Abstract: Carbonized materials were prepared by hydrothermal treatment of waste cotton fiber with terephthalic acid (TPA). The morphology, physical and chemical structural characteristics of the hydrothermally carbonized materials were investigated with scanning X-ray diffraction (XRD), Fouriertransform infrared spectrometer (FTIR), electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and elemental analysis. It shows that the hydrothermally carbonized waste cotton fiber is made up of irregular particles or rod-like substances which have amorphous carbon structure and contain rich oxygen functional groups on the surface. The rod-like substances increase along with the increasing of TPA content. However, only a small amount of TPA can be degraded or grafted onto the surface of the carbonized products while the rest arerecyclable. Results indicated that TPA did not involve in cotton fiber carbonization process directly, but its existence has increased the size and content of rod-like carbon products, and decreased the (C/O) atomic ratios when compared with pure cotton fiber carbonized products.

Key words: waste cotton fiber; terephthalic acid; hydrolysis; carbonization; hydrothermal conditions