Decomposition of refractory aniline aerofloat collector in aqueous solution by an ozone/vacuum-UV (O3/VUV) process

Abstract

ABSTRACT The degradation of refractory aniline aerofloat (AAF) collector was investigated by an ozone/Vacuum-UV (O3/VUV) process. The effects of O3 dosage and initial pH on the AAF degradation were studied. The total organic carbon (TOC) and concentrations of , and anions were measured to evaluate the AAF mineralization. The solid phase extraction and gas chromatography–mass spectrometry (SPE/GC–MS) was developed to identify byproducts. The results showed that 99.84% of AAF could be removed by the O3/VUV, and the AAF degradation was enhanced at higher O3 dosage and initial solution pH. The radical scavenging tests revealed that most of AAF was degraded by OH• radicals, and the O3/UV254nm made the main contribution in AAF degradation in the O3/VUV system. The mineralization extents of C, S, P and N elements of AAF at 180 min reached 47.74%, 93.94%, 17.71% and 45.81%, respectively. At initial pH > 10.0, the EE/O values of AAF degradation by the O3/VUV was below 7.0 kWh m−3 per order, showing the energy consumption was acceptable. The SPE/GC–MS analysis showed that toxic aniline was generated in the O3/VUV oxidation of AAF, but it was further degraded at a longer time. Compared to the ozonation, the O3/VUV had a much lower content of aniline at 180 min. The possible degradation pathways of AAF by the O3/VUV were proposed.