Dispersion Of Nanoparticles Research Articles

Recent advances in nano-modified concrete: Enhancing durability, strength, and sustainability through nano silica (nS) and nano titanium (nT) incorporation

Concrete, essential to global infrastructure, confronts urgent environmental challenges due to its high carbon footprint and resource-intensive production. In response, researchers are exploring nanoparticles, such as nano-silica (nS) and nano-titanium dioxide (nT), to enhance sustainability and performance. This review examines recent advances in their application. Nano-silica, prized for rapid hydration and enhanced strength, emerges as a promising additive. Studies indicate nS accelerates cement hydration, densifies the matrix, and improves durability and impermeability. Silica-based nano-coatings on glass textile-reinforced composites bolster bond strength and resilience. Similarly, nT offers diverse benefits to concrete. Beyond its traditional applications in photocatalysis, nS has been proven to refine pore structure, increase compressive strength, and enhance resistance to elevated temperatures. Additionally, nT adds to the self-cleaning properties of concrete surfaces, making it a promising additive for sustainable construction practices. Despite these advancements, challenges persist in the effective dispersion of nanoparticles within concrete matrices and ensuring their economic feasibility and regulatory compliance. Addressing these challenges will require interdisciplinary collaboration and innovative approaches to optimize dispersion methods, mitigate health risks, and develop robust regulatory frameworks. Future research directions should focus on developing multifunctional nanomaterials capable of imparting multiple desirable properties to concrete simultaneously, such as self-sensing, self-cleaning, and energy harvesting capabilities. Furthermore, efforts to optimize manufacturing processes and scale up production will be essential to realizing the full potential of nano-modified concrete in addressing the sustainability challenges facing the construction industry.

Matrimid/MOP-18 Derived Composite Material for High-Energy Aqueous Hybrid Supercapacitor (HSC) Electrodes

The necessity for substantial advancements in electrical energy storage systems is underscored by the increasing demand driven by the extensive integration of renewable energy sources into the grid, the growing popularity of hybrid and electric vehicles, and the escalating safety requirements. Supercapacitors, characterized by their high-power density, inherently superior safety features, and longer cycle life compared to other energy storage systems, are poised to meet these escalating expectations.In this research, an in situ dispersion of Metal-Organic Polyhedra (MOP)-18 in Matrimid is employed to construct a hybrid supercapacitor electrode with enhanced redox activity and improved electrical conductivity. A uniform solution of Matrimid and MOP-18 was electrospun, subsequently carbonized, and activated with CO2 to yield Cu/Cu2O decorated carbon fiber electrode materials. The remarkable solubility of MOP-18 was leveraged to ensure the even dispersion of nanoparticles. The thermally decomposable porous structure of MOP-18 augmented the surface area and electrolyte accessibility of the fabricated electrode. Conversely, Matrimid provided a highly conductive free-standing carbon for the electrode.The amalgamation of these factors culminated in a notable enhancement in capacitance and energy density in a 6 M KOH electrolyte solution. The synthesized composite material achieved a peak capacitance of 253 Fg-1 and an energy density of 12.5 Whkg-1 at a current density of 1 Ag-1. The materials, methods, and techniques employed in the study can be readily scaled up industrially without significant alterations. As illustrated in the study, the use of soluble metal-organic structures to deliver redox-active materials in highly conductive carbon can result in composite electrode materials with synergistic properties. Figure 1

Inkjet-Assisted Lithography of Templates for the Electroforming of Micromagnets for MEMS Applications

The integration of hard magnetic alloys in the form of patterned layers is one of the most interesting challenges for the manufacturing of energy efficient magnetic microelectromechanical systems (MEMS) [1]. With respect to current state of the art devices, whose working principle mostly relies on the exploitation of Lorentzian forces, MEMS based on permanent magnets can potentially present lower power consumption, larger displacements and stronger actuation forces. However, despite these attractive advantages, it is generally difficult to integrate thick hard magnetic layers with currently employed MEMS fabrication techniques.Electrodeposition is a technique that can be exploited to accomplish this task and that is characterized by many significant advantages: high deposition rates, no necessity of a vacuum system, low cost, possibility to deposit both alloys and composites. In addition, Reverse Pulse Plating (RPP) [2] can be used to mitigate the challenges connected to the deposition of hard magnetic alloys: high residual stress, presence of cracks and inadequate surface finishing. It can also simplify electrolyte formulation, eliminating the need of excessive amounts of additives.Regardless of the material selected, electrodeposition needs a template in order to confer a specific shape to the magnetic layer. Such template is normally manufactured using state-of-the-art technologies like standard lithography. This technique, however, is characterized by the necessity to use photomasks, which are costly and poorly adaptable to geometrical variations. Furthermore, the initial investment for the lithography equipment is typically high. A possible alternative is represented by the use of inkjet printing (IJP). This technology is characterized by low costs, high flexibility and optimal productivity. It can be applied to the micrometric patterning of electroformed layers by following a novel approach described in the present work for the first time: inkjet-assisted lithography (IAL). Briefly, droplets of a dispersion of silver nanoparticles are printed on the surface of a spin coated layer of negative photoresist. Silver is opaque for the UV radiation and it constitutes a mask for the resist. The resist is exposed and developed, forming thus templates usable for electroforming.The present work investigates the application of this approach to the production of thick and crack-free CoNiP micromagnets, which are RPP deposited inside IAL templates. CoNiP was selected due to its low-cost and good magnetic properties (with HC up to 2000 Oe). The alloy is electrodeposited from a chloride based acidic electrolyte [3], using ultra-fast RPP, in micrometric circular pores created via IAL. The diameter of the pores, and consequently the diameter of the finished magnets, can be efficiently tuned by changing the speed of the jetted droplets of silver ink. Conversely, the thickness of the magnets can be tuned by varying the deposition time. The resulting micromagnets, characterized by diameters in the 20-50 µm range and thickness up to 10 µm, are characterized to assess their morphology, phase composition and magnetic properties. The micrometric magnets here described may potentially find application for the realization of powerless MEMS, energy harvesting systems or microelectronic components.[1] N. M. Dempsey, “Hard Magnetic Materials for MEMS Applications” in: Nanoscale Magnetic Materials and Applications, Springer, Boston, MA (2009)[2] S. Pané et al., Electrochim. Acta 56, 8979-8988 (2011)[3] D. Y. Park et al., Electrochim. Acta 47, 2893-2900 (2002)

(Digital Presentation) The Influence of Particle Size on Electrophotocatalytic Properties of Tungsten Trioxide Photoanodes

The need for advanced wastewater treatment technologies has been highlighted owing to the widespread contamination of water sources with toxic and persistent organic chemicals. Thin films of tungsten (VI) oxide (WO3) were prepared by spin-coating and meyer rod coating nanoparticulate dispersions following a top-down approach through ball milling. The morphological properties of the layers were investigated by profilometry. The results showed that the surface area increased with the increase in milling time and for 96 hours sample it showed a nine-fold increase compared to commercial tungsten (VI) oxide powder. The electron microscopic images provided insight into the change in particle size and layer texture which comply with the morphological changes observed by profilometry. The influence of the particle size on the charge generation efficiency was investigated using photoanodes prepared from the studied suspensions. Two distinct formulations of different particle sizes were mixed in variable ratios, and we showed that multimodal coatings exhibit larger photocurrents than monomodal coatings. The main contribution of this work can be found in the economically inexpensive method of preparing thin films WO3.

Characterization, impact and wear properties of treated and as-received graphene nanosheets reinforcement in epoxy resin composites

PurposeThis study aims to explore the enhancement of mechanical properties in epoxy resin composites through the incorporation of graphene nanoparticles, focusing on their impact and wear resistance. It investigates the role of graphene, both treated and untreated, as a reinforcing agent in composites, highlighting the significance of nanoparticle dispersion and surfactant treatment in optimizing mechanical performance.Design/methodology/approachEmploying a novel dispersion technique using a drawing brush, this research contrasts with traditional methods by examining the effects of graphene nanoparticle concentrations treated with surfactants – Polyvinylpyrrolidone (PVP) and Sulphonated Naphthalene Formaldehyde (SNF) – on the mechanical properties of epoxy resin composites. The methodology includes conducting a series of impact and wear tests to assess the influence of graphene reinforcement on the composites' performance.FindingsThe findings reveal a marked enhancement in the composites impact resistance and energy absorption capabilities, which escalate with an increase in graphene content. Additionally, the study demonstrates a significant improvement in wear resistance, attributed to the superior mechanical properties, robust interface adhesion and effective dispersion of graphene. The use of surfactants for graphene treatment is identified as a crucial factor in these advancements, offering profound insights into the development of advanced composite materials for diverse industrial uses.Originality/valueThis study introduces a unique dispersion technique for graphene in epoxy composites, setting it apart from conventional methods. By focusing on the critical role of surfactant treatment in enhancing the mechanical properties of graphene-reinforced composites, it provides a novel insight into the optimization of impact and wear resistance.

Novel V2O3@N-C cathode for superior aqueous zinc-ion batteries via melamine foam templating

Aqueous zinc-ion batteries (AZIBs) are increasingly garnering attention due to their inherent safety features and the economic benefits of using metallic zinc. Among the promising cathode materials for AZIBs, V2O3-based compounds are extensively studied because of their unique tunnel structure and high energy density. However, the broader application of V2O3-based materials is hindered by several challenges, including sluggish reaction kinetics, poor cycling stability, and the lack of effective methods for large-scale synthesis. In response to these limitations, this study utilizes melamine foam as a self-sacrificing template to develop a V2O3@N-C cathode that aims to enhance the performance of aqueous zinc-ion batteries. The resulting cathode benefits from the uniform dispersion of V2O3 nanoparticles and a trace carbon-coated structure enriched with oxygen vacancies, yielding significant reversible capacity (569.62 mA h g−1 at 0.5 A g−1 and 411.63 mA h g−1 at 20 A g−1) and superior cycling stability (369.66 mA h g−1 after 3200 cycles at 10 A g−1). Additionally, ex-situ characterization techniques have been employed to thoroughly investigate the zinc storage mechanism, offering novel insights for the development of high-performance cathode materials for AZIBs.

Molecular engineering controlled electric-optical performance of polymer dispersed liquid crystals

ABSTRACT In this work, the methods of doping different fluorine-containing monomers and fluorine-containing nanoparticles into the mixture were adopted to boost the electro-optical performance of PDLC films. The electro-optical measurements indicate the improved electro-optical performance of PDLCs through the introduction of MX-3 monomer, and the corresponded SEM results demonstrate the successful adjustment of surface morphology. Further doping F-Si@SiO2 nanoparticles into MX-3 monomer-modified PDLC system, the Vth and Vsat values are greatly reduced and reach lowest when F-Si@SiO2 content is 5 wt.%. The enhanced electro-optical property is due to the combined control of fluorine-containing MX-3 monomer and F-Si@SiO2 nanoparticles, the fluorine functional group can promote the uniform dispersion of nanoparticles; the existence of F-Si@SiO2 nanoparticles can regulate the anchoring effect on liquid crystal molecules in the polymer matrix, thus electric-optic characteristics of the PDLC materials are greatly enhanced.

Implementation of nanoparticles for expedition of freezing through storage unit involving conduction mechanism

This work employs an approach to examine the effects of adding alumina nanoparticles with varying diameters (dp) to water on the productivity of cold storage. Utilizing a finned geometry with a curved cold wall, the mesh configuration was adapted to the solid front's location, and unsteady terms were discretized using implicit methods. The concentration (ϕ) of alumina nanoparticles was also evaluated as a key parameter. Results indicated that increasing the concentration of nanoparticles improved cold storage efficiency by approximately 42.11 %. Among the various sizes, medium-sized nanoparticles were most effective, yielding a 20 % improvement in freezing efficiency compared to the smallest size. Optimal nanoparticle dispersion significantly reduced the required cooling time from 9383.58 s to 5507.129 s. This study highlights the substantial benefits of combining fins and nanoparticles to enhance cold storage systems, presenting a notable advancement in thermal management technology.

Design of novel electrochemical sensor functionalized with green nanoparticles for tetracycline monitoring

AbstractIncreasing the release of antibiotics in particular tetracycline in the environment is become one of the most concerns that threat human and animals' health. Regarding their low cost, sensitivity, portability, electrochemical sensors have received attention for tetracycline monitoring. With a nanostructure, diverse active functional sites, and good conductivity, green nanoparticles are considered now as an attractive material for sensors design. The objective of the present paper is then the design of electrochemical sensor functionalized with green nanoparticles based on gum Arabic for tetracycline detection. The green nanoparticles are synthesized by direct reduction of silver nanoparticle with gum Arabic polymer. The intrinsic properties of the obtained nanoparticles are examined using different techniques namely UV–Vis absorption (UV), X‐ray diffraction (XRD), transmission electron microscopy (TEM), and thermogravimetric TGA. To follow up, the sensor modification as well as tetracycline detection, cyclic voltammetry (CV) and square wave voltammetry are carried out. Correlation between the different results have demonstrated good dispersion and homogeneity of green nanoparticles, with good applicability in electrochemical measurements. In fact, the sensor has demonstrated wide concentrations range from 0.1 to 1250 nM with a limit of detection in the order of 0.056 nM, lower than those reported in the literature. The selectivity test, investigated against a various interfering with similar structure to tetracycline, have proven a good discrimination between all molecules. In addition, the sensor was successfully applied to real samples, and the found recovery rates are ranging from 90.4% to 106.9%. The obtained results confirm that green nanoparticles based on gum Arabic could commercially be viable for next generation of electrochemical sensor for tetracycline detection, and also could be applied for the detection of the variety of pharmaceutical pollutants in the environment.

Tunable interlayer spacings Ti3C2Tx MXene/Ni/C for enhanced electromagnetic microwave absorption

While two-dimensional lamellar materials, specifically Ti3C2Tx MXenes, have shown great promise as wave-absorbing materials, the precise design of interlayer spacing poses a persistent challenge. In this study, Ti3C2Tx MXene layers with adjustable interlayer spacings were crafted using a straightforward molecular welding technique. Through the incorporation of Ni nanoparticles onto the Ti3C2Tx MXene layers using a combination of simple mechanical stirring and carbonation reactions, we successfully developed Ti3C2Tx MXene/Ni/C composites featuring a distinct lamellar structure. A uniform dispersion of Ni nanoparticles on the surface of the Ti3C2Tx MXene nanosheets was found with some of the nanoparticles intercalated into the layers. The Ti3C2Tx MXene/Ni/C composites exhibited a maximum reflection loss (RL) value of −42.3 dB at 12.3 GHz, accompanied by an impressive effective absorption bandwidth (EAB) of 5.6 GHz. This outstanding absorption performance could be attributed to various factors, including the dielectric loss of the Ti3C2Tx MXene lamellae, reflections and scattering of multiphase heterostructures, the magnetic loss of the Ni nanoparticles, and their synergistic attenuation. Furthermore, Ni nanoparticles with high electrical conductivity induced vortex currents under the alternating influence of electromagnetic waves (EMWs), resulting in a substantial depletion. This study introduces an innovative approach for synthesizing Ti3C2Tx MXene/Ni/C composites with tunable interlayer spacing, showing their potential for applications in microwave absorption (MA).

Microstructural evolution of the inner oxide layer of a Si-modified austenitic stainless steel exposed to oxygen-saturated lead-bismuth eutectic (LBE): Toward the origin of LBE penetration

Microstructural evolution of inner oxide layer of a Si-modified austenitic stainless steel exposed to oxygen-saturated static lead-bismuth eutectic (LBE) at 550 °C up to 3000 h has been investigated. A dual-phase separated structure consisting of Fe-Cr spinel and (Fe, Cr)1-xNix phase is formed in inner oxide layer, attributed to partitioning of Ni and Cr associated with Fe-Cr spinel formation. SiO2 is preferentially formed preceding the Fe-Cr spinel at internal oxidation frontier, leading to dispersed SiO2 nanoparticles within Fe-Cr spinel. The mechanism of LBE penetration into inner oxide layer is further developed based on preferable dissolution process of (Fe, Cr)1-xNix phase.

Enhanced catalytic transfer hydrogenation of biomass-based furfural into furfuryl alcohol over Co3O4-based mixed oxide catalysts from hydrotalcite

Catalytic furfural (FF) into high value-added furfuryl alcohol (FOL) is a very important biomass improvement process and remains a challenging task. Herein, a series of Co-based composite oxide (CoMgAl-LDO) catalysts with highly dispersed Co3O4-based spinel oxide nanoparticles were synthesized by the topological transformation of Co-based ternary layered hydroxides (CoMgAl-LDH) under calcination conditions and tested for catalytic transfer hydrogenation of FF to FOL using isopropanol (2-PrOH) as hydrogen donor. The CoMgAl-LDO, especially Co1.5Mg1.5Al1-LDO calcinated at 500 °C (Co1.5Mg1.5Al1-LDO-500) offered the outstanding catalytic performance for the catalytic transfer hydrogenation of FF to FOL (99.7 % FF conversion and 95.9 % FOL selectivity), which was attributed to effectively dispersed active sites, abundant acid-base sites and mesoporous structure. Additionally, the Co1.5Mg1.5Al1-LDO-500 catalyst manifested good stability with wider universality to other carbonyl compounds, making the catalytic system extremely economical and practical in various biomass hydrogenation processes.

Modulating the Electrocatalytic CO2-CO Performance by Ag Morphology

Highly selective conversion of CO2 into CO molecules remains a major challenge in electrocatalytic CO2 reduction reactions, and metallic silver-based materials have great potential. However, the selectivity and activity of traditional silver (Ag)-based materials cannot reach the desired level, and the development of new Ag-based materials has become a hot research topic. Here, novel ag-glomerated spore-shaped Ag nanomaterials are reported for the efficient reduction of CO2 to CO. The unique nanostructures endowed with larger specific surface area, and the spore-like dispersed Ag nanoparticles (NPs) have more unsaturated Ag sites, which endowed the catalysts with higher intrinsic activity. Electrochemical tests show that spore-like Ag can obtain a Faraday efficiency (FE) of 95.6% at −1 V vs RHE, which is much higher than that of Ag nanowires (NWs) (73%) and ordinary Ag NPs (83%) synthesized in the same period. By using the three different morphologies of Ag synthesized as a research platform and statistically comparing the FE in the corresponding voltage interval, we obtained the influence of morphology effect on the selectivity of CO product production by electrocatalytic CO2 production over Ag-based catalysts, which can be further used as a guideline for catalyst development.

Influence of Particle Size on Electrophotocatalytic Properties of Tungsten Trioxide Photoanodes

The need for advanced wastewater treatment technologies has been highlighted by the widespread contamination of water sources with toxic and persistent organic chemicals. In this work, thin films of tungsten (VI) oxide (WO3) were prepared by spin-coating and Meyer rod coating nanoparticulate dispersions following a top-down approach through ball milling. The morphological properties of the layers were investigated by profilometry. The results showed that the surface area increased with an increase in milling time for the milled mixture, and, for the sample milled for 96 h, it showed a nine-fold increase compared to the commercial tungsten (VI) oxide powder. The electron microscopic images provided insight into the change in particle size and layer texture which comply with the morphological changes observed by profilometry. The influence of the particle size on the charge generation efficiency was investigated using photoanodes prepared from the studied suspensions. Two distinct formulations of different particle sizes were mixed in variable ratios, and we showed that multimodal coatings exhibit larger photocurrents than monomodal coatings. The main contribution of this work can be found in the economically inexpensive method of preparing thin films WO3.

A Flexible Wearable Strain Sensor Based on Nano-Silver-Modified Laser-Induced Graphene for Monitoring Hand Movements.

The advancement in performance in the domain of flexible wearable strain sensors has become increasingly significant due to extensive research on laser-induced graphene (LIG). An innovative doping modification technique is required owing to the limited progress achieved by adjusting the laser parameters to enhance the LIG's performance. By pre-treating with AgNO3, we successfully manufactured LIG with a uniform dispersion of silver nanoparticles across its surface. The experimental results for the flexible strain sensor exhibit exceptional characteristics, including low resistance (183.4 Ω), high sensitivity (426.8), a response time of approximately 150 ms, and a relaxation time of about 200 ms. Moreover, this sensor demonstrates excellent stability under various tensile strains and remarkable repeatability during cyclic tests lasting up to 8000 s. Additionally, this technique yields favorable results in finger bending and hand back stretching experiments, holding significant reference value for preserving the inherent characteristics of LIG preparation in a single-step and in situ manner.

NANO-GBM trial of AGuIX nanoparticles with radiotherapy and temozolomide in the treatment of newly diagnosed Glioblastoma: Phase 1b outcomes and MRI-based biodistribution

BackgroundIn glioblastoma (GBM), tumor progression occurs mainly within the irradiated tumor volume. To address this challenge, a radiosensitization strategy with intravenous gadolinium-based theranostic nanoparticles (AGuIX) is being explored in the NANO-GBM phase1b/2R trial (NCT04881032). Here, we present the results of the phase 1b part, which is the first-in-human use of these nanoparticles with radiotherapy and chemotherapy for the treatment of newly diagnosed GBM. Material and MethodsEligible patients were aged 18 to 75 years with newly diagnosed and histologically confirmed GBM, with incomplete resection (biopsy or partial surgery). The phase 1b part was a dose escalation approach (Time-to-event Continuous Reassessment Method) with three dose levels: 50, 75, and 100 mg/kg. Patients were treated with RT (60 Gy), and concomitant and adjuvant TMZ, and 4 injections of AGuIX (D-3/-7, D1, D8, and D15). Dose-limiting-toxicity (DLT) was defined as any grade 3–4 adverse event (CTCAE v5.0), excluding alopecia, nausea, and rapidly controlled vomiting. Pharmacokinetic (PK), and biodistribution based on MRI were evaluated. ResultsBetween March 2022 and March 2023, eight patients were enrolled: 1 at 50 mg/kg, 1 at 75 mg/kg, and 6 at 100 mg/kg. All patients received the four AGuIX injections. Only one patient experienced a DLT (at 100 mg/kg): a grade 3 lymphopenia (related to TMZ). The RP2D of AGuIX was determined as 100 mg/kg. AGuIX mean AUC increased with dose. Regions of GBM with moderate (36–123 µM), and high (123–291 µM) or very high (>291 µM) AGuIX concentrations accounted in average for 38.7 and 26.8 %, respectively. ConclusionThese results confirm the lack of AGuIX-related toxicity and the widespread dispersion of nanoparticles throughout GBM. This supports progression to the randomized phase 2 part, utilizing an RP2D of AGuIX of 100 mg/kg (4 injections).

Tailoring ZnO nanostructures for transparent photodetector applications in hybrid liquid crystals

We report on enhancing the electro-optical response of nematic liquid crystal (6CHBT) by doping with increasing concentration of ZnO nanoparticles. Photosensitive response of this hybrid system is shown through the generation of a photocurrent at 450 nm. The critical role of surfactants to ensure uniform dispersion of nanoparticles in the liquid crystal matrix and their interplay with the charge carrier collection process are also demonstrated. These properties allow these hybrid liquid crystals to be used in the design of photodetectors integrated into liquid crystal displays without compromising its transparency.

LLZTO crosslinks form a highly stretchable self-healing network for fast healable all-solid lithium metal batteries

Flexible composite solid electrolytes (CSEs) show great potentials in high-energy all-solid-state lithium metal batteries owing to their easy fabrication, good electrochemical properties, and high safety. However, it remains challenging to achieve good interfacial compatibility between the inorganic fillers and polymer matrix, which affects the lithium-ion transport efficiency and electrochemical performances of CSEs. Herein, a dynamic crosslinked network with Li6.4La3Zr1.4Ta0.6O12 (LLZTO) nanoparticles as the cross-linking point is proposed for fabrication of a rapidly self-healing flexible CSE, which is signed as SHENE. The amino groups in the 3-aminopropyltriethoxysilane modified LLZTO behave as the bridge sites to react with the copolymer of 2-hydroxyethyl methacrylate-g-4-formylbenzoic acid and poly (ethylene glycol) methoxy acrylate to form imine bonds, which effectively connect the organic/inorganic interface. Compared to the traditional physical contact, the covalent imine bonds can not only enhance the interaction between the two phases, but also improve the dispersion of the ceramic LLZTO nanoparticles. Additionally, the dynamic reversibility of imine bonds allows for enhanced mechanical strength and self-repairing capabilities of SHENE. Therefore, a Li||Li symmetrical cell assembled with SHENE can stably cycle for 5000 h at 0.05 mA cm−2 and 25 °C. The corresponding Li/SHENE/LiFePO4 full battery also exhibits good rate performance under various C-rates. Additionally, the Li/SHENE/LFP pouch cell exhibits superior safety under various abuse conditions. Therefore, this work provides new ideas for the uniform dispersion of ceramic nanoparticles in CSEs by the facile design of forming dynamic crosslinked networks.

A Comprehensive Evaluation of Recent Studies Investigating Nanofluids Utilization in Heat Exchangers

This comprehensive review critically examines recent research concerning the application of nanofluids in heat exchangers. The utilization of nanofluids, which are colloidal suspensions of nanoparticles in a base fluid, has garnered significant attention in enhancing heat transfer performance. Various studies have explored the potential benefits and challenges associated with incorporating nanofluids into heat exchanger systems. Through a systematic analysis of recent literature, this review assesses the effectiveness of nanofluids in improving heat transfer efficiency and overall performance of heat exchangers. Key parameters such as nanoparticle concentration, size, and type are thoroughly evaluated to understand their influence on heat transfer characteristics. Additionally, factors such as stability, flow behavior, and thermal conductivity enhancement are scrutinized to provide a comprehensive understanding of nanofluid behavior in heat exchangers. The review also addresses potential limitations and areas requiring further investigation to optimize the utilization of nanofluids in heat exchanger applications. By synthesizing recent findings, this review aims to contribute to the advancement of knowledge in the field of heat exchanger technology and nanofluid applications. Ultimately, the insights provided in this review offer valuable guidance for researchers and engineers seeking to enhance heat transfer processes through the implementation of nanofluid-based heat exchangers. Nanofluids offer advantages like enhanced thermal conductivity and tailored properties, promising optimized heat exchanger designs, leading to energy efficiency and reduced costs. However, challenges remain, such as nanoparticle dispersion and cost-effectiveness, necessitating further research for refinement. Interdisciplinary collaboration is crucial for advancing nanofluid applications, fostering innovation to meet demands for sustainable heat transfer solutions.

Perfluoroalkyl functionalized-Au nanoparticle sensor: Employing rate of spectrum shifting for highly selective and sensitive detection of per- and polyfluoroalkyl substances (PFASs) in aqueous environments

Per- and polyfluoroalkyl substances (PFASs) are emerging contaminants detected ubiquitously and have negative impacts on human health and ecosystem; thus, developing in-situ sensing technique is important to ensure safety. Herein, we report a novel colorimetric-based sensor with perfluoroalkyl receptor attached to citrate coated gold nanoparticles (Citrate-Au NPs) that can detect several PFASs including perfluorocarboxylates with different chain lengths (PFHxA, PFOA, PFNA, PFDA), perfluorooctanoic sulfonate (PFOS), and perfluorooctanoic phosphonate (PFOPA). The sensor detects PFASs utilizing fluorous interaction between PFASs and the perfluoroalkyl receptor of Citrate-Au NPs in a solution at a fixed salt concentration, inducing changes in nanoparticle dispersity and the solution color. The rate of spectrum shift was linearly dependent on PFASs concentrations. Citrate-Au NPs with size between 29 – 109 nm were synthesized by adjusting citrate/Au molar ratios, and 78 nm showed the best sensitivity to PFOA concentration (with level of detection of 4.96 µM). Citrate-Au NPs only interacted with PFASs with perfluoroalkyl length > 4 and not with non-fluorinated alkyl compound (nonanoic acid). The performance of Citrate-Au NP based sensor was strongly dependent on the chain length of the perfluoroalkyl group and the head functional group; higher sensitivity was observed with longer chain over shorter chain, and with sulfonate functional group over carboxylate and phosphonate. The sensor was tested using real water samples (i.e., tap water, filtered river water), and it was found that the sensor is capable of detecting PFASs in these conditions if calibrated with the corresponding water matrix. While further optimization is needed, this study demonstrated new capability of Citrate-Au NPs based sensor for detection of PFASs in water.