Loading Of Nanoparticles Research Articles

Development of Manganese Carbonyl Loaded Upconversion Nanoparticles for Near‐Infrared‐Triggered Carbon Monoxide and Mn2+ Delivery

Photoactivatable carbon monoxide‐releasing molecules (CORMs), typically based on transition‐metal carbonyl complexes, have reliance on activation by UV or visible light that restricts their biomedical applications. To address this limitation, a near‐infrared (NIR)‐responsive nanoplatform is presented based on upconversion nanoparticles (UCNPs) loading with manganese carbonyl complex Mn2(CO)10 that concurrently releases CO and manganese ion (Mn2+). With the UCNPs, the more tissue‐penetrable NIR is used to locally generate UV light for photodecomposition of Mn2(CO)10 into CO and manganese oxide (MnOX), after which MnOX is reduced to Mn2+ by the overexpressed glutathione in cancer cells. Moreover, the released Mn2+ can serve as a magnetic resonance imaging contrast agent to monitor the NIR‐controlled corelease of CO and Mn2+ in real time. Therefore, this nanoplatform can provide a potential strategy for NIR‐enabled spatiotemporally release of CO and Mn2+, enhancing the controlled delivery and biomedical application of CORMs.

Concurrent effect of shear flow and CNT presence on crystallization behavior and electrical properties of polypropylene based nanocomposites: A comprehensive structure-property investigation

The loading of nanoparticle in the polymer matrix affects their response to shear flows applied during the fabrication process. With this in mind, in the present study, the concurrent effect of carbon nanotube (CNT) presence and shear application on the rheological and electrical properties as well as on the crystallization behavior of polypropylene (PP) based nanocomposites has been investigated. The results of rheological analyses showed that the solid-like behavior increases in proportion to the CNT content, and a remarkable increase in the solid-like behavior is obtained at a CNT content of 2 wt%. The isothermal crystallization results corroborated that crystallization temperature increases proportionally with the CNT content, however does not change with shearing. The non-isothermal crystallization findings confirmed that crystallization kinetics promotes with increasing CNT content, and this effect becomes more pronounced with shearing. The results of thermal analysis confirmed that the melting temperature decreases slightly, and the crystallinity remains almost unchanged with increasing CNT content up to 2%. However, when the CNT content rose up to 4%, the crystallinity decreased significantly due to confined crystallization. When this nanocomposite was subjected to shearing, the crystallinity increased. The results of electrical conductivity measurement revealed that the conductivity increases with increasing CNT content, while it decreases with shearing and the vulnerability of nanocomposites to shearing decreases with increasing CNT content.

Nanofiber membranes immobilized with in-situ grown nanoparticles for enhanced wetting resistance in direct contact membrane distillation

Immobilizing nanoparticles (NPs) onto the hydrophobic nanofiber membrane surface is an effective method to enhance its resistance to pore wetting in membrane distillation (MD) due to construction of a hierarchical structure. However, loading NPs onto the fabricated membrane through post-treatment techniques (e.g., electrospray, physical vapor deposition etc.) results in agglomeration of NPs and their weak attachment with membrane surface. To address this issue, we utilize precipitation and crystallization methods to achieve in-situ growth of zinc oxide (ZnO) NPs onto nanofiber surface for intensifying their interaction. Morphological characterization demonstrated that the size and amount of in-situ grown ZnO NPs could be controlled by varying reaction time and concentration of precipitation agent. Furthermore, the resultant nanofiber membrane with higher contact angles (163°) showed stable water flux and effective salt rejection in presence of surfactant and oil. Finally, the kinetics of wetting progression monitored by ultrasonic time-domain reflectometry (UTDR) further confirmed that the early partial wetting induced by surfactants was significantly restrained owing to the hierarchical structure generated by the in-situ grown ZnO NPs. This study suggested the modified nanofiber membrane presented outstanding wetting resistance to low-surface-tension foulants and promise for desalination in MD.

Tuning active sites of carbon nitride using NiO nanoparticles for efficient photocatalytic generation of hydrogen peroxide

The use of solar photocatalysis to produce H2O2 as a new strategy alternative to the anthraquinone method, is less resource intensive and more environmentally friendly. In this study, carbon nitride (CN) loaded with NiO nanoparticles (CN-NiO) was used as photocatalyst for the generation of H2O2 through two electron oxygen reduction reactions (ORR). The existence of NiO nanoparticles improves both the photoactivity and selectivity of the carbon nitride towards two electron ORR. CN-NiO photocatalyst reaches 86 % selectivity for 2e− ORR, and a yield of 4054.1 μmol g−1h−1 for H2O2 generation under simulated sunlight, which is 2.7 times of that for bare CN. NiO nanoparticles promote the separation efficiency of photogenerated electrons and holes in photocatalysts, and also serve as adsorption sites for O2, enhancing the adsorption of O2. Additionally, DFT calculations show that the loading of NiO nanoparticles greatly reduces the energy barrier for the activation of *O2 to *OOH, which facilitates the efficient 2e− ORR photocatalysis. This study may advance knowledge regarding the function of metal oxide nanoparticles in the photocatalytic synthesis of H2O2.

Investigation on structural, optical, thermal, and dielectric properties of cellulose propionate/styrene-maleic anhydride copolymer/molybdenum nanocomposite prepared by pulsed laser ablation

Polymer nanocomposite films of cellulose propionate/styrene-maleic anhydride copolymer/molybdenum (CP/SMAC/Mo) were fabricated by pulsed laser ablation of Mo in the polymer solution for 10, 20, and 30 min. The films were then characterized by various analytical methods. X-ray diffraction (XRD) revealed that the addition of Mo to CP/SMAC removed the crystalline peaks of Mo without changing the amorphous nature of the copolymer. According to the scanning electron microscopy (SEM) and atomic force microscopy (AFM) patterns, Mo atoms were trapped in the amorphous polymer stacks. The energy-dispersive X-ray (EDX) spectrum features C, O, and Mo. FTIR confirmed the embedding of Mo in the polymers. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) were carried out on the samples. The pristine polymer film exhibited a band gap energy of 2.9 eV, which decreased to 2.05 eV because of the loading of the Mo nanoparticles. The intensity of the photoluminescence (PL) peak of the films increases with ablation time such that the absorption intensity of the film at a λmax of 426 nm increases by trifold during the 30 minutes of irradiation, which is consequently due to the increased amount of Mo in the nanostructure. The incorporation of Mo in the polymer matrix enhances the dielectric constant (ε') (6.28-18.13) and ac conductivity (σac) (3.19 × 10−5-1.12 × 10−4 S/cm) of the polymer with negligible dielectric loss. The results suggest possible technological utilization of these materials in such applications as supercapacitors, light-emitting diodes, and organic optoelectronic devices, among others.

Hollow-core fiber loading of nanoparticles into ultra-high vacuum

Many experiments in the field of optical levitation with nanoparticles today are limited by the available technologies for particle loading. Here, we introduce a particle loading method that solves the main challenges, namely deterministic positioning of the particles and clean delivery at ultra-high vacuum levels as required for quantum experiments. We demonstrate the efficient loading, positioning, and repositioning of nanoparticles in the range of 100–755  nm diameter into different lattice sites of a standing wave optical trap, as well as direct loading of 143–365  nm diameter particles into ultra-high vacuum, down to an unprecedented pressure below 10−9  mbar. Our method relies on the transport of nanoparticles within a hollow-core photonic crystal fiber using an optical conveyor belt, which can be precisely positioned with respect to the target trap. Our work opens the path for increasing nanoparticle numbers in the study of multiparticle dynamics and high turn-around times for exploiting the quantum regime of levitated solids in ultra-high vacuum.

Carbonized-wood based composite phase change materials loaded with alumina nanoparticles for photo-thermal conversion and energy storage

The integration of photo-thermal conversion and thermal energy storage is an efficient way to improve the solar energy utilization. Phase change material (PCM) with excellent thermal storage ability is often used in solar energy storage systems. However, PCMs suffer from liquid leakage, low thermal conductivity and insensitivity to light. This work used sol-gel and high-temperature calcination to modify the carbonized-wood (CW) by alumina nanoparticles loaded in the pores to improve the above issues. The combined microscopic and macroscopic test results showed that the modified carbonized-wood provided a good support structure for the paraffin wax (PW) to prepared carbonized-wood based composite phase change materials (CCPCMs). The CCPCMs exhibit noticeable hydrophobicity as well. The thermophysical properties of the CCPCMs were tested and the results showed that the CCPCMs possessed excellent encapsulation rate (85.98 %–91.65 %), enthalpy of phase transition (166.3–176.6 J/g), and good thermal reliability. By high-temperature carbonization and loading of alumina nanoparticles, the photo-thermal conversion efficiency of CCPCMs was optimized to 95.13 % and the surface overheating was weakened. In the simulation experiment of glass chamber, CCPCMs can store heat while maintaining the uniformity of the chamber's temperature. In conclusion, the novel CCPCMs developed in this work are highly promising in the field of solar thermal utilization and storage.

Heterostructured S-TiO2/g-C3N4 Photocatalysts with High Visible Light Photocatalytic Activity

Novel heterojunctions associating graphitic carbon nitride g-C3N4 and S-doped TiO2 nanoparticles were successfully designed and prepared via a hydrothermal method and used for photocatalytic degradations. The loading in S-TiO2 nanoparticles on g-C3N4 was varied (5, 10 and 20 wt%), and the photocatalysts were characterized by XRD, FT-IR, solid-state UV-visible diffuse reflectance, photoluminescence, XPS, TEM and SEM. The S-TiO2 (5%)/g-C3N4 catalyst exhibits the highest activity for the photocatalytic degradation of the methylene blue (MB) dye under visible light irradiation. The high photocatalytic performance originates from the enhanced separation and transfer of photogenerated charge carriers. The S-TiO2 (5%)/g-C3N4 photocatalyst is stable and can be reused five times without a sharp drop in activity, indicating its high potential for wastewater remediation.

Influence of nanoparticle loading on rate of cold storage considering transient conduction

In this numerical investigation utilizing the Galerkin approach, the behavior of a cold storage unit during solidification is analyzed to enhance cold storage efficiency. Passive techniques, such as the application of nanoparticles as additives and the integration of H-shaped fins, are employed. The model is developed based on simplified equations, assuming the neglect of buoyancy force impact, and subsequently solved using the Galerkin approach. Key variables include concentration (ϕ) and shape factor (m). The augmentation of the shape factor “m” significantly increases the rate of cold storage due to enhanced conductivity, resulting in a notable reduction in the solidification process time by about 21.6 % and 8.9 % with the respective increases of ϕ and “m”. This research underscores the practical significance of improving cold storage unit efficiency through the incorporation of passive techniques.

In vivo evaluation of a Nano-enabled therapeutic vitreous substitute for the precise delivery of triamcinolone to the posterior segment of the eye.

This study focused on the design of a thermoresponsive, nano-enabled vitreous substitute for the treatment of retinal diseases. Synthesis of a hydrogel composed of hyaluronic acid and a poloxamer blend was undertaken. Poly(D,L-lactide-co-glycolide) acid nanoparticles encapsulating triamcinolone acetonide (TA) were synthesised with a spherical morphology and mean diameter of ~ 153nm. Hydrogel fabrication and nanoparticle loading within the hydrogel was confirmed via physicochemical analysis. Gelation studies indicated that hydrogels formed in nine minutes and 10min for the unloaded and nanoparticle-loaded hydrogels, respectively. The hydrogels displayed in situ gel formation properties, and rheometric viscoelastic studies indicated the unloaded and loaded hydrogels to have modulus values similar to those of the natural vitreous at 37°C. Administration of the hydrogels was possible via 26G needles allowing for clinical application and drug release of triamcinolone acetonide from the nanoparticle-loaded hydrogel, which provided sustained in vitro drug release over nine weeks. The hydrogels displayed minimal swelling, reaching equilibrium swelling within 12h for the unloaded hydrogel, and eight hours for the nanoparticle-loaded hydrogel. Biodegradation in simulated vitreous humour with lysozyme showed < 20% degradation within nine weeks. Biocompatibility of both unloaded and loaded hydrogels was shown with mouse fibroblast and human retinal pigment epithelium cell lines. Lastly, a pilot in vivo study in a New Zealand White rabbit model displayed minimal toxicity with precise, localised drug release behaviour, and ocular TA levels maintained within the therapeutic window for the 28-day investigation period, which supports the potential applicability of the unloaded and nanoparticle-loaded hydrogels as vitreous substitutes that function as drug delivery systems following vitrectomy surgery.

CO2 capture through gas hydrate formation in the presence of polyethyleneimine-surface-grafted clay

CO2 capture through gas hydrate formation was performed using a stirring-type vessel in the presence of nanoclay and polyethyleneimine-grafted nanoclay. First, the grafting process was implemented via the wet impregnation method. The nanoparticles were characterized using FT-IR, FESEM, EDS, BET, XRD, TGA, Zeta potential, and DLS analyses. The characterization analyses confirmed surface-grafting of the nanoclay. Then, the hydrate formation experiments were implemented at three various nanoparticle loadings (200, 400, and 500 ppm). Water-to-hydrate conversion, CO2 gas consumption, apparent rate constant, and hydrate storage capacity were obtained and compared. Prior to conducting the CO2 hydrate formation experiments in the presence of nanoparticles, the rocking-type and stirring-type vessels were compared to evaluate the hydrate formation rate (using pure water). Stirring-type vessel exhibited higher hydrate formation rates than rocking-type vessel along with improved gas storage performance which resulted in a 22.4% increase in CO2 consumption. Thus, the effect of additives was examined using the stirring-type vessel. Surface-grafted nanoclay led to higher CO2 consumption compared to nanoclay at all concentrations. Using 500 ppm of modified nanoclay, grafted by 50 mass% polyethyleneimine (PEI) solution as additive, the maximum enhancement of CO2 consumption in the hydrate phase in comparison with pure water was obtained, along with the greatest water to hydrate conversion value (39.67). This study introduces a new technique by modifying nanoclay with PEI to improve CO2 storage in gas hydrate phase, presenting potential advancements in gas storage technology.

Fabrication of monolithic omniphobic PVDF membranes based on particle stacking structure for robust and efficient membrane distillation

Robust omniphobic membranes have attracted great attention in improving the continuous service performance of the membrane distillation (MD) in treating high salinity wastewater. However, the fabrication of omniphobic membranes commonly undergoes complex procedures of modification including the construction of rough structures and post-modification using low-surface-energy substances. Herein, monolithic omniphobic polyvinylidene fluoride (PVDF) membranes were conveniently constructed by the combination of porous membranes possess particle stacking structure generated by a one-step vapor-induced phase separation (VIPS) procedure with subsequent surface perfluorination modification. The water contact angle, soybean oil contact angle, and low-surface-tension ethanol contact angle of the perfluorinated modified membrane increased from 139.6°, 45°, and ∼0° of the original membrane to 153°, 141°, and 110°, respectively. In addition, the LEP of the perfluorinated membrane is as high as 0.32 MPa, which is higher than the 0.22 MPa of the original membrane. More importantly, the monolithic omniphobic membrane can maintain a stable water flux without deteriorating salt rejection rate during the entire MD testing due to its high specific surface area, high porosity, three-dimensional micro/nano hierarchical structure, and adjustable pore size. This study offers useful insights for constructing monolithic omniphobic membranes for efficient and robust MD processes without additional nanoparticle loading procedure.

Comparison of Pd Nanoparticle-Decorated Softwood and Hardwood Activated Carbon in Catalytic Reduction of High-Concentrated Industrial 4-Nitrophenol

Carbon-based catalyst from natural wood recently shows a great potential in environmental remediation due to its naturally hierarchical and anisotropic porous structure. However, few studies have focused on the difference in structure-property-function between the two categories of hardwood and softwood. Herein, Pd nanoparticles decorated softwood (Pd/SAC) and hardwood activated carbon (Pd/HAC) were fabricated for catalytic reduction of high-concentrated 4-nitrophenol (4-NP, 2.0 g L−1). The results show that the developed Pd/HAC has larger specific surface area (474 m2 g−1), more abundant pits and nanopores than Pd/SAC (412 m2 g−1), offering Pd/HAC with abundant interpenetrating channels for efficient mass transfer. As a result, Pd/HAC demonstrates outstanding performance in catalytic reduction of 4-NP, with the turnover frequency value up to 1.25 mol4-NP mol−1 min−1, much higher than Pd/SAC (0.92 mol4-NP mol−1 min−1), even at lower Pd nanoparticles loading (0.551 % vs. 0.573 %). The mesopores/micropores ratio of wood-based activated carbon is considered to be an important parameter affecting the mass transfer process. Pd/HAC also demonstrates superior catalytic stability and reusability, with the shedding degree of decorated Pd nanoparticles much lower than Pd/SAC when subjected to 9 cycles. Hardwood is demonstrated to be a promising activated carbon precursor, and exhibits unique hierarchical porous structure that can highly promotes the catalytic performance in industrial wastewater treatment.

Highly elastic, fatigue-resistant, antibacterial, conductive, and nanocellulose-enhanced hydrogels with selenium nanoparticles loading as strain sensors

The fabrication of highly elastic, fatigue-resistant and conductive hydrogels with antibacterial properties is highly desirable in the field of wearable devices. However, it remains challenging to simultaneously realize the above properties within one hydrogel without compromising excellent sensing ability. Herein, we fabricated a highly elastic, fatigue-resistant, conductive, antibacterial and cellulose nanocrystal (CNC) enhanced hydrogel as a sensitive strain sensor by the synergistic effect of biosynthesized selenium nanoparticles (BioSeNPs), MXene and nanocellulose. The structure and potential mechanism to generate biologically synthesized SeNPs (BioSeNPs) were systematically investigated, and the role of protease A (PrA) in enhancing the adsorption between proteins and SeNPs was demonstrated. Additionally, owing to the incorporation of BioSeNPs, CNC and MXene, the synthesized hydrogels showed high elasticity, excellent fatigue resistance and antibacterial properties. More importantly, the sensitivity of hydrogels determined by the gauge factor was as high as 6.24 when a high strain was applied (400–700 %). This study provides a new horizon to synthesize high-performance antibacterial and conductive hydrogels for soft electronics applications.

Enhancement of mechanical and thermal properties of UV‐curable wood coatings by cellulose nanofibrils and carboxylated organo‐montmorillonite

AbstractIn this study, the impact of incorporating cellulose nanofibrils (CNF) and carboxylated organo‐montmorillonite (OMMT), separately or in combination, into a UV‐curable wood coating was evaluated for performance enhancement. This study investigated the influence of nanoparticle loading percentage on the mechanical properties and thermal behavior of the coating, as well as the surface properties of digitally printed decorative wood‐based panels. The results indicated that the addition of CNF or OMMT increased the viscosity of the polymer solutions. Although CNF randomly oriented within the matrices, OMMT adhered to the surface of the polymer matrix. Chemical crosslinking was observed between CNF/OMMT and the coating. The addition of CNF and OMMT improved the thermal stability of the neat UV curing coating. The tensile strength of nanocomposite films with a 6 wt% loading of CNF increased significantly from 7.63 MPa to 12.73 MPa compared to pure films. The reinforcing effect of CNF on the tensile performance was significantly better than that of OMMT. Adding CNF to the matte coating slightly improved the clarity of the printed decorative panels. When CNF and OMMT were added together in the coating, there was a synergistic enhancement in the low gloss and high pencil hardness of the panels.Highlights Both CNF and OMMT were chosen to achieve performance improvements A simple filling method was adopted for preparation of reinforced coating The nanocomposite films exhibited fine thermal and mechanical properties The better integrated property was obtained from the C + CNF3 + OMMT0.8 sample The physicochemical interaction of nanofiller with polymer molecule existed

Application of polyaniline/zinc oxide nanocomposites for non-enzymatic cholesterol detection: A preliminary investigation on the effect of dopants on the morphology, thermal stability, electrochemical and sensing behavior of the nanocomposites

ABSTRACT Cholesterol is a major cause for cardiovascular diseases; and therefore, timely detection of cholesterol is of paramount importance to prevent such diseases. Herein, a non-enzymatic sensor for the detection of cholesterol has been fabricated using polyaniline (PANI) and its nanocomposites (NCs) with ZnO nanoparticles (NPs). For this purpose, a series of NCs has been synthesized by varying the loading of the ZnO NPs as 2%, 3%, 5% and 8% with respect to the weight percentage of the aniline monomer. In addition, two different doping agents, namely camphor sulfonic acid (CSA) and hydrochloric acid, have been used to prepare PANI and its NCs. Electrochemical studies have revealed that as the amount of ZnO NPs increased, the capacitive behavior of the composite also increased. Similar trend was observed in case of HCl-doped polyaniline NCs. PANI/ZnO 8% NCs for both HCl and CSA dopant indicated good capacitive behavior for sensing cholesterol. The best electrode was further tested for sensitivity, and was found to exhibit a value of 0.38 mA mM−1 cm−2. The limit of detection of the prepared sensor was found to be 0.30 mM concentration in PBS buffer under the linearity range of 0.75 mM to 1.5 mM (adj. R2 = 0.97).

Mesoporous Si-WO3-supported Pt catalysts with high catalytic performance and excellent water resistance for toluene oxidation

Reducing emissions of volatile organic compounds (VOCs) is an integral part of improving the quality of the atmospheric environment. Catalytic oxidation has become an effective means of treating low and medium concentration VOCs exhausts due to its advantages in terms of removal efficiency, energy saving and environmental protection. Due to the unique inherent properties of supported precious metal catalysts, they show good catalytic efficiency in VOCs emission reduction. In this study, the mesoporous Si-WO3 support was first synthesized by the P123-assisted sol-gel method, and the xPt/Si-WO3 catalysts with the actual loadings (x = 0.19, 0.48, and 0.81 wt%) of Pt nanoparticles (NPs) were then obtained, physicochemical properties of these materials were characterized using a variety of techniques, and their catalytic activities and water resistance for the oxidation of toluene were evaluated. The results showed that Pt NPs with an average particle size of 2.3−3.3 nm were highly dispersed on the mesoporous Si-WO3 support, and the 0.81Pt/Si-WO3 sample exhibited the highest catalytic activity for toluene oxidation at a space velocity of 20,000 mL/(g h) (T50% = 167 °C and T90% = 180 °C; specific reaction rate at 160 °C = 8.54 µmol/(gPt s), turnover frequency (TOFPt) at 160 °C = 1.67 × 10−3 s−1, and apparent activation energy = 45 kJ/mol). The good catalytic performance of 0.81Pt/Si-WO3 was associated with its large surface area, well dispersed Pt NPs, high adsorbed oxygen species concentration, large toluene adsorption capacity, and strong interaction between Pt NPs and mesoporous Si-WO3. The 0.81Pt/Si-WO3 sample possessed excellent water resistance, and the introduction of 5 vol% or 10 vol% water vapor to the reaction system enhanced toluene oxidation since part of water vapor participated in the oxidation of toluene. In addition, the toluene oxidation pathway might obey the sequence of (adsorbed toluene + adsorbed oxygen species) → benzyl alcohol → (benzoic acid and benzaldehyde) → maleic anhydride → (carbon dioxide and water).

Catalytic activity of Cu2O nanoparticles supported on cellulose beads prepared by emulsion–gelation using cellulose/LiBr solution and vegetable oil

Nanocatalysts tend to aggregate and are difficult to recycle, limiting their practical applications. In this study, an environmentally friendly method was developed to produce cellulose beads for use as supporting materials for Cu-based nanocatalysts. Cellulose beads were synthesized from a water-in-oil emulsion using cellulose dissolved in an LiBr solution as the water phase and vegetable oil as the oil phase. Upon cooling, the gelation of the cellulose solution produced spherical cellulose beads, which were then oxidized to introduce surface carboxyl groups. These beads (diameter: 95–105 μm; specific surface area: 165–225 m2 g−1) have a three-dimensional network of nanofibers (width: 20–30 nm). Furthermore, the Cu2O nanoparticles were loaded onto oxidized cellulose beads before testing their catalytic activity in the reduction of 4-nitrophenol using NaBH4. The apparent reaction rate constant increased with increasing loading of Cu2O nanoparticles and the conversion efficiency was >90 %. The turnover frequency was 376.2 h−1 for the oxidized cellulose beads with the lowest Cu2O loading, indicating a higher catalytic activity compared to those of other Cu-based nanoparticle-loaded materials. In addition to their high catalytic activity, the cellulose beads are reusable and exhibit excellent stability.

Effect of loading method on catalytic performance of Pt/CeO2 system for CO oxidation

The oxygen vacancies of CeO2 play a pivotal role in effectively dispersing and stabilizing noble metal nanoparticles (NPs). During the NPs loading process, the post-treatment condition, e.g. atmosphere, has a certain influence on the oxygen vacancy concentration of CeO2, highlighting the importance of suitable choice of loading technique. Herein, A-Pt/HCeO2 and I-Pt/HCeO2 catalysts are prepared by loading Pt NPs on HCeO2 with abundant oxygen vacancies (obtained from the calcination of a Ce(OH)CO3 precursor under H2) using ALD deposition and impregnation methods, respectively. Through detailed characterization and in situ DRIFTS analysis, it was noted that compared to the I-Pt/HCeO2 catalyst, the A-Pt/HCeO2 catalyst processes a uniform distribution of Pt NPs, more Pt0 active sites and oxygen vacancies, thus exhibiting an outstanding catalytic performance for CO oxidation. The ALD deposition technique mitigates the effects of high-temperature sintering and atmospheric exposure during the loading process of noble metal NPs, offering a more accurate assessment of the catalytic performance of catalysts.

Magnetic nanoparticle loading and application of weak magnetic field to reconstruct the cake layer of coagulation-ultrafiltration process to achieve efficient antifouling: Performance and mechanism analysis

Abandoning the costly development of new membrane materials and instead directly remodeling the naturally occurring cake layer constitutes a dynamic, low-cost, long-lasting, and proactive strategy to "fight fouling with fouling". Several optimization strategies, including coagulation/modified magnetic seed loading and applying a weak magnetic force (0.01T) at the ultrafiltration end, improved the anti-fouling, retention, and sieving performances of conventional ultrafiltration process during the treatment of source water having complex natural organic matter (NOMs) and small molecule micropollutants. Two modified magnetic seeds we prepared were composite nano-seed particles (Fe3O4@SiO2-NH2 (FS) and Fe3O4@SiO2@PAMAM-NH2 (FSP)). Aim of the study was to regulate the formation of cake layer via comprehensive testing of the antifouling properties of optimized processes and related mechanistic studies. It was found to be essential to enhance the interception of xanthate and tryptophan proteins in the cake layer for improving the anti-fouling performance based on the correlation and redundancy analyses, while the use of modified magnetic seeds and magnetic field showed a significant positive impact on water production. Blockage modeling demonstrated the ability to form a mature cake layer during the initial filtration stage swiftly. This mitigated the risk of irreversible fouling caused by pore blockage during the early stage of coagulation-ultrafiltration. Morphologically, the reconstructed cake layer exhibited elevated surface porosity, an internal cavity channel structure, and enhanced roughness that can promote increased water flux and retention of water impurities. These optimized the maturity of the cake layer in both time and space. Density Functional Theory (DFT), Extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory, and Modified Extended Derjaguin-Landau-Verwey-Overbeek (MDLVO) calculations indicated aggregation behavior of matter on the cake layer to be enhanced effectively due to magnetic seed loading. This is mainly due to the strengthening of polar interactions, including hydrogen bonding, π-π* conjugation, etc., which can happen between the cake layer loaded with FSP and the organic matter. Under the influence of a magnetic field, magnetic force energy (VMF) significantly impacts the system by eliminating energy barriers. This research will provide innovative strategies for effectively purifying intricate source water through ultrafiltration while controlling membrane fouling.