Preparation of Activated Carbon Derived from Cotton Linter Fibers by Fused NaOH Activation and Its Application for Oxytetracycline (OTC) Adsorption

摘要

The objective of this research is to produce high surface area activated carbon derived from cottonlinter fibers by fused NaOH activation and to examine the feasibility of removing oxytetracycline (OTC) fromaqueous solution. The cotton linter fibers activated carbon (CLAC) was characterized by N2adsorption/desorption isotherms, Fourier transform infrared spectroscopy (FTIR) and scanning electronmicroscope (SEM). The results showed that CLAC had a predominantly microporous structure with a largesurface area of 2,143 m2/g. The adsorption system followed pseudo-second-order kinetic model andequilibrium was obtained within 24 h. The equilibrium data described well with Langmuir isotherm.Thermodynamic study showed that the adsorption was a spontaneous, exothermic process. Competitiveadsorption took place in the weakly acidic to neutral conditions. Under the strong acidity or strong alkalinecondition, the adsorption of the oxytetracycline was hindered by electrostatic repulsion. The adsorptionmechanism depended on the pH of the solutions as well as the pKaof the oxytetracycline.