Removal of Colour from Waste Water Using Coconut Shell Activated Carbon (CSAC) and Commercial Activated Carbon (CAC)

In this study, series of batch adsorption experiment were conducted to examine the color removal efficiency of CSAC and CACs from waste water. The CAC is coal base activated carbon while the CSAC was manufactured in the laboratory. Yellow dye colour (Tartrazine E102) was utilized as the colourant. The adsorption efficiencies of the adsorbents were evaluated and compared by measuring the percentage of color removed. The effects of solution pH, adsorbent concentration, contact time as well as initial color concentration on the colour removal efficiency were also investigated. The optimum adsorption of color was achieved at low pH (pH 1.68), low initial color concentration (50mg/L) and 12g/l carbon dosage with removal efficiency of 75% for CAC and 45% for CSAC, with one hour agitation. Lower colour removal efficiency of 25% for CAC and 17% for CSAC were obtained at higher pH (pH 9-12), higher initial color concentration (100mg/L) and low carbon dosage, under the same retention time. A comparison of the Langmuir and Freundlich isotherm models of the adsorption data shows that Langmuir isotherm shows higher correlation coefficient, R2. The results indicate that CSAC has the potential as a low cost alternative for colour removal but the efficiency is lower than CSAC