Nanomaterials For Environmental Remediation Research Articles

Green synthesis of Mn3O4@CoO nanocomposites using Rosmarinus officinalis L. extract for enhanced photocatalytic hydrogen production and CO2 conversion

In response to the urgent need for sustainable environmental remediation technologies and clean energy production, this study introduces an eco-friendly synthesized Mn3O4@CoO nanocomposite (MCNC) leveraging the natural reducing capabilities of Rosmarinus officinalis leaves (L.) extract. Focused on the hydrogen evolution reaction (HER) and CO2 methanation, our findings reveal significant enhancements in photocatalytic activity and CO2 methanation efficiency. The MCNC exhibited a promising hydrogen production rate of up to 823 μmol g−1 h−1 and a CO2 conversion efficiency exceeding 84 % under optimal conditions. The investigation highlights the synergistic interfacial effect between Mn3O4 and CoO, contributing to notable performance improvements. Additionally, the study explores the role of catalyst quantity in optimizing reaction efficiencies, presenting a scalable and environmentally benign approach to address global energy and environmental challenges. The apparent quantum efficiency (AQE%) was calculated to be 1.92, 2.39, 2.73, 3.21, 3.44, and 3.56 % for mass values of 15, 25, 35, 45, 55, and 65 mg, respectively. Furthermore, the CO2 methanation also shows a rise with the increase in catalyst quantity. A mass of 0.35 mg achieved a remarkable CO2 conversion efficiency of 71.9 %, while its 0.5 mg counterpart showcased an even more striking CO2 conversion efficiency of 84.4 %. The green synthesis method, characterized by its low energy requirement and the absence of toxic chemicals, aligns with the sustainable practices sought in environmental chemistry and nanotechnology. This work not only opens new avenues for developing efficient photocatalysts but also contributes to the broader application of green synthesized nanomaterials in environmental remediation and clean energy generation.

Environmental significance of the interaction between titanium dioxides and soil solutions

Nanotechnology, especially in the field of photocatalysis, has witnessed rapid advancements, with titanium dioxide being one of the most widely used photocatalysts. As the use of products containing photoactive nanomaterials increases, concerns have arisen regarding their potential release into the environment over time. This release can impact soil, groundwater, and surrounding ecosystems, resulting in nanoparticles being dispersed in water and eventually depleted from the system. This study aimed to investigate how different soil solutions affect the structural, textural properties, and photocatalytic activity of titanium dioxide-based, commercial reference Evonik Aeroxide P25. The Regosol soil solution, characterized by acidic pH, low ionic content, and high organic matter content, induced nanoparticle aggregation and bandgap changes. In addition, the acidic pH hindered the adsorption process, potentially affecting the photocatalytic processes. In contrast, the Chernozem soil solution, with slightly alkaline pH, high ionic content, and low organic matter content, did not significantly alter the morphology or structure of the material. However, various organic compounds were absorbed on the surface, reducing the availability of active sites. The study highlights the importance of understanding the influence of soil solutions on nanomaterials, as it impacts their properties and environmental risks. Results show that the material is still activated, i.e., it can exert its photoactive effect on the environment. This sheds light on the challenges posed by nanoparticles in soil, particularly in terms of their toxicity and consequences for the surrounding ecosystems. The study underlines the need for further research in this area to assess potential risks and optimise the use of nanomaterials in environmental remediation.

Green synthesis of TiO2-Al2O3-ZnFe2O4 nanocomposite using the Hibiscus rosa sinesis and evaluation of its photocatalytic applications

Use of the green approach for the synthesis of nanoparticles has gained significant interest in the field of nanotechnology. The applicability of greener nanomaterials in environmental remediation has unveiled their tremendous properties and potentiality to eradicate the pollutants from nature in ecofriendly manner. In the present paper, we proposed synthesis of TiO2-Al2O3-ZnFe2O4 nanocomposites using flower extract of Hibiscus rosa sinesis via hydrothermal approach. The synthesized product was characterized by several optical and morphological techniques i.e. Field emission scanning electron microscope, X ray diffraction, energy dispersive spectroscopy, Fourier transform infrared spectroscopy and Brunauer Emmett Teller. To conclude, Field emission scanning electron microscope reveals the nanostructures are of 40-130 nm size. X ray diffraction reveals the presence of rutile TiO2 and hexagonal Al2O3 along with ZnFe2O4 crystallites. Barrett-Joyner-Halenda model reveals that the pore volume and pore diameter were found to be 38.206 m2/g, 0.048 cc/g and 3.640 nm, respectively. TiO2-Al2O3-ZnFe2O4 have shown photocatalytic degradation of methylene blue (96.54 ± 1.24%.), industrial sample (88.52 ± 0.64), and heavy metal hexavalent chromium (94.7 ± 3.20%) in the presence of sunlight. Besides, the synthesized product exhibited good antioxidant properties (84 ± 2.1%) against 2,2-diphenyl-1-picrylhydrazyl.

Nanoscale Solutions: The Transformative Applications of Functionalized Nanomaterials in Environmental Remediation

Environmental pollution has become a pervasive and pressing issue in the modern world, mainly arising from human activities that release harmful substances into the air, water, and soil [...]

Nanomaterials for Environmental Remediation: Mechanisms and Efficiency

Nanomaterials have emerged as promising tools for environmental remediation due to their unique physicochemical properties, such as high surface area, enhanced reactivity, and tunable functionalities. This paper reviews the mechanisms through which nanomaterials address environmental pollutants and assesses their efficiency across various remediation processes. The study focuses on metal oxide nanoparticles, carbon-based nanomaterials, and polymeric nanomaterials. Results demonstrate that nanomaterials can significantly enhance the removal of heavy metals, organic pollutants, and pathogens from contaminated water and soil. Mechanistic insights into adsorption, redox reactions, photocatalysis, and antimicrobial actions are explored, along with a discussion on the challenges of scalability and potential environmental risks.

Nanomaterials as endorsed environmental remediation tools for the next generation: Eco-safety and sustainability

The increased peril of various environmental pollutants causing enormous damage to the environment and human beings has raised red flags worldwide. Despite the numerous attempts that are daily made to reduce the amounts of hazardous substances, still there is a need for urgent action toward finding successful solutions for pollutant removal. Therefore, we are witnessing that environmental safety is nowadays a prime global concern and challenge. In that light, nano-remediation is attracting increasing attention as a cutting-edge technology that has the potential to revolutionize the way of managing and remediating hazardous waste and environmental contamination with the potential of addressing environmental problems. However, despite numerous reports on the application of nanomaterials in environmental remediation, there are still many gaps in deciphering the mode of action, eco-safety, and sustainability of various nanomaterials for long-term application. Therefore, this review summarizes the current status of bio-based nanoparticles, and their synthesis over the last decade, from classical to modern innovative ways, where more research attention has been drawn toward environmentally friendly materials and the most recent trends in green direction for their fabrication. Further, it provides a comprehensive discussion to present insights into the state of the art of green-synthesized nanoparticles and emphasizes the key issues in their advantages over the traditional methods and potential obstacles and constraints for their implementation in cleaning up contaminated sites. Lastly, this review points to key steps that should advance current trends and enable further development in boosting the power of nanotechnology for a long-term and sustainable application in environmental remediation.

FexSey@C superlattice nanocrystals for peroxymonosulfate activation: Intrinsic nature of Fe spin state

Two-dimensional layered carbon-coated FexSey nanocrystal superlattices with different crystalline structure (2D FexSey@C NS) are prepared and tested in Fenton-like reaction via PMS activation. The intrinsic nature and properties that govern the activity of 2D FexSey@C NS are deeply elucidated. Experimental analysis and theoretical calculations indicated that the spin state of Fe strongly decided the catalytic activity of 2D FexSey@C NS, and that a high spin state of Fe (4.16 μB) with a large effective magnetic moment not only regulated PMS adsorption (−3.06 eV) for increasing electronic density (0.79 e), but also accelerated interfacial charge transfer for HSO5− decomposition to produce SO4•−. Therefore, among 2D FexSey@C NS, 2D FeSe2 @C NS exhibited the most active performance in PMS activation with brilliant durability and adaptability. The study illustrates a new application of superlattice nanomaterials in environmental remediation and supplies fundamental insight to the intrinsic chemical structure of Fe-based catalysts for PMS activation.

Nonradical pathway dominated activation of peroxymonosulfate by ZnFe2O4/C composites to eliminate tetracycline hydrochloride: Insight into the cycle of Zn/Fe and electron transfer

Magnetic ZnFe2O4 nanoparticles show promising as heterogeneous catalysts in peroxymonosulfate (PMS) activation because of their ease of separation and good reusability. However, the low catalytic activity and easy agglomeration in clusters or clumps limit the application of ZnFe2O4 nanoparticles. Herein, ZnFe2O4 nanoparticles embedding into carbon substrate are prepared. Owing to the anchoring effect of carbon substrate and the improved electron transfer for ZnFe2O4 nanoparticles, the as-prepared magnetic ZnFe2O4/C composites exhibit efficiently catalytic activity in PMS activation, in which 92.0% of tetracycline hydrochloride (TC) can be eliminated. Moreover, the composites show a wide pH adaptation range (3.04–10.99) and good stability. The catalytic oxidation of TC is mainly based on the nonradical pathways, including contributions of 1O2 and electron transport. The high performance of ZnFe2O4/C in PMS activation is mainly attributed to the accelerated redox cycles of Fe3+/Fe2+ and Zn2+/Zn+ and the improved electron transfer. Three possible TC degradation pathways were proposed, and the biotoxicity assessment results further confirm the high efficiency of the ZnFe2O4/C/PMS system. This work provides a simple strategy for the preparation of magnetic ZnFe2O4/C heterogeneous catalyst and a new insight into PMS activation, which promotes the application of spinel nanomaterials in environmental remediation.

Insights into the Photoelectrocatalytic Behavior of gCN-Based Anode Materials Supported on Ni Foams.

Graphitic carbon nitride (gCN) is a promising n-type semiconductor widely investigated for photo-assisted water splitting, but less studied for the (photo)electrochemical degradation of aqueous organic pollutants. In these fields, attractive perspectives for advancements are offered by a proper engineering of the material properties, e.g., by depositing gCN onto conductive and porous scaffolds, tailoring its nanoscale morphology, and functionalizing it with suitable cocatalysts. The present study reports on a simple and easily controllable synthesis of gCN flakes on Ni foam substrates by electrophoretic deposition (EPD), and on their eventual decoration with Co-based cocatalysts [CoO, CoFe2O4, cobalt phosphate (CoPi)] via radio frequency (RF)-sputtering or electrodeposition. After examining the influence of processing conditions on the material characteristics, the developed systems are comparatively investigated as (photo)anodes for water splitting and photoelectrocatalysts for the degradation of a recalcitrant water pollutant [potassium hydrogen phthalate (KHP)]. The obtained results highlight that while gCN decoration with Co-based cocatalysts boosts water splitting performances, bare gCN as such is more efficient in KHP abatement, due to the occurrence of a different reaction mechanism. The related insights, provided by a multi-technique characterization, may provide valuable guidelines for the implementation of active nanomaterials in environmental remediation and sustainable solar-to-chemical energy conversion.

Spherical covalent organic frameworks supported black phosphorus@Au nanocatalysts for nitrophenol hydrogenation in a high efficiently flow-through process

Exfoliated black phosphorus (BP) nanosheets possessing unique electron-reservoir and electron-donor properties could fast electron transfer, promising as a cocatalyst for catalysis. However, the catalytic process was limited by the morphology of BP nanosheets because the continuous pressure deriving from the effluent would dense the channel of stacked BP nanosheets. In this work, spherical covalent organic frameworks were synthesized and used as a platform to support BP nanosheets/Au nanocatalysts. The prepared heterostructure was applied to catalytic reduction of 4-nitrophenol under a flow-through catalytic process. An optimized permeation flux of 2500 L/m−2(−|-)h−1 (LMH)and a reduction efficiency of99 % was achieved. Furthermore, only 0.064 wt% of Au NPs was released after testing for 24 h. Our straightforward strategy to solve the issues suffering from the continuous treatment of effluent would facilitate the application of novel nanomaterials in environmental remediation.

Heavy metal pollution and the role of inorganic nanomaterials in environmental remediation.

Contamination of water and soil with toxic heavy metals is a major threat to human health. Although extensive work has been performed on reporting heavy metal pollutions globally, there are limited review articles on addressing this pernicious phenomenon. This paper reviews inorganic nanoparticles and provides a framework for their qualities required as good nanoadsorbents for efficient removal of heavy metals from water. Different inorganic nanoparticles including metals, metal oxides and metal sulfides nanoparticles have been applied as nanoadsorbents to successfully treat water with high contaminations of heavy metals at concentrations greater than 100 mg l−1, achieving high adsorption capacities up to 3449 mg g−1. It has been identified that the synthesis method, selectivity, stability, regeneration and reusability, and adsorbent separation from solution are critical parameters in deciding on the quality of inorganic nanoadsorbents. Surface functionalized nanoadsorbents were found to possess high selectivity and capacity for heavy metals removal from water even at a very low adsorbent dosage of less than 2 g l−1, which makes them better than conventional adsorbents in environmental remediation.

Applications of Nanomaterials for Heavy Metal Removal from Water and Soil: A Review

Heavy metals are toxic and non-biodegradable environmental contaminants that seriously threaten human health. The remediation of heavy metal-contaminated water and soil is an urgent issue from both environmental and biological points of view. Recently, nanomaterials with excellent adsorption capacities, great chemical reactivity, active atomicity, and environmentally friendly performance have attracted widespread interest as potential adsorbents for heavy metal removal. This review first introduces the application of nanomaterials for removing heavy metal ions from the environment. Then, the environmental factors affecting the adsorption of nanomaterials, their toxicity, and environmental risks are discussed. Finally, the challenges and opportunities of applying nanomaterials in environmental remediation are discussed, which can provide perspectives for future in-depth studies and applications.

Environmentally Sustainable and Ecosafe Polysaccharide-Based Materials for Water Nano-Treatment: An Eco-Design Study.

Nanoremediation, which is the use of nanoparticles and nanomaterials for environmental remediation, is widely explored and proposed for preservation of ecosystems that suffer from the increase in human population, pollution, and urbanization. We herein report a critical analysis of nanotechnologies for water remediation by assessing their sustainability in terms of efficient removal of pollutants, appropriate methods for monitoring their effectiveness, and protocols for the evaluation of any potential environmental risks. Our purpose is to furnish fruitful guidelines for sustainable water management, able to promote nanoremediation also at European level. In this context, we describe new nanostructured polysaccharide-based materials obtained from renewable resources as alternative efficient and ecosafe solutions for water nano-treatment. We also provide eco-design indications to improve the sustainability of the production of these materials, based on life-cycle assessment methodology.

Graphitic Carbon Nitride-Based Heterojunction Photoactive Nanocomposites: Applications and Mechanism Insight.

The design of heterojunction with superior performance of light absorption and appropriate conduction band and valence band potentials is a promising approach for the applications in efficient environmental remediation and the solar energy storage. In recent years, many studies have been devoted to the applications of graphitic carbon nitride (g-C3N4)-based heterojunction photoactive nanomaterials under visible light irradiation due to its excellent physical, optical, and electrical properties, which inspired us to compile this review. Although many reviews demonstrated about the syntheses and applications of g-C3N4 composites, a targeted review on the systematic application and photocatalytic mechanisms of g-C3N4-based heterojunction, in which components are in intimate linkage with each other rather than a physical mixture, is still absent. In this review, the applications of g-C3N4-based heterojunction photoactive nanomaterials in environmental remediation and solar energy storage, such as photocatalytic treatment of persistent organic pollutants, heavy-metal-ion redox, oxidative decomposition of pathogens, water splitting for H2 evolution, and CO2 reduction, are systematically discussed. In addition, some emerging applications, such as solar cells and biosensors, are also introduced. Meanwhile, a comprehensive assessment on the basis of first-principles calculations and the thermodynamics and kinetics of surface catalytic reaction for the electronic structure and photocatalytic properties of g-C3N4-based heterojunction are valued by this review. In the end, a brief summary and perspectives in designing practical heterojunction photoactive nanomaterials also showed the bright future of g-C3N4-based heterojunction. Altogether, this review systematically complements the information that previous reviews have frequently ignored and points out the future development trends of g-C3N4-based heterojunction, which expected to provide important references and right directions for the development and practical applications of g-C3N4-based heterojunction photoactive nanomaterials.

Development of adsorption and electrosorption techniques for removal of organic and inorganic pollutants from wastewater using novel magnetite/porous graphene-based nanocomposites

Abstract Herein, we report a new synthesis route for generating porous on graphene with a scalable and controllable size of micron to submicron through the successive insertion of potassium atoms into interlayers of graphite at low temperature. Comprehensive studies such as physico-chemical analysis confirm that the as-obtained porous graphene has few layers with fewer defects. Further, the magnetically separable magnetite (Fe 3 O 4 )/porous graphene nanocomposites were synthesized through a facile, cost-effective hydrothermal process. The as-prepared nanocomposites were characterized by different analytical techniques. In the nanocomposites, superparamagnetic Fe 3 O 4 nanoparticles with an average size of 30 nm nanoparticles uniformly dispersed on the porous graphene sheets, and they acted as mutual spacers in the nanocomposites to avoid aggregation of the magnetic nanoparticles and restacking of the porous graphene layers. In addition, Fe 3 O 4 /porous graphene nanocomposites possessed high adsorption capacities of dyes and heavy weight metal ions from wastewater. An organic dye methyl violet was used as an adsorbate for investigating the adsorption characteristics of the Fe 3 O 4 /porous graphene nanocomposites. Fe 3 O 4 /porous graphene exhibited rapid adsorption (5 min), high adsorption capacity (Q o -460 mg/g), easy separation and reuse owing to the high specific surface area with porous nature of graphene and high magnetic property of Fe 3 O 4 nanoparticles. Also, the nanocomposite used as an ultrahigh performance of novel capacitive deionization electrodes (CDI) for removal of Pb 2+ and Cu 2+ ions at constant applied potential 1.2 V and constant flow rate 4 ml/min. The results indicate that the Fe 3 O 4 /graphene nanocomposites exhibit an ultrahigh electrosorption for Pb 2+ , Cu 2+ and Cd 2+ ions. The progress made so far will guide further development of graphene based nanostructures with porous and exploration of such porous nanomaterials in environmental remediation toward removal of organic and inorganic contaminants.

<I>A Special Issue on</I> Functional Nanomaterials for Environmental Remediation

<I>A Special Issue on</I> Functional Nanomaterials for Environmental Remediation

Applications of hollow nanomaterials in environmental remediation and monitoring: A review

Hollow nanomaterials have attracted significant attention because of their high chemical and thermal stability, high specific surface area, high porosity, low density, and good biocompatibility. These state-of-the-art nanomaterials have been shown to efficiently adsorb heavy metals, and volatile hazardous substances, photodegrade persistent organic pollutants, and other compounds, and inactivate bacteria. Such properties have enabled the use of these materials for environmental remediation, such as in water/wastewater treatment, soil remediation, air purification, and substance monitoring, etc. Hollow nanomaterials showed higher photocatalytic activity than those without hollow structure owing to their high active surface area, reduced diffusion resistance, and improved accessibility. And, the Doping method could improve the photocatalytic performance of hollow nanomaterials further under visible light. Moreover, the synthetic mechanisms and methods of these materials are important because their size and morphology help to determine their precise properties. This article reviews the environmental applications and potential risks of these materials, in addition to their syntheses. Finally, an outlook into the development of these materials is provided.

Swift Adsorptive Removal of Congo Red from Aqueous Solution by K<SUB>1.33</SUB>Mn<SUB>8</SUB>O<SUB>16</SUB> Nanowires

A swift and efficient approach to converting organic dye effluents into fresh water could be of substantial benefit. In this study, we presented facile hydrothermal synthesis of K1.33Mn8O16 nanowires in ammonium fluoride (NH4F) aqueous solution. The crystallization process of K1.33Mn8O16 nanowires was investigated. The as-obtained K1.33Mn8O16 nanowires were used for swift adsorptive removal of Congo red from aqueous solution without adjusting pH value at room temperature. Adsorption kinetic experimental data are well described by pseudo-second-order rate kinetic model, and the adsorption isotherm fits Langmuir isotherm model. The present investigation provides an efficient approach to designing and fabricating manganese-based nanomaterials for environmental remediation.

Research Progress on the Applications of Iron-containing Nanomaterials in Environmental Remediation

ince nanoscale iron particles and iron-containing nanomaterias are very effective for the transformation and detoxification of a wide variety of common environmental contaminants such as toxic metal ions,halogenated organic compounds and so on,they have been under active research in the field of environment remediation.Due to their large surface areas,high surface reactivity and application flexibility,they provide effective solutions to some of the most challenging environmental cleanup problems.In this paper,the progress of iron-containing nanomaterials and its various applications for recent years were summarized.Meanwhile,their potential microbial toxicity was also assessed,which can be a guide for further study in this research field.

A review on nanomaterials for environmental remediation

This article gives an overview of the application of nanomaterials in environmental remediation. In the area of environmental remediation, nanomaterials offer the potential for the efficient removal of pollutants and biological contaminants. Nanomaterials in various shapes/morphologies, such as nanoparticles, tubes, wires, fibres etc., function as adsorbents and catalysts and their composites with polymers are used for the detection and removal of gases (SO2, CO, NOx, etc.), contaminated chemicals (arsenic, iron, manganese, nitrate, heavy metals, etc.), organic pollutants (aliphatic and aromatic hydrocarbons) and biological substances, such as viruses, bacteria, parasites and antibiotics. Nanomaterials show a better performance in environmental remediation than other conventional techniques because of their high surface area (surface-to-volume ratio) and their associated high reactivity. Recent advances in the fabrication of novel nanoscale materials and processes for the treatment of drinking water and industrial waste water contaminated by toxic metal ions, radionuclides, organic and inorganic solutes, bacteria and viruses and the treatment of air are highlighted. In addition, recent advances in the application of polymer nanocomposite materials for the treatment of contaminants and the monitoring of pollutants are also discussed. Furthermore, the research trends and future prospects are briefly discussed.