Glass Carbon Research Articles

Ultrasound assisted synthesis of CoFe-LDH for the simultaneous electrochemical detection of dopamine and acetaminophen

Herein, CoFe layered double hydroxide composites (CoFe-LDH) were synthesised by a simple ultrasound assisted synthesis method. It has been characterized by scanning electron microscopy (SEM), X-ray diffraction and X-ray photoelectron spectroscopy. CoFe-LDH modified glass carbon electrode was used as dual-function sensors for DA and AP detection. The sensor exhibits a wide detection linear range for DA and AP (2 μM-900 μM), low detection limits (DA: 0.08 μM; AP: 0.37 μM) (S/N = 3). The sensitivity of CoFe-LDH/GCE for DA and AP were 0.54 μA μM−1 cm−2 and 0.55 μA μM−1 cm−2. And it shows good reproducibility, selectivity, and stability. In addition, the sensor demonstrated good recovery rates for the detection of DA and AP in human serum samples.

Investigation of the Durability and Performance of Gears Made of Glass Fiber, Carbon and Bronze-Reinforced Polytetrafluoroethylene Matrix Composite Material

Polymer gears are often used in power transmission due to their numerous advantages. Heat accumulates on polymer gears during operation. Over time, this accumulated heat leads to damage; and shortens the service life of the gears. To prevent this, various fillers are added to the polymer materials. These fillers help to dissipate the heat generated on the gears. In this study, 25% glass fibers, 35% carbon powder, and 60% bronze particles were added to the polytetrafluoroethylene (PTFE) matrix to determine the wear behavior of gears. The properties of the matrix and the filler mainly influence the wear behavior of PTFE composites. The study showed that all composite gears with filler have better wear resistance than pure PTFE gears due to their better thermal stability. After the tests, it was found that the gears made of PTFE + 35% carbon additive had about 12 times better wear rates than those made of pure PTFE. Based on the average temperature values of the experiment, it was found that the mass temperature of gears made of 35% carbon-doped PTFE is about 38-39% lower than that of pure PTFE. This study contributes to the standard studies on heat build-up, thermal damage, and wear of gears made of polymers with different fillers and ratios.

Research progress on bamboo fiber reinforced polymeric composites: Processes, properties, and future directions

AbstractCharacterized by rapid maturation, short growth cycles, and high strength and toughness, bamboo can be compounded with polymers to produce bamboofiber reinforced polymeric composites (BFRPCs). These composites exhibit corrosion resistance comparable to traditional materials such as glass fiber and carbon fiber composites. Additionally, they possess features like low density, high strength, degradability, and environmental friendliness, with low production costs and strong industrial applicability. This paper reviews the accomplishments in BFRPCs and provides an overview of the production processes for BFRPCs. Furthermore, it summarizes the research status of mechanical properties, moisture absorption characteristics, interface performance, and flame retardancy of these composites. The current issues with BFRPCs were analyzed. Finally, the paper explores future research directions and potential applications of BFRPCs.Highlights The performance studies on BFRPCs are comprehensively presented. Composite processing of BFPRCs is reviewed. Pros and cons of various types of BFRPCs are analyzed. Overview of the applications of BFRPCs in various domains is presented. Future trends and challenges of BFRPCs are introduced.

Enhancing Polybutylene Terephthalate (PBT) Composites: A PROMETHEE-Based Comparative Study of Reinforcement Materials

Polybutylene terephthalate (PBT) composites hold significant potential across various industrial applications due to their desirable mechanical, thermal, and electrical properties. In this study, we utilized the PROMETHEE (Preference Ranking Organization Method for Enrichment Evaluations) method to evaluate six alternative reinforcement materials for PBT composites: Glass Fibers (GF), Carbon Fibers (CF), Natural Fibers (NF), Carbon Nanotubes (CN), Nano-clay Particles (NP), and Aramid Fibers (AF). The evaluation parameters considered were Tensile Strength (MPa), Flexural Strength (MPa), Thermal Conductivity (W/mK), Electrical Conductivity (S/m), and Cost ($). Through comprehensive analysis, Carbon Nanotubes emerged as the top-ranked reinforcement material, exhibiting exceptional performance across all evaluation parameters. With high Tensile Strength, Flexural Strength, and Thermal Conductivity, combined with significant Electrical Conductivity, Carbon Nanotubes demonstrated their suitability for demanding applications. Additionally, while the Cost factor was comparatively higher, its superior performance justifies the investment. Conversely, Natural Fibers received the lowest rank among the alternatives. Despite potential advantages in cost-effectiveness and environmental sustainability, Natural Fibers exhibited inferior mechanical and thermal properties compared to other materials. Their low Tensile Strength, Flexural Strength, and negligible Electrical Conductivity highlight limitations in performance for many industrial applications. This study provides valuable insights for engineers and material scientists in selecting suitable reinforcement materials for PBT composites based on specific performance criteria. The PROMETHEE method offers a systematic approach to decision-making, facilitating informed choices in material selection for diverse applications. Future research could explore optimization strategies and further investigate the properties and potential applications of emerging reinforcement materials for PBT composites.

Electrochemical aptasensor with signal amplification strategy of covalent organic framework-derived carbon material for ultrasensitive determination of carbendazim

The inadequate conductivity inherent in some covalent organic frameworks (COFs) presents a challenge for their practical use in electrochemical sensors. To enhance the electrical conductivity of COFs, a high-temperature carbonization process can be employed to carbonize COFs in an inert atmosphere, resulting in the production of COF-derived porous carbon materials. In this study, a highly conductive COF-derived carbon material (COF-T800) was obtained through the calcination of a COF known as TPB-DMTP-COF. Cyclic voltammetry (CV) current responses of the TPB-DMTP-COF electrode, when exposed to [Fe(CN)6]3−/4−, were found to be lower compared to those of a bare glassy carbon electrode (GCE). However, after the carbonization of TPB-DMTP-COF, the COF-T800 electrode exhibited significantly higher current responses than bare GCE. The oxidation current response of COF-T800/GCE in [Fe(CN)6]3−/4− was 3.3 times higher than that of TPB-DMTP-COF, demonstrating superior conductivity for this carbonized material. Subsequently, COF-T800 was employed as an electrochemical aptasensor substrate for signal amplification. This aptasensor had ultrasensitive determination of carbendazim (CBZ) with a linear response from 1.0 × 10−12 to 1.0 × 10−7 M. The detection limit of CBZ was 4.0 × 10−13 M. This aptasensor demonstrated high selectivity and applicability for CBZ. The COF-T800-based electrochemical aptasensor was utilized for detecting CBZ in actual samples with success.

An unlabeled electrochemical sensor for the simultaneous detection of homocysteine and uric acid based on molecularly imprinted recognition for prediction of cardiovascular disease risk

An unlabeled molecular imprinted electrochemical sensor was developed for simultaneous detection of homocysteine and uric acid, based on gold nanoparticles and molecularly imprinted polymer composites modified glass carbon electrode. Gold nanoparticles stably enhanced the electron transfer and improved the sensitivity by acting as a base for enhancing signal for molecularly imprinted polymers. Specific molecular imprinting cavities based on electropolymerization with dopamine were formed to specifically and simultaneously identify homocysteine and uric acid. Combining the good sensitivity of electrochemistry and the excellent selectivity of molecularly imprinted polymer, the difference in peak current position was used to achieve simultaneous detection of homocysteine and uric acid. For this reason, the developed sensor showed the wide detection range of 5.00 × 10−3-1.00 × 103 μmol/L for homocysteine and 5.00 × 10−1-5.00 × 103 μmol/L for uric acid, with the LOD of 5.64 × 10−5 μmol/L and 0.128 μmol/L (S/N = 3). The developed sensor with easy preparation, great selectivity and short detection time could be used in simultaneous detection of homocysteine and uric acid in serum.

Sol-Gel Derived Gelatin-Bioactive Glass Nanocomposite Biomaterials Incorporating Calcium Chloride and Calcium Ethoxide.

Calcium-containing organic-inorganic nanocomposites play an essential role in developing bioactive bone biomaterials. Ideally, bone substitute materials should mimic the organic-inorganic composition of bone. In this study, the roles of calcium chloride (CaCl2) and calcium ethoxide (Ca(OEt)2) were evaluated for the development of sol-gel-derived organic-inorganic biomaterials composed of gelatin, bioactive glass (BG) and multiwall carbon nanotubes (MWCNTs) to create nanocomposites that mimic the elemental composition of bone. Nanocomposites composed of either CaCl2 or Ca(OEt)2 were chemically different but presented uniform elemental distribution. The role of calcium sources in the matrix of the nanocomposites played a major role in the swelling and degradation properties of biomaterials as a function of time, as well as the resulting porous properties of the nanocomposites. Regardless of the calcium source type, biomineralization in simulated body fluid and favorable cell attachment were promoted on the nanocomposites. 10T1/2 cell viability studies using standard media (DMEM with 5% FBS) and conditioned media showed that Ca(OEt)2-based nanocomposites seemed more favorable biomaterials. Collectively, our study demonstrated that CaCl2 and Ca(OEt)2 could be used to prepare sol-gel-derived gelatin-BG-MWCNT nanocomposites, which have the potential to function as bone biomaterials.

Dumbbell shaped nanocomposite Co3O4/CeO2 derived from metal-organic frameworks (MOFs) as an excellent non-enzymatic glucose sensor

Researchers in the field of electrochemistry have recently become interested in the extraordinary features of ternary transition metal oxide nanostructures with spinel structure derived from metal-organic framework (MOFs). In this study, the zeolitic imidazolate framework (ZIF-67), which grows in situ on the surface of another metal organic framework (Ce-BTC), was created using the internal expansion growth method (IEGM), and the resulting complex was then used as a template to create the dumbbell-like nanocomposite. Due to the strong electron conduction of CeO2 in composites, the electrode modified with composite material has good electrochemical activity in alkaline solution. As a glucose sensor, Co3O4/CeO2 nanocomposite modified glass carbon electrode (Co3O4/CeO2/GCE) has better performance with a detection range of 83.75 μM–2796.84 μM, a reasonably good sensitivity of 790.746 μA mM−1·cm−2, an estimated detection limit of 5.5 μA (S/N = 3) and a short response time less than 3s. The modified electrode can continue to function normally even when exposed to various interfering compounds for extended periods of time in the air. The successful use of this enzyme-free glucose sensor in fruit juice demonstrates its remarkable performance and provides ideas for future applications.

Rapid, simple, and simultaneous electrochemical determination of cadmium, copper, and lead in Baijiu using a novel covalent organic framework based nanocomposite.

It is of great significance to develop a simple and rapid electrochemical sensor for simultaneous determination of heavy metal ions (HMIs) in Baijiu by using new nanomaterials. Here, graphene (GR) was utilized to combine with covalent organic frameworks (COFs) that was synthesized via the aldehyde-amine condensation between 2, 5-dimethoxyterephthalaldehyde (DMTP) and 1, 3, 5-tris(4-aminophenyl) benzene (TAPB) to prepare a new GR/COFDPTB/GCE sensor for electrochemical sensing multiple HMIs. Compared with the glass carbon electrode (GCE), GR/GCE and COFDPTB/GCE, the developed sensor exhibited excellent electrochemical analysis ability for the simultaneous detection of Cd2+, Pb2+, and Cu2+ owing to the synergistically increased the specific surface area, the periodic porous network and plenty of effective binding sites, as well as the enhanced conductivity. Under the optimized experimental parameters, the proposed sensor showed good linearity range of 0.1-25μM for Cd2+, and both 0.1-11μM for Pb2+ and Cu2+ with the detection limits of Cd2+, Pb2+, and Cu2+ being 0.011μM, 8.747nM, and 6.373nM, respectively. Besides, the designed sensor was successfully applied to the simultaneous detection of the three HMIs in Baijiu samples, suggesting its good practical application performance and a new method for the rapid detection of HMIs being expended.

Effect of seawater aging on the erosive wear response of aramid fiber reinforced composites

This study presents the effect caused by the saline environment (artificial seawater) on the physical and tribological properties of laminated composite materials reinforced with aramid fibers when they are subjected to erosive wear by sand particles. Composite materials made by epoxy resin and reinforced with glass fiber, carbon fiber and hybrid fiber (aramid with carbon) were studied. The laminates were superficially reinforced with layers of Kevlar fiber and prepared by the vacuum-assisted resin infusion process. The samples were subjected to a seawater accelerated aging process at 70°C for 1122 h. To reproduce erosive wear conditions of marine structural components, sea sand was used as solid particle under conditions of 4.5 bar of pressure, impact speed of 4.7 m/s and impact angle of 90°. The results showed that aged materials absorb more impact energy with respect to unaged counterparts, causing less material loss and a less depth in the wear track. The information generated by this research work may serve for the design and durability analysis of marine structures such as tidal turbine blades.

Pengaruh Perlakuan Kimia Alkalinasi dan Asetilasi terhadap Kekuatan Tarik dan Mikrostruktur Serat Abaka

Today, environmental problems, especially soil pollution due to inorganic waste or waste that does not decompose, are a major problem and need to be solved, especially in developing countries with high populations such as Indonesia. One of the causes of soil pollution problems is the use of inorganic fibers such as glass fiber and carbon fiber. The use of materials that are not environmentally friendly in the industry will cause environmental problems due to nature's inability to decompose the glass fiber material in nature. The focus of this research is to reduce environmental pollution by using natural fibers such as abaca fiber as an alternative to inorganic fibers. This is due to its properties, namely: low density, good specific strength, low price, and a high biodegradable ability so that it can reduce glass fiber or carbon fiber waste that does not decompose. To support this, abaca fiber needs to be hydrophobic so that it becomes compatible with other materials when combined together with other materials. One of the ways that can be done is by alkaline chemical treatment and acetylation using KOH and CH3COOH. Chemical treatment was carried out by dipping abaca banana fibers into a solution of alkaline compounds and acetylated compounds KOH and CH3COOH with a concentration of 5 M and 10 M for 4 hours. After chemical treatment, the abaca banana fibers were characterized for mechanical properties using ASTM D 3379 standards to determine the tensile strength of the fibers and using an optical microscope to determine the microstructure of the abaca fibers.

Preparation of a three-dimensional bimetallic CoFex/ N-doped carbon nanomaterial used as modified electrode for the efficient electrochemical detection of l-tyrosine

The rapid and sensitive detection of l-tyrosine (L-Tyr) has become a vital issue in the fields of medicine and clinical analysis as lack or overdose of L-Tyr in human body could cause disease. In this paper, a three-dimensional cubic CoFex/N-doped carbon nanocomposite (CoFex-N,C) material was prepared by high-temperature calcination of CoFe-Prussian blue analogues (CoFe-PBA) in N2 atmosphere and then modified on glass carbon electrode (GCE) for L-Tyr detection. The prepared CoFex/N,C nanocomposite not only inherits the uniform morphology, and unique bimetallic active center of CoFe-PBA, but also possesses the high conductivity and large ratio area of nitrogen-doped carbon nanomaterials. Under optimum conditions, the CoFex/N,C nanocomposite electrode presented a broad linear scope of 0.8–354.84 μM, a low detection limit of 0.06 μM (S/N = 3), good anti-interference ability, and very high stability. In addition, the acceptable recoveries were obtained for real sample analysis.

Mechanical and thermal properties of short banana fiber reinforced polyoxymethylene composite materials dependent on alkali treatment

Abstract The present study aimed to develop a recyclable composite material based on a natural product, namely banana fiber, instead of synthetic reinforcement elements such as glass fiber or carbon fiber in thermoplastic matrix composites employed in many aspects of daily life. Polyoxymethylene (POM) thermoplastic was used as the matrix material. 3 %, 6 %, and 9 % by weight short natural banana fiber was used as reinforcement. Furthermore, the study improved the mechanical and thermal properties of the composite material with chemical improvements based on alkali treatment of banana fiber. Banana fiber and POM was initially mixed mechanically and then extruded at temperatures between 170 and 190 °C to obtain a homogeneous mixture. The mixture obtained by extrusion was initially cooled in the cooling pool and then passed through the crusher to obtain granules. These granules were pressed in plastic injection molds to obtain standard test samples. The ratio of reinforcement material and the variations in mechanical and thermal properties of the composites induced by the alkali treatment are presented in figures and tables. Furthermore, the changes in cross-sectional material images were examined with electron microscopy scans. The tensile and flexural strength of the material improved with alkali treatment.

Fluorine-functionalized MOF modified GCE for highly sensitive electrochemical detection of persistent pollutant perfluorooctanoic acid

Perfluorooctanoic acid (PFOA) is one of typical per- and polyfluoroalkyl substances (PFASs) in water environments, which attracts global concern due to its high persistence, bioaccumulation, and toxicity. Electrochemical detection provides a feasible, cost-effective, in-situ, and real-time detection approach for PFOA. And the fluorine-functionalized metal-organic frameworks (MOFs) have shown great adsorbing affinity towards PFOA with their fluorophilic interaction, electrostatic interaction, anion-π stacking, large specific area and porous structure. In this work, fluorine-functionalized Ce-UiO-66 (Ce-UiO-66-F) modified glass carbon electrode (GCE) was utilized to effectively and sensitively detect PFOA with redox probe strategy. The adsorption of PFOA occupied cavities of MOFs and blocked the active sites on Ce-UiO-66-F/GCE interface, leading to a decreasing probe current with PFOA concentration increasing. The quantitative detection mechanism was investigated with Langmuir isotherm model and Freundlich-Langmuir isotherm model, transducing the decreasing probe signal into PFOA concentration information. A detection range of 0.40–450 nM was obtained, and the limit of detection (LOD) was estimated to be 0.048 nM, which satisfied the domestic water requirements of Untied State Environmental Protection Agency (USEPA). This work provides a rapid and convenient electrochemical approach to detect PFOA and extends the applicability of MOFs as deployable modifiers for PFAS sensors.

Водородные и галогенные связи в трииодаминобензоатах азотистых оснований

The crystalline structures of three organic salts of triiodoaminobenzoic acid (1–3) and triiodoaminobenzoic acid monohydrate (4) are described, the structural features are established by the X-ray diffraction method. Compound 1: C20H19I6N3O6, М 1158.78; monoclinic syngony, space group Сс; cell parameters: a = 32.0782(10), b = 9.5284(3), c = 9.3745(3) Å;  = 90, β = 90,0(1),  = 90 deg.; V = 2865.35(16) Å3, Z = 4, ρcalc. = 2.684 g/cm3. Compound 2: C16H15I6N3O4, М 1074.71; monoclinic syngony, space group P21/c; cell parameters: a = 8.990(5), b = 28.541(11), c = 9.945(5) Å;  =  = 90, β = 91.23(2) deg.; V = 2551(2) Å3, Z = 4, ρcalc. = 2.798 g/cm3. Compound 3: C17H17I3N2O4, М 694.03; monoclinic syngony, space group I2/a; cell parameters: a = 36.02(2), b = 7.254(5), c = 16.468(9) Å;  =  = 90, β = 105.29(2) deg.; V = 4150(4) Å3, Z = 8, ρcalc. = 2.222 g/cm3. Compound 4: C7H6I3NO3, М 532.83; rhombic syngony, space group Iba2; cell parameters: a = 30.2146(4), b = 13.9830(2), c = 5.80740(10) Å;  = β =  = 90 deg.; V = 2453.57(6) Å3, Z = 8, ρcalc. = 2,885 g/cm3. The crystalline structure of two salts and triiodoaminobenzoic acid monohydrate is distinguished both by domination of hydrogen bonds and multiple halogen bonds. However, the 7-methylquinoline salt is devoid of halogen bonds due to peculiarities of the stack packaging of flat molecules. For two compounds (3 and 4), the features of their thermolysis by thermal analysis (in argon atmosphere) are determined: at the first stage (52 and 73 °C, respectively), the loss of crystallization water occurs; at 700 ° C under the thermolysis conditions of both compounds the decomposition product is glass carbon.

Impact Performance Improvement of Multiscale Hybrid Fiber Reinforced Polymer Composites with CNT

Improving the interface properties of carbon nanotubes increases the mechanical performance of fiber-reinforced polymer matrix composites. Studies on different fiber types and different polymer matrix materials present promising results in literature. The effect of carbon nanotube (CNT) additives on impact performance of fiber reinforced polymer matrix composites produced by vacuum infusion method and drop weight impact test applied. Glass and carbon 1 m2 fiber fabrics were divided into 9 equal square pieces and placed on top of each other to make them multi-layered structure. Fiber reinforcements were produced using vacuum infusion method with epoxy resin. 0.5% of the total composite weight was added to CNT with same production parameters and intraply hybrid composite containing glass, carbon and aramid fibers was also produced. Samples were produced from the composite plates and the drop weight impact test was performed with 50 J impact energy in accordance with ASTM D7136 standard. While this increase could be observed in glass fiber and carbon fiber reinforced composites, the impact energy absorption performance in carbon fiber reinforced composite increased more than 100%. CNT increased the impact performance of multi-layer fiber reinforced polymer matrix composites.

Effect of Fiber Stacking Sequence on Mechanical Property of Polymeric Composite through VARTIM Method and Metallographic Examination

Because of higher specific modulus/strength, lower weight, good corrosion resistance with design flexibility and easy production, carbon fiber reinforced epoxy composites are widely used for many structural applications. Glass woven (plain) and carbon fabric (plain) were studied. Thus, glass fabric-reinforced epoxy composites (GFRCs) and carbon fabric-reinforced composites (CFRCs) were fabricated throughVacuum Assisted Resin Transfer moulding (VARTM) methodology. Firstly, manufacturing unit/control system, preparation stages and some elements used in manufacturing the epoxy based composites are reviewed. Then, effects of stacking sequence of fibers on mechanical properties were investigated and a comparison was made on two types of fabrics on hardness/deformation depth through Stereo Microscope (SM). The experimental results exhibited that the hardnesses measured were around 40.6 HB and 52.4 HRB for GFRP and CFRP, respectively. Improvements in carbon fiber were about 29% in comparison to glass fiber. Further, both hybrid composites made from glass and carbon fiber, the hardnesses values were reduced. In case of C2/G2/C2 hybrid composites, reduction rate was about 9.3% in comparison to C6 fiber reinforced laminate composite. Moreover, it is clearly revealed that there were extensive deformation regions reflecting the white areas because top layer was in G2/C2/G2 samples, but there was no such a white area in C2/G2/C2 composite.

Two-dimensional Ni/Co bimetal pyrophosphate nanosheets for sensitive electrochemical detection of phenol

As a priority pollutant in many regions, phenol in environment may cause severe damage to human health and ecosystem. For the simultaneous detection of phenol in environment, a novel electrochemical sensor has been constructed in this work based on the 2D nickel cobalt pyrophosphate (denoted as NCppi) nanosheets modified glass carbon electrode (GCE). The nickel cobalt pyrophosphate was prepared by a facile hydrothermal method. The prepared 2D nickel cobalt pyrophosphate nanosheet was characterized by X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy. The bimetal nickel cobalt pyrophosphate exhibited favorable catalytic activity in phenol detection. The excellent sensing performance of nickel cobalt pyrophosphate was attributed to its charge transfer mobility and abundant catalytic sites. The nickel cobalt bimetal pyrophosphate was applied to modify glass carbon electrode (denoted as NCppi/GCE) and the obtained sensor processed satisfactory analytic performance in practical detection of phenol. Cyclic voltammetry (CV) was employed to characterize electrochemical behavior of modified GCE and bare GCE in 100 μM phenol solution. Electrochemical impedance spectroscopy (EIS) and CV were employed to characterize the charge transfer process and redox nature of different electrodes in 4 mM Fe(CN)63-/4- containing 0.1 M KCl. Square wave voltammetry (SWV) was employed to detect phenol in 0.2 M phosphate buffer solution (pH=7.0). The fabricated electrochemical sensor with optimized Ni/Co ratio also exhibited a limit of detection (LOD) of 0.25 μM, a limit of qualification (LOQ) of 0.45 μM and a linear range of 0.5–100 μM with a sensitivity of 0.0269 μA/μM using square wave voltammetry (SWV) toward phenol. Besides, the electrochemical sensor showed desirable selectivity. In standard addition test of tap water sample from Longwangzui Water Plant and river water from Xunsi River, the sensor displayed reliable recoveries. The electrochemical sensor still maintained 87.5% current response after 3-week storage. The GCE was 50 $ and the cost of catalytic ink could be ignored. The active surface area of NCppi/GCE was 0.12 cm2.

Study of electro-migration and capture of particles by a charged pendant droplet

To understand the particle scavenging mechanisms by charged droplets in air cleaning technologies, we investigate the phenomena of non-incorporation/non-attachment and return/rebound of airborne particles/clusters upon impacting charged droplets. Using high-speed imaging, the motion and fate of particles and clusters lifted from a surface and colliding with a stationary droplet suspended from an electrified needle are examined in detail. Aggregates of glass beads and carbon particles are employed to explore how material characteristics, such as hydrophobicity/hydrophilicity, conductivity, and dielectric constant, influence their capture by the droplet. Analysis of observed cluster trajectories along with numerical modelling has been carried out to provide insights into their charges and velocities. DC and AC electric field experiments unequivocally demonstrate that the Faradaic induction mechanism at both the ground and droplet surfaces causes the acquisition or reversal of particle charges. The migration of particles and clusters is predominantly governed by Coulombic force, not dielectrophoretic force (DEP). Hydrophobic carbon particle clusters with high conductivity exhibit increased rebound/non-incorporation from the droplet, whereas hydrophilic glass beads with low conductivity do not show significant rebound and readily integrate into the droplet. The study demonstrates that (i) particles deposited on surfaces suffer resuspension and (ii) the capture of particles striking a charged droplet surface may not take place universally but could have a strong dependence on the chemical and material nature of the particles. Although the study is based on aggregated clusters and not on individual particles, it opens up avenues for future research using smaller particles and droplet systems relevant to air-cleaning applications.

Cubic cobalt ferrite anchored on graphene sheets for non-enzymatic electrochemical detection of 17α-ethinyl estradiol in environmental and biological samples

Recently, the endocrine interference of endocrine disruptors on the environment and aquatic organisms has been a hot topic. Ethinyl estradiol (EE2) is an estrogen endocrine disruptor and one of the most widely used ingredients in oral contraceptives, resulting in high emissions and environmental pollution. Therefore, it is urgent to construct a non-enzymic, simple and low-cost sensor to detect EE2 in environmental and biological samples. We successfully prepared cobalt ferric oxide with anti-spinel structure and reduced graphene oxide composite (CoFe2O4/RGO) using hydrothermal synthesis, which decorated on the glass carbon electrode (GCE) to detect EE2. The morphological structure of CoFe2O4/RGO composites was studied by FESEM, HRTEM, EDX, FT-IR, XRD, and XPS techniques. Additionally, the experimental conditions were optimized and the oxidation mechanism of EE2 was explained theoretically and EE2 was detected by CV, EIS, and SWV, which displayed a fantastic current response of EE2. The electrochemical results illustrated that the prepared sensor has good selectivity, high sensitivity, a wide linear range of 0.05–100 μM, and a lower detection limit of 42 nM. Finally, the practicability of the sensor to detect EE2 in real samples was also studied and obtained a satisfactory recovery.