Efficient removal of phenol in aqueous solution by the modified abandoned fine blue-coke: equilibrium, thermodynamic, kinetic, and adsorbent regeneration

The modified abandoned fine blue-coke (MAFB) was used to remove phenol from the aqueous solution efficiently. The effects of initial concentration, temperature, pH, and co-existing salt ions of the phenol solution on the adsorption capacity of MAFB for phenol were investigated. The adsorption equilibrium, thermodynamic, kinetic, and adsorbent regeneration were studied simultaneously. The results showed that the maximum adsorption capacity of phenol onto the MAFB was obtained as 151.74 mg g(-1) at the initial solution concentration of 1100 mg L-1, the temperature of 328 K, and pH of 4.0-6.5. The salt ions of Na+, Cl-, SO42- had little effect on the adsorption capacity. The adsorption isotherm belongs to the L isotherm and the Langmuir model can better describe the adsorption process. Thermodynamics results indicated that the adsorption was entropy increase, spontaneous and endothermic process. The adsorption kinetics was found to follow the pseudo-second-order model. The physical adsorption of pi-pi dispersion interactions could be used to describe the adsorption mechanism. The 60% regeneration rate of the MAFB was reached by three times alcohol desorption at 323 K for 4 h. Compared with other adsorbents, MAFB has better phenol adsorption performance, which makes it a promising and excellent adsorbent to remove phenol from wastewater.