Kinetic and thermodynamic study of adsorptive removal of sodium dodecyl benzene sulfonate using adsorbent based on thermo-chemical activation of coconut shell

Adsorptive separation of Sodium dodecyl benzene sulfonate (SDBS) using thermo-chemically and chemically activated coconut shell based adsorbent as well as using waste graphite powder has been investigated. The dependency of the extent of SDBS removal on pH, concentration, adsorbent dose and temperature has been demonstrated. Under optimized conditions, 92.84%, 39.41% and 34.23% SDBS could be removed in 3 h using Phosphoric Acid Activated Coconut Shell-I (PAACS-I), Phosphoric Acid Activated Coconut Shell-II (PAACS-II) and graphite powder respectively. Adsorption kinetics was established to follow pseudo-second order mechanism and isotherm data fitted well with the Langmuir isotherm. Maximum adsorption capacity was estimated to be 28.57 mg/g under optimized conditions of pH as 2, adsorbent dose of 3 g/L and temperature of 293 K. It was also established that adsorption was spontaneous and exothermic. Appreciable activity till 5th reuse cycle confirmed promising nature of the adsorbent.