Abstract: In order to prepare an eco-friendly copper ion detection reagent, the paper selects dyes that can be complexed with copper ions to change color, using natural dye hematoxylin as the color developer, silk fabric and cotton fabric as the carrier to prepare a color-changing fabric. UV-Vis spectrophotometer was used to test the color change of hematoxylin and copper ions in the solution, and the color change of the colorchanging fabric was tested by a color measurement and color matching instrument. Results indicated that hematoxylin and copper ions in the solution can produce an obvious color reaction; the color-changing fabric can produce a color-changing response detected by the naked eye with a sensitive response when placed in a copper ion solution, and the detection sensitivity can meet the limit requirements of the comprehensive sewage discharge standard. In addition, silk fabric is better than cotton fabric as a carrier of color developer.

Key words: fabric; natural dyes; hematoxylin; heavy metal ion; color reaction