We report a novel application of using orange peel as a new natural dyestuff with strong ultraviolet
absorbance. Orange peel (OP) is an abundant, cheap and readily available agricultural byproduct. Water
extracts from OP were used to dye wool fabrics. Effects of extraction temperature and time on UVeVis
absorbance of the extracted liquor, and effects of dyeing methods and conditions, including pH value,
temperature, time and concentration of OP extracts on the colors of the dyed wool fabrics, were studied.
OP extracts can be readily sorbed by wool directly, with aluminum or iron mordants, both of which are
benign to the environment and human health. The optimum dyeing conditions included dyeing
temperature of 100
C, dyeing time of 120 min, pH 3 for direct dyeing and pH 7e9 for one-bath mordant
dyeing. All the dyed wool fabrics demonstrated good colorfastness to washing with soap, good color-fastness to rubbing and acceptable colorfastness to light. Furthermore, OP extracts had strong and
durable UV-protection properties. The value of UV-protection Factor (UPF) of the wool fabric dyed with
OP extracts using direct dyeing method was about 6 times higher than that of the wool fabric dyed with
normal synthetic dyes with similar shade and depth of shade. After 30 home laundering cycles, theUPF
value of the former was still about 4 times higher than that of the latter. In general, the abundantly
available agricultural byproduct OP has great potential to be utilized as a natural textile dyestuff that
could impart textiles with remarkable UV-protection properties.