Nanotechnology is the creation, manipulation and use of materials at the nanometre size scale (1 to 100 nm). At this size scale there are significant differences in many material properties that are normally not seen in the same materials at larger scales. Although nanoscale materials can be produced using a variety of traditional physical and chemical processes, it is now possible to biologically synthesize materials via environment-friendly green chemistry based techniques. In recent years, the convergence between nanotechnology and biology has created the new field of nanobiotechnology that incorporates the use of biological entities such as actinomycetes algae, bacteria, fungi, viruses, yeasts, and plants in a number of biochemical and biophysical processes. The biological synthesis via nanobiotechnology processes have a significant potential to boost nanoparticles production without the use of harsh, toxic, and expensive chemicals commonly used in conventional physical and chemical processes. The aim of this review is to provide an overview of recent trends in synthesizing nanoparticles via biological entities and their potential applications.

The anodization of aluminum is an electro-chemical process that changes the surface chemistry of the metal, via oxidation, to produce an anodic oxide layer. During this process a self organized, highly ordered array of cylindrical shaped pores can be produced with controllable pore diameters, periodicity and density distribution. This enables anodic aluminum oxide (AAO) membranes to be used as templates in a variety of nanotechnology applications without the need for expensive lithographical techniques. This review article is an overview of the current state of research on AAO membranes and the various applications of nanotechnology that use them in the manufacture of nano-materials and devices or incorporate them into specific applications such as biological/chemical sensors, nano-electronic devices, filter membranes and medical scaffolds for tissue engineering.

Currently, the main drivers for developing Li‐ion batteries for efficient energy applications include energy density, cost, calendar life, and safety. The high energy/capacity anodes and cathodes needed for these applications are hindered by challenges like: (1) aging and degradation; (2) improved safety; (3) material costs, and (4) recyclability. The present review begins by summarising the progress made from early Li‐metal anode‐based batteries to current commercial Li‐ion batteries. Then discusses the recent progress made in studying and developing various types of novel materials for both anode and cathode electrodes, as well the various types of electrolytes and separator materials developed specifically for Li‐ion battery operation. Battery management, handling, and safety are also discussed at length. Also, as a consequence of the exponential growth in the production of Li‐ion batteries over the last 10 years, the review identifies the challenge of dealing with the ever‐increasing quantities of spent batteries. The review further identifies the economic value of metals like Co and Ni contained within the batteries and the extremely large numbers of batteries produced to date and the extremely large volumes that are expected to be manufactured in the next 10 years. Thus, highlighting the need to develop effective recycling strategies to reduce the levels of mining for raw materials and prevention of harmful products from entering the environment through landfill disposal.

Today there is a growing need to develop reliable, sustainable, and ecofriendly protocols for manufacturing a wide range of metal and metal oxide nanoparticles. The biogenic synthesis of nanoparticles via nanobiotechnology based techniques has the potential to deliver clean manufacturing technologies. These new clean technologies can significantly reduce environmental contamination and decease the hazards to human health resulting from the use of toxic chemicals and solvents currently used in conventional industrial fabrication processes. The largely unexplored marine environment that covers approximately 70% of the earth’s surface is home to many naturally occurring and renewable marine plants. The present review summarizes current research into the biogenic synthesis of metal and metal oxide nanoparticles via marine algae (commonly known as seaweeds) and seagrasses. Both groups of marine plants contain a wide variety of biologically active compounds and secondary metabolites that enables these plants to act as biological factories for the manufacture of metal and metal oxide nanoparticles.

The global demand for energy is increasing and the detrimental consequences of rising greenhouse gas emissions, global warming and environmental degradation present major challenges. Solar energy offers a clean and viable renewable energy source with the potential to alleviate the detrimental consequences normally associated with fossil fuel-based energy generation. However, there are two inherent problems associated with conventional solar thermal energy conversion systems. The first involves low thermal conductivity values of heat transfer fluids, and the second involves the poor optical properties of many absorbers and their coating. Hence, there is an imperative need to improve both thermal and optical properties of current solar conversion systems. Direct solar thermal absorption collectors incorporating a nanofluid offers the opportunity to achieve significant improvements in both optical and thermal performance. Since nanofluids offer much greater heat absorbing and heat transfer properties compared to traditional working fluids. The review summarizes current research in this innovative field. It discusses direct solar absorber collectors and methods for improving their performance. This is followed by a discussion of the various types of nanofluids available and the synthesis techniques used to manufacture them. In closing, a brief discussion of nanofluid property modelling is also presented.