Waste Recycling Technologies for Nanomaterials Manufacturing

Nowadays, nanomaterials are used in many areas and applications, including medicine, energy, and environment. The initial cost of the nanomaterials is high; thus, finding another cheap source is required. In addition, waste accumulation is a serious environmental problem. Therefore, recycling waste into valuable nanomaterials is highly required, where it has environmental and economic benefits.

Environmental pollution has been viewed as a serious issue all over the world. Waste management is pressing hard to warn the industry. Humans always produce waste and discard it in some way, influencing the environment. At present, there is no spot on the earth that is not exposed to some sort of waste. These materials may cause immediate health risks to humans and animals. Other wastes persist for a long time in the environment until they reach damaging levels to ecosystems. Hence, the upsurge in waste generated by the industries and human activities needs to be managed. To this end, various recycling methods have been developed and applied for the conversion of wastes into useful forms of materials and also nanomaterials. The common methods applied to recover the generated wastes, including recycling, reducing, and reuse, still need more developments. The main goal of this chapter is to discuss different waste recycling techniques and to provide a comprehensive review about the industrial waste recycling processes. Examples of recycling of particular types of waste are also discussed. Finally, the present status and economic considerations of waste recycling are also investigated and reviewed.

The appearance and fate of nanomaterials (NMs) also are new area of waste management. Information and techniques for investigations are minimal. Nonetheless, it is incredibly likely that nanomaterials used in several items or papers of one type would be in the waste stream. Environmental and environmental risks related to the treatment of nanowastes remain unexplored. Another factor is whether containing nanomaterials, consisting of recycling processes, will affect the waste management capabilities/performance. In comparison, nanomaterials may substitute certain substances that make products, for example, smarter or more efficient, to get into waste management sooner and potentially play a role in waste reduction. Draw up an overview of nanomaterial and waste-related scientific, health, and environmental problems, and assess the available recycling issues of environmental health significance are needed. One ultimate goal is to consider looking for identical statistics to compare the potential hazards associated with the existence of NMs in the waste. The emphasis is on eliminating consumer goods as waste and not creating waste anymore. Alternatively, instead of other residuals (e.g., cosmetics, containers, etc.), attention can be given to appliances and athletic equipment. Consciousness is usually on product forms and waste sources, where knowledge is at all available. Thus, the papers and studies that are indirectly available statistics are implicit delimitations; this research area is relatively new because of the reality. It has also sought to cover goods, however. Concerning incineration, its miles found it more relevant to observe the load and fate of particular NMs in respect of goods categories. After the initial activities, the spectrum can be similarly oriented and fabricated/designed nanomaterials to offer a selected character in a product. Besides, the commonly considered nanomaterials within the context of the EU concept supported. Nevertheless, most of the evidence sources examined no longer detailed nanomaterials in exercise, and as a result, all known sources of information about nanomaterials were included in the waste.

Energy storage electrode materials suffer from high-cost production. For example, cobalt oxide price was increased from 20 to 60 USD per kg in 1998 and 2017, respectively. Consequently, seeking low-cost production methods is essential. Over the years, the ownership of electronic devices has transformed from a human luxury to basic requirements. Following the exponential growth in the electronic gadget demand, the invention of lithium-ion batteries (LiBs) has been the most used energy storage devices in the electronic devices. However, the disposal of LiBs in electronic devices is obvious due to the limited cycle life. In this context, the disposal of LiBs could be a source of environmental calamity, if it will not be treated correctly because of the contained toxic materials and heavy metals such as cobalt, manganese, nickel, and lithium. Furthermore, the recovery of such valuable heavy metals before LiBs disposal is important from the economic and environmental viewpoints. Many processes have been used to extract the cobalt from spent LiBs, such as solvent extraction, acid leaching, chemical precipitation, bioleaching, and electrochemical recovery. The recycled materials were successfully used in many applications, such as supercapacitors. This chapter discusses the fundamental of energy storage devices and illustrates the supercapacitor storage types based on electrical double-layer capacitors and the redox-based capacitors and their materials. Moreover, different approaches for recovering metals from LiBs as a supercapacitor electrode are discussed in detail.

In the last decades, many researchers were inspired to develop recycling technologies for nanomaterial manufacturing and manage the excessive generation of wastes (biomass, biological, plastic, and industrial wastes). Cost-efficient, sustainable process, and good material properties are the requirements to meet for a successful recycling route and, consequently, inducing huge economic and environmental benefits. Moreover, the use of the recycled nanomaterials for several applications was reported in the literature, such as catalysis, energy storage, and biomedical applications. This chapter will be devoted to reviewing the studies carried on the recycling of nanomaterials for battery applications, mainly alkali metal ion batteries (alkali metal: Li, Na, Mg, K), conventional secondary batteries, and alkaline batteries.

The renewable energies have become affordable and accessible door to door due to well-equipped energy storage devices. Lithium-ion batteries (LiBs) and supercapacitors (SCs) are the prominent energy storage devices in the market. Recycling electronic wastes are one of the steps to build a greener and cleaner environment. In this chapter, reusing of disposed spent batteries components to generate electrode materials for LiBs applications has been discussed. Batteries developed from waste-materials are expected to fulfill the demand of people for energy storage devices with the high energy density in consumer electronics. Recycling LiBs will make the energy storage device, market cost-effective. Thus, apt energy storage devices are creating a new generation of electronics with excellent potential to improve the quality of human life. Owing to the advancement in or advanced, the researchers or industries are focused on developing electrodes for smart electronics by fabricating a potential device from the waste materials which is quite a challenging technique. In the context of making the environment clean and free from electronic wastages, recycling the spent batteries could be an estimable step. In this chapter, the basic recycling methods to extract the electrode materials such as different nanostructured oxides and carbon materials will be discussed along with the configuration of various electrodes and electrolytes in batteries. Such extensive discussion can bring out a summary on operational parameters such as stability, storage capacity, energy density, and cycle life of the LiBs developed from spent batteries. The discussions in-depth, on the general pros and cons of conventional energy storage devices, can lead to the next phase for generating advance battery technology from recycling the wastage.

Nowadays, humankind is in urgent need of energy generation and storage systems. The supercapacitor is one of the essential types of storage systems. The high cost of obtaining capacitor electrodes is the reason behind the researchers’ attempts to find low-cost sources. The need for the development of efficient energy storage systems is paramount in meeting the world’s future energy targets, especially when the energy costs are on the increase in addition to the escalating demand. Energy storage technologies can improve efficiencies in supply systems by storing the energy when it is in excess, and then release it timely. Batteries are slowly becoming obsolete due to their poor cyclability (limited to a few thousand) and long charge time (tens of minutes) in comparison to supercapacitors. On the other hand, supercapacitors have a long lifetime and fast charging times. Nowadays, the research focuses on advanced suitable electrode materials that directly reflect in supercapacitor technology enhancement. The researchers have prepared a variety of single components and hybrid electrodes by recycling various environmental wastes. The recycled materials include metal oxides (MnO₂, Co₃O₄, etc.), carbon materials (carbon nanosphere, porous carbon nanoparticles, activated carbon), and hybrid materials (MnO₂/graphene, CaO/AC). The obtained materials exhibited interesting structural and morphological properties as well as excellent energy storage behavior. The recycling technique provides a unique alternative cheap way for getting supercapacitor electrode materials, as well as it helps to maintain a clean environment.

The exploitation of spent battery and electronic waste for the recovery and preparation of metal oxide nanomaterials (MONMs) is vital for technology, economical, sustainable, and environmental research. The recovery of MONMs through recycling waste materials reduces environmental pollutions and saves the primary resources due to industrial consumption. However, the economic benefits of recycling electronic waste for the recovery of these high-value MONMs have still been debated because of the low purity and stability of recovered materials restricting their commercial use. In this chapter, we discuss the motivation and importance of waste recycling for the recovery of nanomaterials, focusing on the possible techniques that can be applied for the efficient synthesis of commercial-grade MONMs (e.g., ferrites, zinc oxides, indium oxides, tin oxides, etc.) with high purity at a minimal cost. Besides, the profit of recovered MONMs in potential applications for wastewater remediation and renewable energy production are addressed.

Nowadays, both developed and developing countries are more concerned about their sensitive natural resources, especially water resources. Therefore, conservation and sustainable utilization of available and limited water resources are a must. Globally, agriculture is the primary water-using sector. Usually, water and soil qualities are monitored and recorded for agricultural purposes through traditional analytical techniques that require planning and effort for sampling. The need for more sensitive and simple techniques is the main driving force for using nanobiosensors. Recycled nanomaterials can be integrated into nanobiosensors so that various nanobiosensors can achieve the same goals with high sensitivity and without sample preparations. The new nanobiosensors can easily operate at low cost and function at a wide range of detection scales. Nanobiosensors can monitor and detect either physicochemical parameters or microbes in remote areas and monitor environmental conditions. Real-time nanobiosensors can boost agricultural production by monitoring the temperature and humidity and regulating the usage of fertilizers/pesticides at a specific time in a targeted location. This chapter provides an insight into the concepts and parameters of nanobiosensors, emphasizing the recent progress of their applications in organic and inorganic pollutants sensing. The chapter also summarizes the statistics of the last two decades for using nanosensors and nanobiosensors for environmental monitoring.

Energy is essential and affects all aspects of our society, including the economy and modern living. However, the unparalleled rise in the global population, technological advancements, and changes in the scope of energy resources are all affecting the present energy landscape. With the increasing demands for energy and over-consumption of fossil energy, CO₂ emission is anticipated to rise over the next decades with devastating consequences on the environment and humans’ lives. To avoid future eventualities, clean energy technologies have evolved with the expectation to diversify the global energy resources. Alternative energies are likely to show a crucial role in meeting not just the future energy needs but to remedy the escalating negative impact of fossil energy. Various clean energy systems, including fuel cells, electrolytic cells, rechargeable batteries, solar cells, etc., have emerged as viable renewable energy systems with even a wider range of applications and less impact on the environment. The efficiency of these energy systems is critical but is dependent on several technical factors, including electrochemical hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR). An efficient electrocatalyst is required to drive the kinetics of these electrochemical processes effectively. However, developing practically efficient electrocatalyst is a significant challenge in terms of striking a balance between cost, performance, and sustainability of the active materials. Irrespective of any challenges, developing cost-effective and efficient electrode materials is vital for large-scale implementations of these energy systems. This chapter discusses the alternatives, recent progress, and future trends of using various waste materials for the development of advanced electrodes for various electrochemical systems.

Fingermarks are of the commonly found evidence at crime scenes or on items submitted about a crime. However, most of these fingermarks are latent and cannot be seen with the naked eye. Powdering is the most common method employed to develop latent fingermark on non-porous surfaces. However, existing commercially available fingermark powders suffer several limitations, such as health problems. Hence, the objective of this study was of nanosilica powders synthesis from agricultural wastes, i.e. bamboo leaves (BL) and rice husks (RH), as a green approach and later applied for fingermark development. To obtain highly purified eco-friendly silica powder, acid leaching of RH and BL was carried out to remove impurities and metallic elements. Thermal combustion of BL and RH under controlled conditions had produced silica ash, and the addition of ash into sodium hydroxide produced sodium silicate solution. The addition of acetone as a polar solvent into sodium silicate before precipitation with acetic acid yielded a spherical form of nanosilica. The yield percentage of nanosilica from RH (12.16%) was higher than that of nanosilica from BL (6.9%). The characterization of synthesized nanosilica was carried out using FESEM, EDX, and ATR-FTIR spectroscopy. FESEM analysis of the nanosilica produced was spherical. The EDX elemental spectra showed significant silicon elements and oxygen in the BL and RH nanosilica. FTIR analysis showed predominant absorbance peaks at 1057 and 1060 cm⁻¹ corresponding to siloxane bonds. The synthesized nanosilica powders were further applied to visualize latent fingermarks on various substrates. The powdering technique using nanosilica powders yielded good quality and clarity of developed fingermark on most of the tested surfaces as compared to commercially available white fingerprint powder. In conclusion, nanosilica powders were successfully synthesized from agricultural wastes and applied in the field of forensic science as latent fingermark detection material for the powdering technique.

Water pollutants are detrimental to human life. High doses of organic or inorganic toxins in drinking water may be responsible for various diseases such as kidney maladies, nervous order disturbances. Water pollution can be arising from urban activities such as industrialization and mining or naturalistic actions such as biological conversions and geological denudation of earth. Treating water and wastewater containing toxicants via an economical and straightforward process is crucial for sustaining humanbeing healthcare and the diverse ecosystems. Currently, controlled removal of hazardous species in water sources, either organic or inorganic, using secure and operative methods still represented great defiance. Therefore, the development of cost-effective and rapid techniques to remove pollutants from the contaminated water was reported. This chapter outlines the latest studies for the preparation of nanosilica (NS) from agricultural, electronic, and industrial waste for the removal of various toxins from polluted water through adsorption strategy. The waste-derived NS can be modified through physical or chemical processes to get highly efficient and economic features for environmental usage. Removal of organic and inorganic pollutant species from polluted water sources using efficient and cost-effective waste-derived NS was ascertained. The NS obtained from natural and urban waste through interrogation of the recently published data, without generation of secondary waste-contaminated water, leads to reduce the risk of water pollution for tomorrow. Furthermore, factors that may promote the performance of waste-derived NS toward the removal of pollutants are summarized, e.g., pH, contact time, temperature, particle size, surface activity, and porosity.

Nowadays, agricultural waste has become increasingly alarming, as it can cause considerable environmental impact. However, it can be utilized for many applications, such as energy production, chemical recovery, and dye adsorptions. Henceforth, rice husk (RH) and ash (RHA) have been used as substitutes to produce silica. Porous and high surface area silica can be widely used in adsorption, separation, thermal insulation, and catalysis. Therefore, it is of great importance to find an economical way to produce nanosilica. Besides, lignin has been underused among all the fractions of biomass because of its complicated structure. Apart from cellulose and hemicellulose, lignin has a significant fraction of biomass. In comparison to other natural adsorbents, lignin residues contain agricultural and wood residues and can be extracted during the precipitation process from black liquor. In addition, lignin residues have higher bio-adsorption capacity and affinity. On the other hand, the industrial activities in developed countries are generating pollutants as wastes into the water stream. The photocatalysis technique is considered as one of the most sustainable approaches, especially for the treatment of water from pollutants. However, its usage has some limitations, such as its high bandgap energy for semiconductor materials, the limitation of photoresponse under sunlight, the short lifetime of active e⁻/h⁺ radicals and the difficulty of separation from water. To overcome these challenges, many techniques have been used and adopted: metal or non-metallic doping, surface modification, using high surface area support as silica, alumina, lignin and carbon materials. This chapter aims to summarize the recent progress in extracted silica and lignin from agricultural waste and their applications as heterogeneous photocatalysts for wastewater treatment.

Water is the origin of life, even though millions around the world agonize from the shortage of clean water. On the other hand, over two billion tons of solid waste are produced annually and represent the major source for wastewater, with an increase in numbers over the next few decades. According to the UN’s Sustainable Development Goals, materials science research has to focus on recovering methods and proper waste managing. This includes two major issues, wastewater treatment and solid wastes, through one process, i.e. removing waste by waste. In this chapter, a comprehensive list of cheap materials prepared from diverse types of agricultural and industrial wastes and their performance towards the reduction of numerous aquatic pollutants has been summarized. This chapter provides an essential perception towards the use of solid wastes as materials/precursor materials for the preparation of nanomaterials to be used as adsorbents, supports and/or photocatalysts for water treatment. Furthermore, the challenges for upcoming studies of adsorbents and photocatalysts derived from waste were explored.

Nowadays, the concept of recycling becomes one of the most general research topics, which for most of the researchers, involves the weekly ritual of placing waste resources such as cans and cardboard into oversizing and placing them outside the houses. Carbon-based nanomaterials possess unique physical and chemical characteristics that make them attractive to use in different directions. For this type of recycling strategies to be more practical, they must be relatively simple and highly resourceful. Carbon nanomaterial’s nucleation is a challenging process, as it requires temperature, renewable sources, and specific types of catalysts. Recently, reported recycling activities include hydrocarbon-rich organic and polymeric material waste as the primary source. In this chapter, discuss the synthesis of carbon nanomaterials using pyrolysis systems in detail. Furthermore, the chapter explores recent step-ups made in the context of this direction.

“There’s Plenty of Room at the Bottom: An Invitation to Enter a New Field of Physics” said Richard Feynman in 1959, this lecture opened the way to the new field of science which we know today as nanotechnology. Materials’ manipulation at a very small size, ranges from 1 to 100 nm (nanoworld or the nano-edge) is well-known as nanotechnology. Since then, a lot of investigations and research were devoted by many researchers around the globe to keep an eye on the different properties and behavior of nanomaterials. Materials with at least one nanoscale dimension are called nanomaterials that have outstanding features compared to their bulk counterparts. These exceptional characteristics are due to the relatively-high surface area and the relatively-large surface atoms compared to those in the inner mass. Thus, nanomaterials have attractive chemical, physical, electronic, physiological, and optical properties. In this chapter, we are covering the historical overview and origin of nanomaterials to their recent applications. In addition, types and applications of recycled carbon-based nanomaterials as an example have also been discussed.

Biomass-derived porous carbons (BPCs) represents one of the most diverse classes of materials with exceptional properties such as high specific surface area, wide availability, biodegradability, low cost, and tunable porous features. A broad range of new carbon materials for suitable applications including water purification, catalyst supports and electrodes for electrochemical capacitors, sensing, and fuel cells have been developed. This not only increased the economic benefits and sustainability of chemical industry but also minimized the environmental impacts. The wide application of various energy technologies for specific purposes is mainly reliant on the design of electrode materials, particularly carbon electrodes. In this chapter, recent developments and breakthroughs of BPCs are presented. Characteristics controlling mechanisms behind their performance, especially pore structure and surface functionality, are discussed, which will direct the rational design of BPCs for practical use. In addition, the progress on application of these materials as electrodes for electrochemical devices such as fuel cells, CO₂ capture, water splitting, and lithium-ion batteries, is summarized.

Wastewater treatment has been drawing more and more attention due to increasing water pollution. The most common sources of water pollution are heavy metals, dyes, plastics, and foods from industries. Animal, agriculture, and farm wastes are other important causes of water pollution. Several adsorbents have been tested for wastewater treatment. Among these, activated carbon (AC) is the best and the most effective adsorbent for a specific class of pollutants because of its abundant starting materials availability, high surface area, surface reactivity, adsorption efficiency, and porosity structure. Although commercial AC has outstanding potential in the industry of water treatment, the usage is limited because of the high cost. The high initial cost and expensive regeneration of AC motivate the search for low cost, disposable ACs from conventional wastes materials to remove dyes, volatile organic compounds, heavy metals, and organic pollutants. The main goal of this chapter is to compare and list the advantages and disadvantages and methods of AC preparation from wastes materials as adsorbents and their application in water treatment to remove pollutants.

Agricultural waste reuse has been gained much interest in various environmental and industrial aspects. The agricultural waste is a rich source of various nanomaterials such as nanosilica (NS), nanocarbon (NC), and nanozeolite (NZ). Through the rice planting to the final product, 20% husk was left as a by-product from the total weight, so-called rice husk (RH). The economic consideration of RH refers to the rich source of NS, NC, and NZ, where RH contents are 70–85% organic matter and inorganic residues (20–25%). Also, rice husk ash (RHA) contents are 60% silica and 10–40% carbon as well as another mineral’s composition. Therefore, there are many approached for producing and extracting NS and NC from RH and RHA using different effective physical and chemical recycling methodologies. The extracted NS from RH and RHA was successfully used for the development and production of NZ. The production of NS, NC, and NZ from RH and RHA is a potential approach for reducing the environmental effect and raising the economic values with highly effective materials in various applications. The valuable usage of NS, NC, and NZ is very high, which can be used in various industrial and environmental aspects such as electronics, ceramic, catalyst support, adsorbents, ion exchangers, water treatment, antimicrobial products, biosensing, and biomedical applications. In this chapter, the various extraction and synthesis methodologies for the controlled formation of NS, NC, and NZ from RH and RHA were reported. Besides, the potential usage and sustainable applications of these materials were successfully presented.

The effect of waste accumulation can be enormously violent for several societies in developing countries. In the overworld, this problem becomes more difficult as there are no obvious specific strategies for actual solid waste management that causes severe environmental hazards. This chapter discusses the recent advances of wastes recycling environmentally friendly technologies to provide economic value toward reducing the high cost and additional ways for nanomaterial production in the petroleum field. It shows how carbon nanostructures can be formed from different waste materials such as waste natural oil, plastic wastes, heavy oil residue, waste engine oil, deoiled asphalt, and scrap tire that have the potential to cause incredible environmental damage in the form of water, air, and land pollution. Particular sorts of this wastes can be reused. However, most of them are left in landfill sites; waste recycling approach has a tremendous economic value besides to their environmental impact: for example, waste reduction, resource conservation, energy conservation, reduction gas emissions from the greenhouse, and reducing the extent of pollution in air and water sources. The chapter is consisting of three parts. Part one is describing carbon nanostructures such as carbon nanotubes, fibers, porous carbon, and microspheres that can be produced from different waste materials. The second part deals with a review of waste materials in the petroleum field that has the probable to cause incredible environmental damage in the form of water, air, and land pollution. Finally, the third part will discuss the multidisciplinary green approach toward the acquisition of high-value carbon-based nanomaterials as a natural precursor by using waste materials.

Citrus peels are a rich source of essential oils (EOs); these oils have efficient antioxidant and insecticidal properties. However, using these EOs is restricted because of technical obstacles such as their poor solubility in water and rapid rate of vaporization. Nanotechnology enables the formulation of the EOs into promising, efficient nanomaterials. These materials can be used in different fields such as water treatment, production of eco-friendly insecticides, and the food industry. Also, the citrus peels are a great source of nanocellulose, which is considered as a promising material used in water treatment and composite industry. This chapter sheds light on the employment of nanotechnology in the production of different nanomaterials from the agricultural wastes of citrus crops.

The small invisible nanofactories of bacteria, fungi, and microalgae represent a green, cheap, and easy biogenic method to build nanosized metal particles in a bottom-up approach. Using waste as the source of metal ions helps environmental remediation and increases waste value by recovering rare, precious, and essential metals. The recovery happens in an eco-friendly way after adjustment of growth conditions and salts concentrations. Models for the waste solutions and real wastewaters were used as the source of platinum group metals and rare metals to be recovered by microorganisms that can process and resist high heavy metals concentrations. The produced nanoparticles are highly efficient candidates for catalytic applications and other potential applications. The high concentration of gold in solid electronic waste scrap is the target for cyanogenic bacteria to solubilize gold, refined by another bacterium in the form of nanogold that can be reused in electronic devices. Microbial biosynthesis of nanoparticles has advantages that far exceed that of other methods, though it is difficult to control the shape, size, and size distribution of nanoparticles produced by this method, and it has low production to be used commercially. Further production enhancement and control over the produced nanoparticles are expected.

This chapter introduces the reader to utilizing plastic wastes as a precursor for the fabrication of carbon nanotubes and the efforts done for this purpose. In addition, it provides a brief introduction to the topic, and an overview of the fundamental concepts of carbon nanotubes, including structure, types, and growth mechanism, is given. The conventional methods of fabricating carbon nanotubes are discussed. Moreover, it describes the methods used to convert plastic waste to carbon nanotubes in detail, while also highlighting the factors affecting each process’s efficiency and the recent progress in this regard.

The low atomic number of carbons, combined with the half-full shell of valence electrons and medium electronegativity, provide an important basis for strong covalent bonding to other carbon atoms and other elements. Moreover, this supports the wide differences of carbon-containing natural atoms, counting the atoms of life. Recent breakthroughs in carbon-based nanomaterials’ science and technology use paraffinic waxes as a carbon source where it consists of not less than 18 carbon number per single paraffin crystal. Paraffinic waxes are considered a cheap by-product in the petroleum refinery, which is considered a source for nanocarbon synthesis, whether it is activated nanocarbon or carbon nanotubes and nanocarbon fibers. This chapter describes the separation of paraffinic petroleum wax, its purification, and characterization, besides that, the synthesis of nanocarbon and its evaluation.

A novel magnetic nanoadsorbent comprising carbon/iron composite was prepared from polyethylene terephthalate waste. The magnetic nanoadsorbent was characterized and applied in the adsorption of diclofenac from water. Batch adsorption experiments were conducted according to a three-factor three-level Box–Behnken design including temperature (°C), pH and adsorbent dose (g L^-1) as the process parameters. A polynomial regression model was used to predict and optimize the parameters for maximum adsorption capacity (mg g^-1) of the nanoadsorbent using response surface modeling. The magnetic nanoadsorbent exhibited a surface area of 288.88 m² g^-1 and a saturation magnetization of 35.4 emu g^-1. Transmission electron microscopy of the nanoadsorbent depicted particle size range within 10–40 nm. The maximum adsorption capacity of the nanoadsorbent for diclofenac was 15.31 mg g^-1 under optimized conditions of 42.65 ºC, 5.74 pH and 1.04 g L^-1 dose. High regression coefficient values (R² = 0.987) in the design experiments suggested considerable goodness of fit for the response surface model. Statistical analysis showed adsorption of diclofenac by the nanoadsorbent was significantly influenced by solution pH. FTIR analysis of the diclofenac loaded nanoadsorbent confirmed the adsorption of diclofenac by the emergence of new diagnostic peaks. The diclofenac loaded nanoadsorbent could be desorbed up to 69.88% by NaOH stripping, suggesting its reuse potential.

Plastic is one of the most significant hazards to the environment. Plastic is a non-biodegradable material, and several toxic chemicals leach out of it and seep through the soil, water, plants, and animals. This leads to cancer and other serious ailments, aquatic life endangerment, and environmental pollution. The use of waste plastic for the synthesis of different types of nanomaterials can not only save the humans and the environment from the dangers of plastic but also provide beneficial substances for other purposes. Different nanomaterials can be synthesized from the waste plastics, such as polyvinyl chloride plastic is used as the carbon source for the fabrication of MoC₂ nanoparticles. These particles are remarkable electrocatalysts that are involved in the generation of sustainable hydrogen. Similarly, polypropylene plastic waste is used for the synthesis of photoluminescent carbon nanoparticles, which are employed as important bioimaging devices. This chapter will elaborate on the use of different types of polymeric plastic for the synthesis of a variety of nanomaterials. The potential applications of the fabricated materials will also be discussed.

Electrospun nanofibers are a class of nanomaterials appropriate for various applications, such as smart films, filter membranes, catalytic supports, energy generation modules, conversion and storage, photonic and electronic sensors, biomedical scaffolding, and other devices. Electrospinning is a flexible and versatile technique for processing nanofiber materials; it consists of an electrohydrodynamic process in which liquids are electrified to create a beam and then stretched into fibers. The basic set up for electrospinning is relatively simple and, therefore, accessible to almost every laboratory. The main components are a high voltage DC power supply, a syringe device, a spinner, and a conductive collector. Due to the increasing consumption of polyethylene terephthalate-based products and their waste disposal issue, increasing environmental concern has led us to transform this waste into valuable products. This chapter focuses on the research studies of electrospun waste polyethylene terephthalate to produce nanofiber, applied in a different application.

The energy derived from the solar activity is a source that can help solve the high demand that humanity presents in terms of thermal energy, but shows disadvantages due to the changes in prolonged periods and to the variability in very short times. The fundamental thing to take advantage of the higher amount of thermal energy derived from the sun is to count on storage systems that accumulate that energy in the form of latent heat. For this purpose, materials that change from the solid phase to the liquid (Phase Change Materials (PCMs)) are used; this way of storing and reserving energy is beneficial because large amounts of material are available, working isothermally during storage and releasing the energy stored in its solidification process. One of the advantages of latent heat storage is that said energy storage and its consequent delivery are presented in a minimal temperature range, called inter-phase or transition zone. The PCMs have appropriate characteristics for the storage of energy. At present, a diverse range of these materials is known with which it has been experienced, obtaining promising results; The most widely used materials are salts and some organic and inorganic materials; It is important to emphasize that these materials are difficult to regenerate insofar as they are subjected to work cycles, noting the decrease in their storage efficiency and consequent dissociation, and on the contrary, paraffins (petroleum by-product) are economical materials with good behavior in storage and with acceptable energy storage ranges.

Aluminium drink cans, which are usually disposed of after use, led to sizable land pollution and environmental problems. The main target of this work is to utilize aluminium waste cans to produce nano-alumina that considered a significant oxide that has wide technological-and industrial-applications. The objectives of this study are to synthesize and characterize nano aluminium oxide (alumina) that produced from aluminium waste cans as well as to evaluate the synthesized alumina in the treatment of palm oil mill effluent (POME). In this study, the aluminium waste cans will be transformed into nano and micro-sized alumina by using the sol–gel method. The effect of ageing time and ageing temperature in synthesizing nano Al₂O₃ has been studied. The properties of the synthesized alumina were characterized via FTIR, XRD, SEM, EDX, and BET. The produced alumina was used as an adsorbent in the treatment of POME through adsorption. The experimental outcomes divulged that the powder of the produced alumina at room-temperature has aloft surface areas that being an appropriate property to be applied as an adsorbent in the treatment of POME. AL-6 h-30 °C gave the highest percentage of 29% in COD removal for POME. In short, the utilization of aluminium waste cans to produce nano Al₂O₃ is feasible. This economic and environmental-friendly route turned waste into valuable adsorbent that can be used extensively in the treatment of the POME.