Ultrasonic treatment of wastewater contaminated with furfural

Abstract

Sonolysis of environmental pollutants is a remediation method of increasing promise. In this study, the sonochemical degradation of furfural which is commonly found in effluents of petroleum refineries was investigated. Mineralization rates at low ultrasound wave frequency were determined in batch mode experiments as a function of furfural concentration, pH, and power density. Results revealed that sonochemical degradation of furfural conversion was clearly enhanced at acidic condition, while the increase of degradation rate was not obviously tangible with increasing the power density. At neutral conditions and power density of 3000 W L⁻¹, maximum removal efficiency of furfural was found to be 83% obtained at 2 h treatment time using 10 mg L⁻¹ initial concentration of furfural. The sonolysis of furfural in a single and binary solution of furfural and phenol was found to be comparable. This study was extended to investigate the sonolysis of furfural, phenol, and chemical oxygen demand (COD) in actual samples of a petroleum refinery effluent. Maximum removal efficiencies were found to be 93, 80, and 93% for COD, furfural, and phenol respectively. Kinetic models applied to the removal of furfural by sonochemical degradation was evaluated for the first order, pseudofirst order, second order, and pseudosecond order kinetic models. The experimental data fitted very well the pseudofirst order kinetic model. It was found that the reaction rate increases with decreasing initial concentration of furfural.

Keywords:

• Ultrasonic waves
• Wastewater treatment
• Furfural
• Advanced oxidation process
• Sonolysis degradation

Acknowledgement

The authors acknowledge the technical support of the University of Technology and Al-Daura petroleum refinery, Ministry of Oil in Iraq.