3.1.2. The effect of material to liquor ratio (MLR)
on the adsorption of lac dye on cotton
Material to liquor ratio (MLR) is another important parameter
which influences the exhaustion of dye and the establishment
of an equilibrium between the concentration of dye on
the fibre and the dye in the dye bath. Shorter liquor ratios shift
the equilibrium in favour of the dye on the fibre and the equilibrium
is also reached more rapidly. The effect of MLR on the
adsorption of lac dye on cotton was investigated under dyeing
conditions of pH 3.0, an initial dye concentration of 480 mg/L,
30 C and a contact time of 2 h. It was found that MLRs of
1:50, 1:100 and 1:150 showed only slight differences in the
amount of the dye adsorbed onto cotton due to lac dye having
a low affinity for cotton [17]. For this reason, increasing the
volume of dye solution showed a slight increment in the dye
adsorbed onto cotton at higher material to liquor ratios. The
maximum of the dye adsorbed per gram of cotton for MLR
1:100 was 5.00 mg/g cotton. Therefore, the MLR of 1:100
was used for the adsorption isotherm of lac dye on cotton..