| Summary: | One of the main problems associated with wastewater from textile industries is colour.
Reactive dyes in industrial discharge, in particular, are difficult to manage as they are not
readily amenable to biological treatment. The present study employs an electrochemical
method using cast iron electrodes and sodium chloride (NaCl) as electrolyte to
decolourise synthetic wastewater containing reactive Red dye (Cibacron Red CR). The
main objective of this study was to determine the optimum combination of influencing
factor levels for dye removal. A laboratory-scale batch experiment was used to
investigate the effect of operating parameters, electrolyte (NaCl) concentration (0.6-1.0
g/l), initial dye concentration (20-100 mg/l), current density (1-3 mA/cm2
) and reaction
time (20-60 min), on colour removal using cast iron electrodes. A scanning UV-visible
spectrophotometer set at 525 nm was used to measure the absorbance before and after the
dye solution was treated. NaCl concentration did not effect dye removal because its
concentration used in this study was found to be greater than the optimum required.
Removal was found to be highly dependent on, current density, initial dye concentration
and reaction time. Increasing the current density and reaction time and lowering the
initial dye concentration showed an increase in the colour removal. The experiment was
conducted following a factorial design with 4 factors at 3 levels each. The results show
that over 99% dye removal may be achieved under optimum operating conditions. The
multiple correlation coefficient of determination, R-Squared was 0.8148. This shows that
the actual data give a quite good fit to the predicted data.
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