Recent Advances in Applied Science and Engineering: Non-Fictional, #1

By DR. ANKITA SAINI and DR. SUNIL KUMAR SAINI

"Recent Advances in Applied Science and Engineering" represents a thorough and state-of-the-art exploration of the most recent developments across various disciplines within the fields of applied science and engineering. Each chapter provides in-depth analyses of emerging technologies, methodologies, and discoveries, emphasizing the practical applications of these advancements to address real-world challenges. Furthermore, the book not only showcases recent achievements but also engages in discussions about potential future directions and challenges in applied science and engineering. This forward-looking approach offers readers a roadmap for upcoming research areas and opportunities for innovation. Serving as an indispensable resource, this book provides a comprehensive overview of the latest developments in these rapidly evolving fields. Whether a researcher or student, readers will find this book to be a valuable reference for staying informed about the most recent advancements shaping the future of applied science and engineering.

• Language: English
• Publisher: Writers Corner
• Release date: Feb 14, 2024
• ISBN: 9798879459364

Book preview

CHAPTER 1

2D Boron Nitride: Revolutionizing Water Purification through Applied Science and Engineering

Neeraja S M ¹*, B. Bindhu ²

¹*Research Scholar, Department of Physics, Noorul Islam Centre for Higher Education,Kumaracoil,Thuckalay, Kanyakumari district, Tamil Nadu, India-629180.

²Dean of Faculty of Science and Humanities, Professor & Head of Department, Department of Physics, Noorul Islam Centre for Higher Education, Kumaracoil, Thuckalay, Kanyakumari district, Tamil Nadu, India-629180.

Corresponding author*: [e-mail]

ABSTRACT

Boron nitride (BN), a versatile and promising material in the realm of advanced materials science and engineering, has recently gained considerable attention for its application in water purification. Recent research highlights the exceptional adsorption capabilities of h-BN materials in the removal of a wide range of organic pollutants from water. The unique structural features and high surface area of h-BN provide an ideal platform for attracting and retaining organic contaminants effectively. The abundant boron and nitrogen sites on its surface provide active binding sites for contaminants, enhancing its adsorption efficiency. 2D BN is increasingly being incorporated into membranes used in water purification. These membranes, marked by their high chemical stability and adjustable porosity, enable precise control over permeability, making them essential in desalination and filtration processes. Advancements in modifying the surface chemistry of h-BN enable the selective adsorption of specific organic pollutants. Through surface functionalization and engineering, researchers can tailor h-BN materials to target particular contaminants, enhancing their removal efficiency. The use of h-BN materials in organic pollutant removal offers sustainable and cost-effective solutions for water treatment. Their efficiency in adsorption processes, combined with their potential for regeneration and reuse, contributes to the development of eco-friendly water purification technologies. The environmental impact of utilizing h-BN materials in water treatment is an ongoing area of research. Efforts are being made to ensure that the production and disposal of h-BN materials align with sustainable and responsible practices.

Keywords—Membrane filtration, Heavy metal removal, Boron nitride, water purification, Two dimensional materials 

I. INTRODUCTION

In the face of growing concerns over water scarcity and pollution, the development of innovative and sustainable water treatment technologies has become paramount. Among the promising advancements in this field, two-dimensional (2D) materials have emerged as a transformative force, offering a unique set of properties that hold immense potential for revolutionizing water treatment practices. 2D materials are characterized by their single-atom thickness, akin to a sheet of paper. This atomically thin structure endows them with exceptional properties, including an extraordinarily high ratio of surface area to volume, remarkable mechanical strength, and tunable electronic and optical properties [1]. These properties make them ideal candidates for various water treatment applications. 2D materials can be incorporated into membranes to enhance their filtration efficiency and selectivity. Their large surface area allows for effective removal of contaminants, while their adjustable pore size enables precise filtration. Because of their extensive surface area and tunable surface chemistry, 2D materials can effectively adsorb diverse array of contaminants from water, including heavy metals, organic pollutants, and pharmaceuticals. 2D materials, particularly transition metal dichalcogenides (TMDs) and graphitic carbon nitride (g-C3N4), exhibit photo catalytic activity enabling them to break down and degrade organic pollutants under light irradiation [2]. 2D materials, such as MXenes and silver nanoparticles, possess antimicrobial properties, making them effective in disinfecting water and eliminating harmful microorganisms. Among the various 2D materials, graphene, a single layer of carbon atoms, has received considerable focus because of its exceptional properties, such as high surface area, excellent electrical conductivity, and chemical stability. Graphene oxide (GO), a derivative of graphene with enhanced hydrophilicity, is also widely explored for water treatment applications. In addition to graphene, MoS2 exhibits photo catalytic activity and can be used to degrade organic pollutants [3]. Hexagonal boron nitride (h-BN): h-BN possesses excellent thermal conductivity and can be used for membrane filtration and desalination. MXenes belong to a category of 2D materials with high surface area and tunable surface chemistry, making them suitable for adsorption and catalysis. Black phosphorus: Black phosphorus exhibits photo catalytic activity and can be used to degrade organic pollutants and produce hydrogen fuel from water.

The utilization of 2D materials in water treatment encompasses a diverse array of applications, each harnessing the unique properties of these materials to address specific water quality challenges. The process of removing salt from seawater to produce freshwater, is a critical technology for regions plagued by water scarcity. Conventional desalination methods, such as reverse osmosis, are energy-intensive and costly. 2D materials, particularly graphene and its derivatives, offer promising solutions for more efficient and sustainable desalination. Their high surface area and tunable pore size enable selective water transport, while their exceptional mechanical strength ensures long-term membrane stability. The removal of contaminants from wastewater is essential for environmental protection and public health. Two-dimensional materials, exemplified by molybdenum disulfide (MoS2) and MXenes, have demonstrated remarkable capabilities in adsorbing and removing a various pollutants, encompassing heavy metals, organic dyes, and pharmaceuticals.. Their large surface area and tunable surface properties allow for targeted adsorption of specific contaminants, effectively purifying wastewater [4].

The utilization of light energy to drive chemical reactions, has emerged as a promising approach for water disinfection.2D materials, particularly graphitic carbon nitride (g-C3N4) and titanium dioxide (TiO2), exhibit exceptional photo catalytic activity, enabling the degradation of harmful microorganisms and organic contaminants under light irradiation. Real-time monitoring of water quality is crucial for ensuring public safety and environmental protection. 2D materials, with their tunable optical and electrical properties, offer promising solutions for developing sensitive and selective water quality sensors. These sensors can detect the presence of various contaminants, providing real-time data for effective water management.

The utilization of 2D materials in water treatment technology is still in its early stages, but the potential benefits are substantial. These materials offer the promise of more efficient, selective, and sustainable water treatment processes, addressing the critical challenges of water scarcity and pollution. As ongoing research and development persist in this field advances, the integration of 2D materials into water treatment systems is poised to revolutionize the way we manage and purify our precious water resources. Hexagonal two-dimensional boron nitride (h-BN) Nano materials, also known as hexagonal boron nitride nanosheets (h-BNNS), are a promising  category of materials characterized by distinctive properties that render them distinctive well-suited for various water treatment applications. These materials exhibit a hexagonal honeycomb lattice structure, similar to graphene, but with alternating boron and nitrogen atoms. This structure gives h-BNNs exceptional thermal and chemical stability, rendering them appropriate for an extensive array of applications. water treatment applications. With their distinct characteristics and capacity for sustainable and cost-effective water purification, h-BNNS hold great promise for addressing the global water crisis [5].

II. BORON NITRIDE: STRUCTURE AND PROPERTIES

Hexagonal boron nitride (h-BN) is a unique and versatile material that exhibits a hexagonal crystal lattice structure composed of alternating boron (B) and nitrogen (N) atoms. This compound is often referred to as the white graphene due to its similar hexagonal lattice structure to graphene, but with alternating B and N atoms instead of carbon. The strong covalent bonds between boron and nitrogen atoms within each layer give h-BN its exceptional properties, while the weak Interactions involving van der Waals forces among the layers allow individual layers to be easily exfoliated. Understanding the structure and properties of hexagonal boron nitride play a vital role in exploring its diverse range of applications in electronics, materials science, and nanotechnology [6].

Structure of h-BN

h-BN crystallizes in the hexagonal crystal system with a space group of P63/mmc. Within each layer, boron and nitrogen atoms form a honeycomb lattice with a bond length of 1.45 Å [7]. The arrangement of atoms in h-BN is similar to that of graphene, with one key difference: in h-BN, the boron atoms are directly aligned above the nitrogen atoms, while in graphene, the carbon atoms are staggered. This difference in atomic arrangement leads to distinct properties between h-BN and graphene. The stacking of h-BN layers follows an AA' stacking pattern, meaning that each boron atom in one layer is positioned directly above a nitrogen atom in the adjacent layer. This stacking pattern is different from graphene, which exhibits an AB stacking pattern. The AA' stacking pattern in h-BN contributes to the weak interlayer interactions and the easy exfoliation of individual layers.

Hexagonal boron nitride possesses a hexagonal lattice structure, which can be visualized as a planar network of B and N atoms arranged in a honeycomb pattern. The crystal structure is analogous to graphene, where each boron atom is covalently bonded to three nitrogen atoms, forming a B-N-B-N hexagonal ring. The layers are stacked on top of each other, creating a three-dimensional crystal lattice [8]. This unique arrangement imparts several remarkable properties to h-BN. One notable characteristic of the h-BN crystal structure is the strong covalent bonding within the layers, while the layers themselves are held together by weaker van der Waals forces. This leads to an elevated thermal and chemical stability of the material. Hexagonal boron nitride is an electrical insulator, in contrast to its carbon counterpart, graphene. The electronic properties of h-BN are mainly governed by the wide energy band gap between the valence and conduction bands. One of the outstanding features of hexagonal boron nitride is its exceptional thermal conductivity. The high thermal conductivity of h-BN, combined with its electrical insulating properties, makes it an ideal candidate for applications in thermal management, such as heat sinks in electronic devices. Additionally, hexagonal boron nitride exhibits thermal stability at high temperatures, making it suitable for use in extreme environments. Hexagonal boron nitride is characterized by its mechanical strength and hardness. The strong covalent bonds within the layers contribute to the material's high mechanical integrity.  The combination of high thermal conductivity, electrical insulation, and mechanical strength makes hexagonal boron nitride an attractive material for various engineering applications. It is employed as a solid lubricant in high-temperature environments, where traditional lubricants may degrade or evaporate. Hexagonal boron nitride is transparent in the visible and infrared regions of the electromagnetic spectrum. The transparency of h-BN, along with its insulating properties, makes it suitable for optical applications. The optical properties of hexagonal boron nitride also make it a potential candidate for applications in photonics and sensors [9].

III. UNIQUE CHARACTERISTICS OF BN SUITABLE FOR WATER TREATMENT APPLICATION

Hexagonal boron nitride (h-BN) exhibits several unique characteristics that make it suitable for water treatment applications. These distinctive features leverage the material's structural, thermal, and chemical properties, contributing to its effectiveness in addressing challenges related to water purification and treatment. Hexagonal boron nitride possesses exceptional thermal stability, maintaining its structural integrity at high temperatures. This characteristic is advantageous in water treatment processes that involve elevated temperatures, such as distillation or certain chemical reactions. The material's ability to withstand extreme thermal conditions makes it a reliable component for water treatment applications where temperature plays a critical role. h-BN is chemically inert, resisting reactions with a wide range of chemicals. This property is crucial for water treatment, where various contaminants and chemicals may be present. The chemical inertness of hexagonal boron nitride ensures that it does not undergo degradation or contribute to undesired reactions in the water treatment process. This stability makes it suitable for applications where maintaining water purity is paramount. Hexagonal boron nitride is inherently hydrophobic, meaning it repels water [10]. This property is beneficial in water treatment applications where the material needs to interact selectively with specific substances while avoiding unnecessary interactions with water molecules. The hydrophobic nature of h-BN can be harnessed in processes like adsorption or separation of hydrophobic contaminants from water, enhancing the efficiency of water treatment methods. The mechanical strength of hexagonal boron nitride adds to its suitability for water treatment applications. In scenarios where the material is used as a filter or membrane, its mechanical robustness ensures durability and longevity. This makes h-BN a reliable component for water treatment systems that require materials capable of withstanding mechanical stresses and pressures.

In certain water treatment applications, particularly those involving medical or biological processes, the biocompatibility of materials is crucial. Hexagonal boron nitride exhibits biocompatible properties, making it suitable for applications where interaction with living organisms or biological components is necessary [11]. This feature expands the potential use of h-BN in water treatment systems designed for medical purposes or biologically sensitive processes. The unique structure of hexagonal boron nitride provides ample surface area and specific sites for adsorption. Adsorption is a key mechanism in water treatment for removing contaminants. The material's ability to adsorb various substances, including organic molecules and certain ions, makes it effective in processes aimed at purifying water by capturing and removing specific pollutants. Hexagonal boron nitride is an electrical insulator, preventing the flow of electricity. This property is advantageous in water treatment applications where electrical conductivity could interfere with the desired processes. The electrical insulation of h-BN makes it suitable for use in components or systems where maintaining non-conductive conditions is essential. In summary, the unique characteristics of hexagonal boron nitride, including its high thermal stability, chemical inertness, hydrophobic nature, excellent mechanical strength, biocompatibility, adsorption capabilities, and electrical insulation, collectively make it well-suited for various water treatment applications. Whether employed as a filter, membrane, or adsorbent material, h-BN contributes to the efficiency, durability, and reliability of water treatment processes [12]. Ongoing research continues to explore and optimize the use of hexagonal boron nitride in advancing water treatment technologies.

IV. SYNTHESIS AND FABRICATION OF H-BN FOR WATER TREATMENT

h-BN has emerged as a promising material for water treatment due to its unique properties, including high surface area, chemical inertness, mechanical strength, and biocompatibility. This property makes it suitable for adsorption-based water treatment processes where contaminants are removed from the water by being bound to the surface of the material. Additionally, h-BN is chemically inert and resistant to harsh chemical environments. This makes it suitable for use in long-term water treatment applications. Several methods have been developed for the synthesis of h-BN, including:

Chemical Vapor Deposition (CVD)

CVD is a versatile method for growing h-BN films on various substrates. It involves the decomposition of precursor gases, such as borazine (B3N3H6) or ammonia borane (NH3BH3), on a heated substrate[13] The precursor gases are typically introduced into a vacuum chamber where they decompose and react to form h-BN on the substrate. CVD is a highly controlled method that can produce h-BN films with high quality and uniformity. In this method, the precursor gases are vaporized and then introduced into a reactor chamber. The gases are then heated and decomposed onto the substrate. The reaction conditions, such as the temperature, pressure, and flow rate of the gases, can be controlled to influence the properties of the h-BN film.

Liquid-Phase Exfoliation (LPE)

LPE involves the exfoliation of bulk h-BN crystals into individual layers using solvents or surfactants. The bulk h-BN crystals are first dispersed in a solvent or surfactant solution and then subjected to sonication or other mechanical agitation. This process causes the layers to separate from each other, producing h-BN nanosheets. LPErepresents a straightforward and scalable method that can produce high-quality h-BN nanosheets with large surface areas.

Thermal Annealing

Thermal annealing of boron oxide (B2O3) and melamine (C3H6N6) is a simple and cost-effective method for producing h-BN nanosheets. The B2O3 and melamine are mixed together and then heated to a high temperature, typically around 1000°C. This process causes the B2O3 and melamine to react, forming h-BN nanosheets [14]. Thermal annealing is a less controlled method than CVD and LPE, and it typically produces smaller and less uniform h-BN nanosheets. In the thermal annealing method, a mixture of boron oxide and melamine is heated at a high temperature in an inert atmosphere. The reaction between the two compounds produces a mixture of h-BN and other byproducts. The mixture is then treated to remove the byproducts and obtain h-BN nanosheets. Thermal annealing is often considered as a simple and cost-effective method and no specialized equipment is required. The annealing process can be used to produce h-BN nanosheets directly on substrates.

V. FABRICATION OF HEXAGONAL BORON NITRIDE FOR WATER TREATMENT APPLICATIONS

Once h-BN is synthesized, it can be fabricated into various forms suitable for water treatment applications. These fabrication techniques include:

Adsorption

h-BN nanosheets can be directly applied as adsorbents for removing contaminants from water. Their high surface area and tunable surface chemistry make them effective for a wide range of contaminants. The polar B-N bonds on h-BN facilitate the interaction with a variety of organic and inorganic pollutants, effectively removing them from the water [15]. The adsorption capacity of h-BN nanosheets can be enhanced by modifying their surface with functional groups that have a high affinity for the target contaminants. h-BN has demonstrated exceptional adsorption capacity for various pollutants, including dyes, pharmaceuticals, and heavy metals. Its high surface area allows for efficient capture of contaminants, while its chemical stability ensures long-term performance.

h-BN effectively adsorbs various organic and inorganic pollutants from water through various mechanisms. The aromatic rings of organic pollutants can interact with the π-electron system of h-BN layers, leading to strong adsorption. The polar B-N bonds in h-BN can form hydrogen bonds with polar contaminants, facilitating their removal. The surface of h-BN can be functionalized with charged groups to enhance electrostatic interactions with specific contaminants [16].

Filteration

h-BN's layered structure can be exploited to create membranes for water filtration. These membranes exhibit high water permeability while effectively rejecting contaminants. The interlayer spacing in h-BN can be tailored to achieve the desired filtration performance, allowing for selective removal of specific pollutants based on their size and molecular properties. h-BN membranes have been successfully applied in various filtration processes, including ultrafiltration, nanofiltration, and reverse osmosis. They have shown promise in removing contaminants such as dyes, heavy metals, and pharmaceuticals from water. h-BN membranes offer several advantages for water filtration including high permeability: excellent selectivity, chemical resistance and thermal stability.

Membrane Fabrication

h-BN nanosheets can be incorporated into polymer membranes for water filtration. This approach combines the high permeability of polymer membranes with the excellent rejection properties of h-BN nanosheets. The h-BN nanosheets can be incorporated into the polymer matrix either by mixing them with the polymer solution before casting the membrane or by coating them onto the surface of a pre-formed membrane. h-BN's layered structure and tunable pore size distribution enable it to achieve high permeability for water molecules while selectively rejecting contaminants [17] This property is crucial for water purification processes such as nanofiltration and reverse osmosis. The inert and hydrophilic nature of h-BN minimizes the adhesion of organic and inorganic contaminants to the membrane surface, reducing fouling and maintaining long-term performance [18]. h-BN exhibits exceptional chemical and thermal stability, making it resistant to harsh water conditions, including high temperatures, extreme pH values, and aggressive chemicals. This stability ensures long-term membrane integrity and performance. h-BN is a non-toxic and environmentally friendly material, offering a sustainable solution for water treatment compared to traditional membrane materials that may pose environmental concerns. h-BN-based membranes have demonstrated promising potential in various water treatment applications. h-BN membranes can effectively remove organic contaminants, dyes, and heavy metals from water, providing high-quality drinking water. h-BN membranes can desalinate seawater and brackish water, producing potable water from non-potable sources. h-BN membranes can remove suspended solids, bacteria, and viruses from water, making it suitable for wastewater treatment and industrial water purification. h-BN can be used as a photo catalyst for the degradation of organic pollutants in water. It can be synthesized as nanoparticles or nanosheets and loaded onto various substrates, such as activated carbon or TiO2. The photo catalytic activity of h-BN can be enhanced by doping it with metals or other materials [19].

Antibacterial Coating

h-BN nanomaterial can be used to develop antibacterial coatings for water filtration membranes and pipes. Their antimicrobial properties can prevent the growth of microorganisms and reduce the risk of waterborne diseases. The h-BN nanomaterial can be applied to the surface of membranes or pipes using various methods, such as dip-coating, spray-coating, or electrophoretic deposition. In this technique, h-BN nanomaterials are deposited onto the surface of a substrate, such as a membrane or pipe. The resulting coating can then prevent the growth of bacteria and other microorganisms. The synthesis and fabrication of h-BN for water treatment applications are critical for realizing its full potential in this field. Various synthesis methods, such as CVD, LPE, and thermal annealing, can produce h-BN with different properties and morphologies. Fabrication techniques, such as adsorption, membrane fabrication, photocatalyst synthesis, and antibacterial coating, allow the integration of h-BN into various water treatment systems. As research continues, advancements in synthesis and fabrication methods will lead to the development of more efficient and cost-effective h-BN-based water treatment technologies [20].

VI. INTEGRATION OF H-BN WITH NANOCOMPOSITE AND HYBRID MATERIALS FOR INCREMENTING WATER PURIFICATION APPLICATIONS

Nanocomposites are materials composed of a matrix material and dispersed nanoparticles. In the context of water purification, h-BN nanoparticles can be incorporated into various matrix materials, such as polymers, metals, or ceramics, to create h-BN nanocomposite. These nanocomposites exhibit improved water permeability, adsorption capacity, and photocatalytic activity, making them effective for removing a wide range of contaminants from water. Hybrid materials are materials that combine different types of materials at the nanoscale. h-BN can be integrated into hybrid materials in combination with other materials, like carbon nanotubes, graphene, and metal oxides. These hybrid materials can exhibit synergistic properties that make them even more effective for water purification applications. For instance, h-BN/carbon nanotube hybrids have demonstrated enhanced adsorption capacity for organic pollutants, while h-BN/graphene hybrids have shown improved photocatalytic activity for degrading harmful contaminants [21].  The integration of h-BN into nanocomposites and hybrid materials has opened up new avenues for water purification applications. h-BN based nanocomposites and hybrid materials can effectively adsorb and degrade organic pollutants, such as pharmaceuticals, pesticides, and industrial chemicals, from water. h-BN can be used to develop membranes for desalination, the process of removing salt from seawater or brackish water to produce freshwater. h-BN based materials can exhibit photocatalytic activity, enabling them to decompose harmful microorganisms and disinfect water. Heavy metal removal: h-BN can be incorporated into nanocomposites and hybrid materials to capture and remove heavy metals from water.

Figure 1 Illustration of Boron Nitride structures and its water treatment applications

A Synergistic Approach to Amplify h-BN's Performance: Nanocomposites, composed of a matrix material and dispersed nanoparticles, offer a versatile platform for incorporating h-BN. By embedding h-BN nanoparticles into various matrix materials, such as polymers, metals, or ceramics, the resultant nanocomposites exhibit improved water permeability, adsorption capacity, photocatalytic activity, and mechanical strength, making them ideal for diverse water purification applications paving the

mechanical strength, making them ideal for diverse water purification applications paving the way for membrane-based water purification. The integration of h-BN nanoparticles into polymers, such as polyamide, polyacrylonitrile, and polyvinylidene fluoride, has significantly enhanced their water permeability and selectivity, making them promising candidates for membrane-based water purification applications [22]. These membranes effectively remove contaminants from water while allowing water molecules to pass through, providing clean and safe drinking water. Metal-based h-BN nanocomposites have emerged as potent photocatalysts for water purification. The incorporation of h-BN nanoparticles into metals, such as titanium, silver, and copper, enhances their photocatalytic activity, enabling the decomposition of harmful microorganisms and the degradation of organic pollutants under light irradiation. These photocatalytic nanocomposites offer a sustainable and energy-efficient approach to water disinfection and contaminant removal. Ceramic-based h-BN nanocomposites offer high thermal stability and chemical resistance, making them suitable for high-temperature water purification applications. The incorporation of h-BN nanoparticles into ceramics, such as alumina, zirconia, and titania, enhances their adsorption capacity and thermal conductivity, enabling efficient removal of contaminants even under harsh conditions [23]. These nanocomposites find applications in industrial wastewater treatment and high-temperature desalination processes.

Hybrid Materials: Unlocking Synergistic Interactions for Multifunctional Water Purification

Hybrid materials, combinations of different materials with distinct properties, offer a powerful approach to synergistically enhance the water purification capabilities of h-BN. By integrating h-BN with other functional materials, such as carbon nanotubes, graphene oxide, and metal oxides, researchers have created advanced hybrid materials with tailored properties for specific water purification applications.

h-BN/carbon nanotube hybrids exhibit exceptional adsorption capacity, photocatalytic activity, and mechanical strength, making them ideal for multifunctional water purification systems. The incorporation of carbon nanotubes into h-BN enhances its electrical conductivity, facilitating electrochemical water purification processes. These hybrids can effectively remove organic pollutants, disinfect water, and desalinate brackish water, offering a comprehensive solution to water purification challenges. h-BN/graphene oxide hybrids offer a large surface area, high adsorption capacity, and excellent biocompatibility, making them suitable for removing a wide range of contaminants from water. The oxygen-rich functional groups on graphene oxide enhance the adsorption of contaminants, while h-BN provides structural stability and chemical inertness [24] These hybrids are particularly effective in removing heavy metals, pharmaceuticals, and pesticides from water. h-BN/metal oxide hybrids exhibit enhanced photocatalytic activity and chemical stability, making them effective for degrading organic pollutants and disinfecting water. The combination of h-BN's photocatalytic properties with the metal oxide's high surface area and redox potential enables efficient contaminant removal under light irradiation. These hybrids can effectively degrade a wide range of organic pollutants, including pharmaceuticals, dyes, and pesticides, while also inactivating bacteria and viruses. The integration of h-BN into nanocomposites and hybrid materials has opened up new avenues for water purification applications, addressing a wide range of water contamination challenges. With ongoing research and development, h-BN-based water purification technologies are poised to play an increasingly significant role in providing clean and safe water for communities worldwide [25].

VII. ENVIRONMENTAL AND HEALTH IMPACT

Water pollution is a pressing global issue with far-reaching consequences on ecosystems, biodiversity, and human health. This review delves into the environmental and health impacts of water pollution while exploring the potential of hexagonal boron nitride (h-BN)-incorporated materials in mitigating these challenges. Water pollution has severe consequences for aquatic ecosystems, leading to a decline in biodiversity. Pollutants such as industrial chemicals, heavy metals, and nutrients disrupt the delicate balance of aquatic environments, impacting fish, plants, and microorganisms. Habitat Disruption: The physical and chemical changes caused by water pollution lead to habitat destruction. Sedimentation, nutrient loading, and the alteration of water chemistry can degrade the quality of habitats, affecting the reproduction and survival of aquatic species.  Excessive nutrient runoff, often from agricultural activities, contributes to eutrophication [26]. This process results in the overgrowth of algae, leading to oxygen depletion in water bodies and the creation of dead zones where marine life cannot thrive. Contaminated water sources become breeding grounds for waterborne pathogens, causing diseases such as cholera, dysentery, and typhoid. Communities without access to clean water and sanitation facilities are particularly vulnerable to these health risks. Industrial discharges introduce a myriad of toxic chemicals into water bodies. Heavy metals like lead, mercury, and persistent organic pollutants pose serious health risks, contributing to chronic illnesses, developmental issues, and neurological disorders in humans. Runoff from agricultural areas carries pesticides and fertilizers into water sources. Consuming water contaminated with agricultural chemicals can lead to health problems, including endocrine disruption, reproductive issues, and an increased risk of certain cancers [27]. By incorporating h-BN into materials, we can enhance their ability to capture and remove a wide range of contaminants from water sources.

Figure 2 Membrane applications of BNNS in various fields.

One notable application of h-BN is in the removal of heavy metals from water. Studies have shown that h-BN nanocomposites exhibit excellent adsorption capacities for metals like lead, cadmium, and mercury [28].This makes h-BN-incorporated materials effective in preventing the entry of these toxic elements into water supplies. Researchers have developed h-BN-based membranes for water filtration, demonstrating high efficiency in removing heavy metals. These membranes can be integrated into water treatment systems to provide a sustainable solution for metal removal. The adsorption capabilities of h-BN extend to organic pollutants, including pesticides and industrial chemicals [29]. Incorporating h-BN into filtration systems can enhance their ability to capture these contaminants, reducing the risk of chemical exposure in water sources. h-BN-modified activated carbon has been employed to create hybrid materials for the removal of organic pollutants. This approach combines the adsorption properties of both materials, resulting in enhanced water purification capabilities. Integrating h-BN into filtration membranes improves their overall performance. These membranes exhibit increased selectivity and efficiency in separating contaminants from water. This makes them suitable for various water treatment processes, including microfiltration and ultrafiltration. Thin-film composite membranes incorporating h-BN have been developed for desalination applications. The inclusion of h-BN enhances the membrane's mechanical strength and adsorption properties, contributing to improved water quality [30].

VIII. CHALLENGES AND FUTURE PROSPECTS

To implement h-BN-incorporated materials on a larger scale, cost-effective production methods must be developed. Researchers are exploring scalable synthesis techniques to make these materials more accessible for widespread water purification applications.However, there are several challenges that need to be addressed before h-BN-based materials and composites can be widely adopted for water treatment. Ensuring the long-term stability of h-BN-incorporated materials is crucial for their sustained effectiveness in water treatment. Research efforts are directed towards understanding the durability of these materials under different environmental conditions.The synthesis of h-BN nanoparticles and nanosheets is still relatively expensive and time-consuming. This makes it difficult to produce h-BN-based materials and composites at a scale that is commercially viable. h-BN nanoparticles have a tendency to agglomerate, which can make it difficult to incorporate them into composites and membranes. This can limit the performance of h-BN-based materials in water treatment applications. The surface of h-BN nanoparticles is relatively inert, which can make it difficult to functionalize them with desired properties, such as increased adsorption capacity or photocatalytic activity. The environmental impact of h-BN production and disposal needs to be carefully assessed to ensure that it is a sustainable material for water treatment applications.Despite these challenges, there are several promising future directions for research on h-BN-based materials and composites for water treatment applications. Researchers are developing new synthesis methods for h-BN nanoparticles and nanosheets that are more scalable and cost-effective. These methods could help to make h-BN-based materials and composites more commercially viable. New strategies are developed to disperse h-BN nanoparticles more effectively into composites and membranes. This could improve the effectiveness of h-BN-based materials in water treatment applications. Implementing newer techniques to functionalize the surface of h-BN nanoparticles with desired properties make h-BN-based materials more versatile and effective for a wider range of water treatment applications. Conducting life cycle assessments to evaluate the environmental impact of h-BN production and disposal, this information will be important for ensuring that h-BN is a sustainable material for water treatment applications. In addition to these specific research directions, there is also a need for more collaboration between researchers, engineers, and industry partners to bring h-BN-based materials and composites to market. This collaboration will be essential for overcoming the challenges and realizing the full potential of h-BN for water treatment applications. Ongoing research is focused on overcoming these challenges and realizing the full potential of hexagonal boron nitride for water treatment.

IX. CONCLUSION

Water pollution poses a significant threat to the environment and human health, necessitating innovative solutions for water purification. Hexagonal boron nitride, with its exceptional adsorption properties, emerging as a favorable choice for addressing water pollution challenges. By incorporating h-BN into materials used for water treatment, we can enhance their ability to remove heavy metals and organic contaminants, contributing to the protection of water resources and public health. While challenges such as scalability and cost-effectiveness remain, ongoing research is paving the way for the practical implementation of h-BN-incorporated materials in water purification technologies. In conclusion, the integration of h-BN holds great potential in the ongoing efforts to control and mitigate the environmental and health impacts of water pollution, offering a sustainable and effective approach to ensure the availability of clean water for current and future generations.

Declaration: The authors state that they do not have any conflicting interests to declare.

REFERENCE

[1] Lin, Y. C.; Torsi, R.; Younas, R.; Hinkle, C. L.; Rigosi, A. F.; Hill, H. M.; Robinson, J. A. Recent Advances in 2D Material Theory, Synthesis, Properties, and Applications. ACS Nano 2023

[2] Yang, R.; Fan, Y.; Zhang, Y.; Mei, L.; Zhu, R.; Qin, J.; Zeng, Z. 2D Transition Metal Dichalcogenides for Photocatalysis. Angew. Chem. Int. Ed. 2023, 62, e202218016

[3] Wu, M. H.; Li, L.; Liu, N.; Wang, D. J.; Xue, Y. C.; Tang, L. Molybdenum disulfide (MoS2) as a co-catalyst for photocatalytic degradation of organic contaminants: A review. Process Saf. Environ. Prot. 2018, 118, 40-58.

[4] González-Poggini, S.; Rosenkranz, A.; Colet-Lagrille, M. Two-dimensional nanomaterials for the removal of pharmaceuticals from wastewater: A critical review. Processes 2021, 9(12), 2160.

[5] Li, H.; Ji, H.; Zhang, R.; Zhang, W.; Pan, B.; Liu, W.; Sun, W. Hydrogen Bonding Rather Than Cation Bridging Promotes Graphene Oxide Attachment to Lipid Membranes in the Presence of Heavy Metals. Environ. Sci.: Nano 2020, 7(8), 2240-2251.

[6] Weng, Q.; Wang, X.; Wang, X.; Bando, Y.; Golberg, D. Functionalized Hexagonal Boron Nitride Nanomaterials: Emerging Properties and Applications. Chem. Soc. Rev. 2016, 45(14), 3989-4012.

[7] Ihsanullah, I. Boron Nitride-Based Materials for Water Purification: Progress and Outlook. Chemosphere 2021, 263, 127970

[8] Rathinasabapathy, S.; Santhosh, M. S.; Asokan, M. Significance of Boron Nitride in Composites and Its Applications. In Recent Advances in Boron-Containing Materials 2020, 63

[9] Roy, S.; Zhang, X.; Puthirath, A. B.; Meiyazhagan, A.; Bhattacharyya, S.; Rahman, M. M.; Ajayan, P. M. Structure, Properties, and Applications of Two-Dimensional Hexagonal Boron Nitride. Adv. Mater. 2021, 33(44), 2101589

[10] Wang, J.; Ma, F.; Liang, W.; Wang, R.; Sun, M. Optical, Photonic, and Optoelectronic Properties of Graphene, h-BN, and Their Hybrid Materials. Nanophotonics 2017, 6(5), 943-976.

[11] Santos, J.; Moschetta, M.; Rodrigues, J.; Alpuim, P.; Capasso, A. Interactions between 2D Materials and Living Matter: A Review on Graphene and Hexagonal Boron Nitride Coatings. Front. Bioeng. Biotechnol. 2021, 9, 612669.

[12] Merlo, A.; Mokkapati, V. R. S. S.; Pandit, S.; Mijakovic, I. Boron Nitride Nanomaterials: Biocompatibility and Bio-applications. Biomater. Sci. 2018, 6(9), 2298-2311.

[13] Chkhartishvili, L. Hydrogen Nanoreservoirs Made of Boron Nitride. Nanomater. Environ. Prot. 2014, 451–467.

[14] Zeng, M.; Chen, M.; Huang, D.; Lei, S.; Zhang, X.; Wang, L.; Cheng, Z. Engineered Two-Dimensional Nanomaterials: An Emerging Paradigm for Water Purification and Monitoring. Mater. Horiz. 2021, 8(3), 758-802.

[15]Ramirez Leyva, J. H. . White Graphene Nanostructured Magnetic