Preparation and characterization of carbon microspheres from waste cotton textiles by hydrothermal carbonization

Abstract

Carbon microspheres were prepared from waste cotton fibers by hydrothermal carbonization (HTC) with the addition of copper sulphate in this work. The important influence factors, temperature, concentration of copper sulphate, resident time were explored here. The smooth and regular carbon microspheres could be formed at 330°C with 0.15 wt% copper sulphate after 6 h from waste cotton fibers. The crystal structures of cotton fibers were destructed in a short resident time with 0.15 wt% copper sulphate from SEM images and XRD patterns of solid products. This strategy provides a new, mild and efficient method to prepare carbon microspheres from waste cotton fibers by HTC. FTIR spectra verified that the abundant functional groups existed on the surface of synthesized carbon microspheres. From XPS and element analysis results, the copper sulphate participated in the forming process of carbon microspheres indeed. The presence of copper sulphate in the carbon microspheres provided a possibility for the application in antibacterial field. Besides, the catalytic mechanism of copper sulphate on the hydrolysis and carbonization of waste cotton fibers were also discussed. In conclusion, the copper sulphate is an efficient agent for preparing carbon microspheres by HTC from waste cotton fibers.