UV Induced Advanced Oxidation Process For The Degradation Of Organic Mercury And Its Application To Mercury Speciation By Atomic Fluorescence Spectrometry

Abstract

A new online advanced oxidation process with high efficiency was proposed for the degradation of organic mercury. The oxidation process is based on a high-efficiency photooxidation reactor in which the reaction tube was passed through a low-pressure mercury lamp. The reactor provided efficient irradiation which resulted in the complete degradation of methylmercury and ethylmercury within 4 s and 6 s, respectively. The highlight of this method is the removal of oxidants and high temperature. The oxidation process is extremely high efficiency and therefore is easy to be coupled with flow injection (FI) and high-performance liquid chromatography (HPLC). In FI system, complete oxidations of organic mercury can be accomplished in the plain medium of 0.5% (v/v) HCl, 1% (v/v) HNO3 and H2O, therefore, simple Hg aqueous standard calibration curves can be used to calibrate both inorganic and organic mercury. The detection limits of Hg, CH3Hg and CH3CH2Hg were found to be 0.02 ng mL. In HPLC system, the detection limits were calculated to be 0.55, 0.84, 0.56 ng ml for Hg, CH3Hg and CH3CH2Hg, respectively. In addition, the method provided good repeatability (< 5% RSD) for both systems. The developed method was validated by determination of certified reference material (GBW 10029, tuna fish) and was further applied in speciation of mercury in spiked environmental waters and biological samples.