Environmental Remediation Applications Research Articles

Preparation of composite based on MXene-Ti3C2 and coconutshell-derived activated carbon for desalination of brackish water

Preparation of composite based on MXene-Ti₃C₂ and coconutshell-derived activated carbon for desalination of brackish water

Defect-enabling zirconium-based metal-organic frameworks for energy and environmental remediation applications.

This comprehensive review explores the diverse applications of defective zirconium-based metal-organic frameworks (Zr-MOFs) in energy and environmental remediation. Zr-MOFs have gained significant attention due to their unique properties, and deliberate introduction of defects further enhances their functionality. The review encompasses several areas where defective Zr-MOFs exhibit promise, including environmental remediation, detoxification of chemical warfare agents, photocatalytic energy conversions, and electrochemical applications. Defects play a pivotal role by creating open sites within the framework, facilitating effective adsorption and remediation of pollutants. They also contribute to the catalytic activity of Zr-MOFs, enabling efficient energy conversion processes such as hydrogen production and CO2 reduction. The review underscores the importance of defect manipulation, including control over their distribution and type, to optimize the performance of Zr-MOFs. Through tailored defect engineering and precise selection of functional groups, researchers can enhance the selectivity and efficiency of Zr-MOFs for specific applications. Additionally, pore size manipulation influences the adsorption capacity and transport properties of Zr-MOFs, further expanding their potential in environmental remediation and energy conversion. Defective Zr-MOFs exhibit remarkable stability and synthetic versatility, making them suitable for diverse environmental conditions and allowing for the introduction of missing linkers, cluster defects, or post-synthetic modifications to precisely tailor their properties. Overall, this review highlights the promising prospects of defective Zr-MOFs in addressing energy and environmental challenges, positioning them as versatile tools for sustainable solutions and paving the way for advancements in various sectors toward a cleaner and more sustainable future.

Synergistic Engineering of Energy Band Alignment and Interfacial Electric Field Distribution over Bi-bismuth-Based Hetero-nanofibers for Boosting Visible-Light-Driven Photocatalytic Ammonia Synthesis and Antibiotic Removal.

Synergistic engineering of energy band alignment and interfacial electric field distribution is essential for photocatalyst design but is still challenging because of the limitation on refined regulation in the nanoscale. This study addresses the issue by employing surface modification and thermal-induced phase transformation in Bi2MoO6/BixOyIz hetero-nanofiber frameworks. The energy band alignment switches from a type-II interface to a Z-scheme contact with stronger redox potentials and inhibited electron traps, and the optimized built-in electric field distribution could be reached based on experimental and theoretical investigations. The engineered hetero-nanofibers exhibit outstanding visible-light-driven photocatalytic nitrogen reduction activity (605 μmol/g/h) and tetracycline hydrochloride removal rate (81.5% within 30 min), ranking them among the top-performing bismuth series materials. Furthermore, the photocatalysts show promise in activating advanced oxidants for efficient organic pollutant degradation. Moreover, the Bi2MoO6/Bi5O7I hetero-nanofibers possess good recycling stability owing to their three-dimensional network structure. This research offers valuable insights into heterojunction design for environmental remediation and industrial applications.

Gd and Ni co-doped BiFeO3 ferrite/r-GO nanocomposite for photocatalytic environmental remediation applications

Synergistic effects of the co-doping of rare earth and transition metals on the structural, electrical and optical, in multi-ferroic BiFeO3 nanoferrites (NFs) combined with reduced graphene oxide (r-GO) nanosheets, photocatalytic degradation properties can be boosted. In this current study gadolinium and nickel-co-doped Bi1-xGdxFe1-yNiyO3 were synthesised via the tartaric acid-assisted sol-gel method and their composite Bi1-xGdxFe1-yNiyO3/r-GO with 10 % reduced graphene oxide (r-GO) via the ultra-sonication route. Phase and structural investigation were carried out using x-ray diffraction (P-XRD), Raman scattering, and Fourier transform infrared (FTIR) analysis, which confirms the successful fabrication of co-doping in the rhombohedral geometry of the perovskite-type Bi1-xGdxFe1-yNiyO3. Electrical conductivity of the fabricated composite material was observed to increase because of the co-doping and the addition of r-GO. Photoluminescence (PL) spectra of co-doped and r-GO composite material exhibited a decline in PL intensity because optical bandgap energies exhibited narrowing of 1.99 eV and 1.91 eV respectively, which indicates the excellent separation and stabilization of photo-excited charge pairs. Special conduction properties of r-GO nanosheets improved electrical and optical properties, a well-porous nature, large surface area, lower bandgap, and increased dye degradation in the Bi1-xGdxFe1-yNiyO3/r-GO photocatalyst showing excellent photo-degradation of cationic malachite green (M.G.) dye, achieving a degradation efficiency of 96.4 % under natural solar light. Hence, the photocatalyst shows excellent stability where quenching of radicals using selective scavengers shows that OH* radicals and e−/h+ pairs are primarily involved in the mechanism of photo-degradation in a basic pH medium, making the as-fabricated material a potential material for photo-catalytic environmental remediation.

Enhanced Cadmium Sensing in Fertilizer Samples using Zeolite-modified Graphite Electrode

Abstract The presence of heavy metals in fertilizers poses significant environmental and health risks, necessitating robust detection methods to ensure agricultural sustainability and food safety. This study focuses on synthesizing Na-P1 zeolite from coal fly ash and fumed silica wastes, employing it as a potent modifier in graphite electrodes to enhance the electrochemical detection of cadmium(II) in fertilizer samples. Through meticulous assessment using cyclic voltammetry, square wave voltammetry, and electrochemical impedance spectroscopy, the electrochemical performance of the zeolite-modified graphite electrode was evaluated. The optimization process involved fine-tuning various parameters such as paste composition, solution pH, scan rate, and analyte concentration. Real sample analysis confirmed the applicability of the method in fertilizer samples. Notably, in an HCl medium (pH=1.0), the SWV oxidation peak of Cd(II) was observed at -0.56 V (vs. SCE) with a deposition time of 20 s and a scan rate of 75 mV∙s⁻¹. The ZGE exhibited a remarkable detection limit of 1 µM and a high sensitivity of 6.581 µA/µM.cm² within a linear detection range of 10-3-10-6 M. These findings highlight the potential utility of Na-P1 zeolite in handheld analytic device manufacturing, offering promising applications in environmental monitoring, resource management, and water and soil resource remediation.

Efficient Catalytic Elimination of Toxic Volatile Organic Compounds via Advanced Oxidation Process Wet Scrubbing with Bifunctional Cobalt Sulfide/Activated Carbon Catalysts.

Advanced oxidation process (AOP) wet scrubber is a powerful and clean technology for organic pollutant treatment but still presents great challenges in removing the highly toxic and hydrophobic volatile organic compounds (VOCs). Herein, we elaborately designed a bifunctional cobalt sulfide (CoS2)/activated carbon (AC) catalyst to activate peroxymonosulfate (PMS) for efficient toxic VOC removal in an AOP wet scrubber. By combining the excellent VOC adsorption capacity of AC with the highly efficient PMS activation activity of CoS2, CoS2/AC can rapidly capture VOCs from the gas phase to proceed with the SO4•- and HO• radical-induced oxidation reaction. More than 90% of aromatic VOCs were removed over a wide pH range (3-11) with low Co ion leaching (0.19 mg/L). The electron-rich sulfur vacancies and low-valence Co species were the main active sites for PMS activation. SO4•- was mainly responsible for the initial oxidation of VOCs, while HO• and O2 acted in the subsequent ring-opening and mineralization processes of intermediates. No gaseous intermediates from VOC oxidation were detected, and the highly toxic liquid intermediates like benzene were also greatly decreased, thus effectively reducing the health toxicity associated with byproduct emissions. This work provided a comprehensive understanding of the deep oxidation of VOCs via AOP wet scrubber, significantly accelerating its application in environmental remediation.

Modified-TiO2 Nanotube Arrays as a Proficient Photo-Catalyst Nanomaterial for Energy and Environmental Applications

Recently, TiO2 nanotube arrays (TNTAs) have attracted researcher’s attention in the fields of energy production and environmental remediation applications; this is mainly due to their unique optoelectronic characteristics, corrosion resistance, chemical and mechanical stability. In this study, the ability of employing of TiO2 nanotube arrays-based catalysts in the field of photocatalytic CO2 reduction has been investigated. Possible modification strategies have been presented for improving the TNTAs performance by using different types of nanomaterials including graphitic carbon nitrides (g-C3N4), metal-organic frame work (MOF), reduced graphene oxide (RGO) and gold nanoparticles (Au NPs). The TNTAs composites were characterized using XRD and FESEM analyses and the results revealed the successful synthesis of these composites. The TNTAs and their composites exhibited good results for the photo-conversion of CO2 into CH4 gas product. This study gives new ideas for making and developing low-cost Ti metal-based nanomaterials which can be used in the future for recycling the CO2 gas emissions into useful solar fuels.

Phase transition influenced photocatalytic dye degradation capability of pure and Eu-doped CoMoO4 polymorphic nanostructures

ABSTRACT The efficient degradation of organic dyes via photocatalysis presents a critical environmental challenge, necessitating advancements in catalyst design and performance. This study investigates the potential of pure and Eu doped CoMoO4 polymorphic nanostructures in addressing this challenge. Our primary focus is on enhancing the efficiency and stability of photocatalysts under diverse condition by performing sol–gel synthesis. Characterization techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet–visible (UV-visible) analysis and Raman analysis was employed to elucidate structural and morphological changes. Our results highlight the significant enhancement in photocatalytic activity achieved through phase transitions induced by Eu doping. This enhancement is attributed to the creation defect sites and the establishment of improved charge transfer pathways within the CoMoO4 nanostructures. By shedding light on the role of phase transition in photocatalysis, this study contributes valuable insights for the design of efficient and durable photocatalysts for environmental remediation application.

Interfacing Langmuir-Blodgett and Pickering Emulsions for the Synthesis of 2D Nanostructured Films: Applications in Copper Ion Adsorption.

This research focuses on developing a 2D thin film comprising a monolayer of silica nanoparticles functionalized with polyethyleneimine (PEI), achieved through a novel integration of Langmuir-Blodgett (L-B) and Pickering emulsion techniques. The primary aim was to create a nanostructured film that exhibits dual functionality: iridescence and efficient metal ion adsorption, specifically Cu(II) ions. The methodology combined L-B and Pickering emulsion polymerization to assemble and stabilize a nanoparticle monolayer at an oil/water interface, which was then polymerized under UV radiation to form an asymmetrically structured film. The results demonstrate that the film possesses a high adsorption efficiency for Cu(II) ions, with the enhanced mechanical durability provided by a reinforcing layer of polyvinyl alcohol/glycerol. The advantage of combining L-B and Pickering emulsion technology is the ability to generate 2D films from functional nanoparticle monolayers that are sufficiently sturdy to be deployed in applications. The 2D film's practical applications in environmental remediation were confirmed through its ability to adsorb and recover Cu(II) ions from aqueous solutions effectively. We thus demonstrate the film's potential as a versatile tool in water treatment applications owing to its combined photonic and adsorptive properties. This work paves the way for future research on the use of nanoengineered films in environmental and possibly photonic applications focusing on enhancing the film's structural robustness and exploring its broader applicability to other pollutants and metal ions.

Bio-fabrication and Characterization of Green Synthesized Nanoparticles from Commercial Honey

Green approaches to nanoparticle synthesis offer sustainable and environmentally friendly alternatives, avoiding hazardous chemicals typical in traditional methods. This study characterizes nanoparticles (NPs) synthesized from silver nitrate (AgNO3) and iron oxide (Fe2O3) using commercial honey as a reducing and capping agent. Characterization revealed significant disparities between silver NPs (AgNPs) and iron NPs (FeNPs). AgNPs had a larger particle size (Z-average: 3115.67 nm) compared to FeNPs (Z-average: 1813 nm). AgNPs showed a monodisperse population, while FeNPs had a slightly broader size distribution. Additionally, AgNPs had a higher particle concentration (mean count rate: 505.17 kcps) than FeNPs (mean count rate: 296.65 kcps). Both AgNPs and FeNPs displayed negative surface charges, at -6.499 mV and -1.652 mV, respectively, where FeNPs exhibit a slightly higher value. Elemental composition analysis by scanning electron microscope – energy dispersive X-ray (SEM-EDX) revealed that AgNPs are primarily composed of silver, carbon, and oxygen, whereas FeNPs consisted mainly of iron, oxygen, and carbon. These findings provide insights into the physical and chemical properties of AgNPs and FeNPs synthesized using commercial honey. Understanding these properties is essential for optimizing synthesis processes and exploring applications in medicine, catalysis, and environmental remediation. The eco-friendly synthesis approach using honey underscores the potential for sustainable nanomaterial production. Further research can explore specific applications and benefits of AgNPs and FeNPs synthesized through this green method, offering an efficient and economical alternative for nanoparticle synthesis.

Hydrothermally Synthesized ZnCr- and NiCr-Layered Double Hydroxides as Hydrogen Evolution Photocatalysts.

The layered double hydroxides (LDHs) of transition metals are of great interest as building blocks for the creation of composite photocatalytic materials for hydrogen production, environmental remediation and other applications. However, the synthesis of most LDHs is reported only by the conventional coprecipitation method, which makes it difficult to control the catalyst's crystallinity. In the present study, ZnCr- and NiCr-LDHs have been successfully prepared using a facile hydrothermal approach. Varying the hydrothermal synthesis conditions allowed us to obtain target products with a controllable crystallite size in the range of 2-26 nm and a specific surface area of 45-83 m2∙g-1. The LDHs synthesized were investigated as photocatalysts of hydrogen generation from aqueous methanol. It was revealed that the photocatalytic activity of ZnCr-LDH samples grows monotonically with the increase in their average crystallite size, while that of NiCr-LDH ones reaches a maximum with intermediate-sized crystallites and then decreases due to the specific surface area reduction. The concentration dependence of the hydrogen evolution activity is generally consistent with the standard Langmuir-Hinshelwood model for heterogeneous catalysis. At a methanol content of 50 mol. %, the rate of hydrogen generation over ZnCr- and NiCr-LDHs reaches 88 and 41 μmol∙h-1∙g-1, respectively. The hydrothermally synthesized LDHs with enhanced crystallinity may be of interest for further fabrication of their nanosheets being promising components of new composite photocatalysts.

Advanced oxidation processes (AOPs): Navigating from MOS to COS and X-COS systems - Unraveling strategies, tackling challenges, and pioneering advances

This article presents a significant advancement in the field of photocatalysis through the synthesis of a MSO(Metal oxide semiconductor), COS (coupled oxide semiconductor) and X-COS(doped coupled oxide semiconductor) nanocomposite systems with diverse morphologies, including nanoflowers, nanorods, nanosheets, nanotubes and spherical shapes. In this particular study, we propose a hybrid methodology that amalgamates the coupling of CuO and ZnO oxides and the doping of various elements resulting in a comprehensive study of the relationship between morphology and photocatalysis. The degradation efficiency for various pollutants, including Methylene Blue (MB), Methyl Orange (MO), Green Malachite (GM), and Rhodamine B (RhB), was systematically investigated, employing distinct degradation mechanisms. Our study reveals that X-COS materials exhibit superior surface area, heightened porosity, and elevated specific capacitance, higher light absorption while minimizing energy and surface losses (VELF and SELF), accompanied by a well-suited morphology. These distinctive structural features of X-COS contribute to its enhanced photocatalytic efficiency when compared to MOS and COS systems. Our research not only consolidates the fundamental principles governing the photocatalytic properties of materials but also unveils critical strategies for fabricating highly efficient catalysts. In conclusion, this work significantly contributes to the evolving landscape of photocatalysis, offering a nuanced understanding of the synergistic relationship between morphology and catalytic efficiency. The findings not only broaden the scope of fundamental principles but also pave the way for the development of highly effective catalytic materials with diverse morphologies for environmental remediation applications.

Modified ceramic membrane with temperature responsiveness and self-cleaning property for efficient separation and catalysis

Composite membrane that integrating catalytic degradation with membrane separation offers a promising solution for one-step treatment of complex wastewater. However, the challenge of membrane fouling by multi-component pollutants, impedes their broader applications. Herein, building on previous work, temperature responsive polymers are grafted onto a nano-Ag decorated ceramic substrate for enhanced dye removal and anti-fouling property. The grafting process is optimized in terms of reaction temperature (75 ℃), reaction time (4 h), and monomer concentration (VMDMO: 0.01 M, MATE: 0.02 M, DMAEMA: 0.04 M). The morphology of the membrane surface after each modification step is characterized by FESEM. The prepared composite membrane manifests temperature-responsive property. As the temperature rises from 20 °C to 85 °C, the pure water flux of the membrane increases from 68.8 L m-2h−1 to 434.4 L m-2h−1 (0.1 MPa), reflecting a six-fold enhancement. And this temperature response is reversible. In oil-in-dye containing water treatment, the composite membranes demonstrate an oil separation efficiency exceeding 98.0 % and a dye degradation efficiency surpassing 99.0 %. By elevating the ambient temperature, the flux recovery of the composite membrane is 91.2 %, which is much higher than that of the original membrane (58.8 %). This is ascribed to the physical configuration and wettability changes of the grafted polymers at different temperature, which facilitate the release of foulants. This study introduces a novel strategy (surface modification with temperature responsive polymer) for preparing anti-fouling ceramic composite membrane with the function of catalytic degradation of dyes. It would have potential applications in environmental remediation.

Hydrogen-bond stabilized π-π stacking in the solvent-induced dimerization of 4-nitro-1-naphthol: A spectroscopic and computational investigation

π-π Stacking is crucial for stabilizing molecular structures and facilitating interactions in biological systems and chemical processes. The presence of electron-withdrawing and electron-donating substituents, particularly the hydroxyl group, significantly influences the energetics and energetically favorable configurations of π-stacked complexes. In this study, we utilized UV–Vis absorption and resonance Raman spectroscopies, alongside density functional theory (DFT) calculations, to investigate the competition between dissociation and self-aggregation of 4-nitro-1-naphthol (NNH) in various polar solvents. Our results demonstrate the self-aggregation of NNH in polar solvents and identify the most likely dimer configuration, which is antiparallel π-stacked and stabilized by hydrogen bonds between hydroxyl and nitro groups. Given its broad applications in mass spectrometry, environmental remediation, and aerosol tracking, a comprehensive understanding of the molecular interactions and structural properties of NNH is essential for its effective use in various scientific fields.

Aqueous CuS nanocrystals via a flow synthesis approach

AbstractAqueous synthesis of covellite CuS nanoparticles holds significant importance in the field of nanomaterials and environmental sustainability. Using water as a solvent and reactant in the synthesis process aligns with green chemistry principles. It enhances nanoparticle production's scalability and safety. CuS nanoparticles have gained attention for their diverse applications in catalysis, energy storage, and environmental remediation. Aqueous synthesis reduces the environmental footprint associated with hazardous organic solvents, making it an eco‐friendly approach. We report on synthesis routes toward covellite CuS nanocrystals (NCs), emphasizing easy and fast synthesis techniques. Additionally, we develop a flow synthesis of small near infrared active CuS NCs in a custom‐made flow reactor. Combining the advantages of aqueous synthesis and flow chemistry yields a robust and sustainable method for producing covellite CuS NCs readily dispersible in water medium, paving the way for their widespread application in diverse fields.

Dual-Catalysts-Embedded spontaneously propelling asymmetric micromotors using triple emulsion microfluidic synthesis for highly efficient nano/microplastic removal

Plastics, which are pivotal in modern technological progress and have a broad range of applications, now pose a significant environmental and health risk globally. Despite their detrimental environmental effects, there is a lack in research on effective plastic removal and treatment strategies. Addressing this urgent issue necessitates the development of innovative and efficient materials and methods for removing plastics from contaminated environments. In this study, we utilized a microfluidic technique to create novel and eco-friendly asymmetrically structured micromotors made of glucose oxidase (GOx)/catalase (Cat) embedded in polyethylene glycol diacrylate (PEGDA). These micromotors are specifically engineered to efficiently remove substantial amounts of plastics from ecosystems. The microfluidic process enabled the production of micromotors with uniform yet asymmetric shapes through aqueous two-phase separation and UV polymerization. By incorporating functional nanomaterials, these micromotors can be customized for specific wastewater treatment needs. Our design utilizes GOx and Cat to consume glucose as fuel, generating oxygen microbubbles. These bubbles not only propel the micromotors but also capture suspended plastic nano/micro-particles, effectively removing them from aquatic environments. The high surface tension of the bubbles allows for the entrapment of plastics at their interface, facilitating their removal from the water. In addition, non-toxic nature of these GOx/Cat PEGDA micromotors makes them especially suitable for environmental remediation and biological applications, addressing the urgent need for environmentally benign solutions to plastic pollution.

Strategic Ni integration to study its impact on the photoluminescence and photocatalytic performances of SnO2 nanorod architecture

The sol-gel process was utilized to fabricate SnO2 nanoparticles, both in their pure form and with the addition of Ni dopants. The nanoparticles obtained were further examined to ascertain the characteristics associated with their structure, alterations in band gap, and photocatalytic performance. The insertion of nickel ions into tin sites hinders the formation of grain growth in tin oxide. The variation in the valence states and ionic radius of Sn4+ and Ni2+ ions, as revealed by X-ray diffraction (XRD) study, accounts for this disparity. FTIR measurements indicate the existence of stretching vibrations of metal-oxygen bonds that include Ni ions in the doped samples. The photoluminescence (PL) analysis reveals that the introduction of nickel doping alters the band structure of SnO2, leading to the creation of additional defect states, such as oxygen vacancies inside the crystal lattice. A study was undertaken to investigate the photocatalytic (PC) activity of SnO2 in the presence of Ni dopants. The results revealed a noticeable improvement in the efficiency of photodegradation. The degradation of Congo red (CR) dye using Ni-SnO2 nanocrystals achieves an efficiency of 94.88 % within a duration of 180 minutes. An analysis has been conducted on the impact of dye content, photocatalyst dosage, and pH on the degradation efficiency. As per the study, lower dose of Ni-SnO2 has shown better degradation efficiency in comparison to other studies. The improved performance of Ni-SnO2 can be ascribed to two main factors: the inhibition of carrier recombination due to the inclusion of defective states, and the production of hydroxyl radicals (OH•). The stability and reusability of these photocatalysts have been noted in their efficient application for environmental remediation.

Emerging trends of ferrite-based nanomaterials as photocatalysts for environmental remediation: A review and synthetic perspective

Efficient wastewater treatment processes are in high demand for removing organic and inorganic pollutants. Photocatalysis, as an environmentally friendly technology, has shown significant progress in the treatment of contaminated wastewater. This review explores the potential of spinel ferrite-based nanomaterials as efficient photocatalysts for wastewater treatment. To enhance their properties, ferrites have been combined with advanced materials, such as BiOX, MXene, and g-C3N4 to form binary and ternary nanocomposites. We highlight the state-of-the-art in these binary and ternary spinel ferrite nanocomposites in the photocatalytic degradation of organic pollutants. These ferrite nanocomposites showed superior photocatalytic performance due to enhanced properties such as increasing the capacity for light utilization, slowing electron-hole recombination, and reducing agglomeration. Furthermore, our review explores recent research on template-assisted synthesis, a novel approach for fine-tuning the morphology of spinel ferrites and enhancing their catalytic efficiency. The impact of both the soft and hard templates on the properties of the produced ferrite nanomaterials is discussed. Overall, this unique combination of advanced nanocomposite materials and structural control using template-assisted approaches paves the way for a new generation of highly efficient photocatalysts. Thus, we provide a comprehensive overview of recent advances in the development of ferrite nanocomposites, underlining their potential as photocatalysts for environmental remediation applications.

Multi-functional copper oxide nanoparticles synthesized using Lagerstroemia indica leaf extracts and their applications

Developing multifunctional nanomaterials through environmentally friendly and efficient approaches is a pivotal focus in nanotechnology. This study aimed to employ a biogenic method to synthesize multifunctional copper oxide nanoparticles (LI-CuO NPs) with diverse capabilities, including antibacterial, antioxidant, and seed priming properties, as well as photocatalytic organic dye degradation and wastewater treatment potentials using Lagerstroemia indica leaf extract. The synthesized LI-CuO NPs were extensively characterized using UV–vis spectroscopy, dynamic light scattering (DLS), X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Fourier transform-infrared spectroscopy (FT-IR). The colloid displayed surface plasmon resonance peaks at 320 nm, characteristic of LI-CuO NPs. DLS analysis revealed an average particle size of 93.5 nm and a negative zeta potential of −20.3 mV. FTIR and XPS analyses demonstrated that LI-CuO NPs possessed abundant functional groups that acted as stabilizing agents. XRD analysis indicated pure crystalline and spherical LI-CuO NPs measuring 36 nm in size. Antibacterial tests exhibited significant differential activity of LI-CuO NPs against both gram-negative (Escherichia coli, Salmonella typhimurium) and gram-positive (Staphylococcus aureus and Listeria monocytogenes) bacteria. In antioxidant tests, the LI-CuO NPs demonstrated a remarkable radical scavenging activity of 97.6 % at a concentration of 400 μg mL−1. These nanoparticles were also found to enhance mustard seed germination at low concentrations. With a remarkable reusability, LI-CuO NPs exhibited excellent photocatalytic performance, with a degradation efficiency of 97.6 % at 150 μg/mL as well as a 95.6 % reduction in turbidity when applied to wastewater treatment. In conclusion, this study presents environmentally friendly method for the facile synthesis of LI-CuO NPs that could potentially offer promising applications in biomedicine, agriculture, and environmental remediation due to their multifunctional properties.

Synergistic reduction of nitrophenols by Au-CDs nanoconjugates with NaBH4

Developing sustainable and innovative approaches for the efficient reduction of nitrophenols is crucial for environmental remediation, for managing health concerns posed by their widespread presence as hazardous pollutants in industrial effluents and contaminated water. We report the use of 12.9 ± 1 nm (TEM data) sized gold carbon dot nanoconjugates (Au@CDs) for catalytic conversion of o, m, p-nitrophenols to aminophenols by sodium borohydride. A simple approach was followed to synthesize ultra-small and highly stable Au@CDs, using citric acid and PEG as reducing and stabilizing agents. X-ray diffraction analysis verified the formation of nano-crystalline nanoconjugates. These nanoconjugates showed a remarkable catalytic activity in the range of 0.22–0.33 s−1 (varying with nanoconjugate concentration) which was much higher compared to conventional chemical methods of reduction. All the catalytic reaction experiments were performed at room temperature (27 ± 2 °C). Furthermore, an increase in rate constant was observed with increasing concentration of nanoconjugates. The catalytic activity of Au@CDs nanoconjugates was observed to be in order of m-nitrophenol > o-nitrophenol > p-nitrophenol with apparent rate constant (k aap) values of 0.068, 0.043 and 0.031, respectively. Comparative analysis with GNPs, CDs and Au@CDs nanoconjugates stated that the nanoconjugates had superior catalytic activity. The research can have significant implications in the development of new strategies for environmental remediation and biomedical applications.