الفهرس | Only 14 pages are availabe for public view |
Abstract The separation of oil-in-water emulsions has become an extremely important for both environmentally and industrial related applications. Herein, graphene-based foam (rGO@MF) was developed and utilized for separating various heavy oil-in-water emulsions as well as oil/water mixtures. The superhydrophobic sponge was engineered through facile surface-treatment and hydrothermal steps. The surface and structural properties of the rGO@MF sponge and the nanoemulsions were thoroughly characterized by advanced techniques. The high-resolution SEM and EDX mapping confirmed the homogeneous distribution of rGO sheets surrounding the fibers. The developed rGO@MF foam showed excellent chemical stability and durability. The correlation between the oil type, droplet size and concentration of oil/water mixtures and emulsions, and the rGO@MF adsorption capacity and removal efficiency, were extensively investigated. For the oil/water mixture, the rGO@MF modified foam showed excellent adsorption performance for various oils and organic solvents exhibited high adsorption capacity up to 140 g/g for chloroform. In addition to, the adsorption capacity of the rGO@MF modified foam even reach up 127 g/g for chloroform after it was reused 10 times by squeezing. The developed superhydrophobic rGO@MF foam showed water contact angle of " ~ "164º and exhibited superior adsorption capacity and removal efficiency of up to 5647 mg/g and 95±3% respectively, for crude oil-in-water of 30 g/l. Besides, the rGO@MF modified sponge is demonstrated to have excellent recyclability. The adsorption capacity of the rGO@MF modified foam even reach up to 92% after it was reused 10 times by squeezing. The rGO@MF foam maintained its high separation performance over ten consecutive adsorption cycles. The calculated activated adsorption energy for crude oil-in-water emulsion on rGO@MF foam was 16.59 kJ mol-1 indicating a physical adsorption process. The adsorption kinetics and interactions were carefully explored and a general mechanism of separation for both oil-in-water nanoemulsions and oil/water mixtures was introduced. In addition to rGO@MF foams its practical application as flexible strain sensors of different dimensions. These unique foam show enhanced mechanical strength and excellent electromechanical properties, which possesses the capability of detecting multiple deformation forms including tensile strain, impact, bending, and twisting. |