Granular activated carbon coupled with microwave energy for treating pentachlorophenol-containing wastewater

[[abstract]]The combined adsorption by granular activated carbon (GAC) and thermal treatment by microwave energy were used to treat pentachlorophenol (PCP)-containing wastewater. GAC was used to adsorb and concentration PCP from the aqueous solution; the exhausted GAC was then subject to microwave treatment. The microwave energy, which is readily absorbed by GAC, can be transformed into heat inside the particles because of dipole rotation and ionic conduction; the resulting heat is capable of desorbing PCP. Results of laboratory studies show that if 1 g GAC was used to adsorb PCP from a 0.5 mL solution containing 1000 mg/L PCP and the exhausted GAC was subject to 600 W microwave energy for 100 s, more than 99% PCP can be destroyed. The PCP was decomposed into intermediate products such as benzene and other forms of radicals or hydrocarbon compounds, which are then oxidized into inorganic end products, e.g., H2O, CO2, and HCl. The results obtained in this research will promote the understanding of this innovative process of applying the microwave energy to decompose the adsorbed PCP and reuse GAC in treating PCP-containing wastewater