Comparative removal of phenols and its chlorinated derivatives by carbon-coated monolith: equilibrium, kinetics and regeneration studies.

The adsorptive performance of phenol, 4-chlorophenol (4-CP) and 2,4-dichlorophenol (2,4-DCP) onto carbon-coated monolith (CCM) was comparatively evaluated by batch mode. Experiments were carried out by varying pH, contact time, initial adsorbate concentration and reaction temperature. Regeneration performance of CCM was also assessed. The studies showed optimum 2,4-DCP adsorption, followed by 4-CP and phenol at pH 5. The adsorption equilibration time for phenol, 4CP, 2 and 4-DCP were 600, 470 and 400 min, respectively. The equilibrium adsorption capacities were increased 13.1–37.6 mg/g for 50–250 mg/L (phenol), 51.9–93.7 mg/g for 250–450 mg/L (4-CP) and 84.3–117.5 mg/g for 400–600 mg/L (2,4-DCP), respectively. The adsorption at different temperatures was monolayer as depicted by linear and non-linear isotherm models. Kinetic studies showed better applicability of pseudo-second-order kinetics model. The adsorption increases with increase in reaction temperature from 30 to 50°C showing endothermic adsorption process. Desorption and regeneration studies showed optimum phenol recovery with ethanol with 12.9% loss in adsorption after four consecutive cycles. [ABSTRACT FROM PUBLISHER]