Characterizing the degradation of refractory organics from incineration leachate membrane concentrate by VUV/O3

Abstract

In this study, we used a combined vacuum-ultraviolet (VUV) and O3 process treating the chemical precipitation pre-treated incineration leachate membrane concentrate to further decompose substantial refractory organics which led to membrane organic fouling in the subsequent membrane distillation process. The highest removal of COD (88.1%) was achieved when 50 mg/min of O3 dosage was used at a pH of 11.5–12. Multi-spectrum methods, molecular weight distribution (MW), gas chromatography-mass spectrometry (GC–MS), two-dimensional correlation spectroscopy (2D-COS), and hetero-spectral 2D-COS were used to investigate the organics degradation mechanism. The combined action of O3 and hydroxyl radicals (•OH) effectively degraded macromolecular organics with high aromaticity and high conjugation (mainly distributed at 1–3 kDa) into aliphatic products with lower molecular weight (<1 kDa) and simple structures. The order of organics that were oxidized were humic-like acids > fulvic-like acids > protein-like substances. Organic acids (acetate, propionate, and butyrate) also accumulated in the VUV/O3 systems.