A study of 4-chlorophenol continuous adsorption on nano graphene oxide column: Model comparison and breakthrough behaviors

Abstract

Removal of 4-chlorophenol in a continuous fixed-bed column was investigated by using nano graphene oxide (NGO) adsorbent in this study. The adsorbent (NGO) was characterized by X-ray diffraction (XRD) analysis and scanning electron microscopy analysis. Variables in the adsorption process were bed depths (5, 10 and 15 cm), flow rate (1, 2 and 4 mL/min), influent 4-chlorophenol concentrations (5, 10, 15, 20 and 30 mg/L) and influent solution pH (6–7). The enhancement of adsorption is favored by decreasing 4-chlorophenol concentration and flow rate and increasing bed depth. Indeed, the best result obtained in this study was 145.2 mg/g of adsorption capacity under 4-chlorophenol concentration of 5 mg/L at a flow rate of 1 mL/min toward a bed depth of 15 cm. The results of the study showed that the ideal 4-chlorophenol adsorption followed well the Thomas and Yoon–Nelson models for predicting breakthrough behavior at different flow rates and bed depths. Finally, increasing flow rate, decreasing bed depth and increasing influent 4-chlorophenol concentration resulted in the breakthrough time and exhaustion time decreasing.