with activated carbon and fly ash, respectively, for an initial dye concentration of
20 mg/L.
2.12 Effect of Temperature
The adsorption of acid magenta dye on the activated carbon and fly ash was carried
out at initial acid magenta dye concentration (20 mg/L) at different temperature. The
dye adsorption increased on the activated carbon and fly ash with a rise in temperature from 30 to 60
C (Fig. 4). This is mainly due to the increased surface activity at
high temperature, suggesting that adsorption of acid magenta dye on activated
carbon and fly ash obeys an endothermic process. Maximum removal of acid
magenta dye 71 and 67% was observed with activated carbon and fly ash, respectively, at 50
C.
2.13 Phytotoxicity Study
The phytotoxicity test with seeds of Vigna radiata showed toxicity of acid magenta
dye. The significant differences were observed among various treatments for all the
parameters studied, i.e., seed germination and other growth characteristics such as
length of plumule and radicle and vigor index of the mung bean seeds. In control
97% seed germination was observed, whereas dye (20 ppm) treated seeds of
V. radiata exhibited only 40% germination [24]. The germination of mung bean
0
20
40
60
80
100
2
4
6
8
1 0
Dye removal (%)
pH
AC
FA
Fig. 3 Adsorption of acid magenta dye at different pH by different adsorbents
268
R. T. Kapoor