Gerrard E J Poinern

Globally, the presence of microplastic materials in the environment is widespread, and their largest concentrations can be found in coastal ecosystems and within mid-ocean gyres. Since the inception of mass plastic product manufacturing in the middle of the twentieth century, these durable, lightweight, and inexpensive materials have been, and continue to be, extensively exploited by humans. However, the presence of large numbers of microplastics in marine ecosystems in recent years has become a serious environmental issue that has attracted widespread interest in both the scientific and the broader community at large. In particular, the ingestion and subsequent detrimental health effects on many marine species are the most noticeable and alarming impacts of microplastics. Furthermore, recent studies have also shown microplastics can accumulate, concentrate, and act as vectors for conveying toxic pollutants within the food chain. Another feature of microplastics is their ability to transport marine species from one ecosystem to another where they become threats to local indigenous marine species. Because of the serious nature of microplastic pollution, it is important to understand their impact on coastal ecosystems and ocean gyres. This chapter discusses four aspects of microplastic pollution: 1) sources of both primary and secondary microplastics; 2) their physical and chemical behavioral properties; 3) bioavailability and behavioral properties of microplastics and their interactions with marine organisms; and 4) future perspectives, which highlights key areas of research needed to elucidate the effects of microplastic pollution in the marine environment. Importantly, understanding these four aspects of microplastic pollution will assist in directing future marine pollution research and assist policymakers to develop appropriate management strategies.

Calcium carbonate (CaCO3) micro/nanoparticles have attracted considerable medical research interest in therapeutic applications such as controlled pharmaceuticals for cancer treatment, tumor imaging, and gene therapy. The advantages of using CaCO3 micro/nanoparticles in these applications arise from their properties. Some of these advantageous properties include pH sensitivity, biocompatibility, safety, and biodegradability. Crucially, CaCO3 micro/nanoparticles are stable at normal physiological pH (~ 7.3) in the blood circulation system, while in more acidic pH tumor environments, they readily decompose. Thus, the slow degradation of their porous core allows these particles to be employed as carriers for contrast agents used in biomedical imaging procedures or utilized as sustained-release carriers for the targeted delivery of anticancer drugs and gene therapies. The chapter provides an overview of recent research into developing delivery carriers based on CaCO3 micro/nanoparticles for the transport of pharmaceutical agents to tumors. The study discusses cancer, the advantages of using a nanomedicine approach for treating cancer, and various methods for producing CaCO3 micro/nanoparticles. This is followed by a summary of the current research into using CaCO3-based particles for biomedical imaging, targeted drug delivery, and gene therapy. Notably, the chapter highlights the potential use of CaCO3 micro/nanoparticles as a safe and efficient drug delivery platform for cancer treatment.

Over the course of more than a century, our society, as well as its prosperity, has benefited from the burning of hydrocarbon-based fossil fuels (FF) to generate energy. However, the burning of FFs has disrupted the natural environment through the release of toxic gases like carbon dioxide (CO2), nitrous oxide, and methane. Despite this, the usage of FFs is predicted to continue increasing at a rate of 1.3% per year up until the year 2030, thereby increasing greenhouse gas emissions and exacerbating global climate change. The aviation sector plays a pivotal role in the modern world in facilitating communication, trade, and marketing on a global scale. It is also a major contributor to the production of greenhouse gases like CO2. An alternative to FFs for aviation are biofuels, which can be simply described as any energy-rich chemical generated from biomass. Biofuels are special because they combine many desirable qualities in one product. For instance, they are renewable, biodegradable, low toxic, diverse, and easily available. Nanometer-scale catalysts play an important role in producing renewable biofuels under ecologically benign settings. The development of catalytic nanomaterials has been prioritized, along with biodiesel and high-density fuels, as an important area of study. Nanocatalysts such as solid-state catalysts are reusable and due to their nano size are highly active, similar to the properties of homogeneous catalysts. Furthermore, they exhibit novel and distinctive catalytic activities that are unachievable by similar materials with dimensions larger than the nanometer scale. This chapter focuses on Fischer-Tropsch synthesis as the downstream technology for sustainably producing aviation fuels. All reactions and mechanisms, the synthesis procedure, and the characterization of the nanocatalysts, including other related properties and processes, are discussed in the chapter.

This chapter presents an overview of the status of research into inorganic membranes and solid oxide electrolysis cells. Both can be used for gas separation, while solid oxide-based membrane fuel cell research has focused on generating electrical energy. Microporous membranes made from silica, carbon, and zeolite are initially discussed, before dense metallic and ceramic membranes are considered. Progress made toward developing fluorites and perovskite materials for membrane technologies is also discussed. This is followed by an overview of recent progress into high-temperature solid oxide cells for gas separation processes and fuel cell applications and discusses the basic operating principles of both electrolysis and fuel cells. In addition, challenges in designing high-performance electrodes, electrolytes, and issues relating to degradability and long-term durability are also examined. Crucially, the thermal energy needed to operate solid oxide cells can be supplied from external sources like industrial waste heat. In the electrolysis mode, electrical energy from renewable energy sources can be used to power these cells. In the fuel cell mode, these cells are promising electrochemical conversion devices with high electrical efficiencies and fuel flexibility. Typically, gases like hydrogen (H2) and oxygen (O2, usually from air) are supplied, and through the electrochemical oxidation of H2 (as fuel), electrical energy is generated. The review concludes with a discussion of the challenges facing these devices, and future research needed for further development. It is believed that future developments in producing new nanomaterials and improvements in material properties of existing materials, combined with advanced fabrication processes, will deliver commercially viable and large-scale manufacturing of these devices soon.

Silico-doped hydroxyapatite is currently being investigated as a promising biocompatible material for use in a number of dental and bone restorative procedures. Silicon's beneficial effects include promoting biological mineralization and bone formation. In this chapter's study, work silicon-doped (3% and 7%) nanometer-scale hydroxyapatite powders were synthesized using a combined ultrasonic and microwave heating-based method before being annealed at either 400 °C or 800 °C. Subsequent XRD pattern analysis revealed the silicon-doped hydroxyapatite powders had a crystalline nature. Increasing silicon content was found to inhibit grain growth and reduce crystallinity. X-ray peak broadening analysis revealed that increasing amounts of silicon in the hydroxyapatite lattice structure produced distortion that increased lattice constants, the unit cell volume, and lattice strain. Both FT-IR and EDS analysis techniques revealed (SiO4)4- ions were being substituted for (PO4)3- ions in the hydroxyapatite lattice structure. In addition, electron microscopy studies found the presence of silicon in the hydroxyapatite lattice structure inhibited grain growth. Image analysis also confirmed increasing silicon content reduced grain growth and influenced grain morphology.

The present study evaluates the potential use of graphene oxide (GO) and reduced graphene oxide (RGO) additives to improve the photothermal response and evaporation rates of basin water used in solar thermal stills. The prepared GO-based and RGO-based test solutions were dilute, well dispersed, and stable. Improvements in photothermal response and evaporation rates were found to be significant. The best-performing fluid was the 30% RGO stock solution-based water solution, which achieved a temperature enhancement of 5.2% and a significant evaporation rate improvement of 30.5% compared to pure water samples. Importantly, the evaporation rates achieved were at relatively lower solution temperatures that were typically between 39 and 41 °C, thus highlighting the advantage of adding either GO or RGO to basin water to improve evaporation rates for solar thermal stills operating at lower temperatures. All GO- and RGO-based solutions displayed excellent dispersion stability over the investigated temperature range.

In this book, we summarize and discuss current research efforts aimed at mitigating the effects of three global challenges facing humanity. The increasing rapid growth of the global population and industrialization is not only creating serious problems for humanity today, but it is also creating challenges for the future [1]. The result of increasing global population growth and industrialization is greater demand for both energy and water. Thus, industrialization, economic growth, and improving human health are all dependent on energy and water. The sustainable management of both resources must be achieved to overcome the challenges of climate change and deliver food security. Crucially, both challenges are exacerbated by population growth, industrial development, and diminishing natural resources [2]. Fossil fuels are predominantly used to address the current energy demand. These fuels supply around 86% of the energy needed to power the world's economy. Significantly, over the next 20 years, the global population is expected to increase by 1.5 billion and will result in a total global population of around 8.8 billion people [3]. And because of the reliance on fossil fuels, the population increase will also translate into larger quantities of harmful greenhouse gases being discharged into the atmosphere. The detrimental impact of accumulating greenhouse gases in the atmosphere is a very serious problem. Recent studies have highlighted the need to limit global temperature rises to no more than 2 °C of pre-industrial levels [4,5]. Consequently, global decarbonization of electricity generation, industrial and transportation sectors must immediately take place to reduce the global warming trend [6].

Rising population, climate change, pests and pathogens, environmental contamination, and rising demands for water and energy are all putting significant strains on the world's agricultural systems. Nanotechnology (NT) has a critical role in delivering advanced biotechnological solutions for many of the challenges facing agriculture today. Eco-friendly nanoparticle-based carrier systems can deliver bioengineered sustainable agrochemicals to improve crop productivity and reduce environmental degradation. Nanomaterials have unique properties such as extremely small sizes and large surface areas and can be used as controlled release carriers for the delivery of inorganic, organic, and genetic materials for many agricultural applications. Several studies have already reported the positive effect of nano-fertilizers and nano-pesticides on crop production. Nanomaterial-based carrier systems can also be used to deliver genes directly into plant cells and enhance genome editing efficiency. This chapter summarizes the current efforts being made to develop nanomaterial-based carrier systems for the delivery of the next generation of agrochemicals and genetic materials. Pathogen control through nano-pesticides and nutrient delivery through nano-fertilizers are discussed for five major global crops, namely rice, wheat, maize, potato, and chickpea. The chapter also discusses nanomaterial-based technologies that can be used to overcome barriers associated with gene therapy and genome editing. It is believed that advances in this field will greatly assist in improving crop quality and productivity, thereby providing environmentally friendly and sustainable food security to the ever-increasing global population. Moreover, given the fast evolution of nanotechnologies in the device sphere, this chapter also discusses the potential for fabrication, control, manipulation, and engineering of DNA bases at the molecular level with atomic force microscopy AFM-based scanning probes like Dip-Pen lithography.

Increasing food production levels to feed an ever-growing global population has also inevitably created a large and ever-growing amount of food waste. The disposal of increasingly larger amounts of food waste has a serious impact on the environment. In recent years, there has been significant interest in waste valorization strategies for converting and managing food waste by developing new sustainable manufacturing processes. The present work summarizes current global waste valorization strategies and the various physical, physicochemical and biological processes that can be used to manufacture valorized products. While future perspectives are also discussed.