Removal of Aromatic Compounds from Wastewater by Biodiesel

Wastewater from chemical plant, refinery and pharmaceutical factory contains many kinds of aromatic compounds. Wastewater including aromatic compounds is hazardous and difficult to be biodegraded. This study concerned the method of extracting aromatic compounds from the wastewater using biodiesel as extracting solvent. Biodiesel as solvent has some special characteristics: its solubility in water is smaller, its flash point is higher, it is nontoxic, and it is biodegradable. In this work, the solute removal rate, COD removal rate and solvent recovery were studied. In addition, the multistage countercurrent extraction experiments were carried out. The results showed that the multistage extraction rates of aniline, nitrobenzene and phenol were greater than 98.67%. The recovery performance of biodiesel was better. Biodiesel is a better extracting solvent for the wastewater containing aromatic compounds.