SPECTROPHOTOMETRIC MEASUREMENTS OF RHODAMINE B AS A DYE TRACER FOR BRINE OUTFALL LABORATORY EXPERIMENTS

Rhodamine B (RhB) as a dye tracer is widely used both in laboratory scale and in-situ studies about determination of wastewater plumes' movement and their dilution characteristics in marine environments. RhB added salt (mainly NaCl) water solutions are used on brine outfall laboratory physical model experiments. Some of the experiments in laboratory tanks can be conducted via taking samples inside the discharged brine jets. Taken samples can be measured by optical methods such as ultraviolet visible spectrophotometry for determination of dye tracer concentrations and dilution levels. However, absorbance specifications of a dye tracer, like RhB, might be affected by high concentrations of NaCI in discharge solutions. This study, aimed at determining the effect of variable NaCl concentration, which represents the discharged solutions, on prepared with RhB as a dye tracer which are diluted with distilled water in the laboratory. Absorbance levels of variable dilutions of source discharge solution were obtained and their differences were compared with different levels of NaCI concentrations. In order to decrease the experimental errors for tap water used in lab scale dye tracer studies, a mathematical expression for Salinity (S)-Absorbance (I)/Concentration(c) relation was suggested in the studied range for salinity 30-100 ppt.