Eosin Y removal using citric acid-treated corncob

In this study, citric acid-treated corncob (CATC) was used to remove Eosin Y (EY) from aqueous solutions by adsorption. The effects of initial solution pH, adsorbent particle size, contact time, and temperature on the adsorption of EY onto CATC were studied by static experiments. The Henry, Langmuir, and Freundlich isotherms were used to fit the equilibrium data. Pseudo-first-order, the pseudo-second-order, and Elovich models were used to test the kinetic data. It was found that the Henry and Freundlich isotherms gave a good description of the equilibrium process. The equilibrium capacity of 41.79 mg·g –1 was obtained for 300 mg·L –1 of EY concentration, pH = 4.0, a temperature of 323 K, and 2.5 g·L –1 of CATC dosage. Both the pseudo-second-order and Elovich models could provide a perfect fit for the kinetic data of the EY on the CATC, indicating that chemical interactions occur during adsorption. Based on the thermodynamic analysis, EY adsorption by CATC was endothermic and spontaneous. These findings suggested that CATC was highly promising as a low-cost and efficient adsorbent for the treatment of EY wastewater.