Utilization of Citrus aurantium peels for sustainable production of high surface area type I microporous nano activated carbons

Abstract

Orange (Citrus aurantium) peel was investigated for producing microporous nano activated carbons (OPAC). One-step chemical activation process by zinc chloride as an activating agent and a carbonization temperatures ranging from 500 to 900 °C was used to produce OPAC having high surface area of type I. The effects of carbonization temperature, impregnation ratio, and impregnation time on the properties of the OPAC were studied. The prepared activated carbons were characterized by FTIR; Brunauer–Emmett–Teller (BET); TGA; TEM, SEM, and EDAX analyses; the point of zero charge; and Boehm titration method. The maximal surface area of OPAC was activated by using the impregnation (orange peel/ZnCl2) ratio of 2:1, 700 °C carbonization temperature, and a 30-min holding time. The BET surface area, the total pore volume, and the micropore volume were 1228.2 m2/g, 0.5516, and 0.5482 cm3/g, respectively. The total pore volume increased with the increase of the activation temperature. The minimum pore diameter was 0.7 nm and the mean pore diameter was 1.797 nm. The results proved that the ZnCl2 chemical activation is a useful technique to prepare high surface area activated carbon from Citrus aurantium peels with nano pore size structure.