Carbon Microparticles Research Articles

Sustainable Biochar Carbon Biosorbent Based on Tamarind (Tamarindusindica L) Seed: Literature Review, Preparation, and Adsorption Isotherm

In the need for a sustainable environment and clean water for assisting sustainable development goals (SDGs) in developing countries, this study demonstrates the way how to produce biochar carbon microparticles from tamarind seed waste and investigates the proposal mechanism during the adsorption by comparing results with ten adsorption isotherm models. In short, carbon microparticles (sizes of 500, 1000, and 2000 m) were prepared by carbonizing saw-milled tamarind seeds at 250 C. The adsorption was evaluated in the batch reactor for adsorbing curcumin (as a model of dye). The models confirmed the formation of a layer with physisorption characteristics and binding energy due to the existence of the Van der Waals force. The adsorption profile was also done by varying adsorbent sizes and initial adsorbate loadings. Small-sized adsorbents gave impacts the improvement of adsorption capacity due to the presence of a larger surface area, a larger number of adsorption sites, and additional adsorbate-adsorbate interaction. Fewer loadings of the adsorbate results in less adsorption efficacy due to the less adsorbate-adsorbent contact and interaction. Understanding the processes happening is beneficial for future advances and applications, such as catalysts and adsorbents, particularly concerning the utilization of carbon materials from organic waste.

PEO-based mixed matrix membranes containing N-doped microporous carbon microparticles for enhanced CO2/N2 separation

As a promising strategy to reduce greenhouse gas emissions, carbon dioxide capture from industrial and power plants has been proposed. Due to its advantages of low consumption and a modest environmental impact, membrane technology has been widely used in the gas separation process. Advanced porous fillers can be successfully added into the polymer matrix to create mixed matrix membranes (MMMs) with simple processing and applicable gas separation performance. The high porosity and stability of microporous carbon materials make them desirable for use in the gas separation process. Herein, N-doped microporous carbon microparticles (NMCP) were successfully synthesized and incorporated into UV crosslinked polyethylene oxide (XLPEO) matrix membranes. Fast CO2 transport channels are created in MMMs by rationally constructing NMCP fillers with ultra-micropores (∼0.53 nm), high-content heteroatoms (N, 13.94%), and two-dimensional morphology. The relationship between the structure of the NMCP samples and the gas separation performance of MMMs was discussed. Additionally, tests were conducted on the effects of NMCP loading, operating conditions, and long-term stability of NMCP/XLPEO membranes. NMCP/XLPEO membranes with a 2.5 wt% NMCP loading displayed a CO2 permeability of 606 Barrer and a CO2/N2 selectivity of 56.4, approaching the 2019 upper bound. This work offers a novel perspective to build fast gas transport channels in porous carbon-based MMMs for carbon capture.

Laser-induced thermal emission of carbon microparticles on transparent heat-sink substrates

Thermal emission is an informative tool to study materials’ properties at high temperatures under laser irradiation. The kinetics decay of laser-induced thermal emission from carbon microparticles deposited on heat-sink surfaces of transparent dielectrics (glass and sapphire) was studied. A Q-switched YAG:Nd3+ laser (pulse duration τi = 20 ns, energy/power density 0.5 J·cm–2, 25 MW·cm–2) was employed to excite thermal emission. In calculations, the classical heat conduction equation was used. With increasing the thermal conductivity of substrate (from glass to sapphire), reduction in the emission pulse duration has been observed.

Hidro(solvo)termal destekli silika aerojellerin sentezi, modifikasyonu ve onların adsorpsiyon çalışmalarında kullanımı

The hydro(solvo)thermal synthesis method was used to successfully synthesize bare silica aerogels and nano- and microparticle-embedded silica aerogels containing SiO2 and carbon microparticles in this study. New groups were added to these structures through modification. In the study, first, the effect of the variables was systematically examined to determine the optimum conditions. The most suitable recipe for silica aerogel was created. SiO2 and CP particles were synthesized, and modified silica aerogels were prepared with these particles and agents containing amine. For the characterization of synthesized silica aerogel, particles (SiO2, CP) and particle-embedded silica aerogels, TGA, SEM, DLS and BET-BJH techniques were used. These structures were used as adsorbent in environmental applications such as removing organic pollutants like 4-nitro phenol, methylene blue, Victoria blue, bromophenol blue etc. from aqueous media. In this environmental application, the adsorption capacity (mg/g) was determined by using UV-vis spectroscopy. The prepared structures are good adsorbents, and the adsorption capacity can be increased 18-fold with modification.

Effects of pigment volume concentration on radiative cooling properties of acrylic-based paints with calcium carbonate and hollow silicon dioxide microparticles

ABSTRACT Radiative cooling paints offer a sustainable method for reducing energy demand in buildings. This work investigates the effects of particle volume concentration (PVC) of calcium carbonate (CaCO3) and hollow silicon dioxide (SiO2) microparticles in acrylic-based paints on cooling capability. Paint solar reflectance increases as the total PVC increases until a peak PVC is reached. The addition of CaCO3 improves solar reflectance due to an enhancement in near-infrared reflection but decreases thermal emission. The paint, with a total PVC of 0.45 and a CaCO3:SiO2 PVC ratio of 1:1, offers the right balance between solar reflection and thermal emissivity and achieves the best cooling performance. This work demonstrates that the CaCO3-SiO2 paint system allows tuning of the radiative cooling performance.

Sequentially citric acid-KMnO4-modified surface of activated carbon microparticles to enhance the capability of loading silver nanoparticles as a bacterial sensor material

Sequentially citric acid-KMnO4-modified surface of activated carbon microparticles to enhance the capability of loading silver nanoparticles as a bacterial sensor material

Sustainable Biochar Carbon Microparticles Based on Mangosteen Peel as Biosorbent for Dye Removal: Theoretical Review, Modelling, and Adsorption Isotherm Characteristics

Environmental problems and global energy demand increase every day. The quality of water and sanitation is a very hot topic of discussion. The principles of sustainable development (SDGs) by utilizing renewable materials need to be applied to overcome this problem. One way is through the use of agricultural waste as a renewable carbon material. The study aims to analyze the adsorption characteristics of sustainable carbon microparticles based on mangosteen peel for dye removal. This study also evaluates adsorption isotherms based on its microparticle size effects. In short, carbon preparation was started by mangosteen peel carbonization at 250˚C for 5 hours and tested using sieves (i.e., 125, 250, 500, 1000, and 2000 μm) to obtain a certain size of carbon. Adsorption was evaluated based on a specific particle size using a batch adsorption reactor. Curcumin was used as a model organic dye. The findings showed that particle sizes influence physical adsorption with repulsive interactions between adsorbates. Adsorption in the large particles (i.e. 2000 and 1000 μm) occurs in the multilayer adsorption process with pore filling, while that in the small particles (i.e., 500 μm) occurs in the monolayer adsorption process with pore filling. Small-sized carbon does not provide enough active sites (such as the absence of a pore structure on the surface) for the adsorbate, leading to the creation of a monolayer during adsorption. Meanwhile, in large-sized carbon, the pore-filling mechanism in the adsorbent surface cause the formation of multilayer adsorption. This research is important to understand the application of adsorption using agricultural waste-based adsorbents by observing the phenomena occurring during the adsorption process.

A General Biomineralization Strategy to Synthesize Autologous Cancer Vaccines with cGAS-STING Activating Capacity for Postsurgical Immunotherapy.

Autologous cancer vaccines constructed by nonproliferative whole tumor cells or tumor lysates together with appropriate adjuvants represent a promising strategy to suppress postsurgical tumor recurrence. Inspired by the potency of cytosolic double-stranded DNA (dsDNA) in initiating anticancer immunity by activating the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway, we herein report the concise synthesis of a cGAS-STING agonist through dsDNA-templated biomineralization growth of calcium carbonate (CaCO3) microparticles. The yielded DNA@CaCO3 can activate the intracellular cGAS-STING pathway of dendritic cells (DCs) by promoting endosomal escape of dsDNA, triggering their maturation and activation as a potent immune stimulator. Upon intratumoral injection, DNA@CaCO3 can reverse the immunosuppressive tumor microenvironment by simultaneously provoking innate and adaptive antitumor immunity, thereby effectively suppressing the growth of murine CT26 and B16-F10 tumors in mice. Furthermore, via CaCO3-based biomineralization of complete tumor lysates, we constructed a personalized autologous cancer vaccine with intrinsic cGAS-STING activation capacity that could provoke tumor-specific immune responses to not only delay the growth of challenged tumors but also synergize with anti-PD-1 immunotherapy to suppress postsurgical tumor recurrence. This study highlights a CaCO3-based biomineralization method to prepare autologous cancer vaccines in a concise manner, which is promising for personalized immunotherapy and clinical translation.

Vaterite microparticle-loaded methylene blue for photodynamic activity in macrophages infected with Leishmania braziliensis.

Calcium carbonate (CaCO3) exhibits a variety of crystalline phases, including the anhydrous crystalline polymorphs calcite, aragonite, and vaterite. Developing porous calcium carbonate microparticles in the vaterite phase for the encapsulation of methylene blue (MB) as a photosensitizer (PS) for use in photodynamic therapy (PDT) was the goal of this investigation. Using an adsorption approach, the PS was integrated into the CaCO3 microparticles. The vaterite microparticles were characterized by scanning electron microscopy (SEM) and steady-state techniques. The trypan blue exclusion method was used to measure the biological activity of macrophages infected with Leishmania braziliensis in vitro. The vaterite microparticles produced are highly porous, non-aggregated, and uniform in size. After encapsulation, the MB-loaded microparticles kept their photophysical characteristics. The carriers that were captured allowed for dye localization inside the cells. The results obtained in this study indicated that the MB-loaded vaterite microparticles show promising photodynamic activity in macrophages infected with Leishmania braziliensis.

An Electrochemical Sensor for the Determination of Trace Concentrations of Cadmium, Based on Spherical Glassy Carbon and Nanotubes.

The practical application of a novel, eco-friendly electrochemical sensor based on low-dimensional structures, spherical glassy carbon microparticles, and multiwall carbon nanotubes is described. This sensor, modified with a bismuth film, was used for the determination of Cd(II) by the anodic stripping voltammetric method. The instrumental and chemical factors influencing the sensitivity of the procedure were thoroughly investigated and their most favorable values were selected (acetate buffer solution pH = 3 ± 0.1; 0.15 mmol L-1 Bi(III); activation potential/time: -2 V/3 s; accumulation potential/time: -0.9 V/50 s). Under the selected conditions, the method exhibited linearity in the range of 2 × 10-9 to 2 × 10-7 mol L-1 Cd(II) with a detection limit of 6.2 × 10-10 mol L-1 Cd(II). The results obtained also showed that the application of the sensor for Cd(II) detection did not experience any significant interference in the presence of a number of foreign ions. The applicability of this procedure was evaluated using TM-25.5 Environmental Matrix Reference Material and SPS-WW1 Waste Water Certified Reference Material as well as river water samples through addition and recovery tests.

Effect of phage vB_EcoM_FJ1 on the reduction of ETEC O9:H9 infection in a neonatal pig cell line

Enterotoxigenic Escherichia coli (ETEC) colonizes the intestine of young pigs causing severe diarrhoea and consequently bringing high production costs. The rise of antibiotic selective pressure together with ongoing limitations on their use, demands new strategies to tackle this pathology. The pertinence of using bacteriophages as an alternative is being explored, and in this work, the efficacy of phage vB_EcoM_FJ1 (FJ1) in reducing the load of ETEC EC43-Ph (serotype O9:H9 expressing the enterotoxin STa and two adhesins F5 and F41) was assessed. Foreseeing the oral application on piglets, FJ1 was encapsulated on calcium carbonate and alginate microparticles, thus preventing phage release under adverse conditions of the simulated gastric fluid (pH 3.0) and allowing phage availability in simulated intestinal fluid (pH 6.5). A single dose of encapsulated FJ1, provided to IPEC-1 cultured cells (from intestinal epithelium of piglets) previously infected by EC43, provided bacterial reductions of about 99.9% after 6 h. Although bacteriophage-insensitive mutants (BIMs) have emerged from treatment, the consequent fitness costs associated with this new phenotype were demonstrated, comparatively to the originating strain. The higher competence of the pig complement system to decrease BIMs’ viability, the lower level of colonization of IPEC-1 cells observed with these mutants, and the increased survival rates and health index recorded in infected Galleria mellonella larvae supported this observation. Most of all, FJ1 established a proof-of-concept of the efficiency of phages to fight against ETEC in piglet intestinal cells.

First experience with 224Radium-labeled microparticles (Radspherin®) after CRS-HIPEC for peritoneal metastasis in colorectal cancer (a phase 1 study).

Peritoneal metastasis (PM) from colorectal cancer carries a dismal prognosis despite extensive cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC). With a median time to recurrence of 11-12 months, there is a need for novel therapies. Radspherin® consists of the α-emitting radionuclide radium-224 (224Ra), which has a half-life of 3.6 days and is adsorbed to a suspension of biodegradable calcium carbonate microparticles that are designed to give short-range radiation to the serosal peritoneal surface linings, killing free-floating and/or tumor cell clusters that remain after CRS-HIPEC. A first-in-human phase 1 study (EudraCT 2018-002803-33) was conducted at two specialized CRS-HIPEC centers. Radspherin® was administered intraperitoneally 2 days after CRS-HIPEC. Dose escalation at increasing activity dose levels of 1-2-4-7-MBq, a split-dose repeated injection, and expansion cohorts were used to evaluate the safety and tolerability of Radspherin®. The aim was to explore the recommended dose and biodistribution using gamma-camera imaging. The results from the planned safety interim analysis after the completion of the dose-limiting toxicity (DLT) period of 30 days are presented. Twenty-three patients were enrolled: 14 in the dose escalation cohort, three in the repeated cohort, and six in the expansion cohort. Of the 23 enrolled patients, seven were men and 16 were women with a median age of 64 years (28-78). Twelve patients had synchronous PM stage IV and 11 patients had metachronous PM [primary stage II; (6) and stage III; (5)], with a disease-free interval of 15 months (3-30). The peritoneal cancer index was median 7 (3-19), operation time was 395 min (194-515), and hospital stay was 12 days (7-37). A total of 68 grade 2 adverse events were reported for 17 patients during the first 30 days; most were considered related to CRS and/or HIPEC. Only six of the TEAEs were evaluated as related to Radspherin®. One TEAE, anastomotic leakage, was reported as grade 3. Accordion ≥3 grade events occurred in a total of four of the 23 patients: reoperation due to anastomotic leaks (two) and drained abscesses (two). No DLT was documented at the 7 MBq dose level that was then defined as the recommended dose. The biodistribution of Radspherin® showed a relatively even peritoneal distribution. All dose levels of Radspherin® were well tolerated, and DLT was not reached. No deaths occurred, and no serious adverse events were considered related to Radspherin®.Clinical Trial Registration: Clinicaltrials.gov, NCT03732781.

Asymmetric Mesoporous Carbon Microparticles by 3D-Confined Self-Assembly of Block Copolymer/Homopolymer Blends and Selective Carbonization

Asymmetric Mesoporous Carbon Microparticles by 3D-Confined Self-Assembly of Block Copolymer/Homopolymer Blends and Selective Carbonization

Nano-and Microparticles of Carbon as a Tool for Determining the Uniformity of a Diffuse Discharge Exposure

At present, a diffuse discharge plasma of air and other gases at atmospheric pressure is widely used for the surface treatment of various materials. However, in many papers it is stated that erosion damages occur on flat anodes (targets) as a result of the discharge plasma action. The shape of these damages depends on the discharge mode. In this study, the exposure uniformity was investigated by using nano- and micro-sized carbon particles deposited on a flat copper anode (a carbon layer). The diffuse discharge was formed in a ‘point-plane’ gap with a non-uniform electric field strength distribution by applying voltage pulses with an amplitude of 18 kV. It has been established that at a gap width of 8–10 mm, an imprint of the discharge plasma on the carbon layer deposited on a copper anode has no traces of local erosion. In order for erosion to occur on the surface of the anode in the form of uniformly distributed microcraters, it is necessary to increase the current density at the anode, for example, by decreasing the gap width. When decreasing the gap width to 6 mm and less, spark channels occur. They damage both the carbon layer and the copper anode in its central part. It has been shown that there are three characteristic zones: a color-changing peripheral part of the carbon layer, a decarbonized central part of the anode, and an annular zone located between the central and peripheral parts and containing individual microcraters.

Using phenolic polymers to control the size and morphology of calcium carbonate microparticles.

Calcium carbonate (CaCO3) is a naturally occurring mineral that occurs in biology and is used industrially. Due to its benign nature, CaCO3 microparticles have found use in the food and medical fields, where the specific size of the microparticles determine their functionality and potential applications. We demonstrate that phenolic polymers with different numbers of hydroxy groups can be used to control the diameter of CaCO3 microparticles in a range of 2-9 μm, and obtained particles were relatively uniform. The largest particles (∼9 μm in diameter) were obtained using poly(2,3,4,5-tetrahydroxystyrene) (P4HS), which showed the highest water solubility among the tested phenolic polymers. The polymer concentration and stirring speed influenced the size of microparticles, where the size of the obtained particles became smaller as the concentrations of phenolic polymers increased and as the stirring speed increased, both likely due to promoting the formation of a large number of individual crystal seeds by shielding seed-seed fusion and increasing the chances for precursor contact, respectively. The preparation time and temperature had a great influence on the morphology of the CaCO3 particles, where vaterite transforms into calcite over time. Specifically, aragonite crystals were observed at preparation temperature of 80 °C and vaterite particles with rough surfaces were obtained at 40 °C. Molecular weight and scale of reaction were also factors which affect the size and morphologies of CaCO3 particles. This research represents a facile method for producing relatively monodisperse CaCO3 microparticles with diameters that have previously proven difficult to access.

Modulation of double-network hydrogels via seeding calcium carbonate microparticles for the engineering of ultrasensitive wearable sensors

Stretchable and tough double-network hydrogels mediated by CaCO3 microparticles can be used to monitor human motions and mild pain signals at the wound site.

Complex destruction of textured water-repellent coatings under the influence of UV and water flow

The resistance of micro- and nanotextured coatings to aggressive factors of ultraviolet radiation, immersion in water and water flow has been studied. These coatings were obtained using calcium carbonate microparticles modified with stearic acid and colloidal silica nanoparticles treated with dimethyldichlorosilane. The inherent aging rate of polymeric materials under UV radiation is compared with the treated surface layer of hydrophobized particles. The influence of immersion in water and friction of the water flow on the Cassie state stability have been established. А mechanism for the destruction of organo-mineral coatings based on the balance of the rates of UV degradation, detachment of particles in water, degradation of the polymer and the treated surface layer of particles is proposed.

Carbon fiber supported Co/Co3O4-embedded N-doped carbon microparticles for efficient overall seawater splitting and oxygen reduction

Due to low cost and abundance, direct seawater splitting to produce hydrogen is an encouraging strategy to alleviate the consumption of fossil energy, while also avoiding freshwater stress. However, when natural seawater is utilized as the electrolyte, the catalysts on the cathode and anode of water splitting should not only have high activity to promote energy efficiency, but also have good stability and durability to resist the corrosion of chloride ions. Herein, a hierarchical carbon-based catalyst for hydrogen and oxygen evolution, ZIF-67/CF-1, was prepared by annealing a composite of ZIF-67 and carbon fiber (CF). It exhibits good electrocatalytic activity and stability for overall splitting in natural seawater and neutral PBS solution. Impressively, when an electrolyzer consisting of ZIF-67/CF-1||ZIF-67/CF-1 is applied to overall seawater splitting, the current density of 10 mA/cm2 is achieved with a drive voltage of 2.46 V, which is only 0.28 V higher than precious metal-based electrolyzer (Pt/C||IrO2). Meanwhile, ZIF-67/CF-1 shows outstanding catalytic ability for oxygen reduction (E1/2 = 0.84 V, Tafel slope = 66.9 mV/dec), also demonstrating its application potential in rechargeable batteries and fuel cells.

Intraperitoneal alpha therapy with 224Ra-labeled microparticles combined with chemotherapy in an ovarian cancer mouse model.

A novel alpha-therapy consisting of 224Ra-labeled calcium carbonate microparticles (224Ra-CaCO3-MP) has been designed to treat micrometastatic peritoneal disease via intraperitoneal (IP) administration. This preclinical study aimed to evaluate its efficacy and tolerability when given as a single treatment or in combination with standard of care chemotherapy regimens, in a syngeneic model of ovarian cancer in immune competent mice. Female C57BL/6 mice bearing ID8-fLuc ovarian cancer were treated with 224Ra-CaCO3-MP 1 day after IP tumor cell inoculation. The activity dosages of 224Ra ranged from 14 to 39 kBq/mouse. Additionally, 224Ra-CaCO3-MP treatment was followed by either carboplatin (80 mg/kg)-pegylated liposomal doxorubicin (PLD, 1.6 mg/kg) or carboplatin (60 mg/kg)-paclitaxel (10 mg/kg) on day 14 post tumor cell inoculation. All treatments were administered via IP injections. Readouts included survival, clinical signs, and body weight development over time. There was a slight therapeutic benefit after single treatment with 224Ra-CaCO3-MP compared to the vehicle control, with median survival ratios (MSRs) ranging between 1.1 and 1.3. The sequential administration of 224Ra-CaCO3-MP with either carboplatin-paclitaxel or carboplatin-PLD indicated a synergistic effect on overall survival at certain 224Ra activities. Moreover, the combinations tested appeared well tolerated in terms of weight assessment in the first 4 weeks after treatment. Overall, this research supports the further evaluation of 224Ra-CaCO3-MP in patients with ovarian cancer. However, the most optimal chemotherapy regimen to combine with 224Ra-CaCO3-MP should be identified to fully exploit its therapeutic potential.

Carbon injection to support in‐situ smoldering remediation

AbstractPer‐ and polyfluoroalkyl substances (PFAS) are a group of anthropogenic contaminants that are receiving increasing concern due to their associated negative health effects. The properties of PFAS result in their persistence and stability, which present challenges for remediation. Activated carbon is currently the most widely used method for PFAS treatment since carbon microparticle injection can be used for in‐situ treatment; however, this method does not result in PFAS destruction. Thermal treatment is a promising posttreatment method that can be used with activated carbon as long as sufficient PFAS‐destroying temperatures are achieved (>900°C). A promising in‐situ thermal treatment technology is Self‐Sustaining Treatment for Active Remediation (STAR), which uses smoldering combustion to destroy organic contaminants embedded within a porous matrix. This study investigates carbon injection to support STAR for the treatment of PFAS. Four solutions were used (1) 17% colloidal activated carbon (CAC); (2) 23% CAC; (3) 17% powdered activated carbon (PAC); and, (4) 23% PAC. Smoldering temperatures greater than the required PFAS destruction temperature were reached if 50 g carbon/kg sand was achieved for injection and soil‐mixing delivery methods. Moreover, emulsified vegetable oil (EVO) was a successful secondary surrogate fuel to enhance smoldering temperatures when supplied at a quantity less than or equal to carbon microparticles. These findings present the necessary intermediate laboratory work to evaluate methods that will achieve PFAS treatment through STAR when applied in the field.