Adsorptive removal of acid orange 7 from industrial effluents using activated carbon and conducting polymer composite – A comparative study

Abstract

The feasibility of removing Acid Orange7 (AO7) from industrial effluents using two different adsorbents namely Activated Carbon (CAC) and Polypyrrole Polymer Composite (PPC) prepared from Casuarina wood has been analysed. Batch mode adsorption studies are performed in order to investigate the adsorption capacities of these adsorbents by varying initial dye concentration, agitation time, temperature and <i>p</i>H. Results reveal that adsorption capacity decreases from 83.4 to 60.5% for CAC and from 95.1 to 72.6% for PPC at 30°C with an increase in the initial concentration from 25 to 100 mg/L. A comparative study on the adsorptive capacities of CAC and PPC have been carried out and it was inferred that PPC had better adsorption capacity than CAC at an initial concentration of 50 mg/L at 30, 35 and 40°C. The calculated <i>q</i>_e values agree very well with experimental values. The regression coefficient values above 0.98 confirm that adsorption follows second order kinetics. The increase in Langmuir adsorption capacity (Q₀) from 7.8036 to 9.5082 mg/g for CAC and 8.1873 to 11.0087 mg/g on increasing the temperature from 30 to 40°C accounts for the endothermic nature of the process. The present study confirms the potentiality of an abundant low cost solid waste material and its availability for the removal of acidic dyes from industrial effluents