Three-Dimensionally Bonded Hydrophobic Spongy Graphene with Super Compressive Elasticity for Oil-Water Separation

  • Oscar Bagoole

Student thesis: Master's Thesis

Abstract

Pollution by crude oil and its constituents as well as various organic solvents is a cause for dire environmental and marine life problems every year. Conventional methods and materials like oil skimmers, combustion, expandable pearlite and zeolites to name a few have been used to tackle the problem since the discovery of the off shore drilling. However, the chronic issue with these methods is the low oil loading capacity and undesired water intake. Moreover, some microporous polymers have also been experimented upon as sorbents, these show relatively high absorption ability but they have a drawback of high cost of manufacture and unknown environmental hazards. Therefore, three-dimensional(3D) graphene sponge is an invaluable and feasible substitute to various natural absorbers and organic materials due to the intrinsic oleophilic nature of the graphene. In this dissertation, modified Hummer's method has been used to prepare graphene oxide (GO) solution that ultimately is used to fabricate 3D graphene sponges. The 3D graphene sponges are functionalized through a low-cost and facile vapor-based surface enhancement approach. Functionalization of graphene sponge by Trichloro(1H,1H,2H,2H-perfluorooctyl)silane modified the wettability properties leading to a super hydrophobic nature with adsorption weight gains in excess of 3300% for crude oil. The measured contact angle in water is found to be in excess of 160°. Furthermore, the elastic compression modulus of 3D-Graphene sponge which is measured through a series of compression tests is found to be about 22.3 kPa. These mechanical properties give a surface area that is ideal for maximum adsorption of not only crude oil but also diesel and other types of oil. Equilibrium modeling of the oil removal process through Langmuir, Freundlich, Temkin and Dubinin–Radushkevich Isotherms isotherms confirms the properties as an exceptional absorbent for crude, diesel oil and hexane. The sorbed oils can be removed from within the sponges by heat treatment. The sorption capacity of the sponge was found to decrease by only 5% after 5 sorbing and resorbing cycles.
Date of AwardMay 2017
Original languageAmerican English
SupervisorAmal Al Ghaferi (Supervisor)

Keywords

  • Water Decontamination
  • Oil Pollution
  • Oil Cleanup
  • 3D
  • Graphene Sponges.

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