The excellent electrical conductivity and ease of functionalization make graphene a promising material for use in enzymatic bioelectrodes and biofuel cells. Enzyme based biofuel cells have attracted substantial interest due to their potential to harvest energy from organic materials. This review provides an overview of the functional properties and applications of graphene in the construction of biofuel cells as alternative power sources. The review covers the current state-of-the-art research in graphene based nanomaterials (physicochemical properties and surface functionalities), the role of these parameters in enhancing electron transfer, the stability and activity of immobilized enzymes, and how enhanced power density can be achieved. Specific examples of enzyme immobilization methods, enzyme loading, stability and function on graphene, functionalized graphene and graphene based nanocomposite materials are discussed along with their advantages and limitations. Finally, a critical evaluation of the performance of graphene based enzymatic biofuel cells, the current status, challenges and future research needs are provided.

Polymethylmethacrylate-graphene (PMMA/RGO) nanocomposites were prepared via in situ bulk polymerization using two different preparation techniques. In the first approach, a mixture of graphite oxide (GO) and methylmethacrylate monomers (MMA) were polymerized using a bulk polymerization method with a free radical initiator. After the addition of the reducing agent hydrazine hydrate (HH), the product was reduced via microwave irradiation (MWI) to obtain R-(GO-PMMA) composites. In the second approach, a mixture of graphite sheets (RGO) and MMA monomers were polymerized using a bulk polymerization method with a free radical initiator to obtain RGO-(PMMA) composites. The composites were characterized by FTIR, 1 H-NMR and Raman spectroscopy and XRD, SEM, TEM, TGA and DSC. The results indicate that the composite obtained using the first approach, which involved MWI, had a better morphology and dispersion with enhanced thermal stability compared with the composites prepared without MWI.

Increased industrial and agricultural activity has affected the availability of phosphorus (P) in nature and has caused a significant imbalance in the P cycle with long-term consequences on ecosystem health and sustainability. While P is an essential element for food production as well as plant and animal nutrition, it is also a limited nonrenewable resource whose availability is expected to decrease in the next century. Widespread application of P-based fertilizers and their excessive accumulation in water bodies leads to eutrophication which is associated with overgrowth of harmful algal blooms and degradation of water quality. This paper provides an overview of contemporary challenges and methodologies for improving P use efficiency and sustainability in the environment. Technologies and processes for the removal of P-containing compounds from water through the use of functional nanomaterial sorbents with tailored surface properties for capture, removal, and recycling are described. Various classes of materials including carbon-based, zeolites, mesoporous silica, metal organic frameworks, metal oxides and hydroxides, biomass-derived materials, and P-binding receptors are reviewed along with their properties, binding affinity, and adsorption capacity. The potential of these materials to control the amount of P in the environment and create decision support tools for water resource management is also discussed, with examples of applications.

Ionotropic alginate hydrogels are versatile materials for a wide range of applications. Their biocompatibility and biodegradability have made them perfect candidates for biomedical applications such as tissue engineering and drug...

A review describing functional nanostructures for portable and printable enzyme biosensors. Specific physicochemical and surface properties of nanoparticles used as carriers and sensing components and their assembly are discussed with an overview of current and emerging techniques enabling large scale roll-to-roll fabrication and miniaturization. Their integration in flexible, wearable and inexpensive point-of-use devices, and implementation challenges are also provided with examples of applications.