Removal and recovery of phenol from phenolic wastewater via ion exchange and polymeric resins

Different polymeric adsorbents, Amberlites XAD-4, XAD-7, IRA-94, and Ionac AFP-329, as well as activated carbon, were chosen for study based on their reported effectiveness in the removal of phenol from wastewater. These adsorbents were tested for efficiency, equilibrium time, and overall capacity. Apart from activated carbon, AFP-329 proved to have the highest removal efficiency, the shortest equilibrium time, and the highest capacity for phenol. Based on this solid-liquid equilibrium data, isotherms were constructed for each adsorbent. The data for all adsorbents used can be fitted by a Freundlich-type equation. The desorptive properties of the adsorbents were investigated using temperature as a driving force. At elevated temperatures of 50, 60, and 70 degreesC, XAD-4 showed an excellent and almost complete desorption capability. It also required the smallest amount of energy. Activated carbon showed the least desorption capability at these moderate temperatures. It appears that macroreticular polymeric resins offer a suitable alternative to the more conventional activated carbon. Further, it is apparent that a cyclic adsorption system with thermal regeneration using polymeric resins and working at moderate temperatures can be used to effectively remove and recover the chemical phenol from wastewater influents.