Production and characterization of activated carbon from industrial textile waste through chemical and physical activation methods

The aim of this study is to produce activated carbon from three different textile wastes through chemical and physical activation methods. Activated carbon was obtained from raw textile wastes and from these wastes after carbonization at 500 °C using KOH as the chemical activating agent, and the characterization of the resulting activated carbons was carried out. In addition, activated carbon was produced from raw textile wastes by the physical activation method, and the characterization of the obtained activated carbons was performed. The textile wastes used in this study consist of black yarn waste generated during denim fabric production processes (80% cotton, 20% polyester), denim fabric waste (98.5% cotton, 1.5% elastane), and sized warp yarn waste (100% cotton). These wastes were used both in their raw form and after applying a carbonization process. For the carbonization process, the textile wastes were heated to 500 °C at a heating rate of 10 °C/min under a nitrogen gas flow rate of 100 mL/min, and carbonization was carried out by holding the maximum temperature for 1 hour. Textile wastes carbonized at 500 °C and raw textile wastes were impregnated with KOH at weight ratios of 1:1, 1:2, and 1:3 (1 part carbonized material to 3 parts KOH) using distilled water. After impregnation, the samples were dried in an oven and then activated in a cylindrical furnace at a maximum temperature of 800 °C with a heating rate of 10 °C/min under a nitrogen flow rate of 100 mL/min for 1 hour. As a result of the chemical activation of carbonized products, the highest surface area (1826.98 m²/g) was obtained for the CD17K2 (denim fabric waste) sample treated with KOH at a 1:2 ratio. For the raw textile wastes, the highest surface area (1181.21 m²/g) was determined for the CD17H1 (denim fabric waste) sample treated with KOH at a 1:1 ratio. In the physical activation process, raw textile waste samples consisting of denim fabric waste and black yarn waste (PBD and SUI) were heated at a rate of 10 °C/min to a maximum temperature of 600 °C and held for 1 hour. Subsequently, the temperature was increased to 950 °C at a heating rate of 10 °C/min and maintained for 30 minutes, during which steam was introduced at 900 °C. Among the activated carbons obtained by physical activation, the lowest surface area was found to be 574.26 m²/g for SUIFA (black yarn waste), while the highest surface area was 656.02 m²/g for PBDFA (denim fabric waste). The physicochemical characteristics of the activated carbons obtained from carbonized and raw textile wastes were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) surface area analysis, elemental analysis, and Fourier transform infrared spectroscopy (FT-IR).