A detailed analysis of the thermal expansion mechanism of graphite oxide to produce functionalized graphene sheets is provided. Exfoliation takes place when the decomposition rate of the epoxy and hydroxyl sites of graphite oxide exceeds the diffusion rate of the evolved gases, thus yielding pressures that exceed the van der Waals forces holding the graphene sheets together. A comparison of the Arrhenius dependence of the reaction rate against the calculated diffusion coefficient based on Knudsen diffusion suggests a critical temperature of 550 °C which must be exceeded for exfoliation to occur. As a result of their wrinkled nature, the functionalized and defective graphene sheets do not collapse back to graphite oxide but are highly agglomerated. After dispersion by ultrasonication in appropriate solvents, statistical analysis by atomic force microscopy shows that 80% of the observed flakes are single sheets.

Single Sheet Functionalized Graphene by Oxidation and Thermal Expansion of Graphite

Application of low-cost adsorbents for dye removal – A review

A novel superhydrophilic and underwater superoleophobic hydrogel-coated mesh for oil/water separation.

PROMETHEE: A comprehensive literature review on methodologies and applications

The construction of nanoporous membranes is of great technological importance for various applications, including catalyst supports, filters for biomolecule purification, environmental remediation and seawater desalination. A major challenge is the scalable fabrication of membranes with the desirable combination of good thermal stability, high selectivity and excellent recyclability. Here we present a self-assembly method for constructing thermally stable, free-standing nanowire membranes that exhibit controlled wetting behaviour ranging from superhydrophilic to superhydrophobic. These membranes can selectively absorb oils up to 20 times the material's weight in preference to water, through a combination of superhydrophobicity and capillary action. Moreover, the nanowires that form the membrane structure can be re-suspended in solutions and subsequently re-form the original paper-like morphology over many cycles. Our results suggest an innovative material that should find practical applications in the removal of organics, particularly in the field of oil spill cleanup.

Superwetting nanowire membranes for selective absorption

This paper reviews the synthesis and the absorbing properties of the wide variety of porous sorbent materials that have been studied for application in the removal of organics, particularly in the area of oil spill cleanup. The discussion is especially focused on hydrophobic silica aerogels, zeolites, organoclays and natural sorbents many of which have been demonstrated to exhibit (or show potential to exhibit) excellent oil absorption properties. The areas for further development of some of these materials are identified.

/pdf/porous-materials-for-oil-spill-cleanup-a-review-of-synthesis-1pffbcod1y.pdf

Porous Materials for Oil Spill Cleanup: A Review of Synthesis and Absorbing Properties

Adsorption of hydrocarbons on organo-clays - implications for oil spill remediation

/pdf/raman-and-infrared-spectroscopy-of-selected-vanadates-1j78q46q35.pdf

Raman and infrared spectroscopy of selected vanadates.

Surface characterisation of selected sorbent materials for common hydrocarbon fuels

https://core.ac.uk/download/pdf/10873182.pdf

Onuma Carmody

Papers

Porous Materials for Oil Spill Cleanup: A Review of Synthesis and Absorbing Properties

Adsorption of hydrocarbons on organo-clays - implications for oil spill remediation

Raman and infrared spectroscopy of selected vanadates.

Surface characterisation of selected sorbent materials for common hydrocarbon fuels

Molecular structure of the uranyl mineral andersonite—a Raman spectroscopic study