Removal of Co (II) by Adsorption Using Activated Carbon Prepared from Tomato Waste: Effect of Carbonization Temperature

Abstract

In this study, the use of low-cost, locally available and eco-friendly adsorbents has been investigated as an alternative to the current expensive methods of removing cobalt from aqueous solutions. Activated carbon was obtained from tomato plant waste by applying carbonization at 450°C (classified as AC-I) and 550°C (classified as AC-II). The activated carbons were characterized using elemental analysis, scanning electron microscopy, and Fourier transform infrared spectroscopy. Cobalt adsorption has been investigated using different process parameters like pH, adsorbent dosage, and initial cobalt concentration. The highest Co (II) removal was found at 30°C as 99.96% by using AC-II. Generally, it can be stated that, activated carbon that carbonized at 550°C were more efficient than the activated carbon that carbonized at 450°C. The Langmuir and Freundlich adsorption isotherm models were applied to describe the equilibrium isotherms and the isotherm constants were determined. It was found that the data fitted well to Freundlich model. The pseudo-first-order and pseudo-second-order kinetic models were used to describe the kinetic data.