RESUMEN
The augmented demands of textile materials over time have brought challenges in the disposal of substantial volumes of waste generated during the processing and end of life of such materials. Taking into consideration environmental safety due to discarding of textile waste, it becomes critical to recuperate useful products from such waste for economic reasons. The present work deals with the preparation of porous and electrically conductive activated carbon fabric by a novel single stage method of simultaneous carbonization and physical activation of Kevlar feedstock material procured from local industries, for effective electromagnetic (EM) shielding applications. The Kevlar fabric waste was directly carbonized under a layer of charcoal without any intermediate stabilization step at 800 °C, 1000 °C, and 1200 °C, with a heating rate of 300 °C/h and without any holding time. The physical and morphological properties of the activated carbon, influenced by carbonization process parameters, were characterized from EDX, X-ray diffraction, SEM analysis, and BET analysis. Furthermore, the electrical conductivity was analyzed. Finally, the potential application of the activated material for EM shielding effectiveness was analyzed at low (below 1.5 GHz) and high (2.45 GHz) frequencies. The phenomena of multiple internal reflections and absorption of electromagnetic radiations was found dominant in the case of activated carbon fabric produced at higher carbonization temperatures.
RESUMEN
The presented study proposed simple and low-cost approach for improvement in UV protection and superhydrophobic properties of cotton fabrics by coating of mechanically activated fly ash particles. The maximum UV blocking was observed for 3 wt% fly ash, where UV transmittance decreased from 14.19% of untreated fabric to 0.11% of coated fabric. After subsequent treatment of Trimethoxy(octadecyl)silane (OTMS) on fly ash coated fabrics, the water contact angle was increased to 143°, 147° and 153° for fly ash concentration of 1, 2 and 3 wt% respectively. From Cassie-Baxter theories, the unwetted fraction of air pockets were estimated to be 43%, 55% and 67% respectively for 1, 2 and 3 wt% of fly ash particles. Furthermore, the coated fabrics showed great potentials for separation of floating oil layer, underwater oil droplet or oil/water mixture. The separation efficiency of 98%, 96%, 97% and 95% was obtained for selected model oils toluene, n-hexane, chloroform and petro ether, respectively.
