Surface characterization and sorption efficacy of tire-obtained carbon: Experimental and semiempirical study of rhodamine B adsorption

This work focuses on the surface characterization and sorption activity of carbon derived from waste tires. The carbon was prepared by thermal treatment of waste rubber tires, followed by exposure to nitric acid and hydrogen peroxide. The tiredobtained activated carbon (AC) was evaluated using a variety of techniques. Fourier transform infrared spectroscope and Raman spectra reveal existence of hydroxyl and carboxylic groups on AC surface. Scanning electron microscope and Brunauer-Emmett-Teller revealed the porosity of AC is well developed with mesopore structure (mesopore volume of 0.96 cm³/g). AC was tested for Rhodamine B sorption, and the adsorption kinetics well fitted using a pseudo second-order kinetic model. The adsorption isotherm data could be well described by the Langmuir model. Semiempirical calculations using Austin Model 1 were performed to explain the adsorption at molecular level. Binding enthalpies in the range of 0.5-4 kcal/mol of four possible scenarios were computed. We believe the combination between experimental work and semiempirical calculations allows for a better understanding of Rhodamine B molecules adsorption on the AC surface.