Abstract
Surfactant-based technologies have been studied for the treatment of radioactive waste containing isotopes of radium. Nevertheless, the use of combined processes to remove radium from radioactive oil sludge is scarce in the literature. The objective of this work was to investigate the potential of a non-ionic surfactant to remove radium from raw oil sludge (ROS) and pre-treated, microwave-irradiated oil sludge (POS). Characterization of ROS and POS was made using the following methods: Thermal Gravimetric Analysis, X-ray diffraction, Scanning Electron Microscopy coupled with Energy-Dispersive X-ray Spectroscopy, and gamma spectrometry. The effects of surfactant concentration (0.5-7.5%), temperature (25-60 degrees C), and contact time (30 and 60 min) were investigated. For ROS, little or no influence on the decontamination process was found for variations in the selected process parameters. For POS, the lowest surfactant concentration (2.5%) was the most efficient, removing about 94% of 226Ra and 228Ra. Neither contact time nor temperature affected removal. For ROS, removal percentages were 50-60% for 226Ra and 35-45% for 228Ra. The results indicated that the surfactant acted more efficiently in the decontamination of POS.
NSTL
Elsevier