scholarly journals Titanium Dioxide/Graphene and Titanium Dioxide/Graphene Oxide Nanocomposites: Synthesis, Characterization and Photocatalytic Applications for Water Decontamination

Catalysts ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 491 ◽  
Author(s):  
Amr Tayel ◽  
Adham Ramadan ◽  
Omar El Seoud
Keyword(s):  
Titanium Dioxide ◽  
Graphene Oxide ◽  
Band Gap Energy ◽  
Water Decontamination ◽  
Photogenerated Electrons ◽  
Recent Developments ◽  
Low Toxicity ◽  
Light Absorbance ◽  
Photocatalytic Applications ◽  
Positive Holes

The use of titanium dioxide, TiO2 as a photocatalyst in water decontamination has witnessed continuous interest due to its efficiency, stability, low toxicity and cost-effectiveness. TiO2 use is limited by its large band gap energy leading to light absorbance in the UV region of the spectrum, and by the relatively fast rate of recombination of photogenerated electrons and positive holes. Both limitations can be mitigated by using carbon-TiO2 nanocomposites, such as those based on graphene (G) and graphene oxide (GO). Relative to bare TiO2, these nanocomposites have improved photocatalytic activity and stability under the UV–visible light, constituting a promising way forward for improved TiO2 photocatalytic performance. This review focuses on the recent developments in the chemistry of TiO2/G and TiO2/GO nanocomposites. It addresses the mechanistic fundamentals, briefly, of TiO2 and TiO2/G and TiO2/GO photocatalysts, the various synthesis strategies for preparing TiO2/G and TiO2/GO nanocomposites, and the different characterization techniques used to study TiO2/G and TiO2/GO nanocomposites. Some applications of the use of TiO2/G and TiO2/GO nanocomposites in water decontamination are included.

Graphene Oxide and Its Derivatives: Their Synthesis and Use in Organic Synthesis

2019 ◽  
Vol 23 (2) ◽  
pp. 188-204 ◽  
Author(s):  
Xiangjun Peng ◽  
Xianyun Xu ◽  
Fujiang Huang ◽  
Qian Liu ◽  
Liangxian Liu
Keyword(s):  
Graphene Oxide ◽  
Carbon Materials ◽  
Device Fabrication ◽  
Organic Reactions ◽  
Bond Forming ◽  
Bond Forming Reactions ◽  
Modern Physics ◽  
Recent Developments ◽  
Optical And Mechanical Properties ◽  
Nitrogen Double Bond

Since Geim and co-workers reported their groundbreaking experiments on graphene, research on graphene oxide (GO) and its derivatives has greatly influenced the field of modern physics, chemistry, device fabrication, material science, and nanotechnology. The unique structure and fascinating properties of these carbon materials can be ascribed to their eminent chemical, electronic, electrochemical, optical, and mechanical properties of GO and its derivatives, particularly compared to other carbon allotropes. The present Review aims to provide an overview on the recent developments in the preparation of GO and its derivatives and their applications in organic reactions. We will first outline the synthesis of GO and its derivatives. Then, we will discuss the major sections about their application as stoichiometric and catalytic oxidants in organic reactions, a particular emphasis on the carbon-carbon, carbon-oxygen, and carbon-nitrogen single bond-forming reactions, as well as carbon-oxygen and carbon-nitrogen double bond-forming reactions. Simultaneously, this Review also describes briefly transition metal supported on GO or its derivatives as a catalyst for organic reaction. Lastly, we will present an outlook of potential areas where GO and its derivatives may be expected to find utility or opportunity for further growth and study.

Graphene: Insights on Biological, Radiochemical and Ecotoxicological Aspects

2021 ◽  
Vol 17 (1) ◽  
pp. 131-148
Author(s):  
Xing Haixia ◽  
Aline Oliveira da Silva de Barros ◽  
Francisco do Vale Chaves e Mello ◽  
Fan Sozzi-Guo ◽  
Cristina Müller ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Graphene Quantum Dots ◽  
Covalent Bonds ◽  
Cell Internalization ◽  
Functional Density Theory ◽  
Ecotoxicological Evaluation ◽  
Plasmatic Membrane ◽  
Low Toxicity ◽  
The Impact

Graphene, including graphene quantum dots, its oxide and unoxidized forms (pure graphene) have several properties, like fluorescence, electrical conductivity, theoretical surface area, low toxicity, and high biocompatibility. In this study, we evaluated genotoxicity (in silico analysis using the functional density theory-FDT), cytotoxicity (human glioblastoma cell line), in vivo pharmacokinetics, in vivo impact on microcirculation and cell internalization assay. It was also radiolabeled with lutetium 177 (177Lu), a beta emitter radioisotope to explore its therapeutic use as nanodrug. Finally, the impact of its disposal in the environment was analyzed using ecotoxicological evaluation. FDT analysis demonstrated that graphene can construct covalent and non-covalent bonds with different nucleobases, and graphene oxide is responsible for generation of reactive oxygen species (ROS), corroborating its genotoxicity. On the other hand, non-cytotoxic effect on glioblastoma cells could be demonstrated. The pharmacokinetics analysis showed high plasmatic concentration and clearance. Topical application of 0.1 and 1 mg/kg of graphene nanoparticles on the hamster skinfold preparation did not show inflammatory effect. The cell internalization assay showed that 1-hour post contact with cells, graphene can cross the plasmatic membrane and accumulate in the cytoplasm. Radio labeling with 177Lu is possible and its use as therapeutic nanosystem is viable. Finally, the ecotoxicity analysis showed that A. silina exposed to graphene showed pronounced uptake and absorption in the nauplii gut and formation of ROS. The data obtained showed that although being formed exclusively of carbon and carbon-oxygen, graphene and graphene oxide respectively generate somewhat contradictory results and more studies should be performed to certify the safety use of this nanoplatform.

Sunlight assisted degradation of dye molecules and reduction of toxic Cr(vi) in aqueous medium using magnetically recoverable Fe3O4/reduced graphene oxide nanocomposite

RSC Advances ◽  
2016 ◽  
Vol 6 (13) ◽  
pp. 11049-11063 ◽  
Author(s):  
Purna K. Boruah ◽  
Priyakshree Borthakur ◽  
Gitashree Darabdhara ◽  
Chaitanya K. Kamaja ◽  
Indrapal Karbhal ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Aqueous Medium ◽  
Reduced Graphene Oxide ◽  
Dye Molecules ◽  
Reduced Graphene ◽  
Magnetically Recoverable Catalysts ◽  
Recoverable Catalysts ◽  
Photocatalytic Applications

In view of the significant impact of magnetically recoverable catalysts in photocatalytic applications, Fe3O4/rGO nanocomposite photocatalyst was synthesized and utilized as an efficient photocatalyst for the degradation of dye molecules and reduction of the toxic Cr(vi).

scholarly journals Nanocomposites of Chitosan/Graphene Oxide/Titanium Dioxide Nanoparticles/Blackberry Waste Extract as Potential Bone Substitutes

Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3877
Author(s):  
Carlos Humberto Valencia-Llano ◽  
Moisés A. Solano ◽  
Carlos David Grande-Tovar
Keyword(s):  
Titanium Dioxide ◽  
Graphene Oxide ◽  
New Technologies ◽  
Bone Structure ◽  
Bone Cells ◽  
Critical Size ◽  
Titanium Dioxide Nanoparticles ◽  
Bone Substitutes ◽  
Critical Size Defect ◽  
Waste Extract

New technologies based on nanocomposites of biopolymers and nanoparticles inspired by the nature of bone structure have accelerated their application in regenerative medicine, thanks to the introduction of reinforcing properties. Our research incorporated chitosan (CS) covalently crosslinked with glutaraldehyde (GLA) beads with graphene oxide (GO) nanosheets, titanium dioxide nanoparticles (TiO2), and blackberry processing waste extract (BBE) and evaluated them as partial bone substitutes. Skullbone defects in biomodels filled with the scaffolds showed evidence through light microscopy, scanning electron microscopy, histological studies, soft tissue development with hair recovery, and absence of necrotic areas or aggressive infectious response of the immune system after 90 days of implantation. More interestingly, newly formed bone was evidenced by elemental analysis and Masson trichromacy analysis, which demonstrated a possible osteoinductive effect from the beads using the critical size defect experimental design in the biomodels. The results of this research are auspicious for the development of bone substitutes and evidence that the technologies for tissue regeneration, including chitosan nanocomposites, are beneficial for the adhesion and proliferation of bone cells.

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