Among various classes of dyes, cationic (basic) dyes are
frequently used in acrylic, nylon, silk, and wool dyeing in
textile industry. As a result of good solubility of synthetic
dyes, they are one of the main contaminant to be identified
as water pollutants and may be found mostly in trace quantities
in industrial wastewaters. The presence of dyes in
water streams prevents light from penetration and has a
negative effect on photosynthesis. Properties such as recalcitrant
nature, toxicity, and non-biodegradability are the
result of complex structures of dyes; therefore, they are a
big threat to human and environmental health and must be
removed from wastewaters before discharging into water
bodies