The mixed dye used consists of mixture between methyl
orange (MO), naphthol blue black (NBB), reactive blue 2 (RB
2), methylene blue (MB), direct red 81 (DR 81) and rhodamine
6G (Rh 6G). The 300 ml of 1000 ppm mixed dye stock solution
was prepared by mixing each 50 ml of 1000 ppm stock solution
for six mentioned dyes. The dye solution was stirred continuously
for 3 min using magnetic bar. The prepared dye solution
Fig. 1. UV–vis absorption spectra of six types of dyes and mixed dye.
was transferred and sealed in volumetric flask and kept overnight
in the dark to attain equilibrium and to avoid preactivation by
room light or sunlight. Then, 10 ppm mixed dye was prepared
from the stock solution with addition of 0.1 M NaCl as supporting
electrolyte. The UV–vis spectra of mixed dye and other six
dyes (10 ppm) are shown in Fig. 1.
The textile effluents were collected from a local textile factory.
The effluent was stored at 0 ◦C in volumetric flasks and
used without previous filtration. Two types of textile effluents
were obtained namely raw and pre-treated. The raw textile effluent
refers to the original disposal from the textile furnishing and
finishing process while textile effluent with pre-treatment had
undergone coagulation–flocculation and biologically treatment
at the factory wastewater treatment plant. For both effluents,
0.1 M NaCl was added as supporting electrolyte.