Characterization of tannery sludge activated carbon and its utilization in the removal of azo reactive dye

The removal of azo Reactive Red 31(RR31) from synthetic dye solution using tannery sludge-developed activated carbon (TSC) was investigated.

TSC was prepared from a combination of physical and chemical activation. The developed TSC was characterized by FT-IR, SEM, TG-DTA, specific surface area and zero point charge of pH (pH(zpc)). The isotherm models, kinetic models and thermodynamic parameters were also analysed to describe the adsorptive behaviour of TSC. The effect of contact time, initial dye concentration, carbon dosage, agitation speed, initial pH and temperature were carried out for batch adsorption studies. The isotherm plot of the dye RR31 on TSC fitted better with the Langmuir adsorption isotherm than the Freundlich model.

The maximum monolayer adsorption capacity of TSC in the removal of RR31 ranged from 23.15 to 39.37 mg/g. The thermodynamic parameters showed the endothermic and physical nature of the Reactive Red 31 adsorption on TSC. The entropy and enthalpy values were 181.515 J/Kmol and 5.285 kJ/mol, respectively.

The developed cationic tannery sludge carbon was found to be an effective adsorbent in the removal of the anionic azo reactive dye RR31.