2.4. Effect of solution pH and ionic strength on
reactive dye adsorption
The effect of solution pH and ionic strength on dye adsorption
was investigated according to the following procedure. A
mass of 0.250 g of dried activated carbon (300e500 mm particle
diameter) was added to a number of 250 cm3 glass bottles
containing 100.0 cm3 of 6.0 104 mol/dm3 dye solution.
The pH of the dye solutions was adjusted over the range pH
2epH 10 using 0.5 M HNO3 or 0.5 M NaOH solutions (prior
to the addition of the adsorbent). The bottles were sealed and
placed in the shaker at 25 1 C for seven days. The effect of
ionic strength on the adsorption of the dyes was investigated
according to the following procedure. A mass of 0.250 g of activated
carbon (300e500 mm particle diameter) was added to
1000 cm3 solutions of 6.0 104 mol/dm3 of dye with varying