Role of nanomaterials in water treatment applications: a review.

Graphene, an atomically thin two-dimensional carbonaceous material, has attracted tremendous attention in the scientific community, due to its exceptional electronic, electrical, and mechanical properties. Indeed, with the recent explosion of methods for a large-scale synthesis of graphene, the number of publications related to graphene and other graphene based materials has increased exponentially. Particularly the development of easy preparation methods for graphene like materials, such as highly reduced graphene oxide (HRG) via reduction of graphite oxide (GO), offers a wide range of possibilities for the preparation of graphene based inorganic nanocomposites by the incorporation of various functional nanomaterials for a variety of applications. In this review, we discuss the current development of graphene based metal and metal oxide nanocomposites, with a detailed account of their synthesis and properties. Specifically, much attention has been given to their wide range of applications in various fields, including electronics, electrochemical and electrical fields. Overall, by the inclusion of various references, this review covers in detail the aspects of graphene-based inorganic nanocomposites.

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Graphene based metal and metal oxide nanocomposites: synthesis, properties and their applications

Antibacterial applications of graphene-based nanomaterials: Recent achievements and challenges.

Bacteria mediated infections may cause various acute or chronic illnesses and antibiotic resistance in pathogenic bacteria has become a serious health problem around the world due to their excessive use or misuse. Replacement of existing antibacterial agents with a novel and efficient alternative is the immediate demand to alleviate this problem. Graphene-based materials have been exquisitely studied because of their remarkable bactericidal activity on a wide range of bacteria. Graphene-based materials provide advantages of easy preparation, renewable, unique catalytic properties, and exceptional physical properties such as a large specific surface area and mechanical strength. However, several queries related to the mechanism of action, significance of size and composition toward bacterial activity, toxicity criteria, and other issues are needed to be addressed. This review summarizes the recent efforts that have been made so far toward the development of graphene-based antibacterial materials to face current challenges to combat against the bacterial targets. This review describes the inherent antibacterial activity of graphene-family and recent advances that have been made on graphene-based antibacterial materials covering the functionalization with silver nanoparticles, other metal ions/oxides nanoparticles, polymers, antibiotics, and enzymes along with their multicomponent functionalization. Furthermore, the review describes the biosafety of the graphene-based antibacterial materials. It is hoped that this review will provide valuable current insight and excite new ideas for the further development of safe and efficient graphene-based antibacterial materials.

https://www.mdpi.com/2079-4991/9/5/737/pdf

Antibacterial Properties of Graphene-Based Nanomaterials

Complications related to infectious diseases have significantly decreased due to the availability and use of a wide variety of antibiotics and antimicrobial agents. However, excessive use of antibiotics and antimicrobial agents over years has increased the number of drug resistant pathogens. Microbial multidrug resistance poses serious risks and consequently research attention has refocused on finding alternatives for antimicrobial treatment. Among the various approaches, the use of engineered nanostructures is currently the most promising strategy to overcome microbial drug resistance by improving the remedial efficiency due to their high surface-to-volume ratio and their intrinsic or chemically incorporated antibacterial activity. Graphene, a two-dimensional ultra-thin nanomaterial, possesses excellent biocompatibility, putting it in the forefront for different applications in biosensing, drug delivery, biomedical device development, diagnostics and therapeutics. Graphene-based nanostructures also hold great promise for combating microbial infections. Yet, several questions remain unanswered such as the mechanism of action with the microbial entities, the importance of size and chemical composition in the inhibition of bacterial proliferation and adhesion, cytotoxicity, and other issues when considering future clinical implementation. This review summarizes the current efforts in the formulation of graphene-based nanocomposites with antimicrobial and antibiofilm activities as new tools to tackle the current challenges in fighting against bacterial targets. Furthermore, the review describes the features of graphene–bacterial interactions, with the hope to shed light on the range of possible mode of actions, serving the goal to develop a better understanding of the antibacterial capabilities of graphene-based nanostructures.

/pdf/antibacterial-activity-of-graphene-based-materials-3vup9mb8ry.pdf

Antibacterial activity of graphene-based materials

Graphene–Fe3O4 (G–Fe3O4) composite was prepared from graphene oxide (GO) and FeCl3·6H2O by a one-step solvothermal route. The as-prepared composite was characterized by field-emission scanning electron microscopy, transmission electron microscopy, dynamic light scattering and X-ray powder diffraction. SEM analysis shows the presence of Fe3O4 spheres with size ranging between 200 and 250 nm, which are distributed and firmly anchored onto the wrinkled graphene layers with a high density. The resulting G–Fe3O4 composite shows extraordinary adsorption capacity and fast adsorption rates for the removal of Pb metal ions and organic dyes from aqueous solution. The adsorption isotherm and thermodynamics were investigated in detail, and the results show that the adsorption data was best fitted with the Langmuir adsorption isotherm model. From the thermodynamics investigation, it was found that the adsorption process is spontaneous and endothermic in nature. Thus, the as-prepared composite can be effectively utilized for the removal of various heavy metal ions and organic dyes. Simultaneously, the photodegradation of methylene blue was studied, and the recycling degradation capacity of dye by G–Fe3O4 was analyzed up to 5 cycles, which remained consistent up to ∼97% degradation of the methylene blue dye. Although iron oxide has an affinity towards bacterial cells, its composite with graphene still show antibacterial property. Almost 99.56% cells were viable when treated with Fe3O4 nanoparticle, whereas with the composite barely 3% cells survived. Later, the release of ROS was also investigated by membrane and oxidative stress assay. Total protein degradation was analyzed to confirm the effect of the G–Fe3O4 composite on E. coli cells.

Mudaliar T. Vanchinathan

Papers

Adsorption, photodegradation and antibacterial study of graphene???Fe3O4 nanocomposite for multipurpose water purification application