. The amount of dye in the solution was
monitored by UVevisible absorption spectroscopy (Cary 1E
UVevisible spectrophotometer) until the absorbance values
at lmax 487 nm remained constant. The initial and equilibrium
dye concentrations were determined using a calibration curve
based on absorbance at lmax 487 nm versus dye concentration
in standard lac dye solutions.