/base titration using 0.5-M sodium hydroxide solution and phenolphthalein solution as an indicator. Iodine tests were conducted on the treated filter-cake solids to examine the presence of starch. The pH and density were measured for various solutions. Coreflood experiments were conducted on sandstone core plugs. The coreflood-test procedure is provided in the complete paper.

Evaluation of highly adsorptive Guefoams (multifunctional guest-containing foams) as a potential sorbent for determination of volatile organic compounds (VOCs) by means of thermal desorption

The present work delves into the feasibility of employing a novel structured sorbent referred to as GFAD (Guefoam Adsorption Device) for the determination of volatile organic compounds (VOCs) in liquid samples. The chosen method has been static headspace sorptive extraction-thermal desorption gas chromatography mass spectrometry (HSSE-TD-GC–MS). The GFAD comprises an aluminum cellular material with a distinct replication structure and a solid guest phase consisting of activated carbon particles dispersed within the cavities of the cellular aluminum. The extensive specific surface area, robustness, and exceptional thermal conductivity of this pioneering material offer distinct advantages over commercially available polydimethylsiloxane-based Twister® devices. Therefore, the trapping efficiency for volatile organic compounds is enhanced, and it is possible to perform the analysis of concentrated samples. According to computational simulations, it has been demonstrated that GFAD has a high heat conductivity. As a result, the desorption efficiency is improved, and minimal temperature gradients are generated throughout the GFAD during the heating process. Besides, the energy consumption is significantly lowered, thus aligning with environmentally conscientious and sustainable analytical practices.The experimental results give a proof of the suitability of the GFAD for determining gaseous compounds in liquid samples through HSSE-TD-GC–MS. For volatile species, the new material provides higher peak areas and lower limits of detection than a commercially available Twister® device. Furthermore, the GFAD is reusable, its adsorbing properties remaining unchanged during, at least, 100 consecutive analyses. In addition, unlike to the Twister®, no intense siloxane peaks are observed in the chromatograms obtained with the GFAD. The feasibility of qualitative and semi-quantitative analysis with the new accessory has been demonstrated with both standards and a cereal bioethanol real sample.Graphical abstract

Microbially Inspired Calcium Carbonate Precipitation Pathway Integrated Polyelectrolyte Capsules (MICPC) for Biomolecules Release.

Complexation between oppositely charged polyelectrolytes offers a facile single-step strategy for assembling functional micro-nano carriers for efficient drug and vaccine delivery. However, the stability of the delivery system within the physiological environment is compromised due to the swelling of the polyelectrolyte complex, driven by the charge shielding effect, and consequently leads to uncontrollable burst release, thereby limiting its potential applications. In a pioneering approach, cellular pathway-inspired calcium carbonate precipitation pathways are developed that are integrated into polyelectrolyte capsules (MICPC). These innovative capsules are fabricated at the interface of all-aqueous microfluidic droplets, resulting in a precisely controllable and sustained release profile in physiological conditions. Unlike single-step polyelectrolyte assembly capsules which always perform rapid burst release, the MICPC exhibits a sustainable and tunable release pattern, releasing biomolecules at an average rate of 3-10% per day. Remarkably, the degree of control over MICPC's release kinetics can be finely tuned by adjusting the quantity of synthesized calcium carbonate particles within the polyelectrolyte complex. This groundbreaking work not only deepens the insights into polyelectrolyte complexation but also significantly enhances the overall stability of these complexes, opening up new avenues for expanding the range of applications involving polyelectrolyte complex-related materials.

Structural and electrophysical properties of nanoporous carbon materials obtained from apricot pits

The dependencies of the electrophysical characteristics of nanoporous carbon material (NCM) on the compaction degree of its particles have been investigated in the presented study. It has been found that the maximum value of the electrical conductivity is achieved at a pressure of 2.5 MPa. Furthermore, it has been revealed that the formation of O-compounds on the surface of the studied materials leads to a decrease in electrical conductivity. The correlation between structural-adsorption and electrical-conductive properties of NCMs has been established. Moreover, it has been demonstrated that an increase in the amount of potassium hydroxide results in a decrease in electrical conductivity due to the breakdown of small carbon particles and an increase in contact resistance, while the specific surface area enlarges due to the development of porosity and an increase in the total pore volume.

Toughening poly(lactic acid) by CaCO3 treated with waste lower purity dimer fatty acid

With the growing emphasis on environmental conservation, the utilization of biomass resources has garnered increasing attention. Dimer acid, derived from vegetable oils, serves as a high-quality chemical raw material while the waste lower purity dimer acid (WLPDA) will result in environmental pollution and resource wastage. In this work, WLPDA was employed as a surface modifier for calcium carbonate (CaCO3) particles with the aim of toughening of poly(lactic acid) (PLA). The addition of WLPDA demonstrates excellent modifying effects on CaCO3, achieving an activation index of 100% and an increased contact angle from 14° to around 120°. Furthermore, the PLA/WLPDA modified CaCO3 (D-CaCO3) composites exhibit noticeably toughening effects, with a maximum increase of 87% in impact strength. The improvement can be attributed to the favorable plastic deformation of interparticle ligaments following particle-matrix debonding and the long aliphatic chains of WLPDA. This research highlights the viability of replacing stearic acid with WLPDA as the surface modifier for inorganic fillers, providing a promising alternative for the toughening modification of polymers. Additionally, it presents a novel approach for the comprehensive utilization of dimer acid biomass resources.

The influence of flow electrode channel design on flow capacitive deionization performance: Experimental and CFD modelling insights

Flow capacitive deionization (FCDI) is an emerging desalination technology at which flow electrodes (shear-thinning flowable carbon slurries) are used to remove ions from saline water. The geometry of flow electrode channels, which provide the path and ensure the distribution and mixing of the flow electrodes, is one of the most important aspects to be optimized. This work presents experimental and computational fluid dynamics (CFD) modelling analysis of the influence of the geometry of flow electrode channels on FCDI performance. Flow electrode gaskets (with open, serpentine (short) horizontal and serpentine (long) vertical channels) were 3D printed using a polyethylene terephthalate glycol (PET-G) filament. The FCDI cell with a vertical serpentine flow electrode channel exhibited the poorest performance due to channel blockage by carbon particles, while the best results were achieved with a horizontal serpentine flow electrode channel. CFD simulations aided in understanding this behaviour by showing that the channel geometry strongly affects the local shear rate, and thus the local viscosity of flow electrodes. Thus, it is recommended to design channels that induce flow disturbance aiming for increasing the shear rate and hence reducing flow electrode viscosity, therefore promoting their flowability and reducing clogging chances.

Black carbon instrument responses to laboratory generated particles

Accurate measurement of black carbon (BC) particles is vital for climate models as well as air quality assessments. While the need for BC particle measurement has been recognized, standardization of instruments and procedures for ambient measurement is still underway. In this study, we used laboratory generated soot particles to assess nine instruments targeting BC mass concentration measurement. The measurement matrix included different BC concentrations (ranging from atmospheric levels to combustion emission levels), different particle coatings, two particle sources (gas burner and spark generator) and two dilution methods. The nine instruments included six different models: aethalometers AE33 and MA200, thermo-optical OC-EC analysis, multi-angle absorption photometer MAAP 5012, photoacoustic instrument MSS, and soot particle aerosol mass spectrometer SP-AMS. The main discrepancy we observed was that the SP-AMS results were systematically lower, approximately only half of the BC measured by other instruments. A portion of this is explained by particle losses in the aerodynamic lens of the SP-AMS and the parameters used in the data analysis. Some smaller discrepancies were identified for the other instruments, but overall, the median values from were within 25 % of each other. Instruments’ operation principles and covered concentration ranges need to be carefully considered especially in emission measurements where the aerosols can have high temporal variation as well as high BC concentrations. In general, the results can decrease the uncertainties in climate and air quality studies by providing tools for more accurate and comparable BC measurements and when the existing BC data is interpreted.

Jet aircraft lubrication oil droplets as contrail ice-forming particles

Abstract. The radiative characteristics and lifetimes of contrails are dependent on the number concentration of ice-forming particles in the engine exhaust plume. Aircraft gas turbine engines produce a variety of particles, yet it is understood that non-volatile black carbon aggregates are the dominant source of ice-forming particles with typical, fossil-derived jet fuel. However, with cleaner combustion technologies and the adoption of alternative fuels (e.g. hydrogen or synthetic aviation fuel), non-volatile black carbon particle emissions are expected to decrease or even be eliminated. Under these conditions, contrail properties will depend upon the concentration and characteristics of particles other than black carbon. Ultrafine (< 100 nm) jet lubrication oil droplets constitute a significant fraction of the total organic particulate matter released by aircraft; however, their ability to form contrail ice crystals has hitherto been unexplored. In this work, we experimentally investigate the activation and freezing behaviour of lubrication oil droplets using an expansion chamber, assessing their potential as ice-forming particles. We generate lubrication oil droplets with a geometric mean mobility diameter of (100.9 ± 0.6) nm and show that these activate to form water droplets, which subsequently freeze when the temperature is below ∼ 235 K. We find that nucleation on lubrication oil droplets should be considered in future computational studies – particularly under soot-poor conditions – and that these studies would benefit from particle size distribution measurements at cruise altitude. Overall, taking steps to reduce lubrication oil number emissions would help reduce the climate impact of contrail cirrus.

Geostatistical modeling approach for studying total soil nitrogen and phosphorus under various land uses of North-Western Himalayas

The distribution of total soil nitrogen (TSN) and total soil phosphorus (TSP) plays a pivotal role in shaping soil quality, fertility, agricultural practices, and environmental balance, especially in ecologically sensitive regions like the North-Western Himalayas (NWH). The primary objectives of this study were to contribute to clarify the impact and the rationale of various land uses on the spatial variation of TSN and TSP in the corresponding soils. This study aimed to explore the relation of TSN and TSP distribution in NWH soils with various factors like landscape physiography and soil physical and chemical properties using random sampling and geostatistical analyses. Employing random sampling, 300 soil surface samples (at a depth of 0–20 cm) were collected across various 500 m × 500 m grids from agriculture, horticulture, forest and fallow lands in the NWH region. The spatial land heterogeneity of TSN and TSP were systematically analyzed using standard statistical and geostatistical approaches (Gaussian, spherical, exponential, and linear). Results revealed a decreasing order of TSN and TSP levels i.e., horticulture (0.410 and 0.723 mg/kg) > agriculture (0.314 and 0.597 mg/kg) > forest (0.236 and 0.572 mg/kg) > fallow (0.275 and 0.342 mg/kg). Stepwise multiple regression results demonstrated a correlation between TSN and soil organic carbon (SOC), while TSP was correlated with soil organic carbon (SOC) and fine-grained soil particles. Nugget % values indicated the following spatial variability for TSN: agricultural (1.4) > horticultural (3.2) > forest (3.9) > fallow land (4.8) > mixed land (5.8), whereas the spatial variability of TSP showed a similar trend for all land uses. The optimized conceptual framework and isotropy models varied for TSN and TSP on dependence on land use type. The results of this study revealed the spatial patterns and land use-related variations and improved the prediction of nutrient distribution, so contributing an optimized conceptual framework for future studies. Finally, this study provided crucial insights to enhance soil quality, fertility, agricultural sustainability, and environmental equilibrium in the ecologically fragile NWH region, contributing to solve a significant research gap in the global understanding of soil dynamics.

Could cigarette smoke be associated with metaplastic type of meibomian gland dysfunction?

Madam, The meibomian glands are located in the tarsal plates of the eyelids. The diseases involving these glands belong to a broad classification. However, the metaplastic diseases of the meibomian gland are the focus of this letter.1 We intend to propose the possible role of cigarette smoke as an active agent in developing metaplastic type of meibomian gland dysfunction (MGD). A meibomian gland is made up of multiple acini that are arranged around a long central duct. Owing to its vigorous function of producing meibum and maintaining tear film stability, the gland requires a constant turnover and differentiation of cells. Consequently, during this intricate cascade of continuous production and differentiation of cells, even a slight deviation from normality can lead to drastic pathological effects.2 We presume that oxidative stress can produce such a pathologic deviation. One of the most common causes of increased oxidative stress in cells is exposure to cigarette smoke. It has also been experimentally established that cigarette smoke is a well-known inducer of metaplastic changes; especially known to cause squamous metaplasia in the bronchial epithelium.3 Therefore, exposure to cigarette smoke may also be a culprit when the meibomian orifice, owing to its superficial location on the eyelid, is exposed to the components of cigarette smoke. Cigarette smoke contains carbon particles and other toxic compounds that begin the cascade of inflammation and during the attempts of phagocytic elimination of these toxic compounds, inflammatory damage to DNA and proteins can occur.4 The aspect of protein damage and hyperkeratinization in response to increased oxidative stress has already been studied and implicated in the pathogenesis of MGD.2 Furthermore, it has been demonstrated that EGF (Epidermal Growth Factor) is produced in epithelial cells in response to smoke and that further increases the possibility of metaplastic as well as hyperplastic changes.5 Therefore, we suggest that there exists a strong relation between exposure to cigarette smoke and the development of metaplastic meibomian gland dysfunction. Further studies in this regard might help in prevention, as well as newer diagnostic approaches towards MGD especially in populations exposed to cigarette smoke on a regular basis.

Preparation of Silicon Carbide Powder from Amorphous Silica and Investigation of Synthesis Mechanism

An innovative process for preparing silicon carbide (SiC) from acid leaching residue of ferronickel slag through a carbon–thermal reduction process was proposed in this study. The results indicate that the acid leaching residue is an ideal silicon source for SiC preparation according to its high amorphous silica content of 84.20% and fine particle size of d50 = 29.16 μm. Compared with carbon black, activated carbon, and graphite, coke is the more appropriate carbon source for SiC preparation. A micron-size SiC powder with grade of 88.90% and an average particle size (d50) of 44.68 μm can be obtained under the following conditions: the mass ratio of coke to leaching residue as 1.2:1, in an air atmosphere, reducing at 1600 °C for 3 h, following by decarbonizing at 700 °C for 4 h. The XRD, SEM and FTIR analyses show that the prepared powder is 3C-SiC and belongs to the β-SiC crystal type. Based on thermodynamic analysis and micromorphology observation, it can be concluded that with amorphous silica as the silicon source, the carbon–thermal synthesis of SiC powder follows both the solid–solid reaction mechanism and the gas–solid mechanism. The SiC created through solid–solid reaction is primarily nucleated in situ on amorphous SiO2, with a size close to that of the original acid-leaching slag, while the SiC generated according to the gas–solid mechanism mainly nucleates heterogeneously on the surface of carbon particles, resulting in a smaller particle size and mostly adhering to the surface of solid–solid nucleated SiC particles. This study provides a feasible method for the effective utilization of amorphous silica, which is also significant for the efficient consumption of the vast acid leaching residue.

Role of CO2 and Glycerol in the Formation of Urchin-Like Strontium Carbonate Particles

Role of CO₂ and Glycerol in the Formation of Urchin-Like Strontium Carbonate Particles

Synthesis of High-Precision Sub-Micron CaCO3 Anticancer Drug Carriers from Coral Remains

Calcium carbonate (CaCO3) particles have attracted increasing attention as a promising material for drug delivery systems. In this study, coral remains were utilized as a raw material for a novel drug carrier. A series of pre-treatment and parameter experiments were conducted to synthesize sub-micron spherical CaCO3 particles. The CaCO3 particles exhibited uniform size distribution, with the minimum mean size being only 344 nm. The effects on the CaCO3 crystal phases and particle sizes were also discussed in this study. Drug loading experiments were also conducted to assess the feasibility of the CaCO3 drug carrier. We loaded TRITC-Dextran into CaCO3 particles for the simulation experiments. The loading capacity reached up to 9.6 wt.%, which was as high as common drug carriers such as liposomes. In this study, we aimed not only to tackle the local environmental issues caused by coral remains, but also to synthesize a suitable drug carrier for cancer therapy using the outstanding properties and low cost of CaCO3.