Arc-discharge Plasma Conversion of Asphaltene-rich Oil-industry Waste into Carbon Materials

Abstract

One of the major environmental challenges in the oil industry is the accumulation of heavy asphaltene-rich residues, which are difficult to process and are often underutilized as carbon resources. In this study, asphalt obtained as a by-product of the solvent deasphalting (SDA) process was converted into graphitized carbon materials by vacuum-free direct-current arc-discharge plasma treatment. The plasma route enabled rapid transformation of the asphaltene-rich feedstock into carbon products containing graphite-like domains, nanoonions, and polyhedral graphite particles. Comprehensive physicochemical characterization confirmed substantial dehydrogenation, deoxygenation, and structural ordering of the initial organic matrix, together with high thermal stability and measurable porosity in the resulting carbon material. The obtained carbon was further evaluated as a precursor for carbide synthesis under vacuum-free arc conditions. X-ray diffraction analysis confirmed the formation of cubic silicon carbide SiC (with carbide phase is 56 wt% (without annealing) and 85 wt% (after annealing), JCPDS 29-1129) and chromium carbide Cr₃C₂ (with carbide phase 84 wt% (without annealing), JCPDS 35–0804), demonstrating that the SDA-asphalt-derived carbon can serve as an effective carbon source for rapid carbide formation. The results highlight a practical route for converting problematic oil-industry waste into value-added graphitized carbon and carbide materials. This approach expands the utilization potential of asphaltene-rich residues and offers a promising waste-valorization strategy with relevance to chemical engineering applications.