ORANGE PEEL AS SUBSTRATE TO SYNTHESIZE CONDUCTIVE CARBON NANOSTRUCTURES BY A GREEN THERMAL PROCESS

Abstract

Orange (Citrus sinensis L.) peel (OP) has been considered a waste due to its high processing costs and complicated management, resulting in environmental pollution issues. Alternatives have been proposed to generate economic benefits by developing efficient technologies to produce and store electrical energy. Moreover, valorization of OP will bring municipal and agro-industrial waste management reduction. This work aimed to develop a cost-effective and environmentally friendly thermal process to synthesize a conductive carbon from OP using a new methodology herein described. First, the OP was washed using an ultrasonic bath and dried by sun and dehydrated in muffle. Then, dehydrated pieces of OP were covered with fine-grained sea sand to limit air interaction and was carbonized at 1000 degrees C for one hour. The resulting bio-carbon was analyzed by cyclic voltammetry. The electrical double layer capacitance was estimated to assess the electrochemical behavior of the carbon in the electrolyte. Interestingly, with the newly proposed heat treatment, the carbon material showed a specific capacitance of 272 F/g at 20 mV/s. Therefore, the new proposed thermal process allows the synthesis of graphitized carbon with good electrochemical properties at a low cost. The results show the potential for the development of new conductive carbon materials from residual biomass by a simple, economical, and environmentally friendly air-limited heat treatment.