Adsorption of Pentachlorophenol from Aqueous Solution onto Activated Carbon Fiber

Abstract

Experimental data for the equilibrium adsorption of pentachlorophenol (PCP) onto activated carbon fibers (ACFs) in the form of felt (AC-felt) and cloth (AC-cloth) were obtained in a batch adsorber. The effect of pH on the adsorption capacity was investigated by determining the adsorption isotherm in the pH range from 6 to 12. It was found that the adsorption capacity was reduced upon increasing the pH from 6 to 12. The speciation diagram of PCP revealed that PCP was adsorbed on the ACFs as the pentachlorophenolate ion. The adsorption capacity was diminished slightly upon increasing the temperature from 15 to 35 °C. The adsorption of PCP on AC-felt was due to dispersion forces caused by π−π interactions. These interactions explained why the adsorption of PCP on the AC-felt was reversible. Also, the adsorption capacity of the AC-felt was 1.7 times higher than that of the AC-cloth because the AC-felt contained a greater concentration of basic sites that made the π−π interactions stronger. It was concluded that PCP was adsorbed considerably on the ACFs and that the adsorption capacity was highly dependent on the form and properties of the ACFs as well as the solution pH.