RESUMEN
The superhydrophobic feature is highly desirable for oil/water separation (OWS) operation to achieve excellent separation efficiency. However, using hazardous materials in fabricating superhydrophobic surfaces is always the main concern. Herein, superhydrophobic filters were prepared via an eco-friendly approach by anchoring silica particles (SiO2) onto the cotton fabric surface, followed by surface coating using natural material-myristic acid via a dip coating method. Tetraethyl orthosilicate (TEOS) was used in the synthesis of SiO2 particles from the silica sol. In addition, the impact of the drying temperature on the wettability of the superhydrophobic filter was investigated. Moreover, the pristine cotton fabric and as-prepared superhydrophobic cotton filters were characterised based on Fourier-transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX) and contact angle (CA) measurement. The superhydrophobic cotton filter was used to perform OWS using an oil-water mixture containing either chloroform, hexane, toluene, xylene or dichloroethane. The separation efficiency of the OWS using the superhydrophobic filter was as high as 99.9%. Moreover, the superhydrophobic fabric filter also demonstrated excellent durability, chemical stability, self-healing ability and reusability.
RESUMEN
Nanomaterials can be incorporated in the synthesis of membrane to obtain mixed-matrix membrane with marked improvement in properties and performance. However, stability and dispersion of the nanomaterials in the membrane matrix, as well as the need to use high ratio of nanomaterials for obvious improvement of membrane properties, remain a major hurdle for commercialization. Hence, this study aims to investigate the improvement of polyamide 6,6 membrane properties with the incorporation of silver nanoparticles decorated on graphene oxide (Ag-GO) nanoplates and at the same time focus is given to the issues above. Graphene oxide nanoplates were synthesized using the modified Hummers' method and decorated with silver before embedded into the polyamide 6,6 matrix. Physicochemical characterizations were conducted on both nanoplates and the mixed-matrix Ag-GO polyamide 6,6 membrane. The issues of Ag agglomeration and leaching were not observed, which could be attributed to the decoration of Ag on GO that helped to disperse the nanomaterials and provided a better anchor point for the attachment of Ag nanoparticles. The synthesized membrane showed marked improvement regarding flux (135% increment) and antifouling (40% lower irreversible fouling), which could be ascribed to the more negative charge of membrane surface (-14 ± 6 to -31 ± 3.8 mV) and hydrophilicity (46% enhancement) of the membranes. With minimal embedment of Ag nanoparticles, the membrane showed superior antibacterial property where the E. coli bacteria could not form a single colony on the membrane surface. Overall, the decoration of Ag on GO nanoplates could be a promising approach to resolve the agglomeration and leaching issues as well as reduce the amount of precious Ag in the synthesis of Ag-GO polyamide 6,6 membrane.
