Ultrasound‐modified asphaltene from heavy oil: A sustainable adsorbent for dye removal in wastewater

Asphaltenes are highly aromatic, polar, and undesirable components present in crude oil, possessing a higher percentage in heavier crude oil. In this work, the influence of ultrasound on asphaltene from heavy oil was investigated, and found that asphaltene size was reduced from 10 to 1 μm at an ultrasound set power of 100%. SEM analysis showed that treated sonicated raw asphaltene (TRasp‐100) has more voids and cracks than treated raw asphaltene (TRasp), while BET indicated a higher surface area (40.952 m 2 /g) for TRasp‐100 due to ultrasound, with NMR confirming structural changes, and FTIR showing no significant functional group alterations after sonication. Due to its rich carbon composition, asphaltene was acid‐modified and applied as a potent adsorbent for eliminating methyl orange (MO) from wastewater. It was found that ultrasound‐treated asphaltene achieved 87% removal of MO at 50 mg/L concentration under pH 4, 313 K, and 90 min contact time, whereas raw asphaltene adsorbed 69% under the same condition. The equilibrium data for ultrasound‐influenced asphaltene were evaluated from Freundlich and Langmuir isotherms. To analyze the kinetics, pseudo‐first‐order, pseudo‐second‐order, and intraparticle diffusion equations were applied. The thermodynamic parameters , , and were evaluated in this study.