Verification Of Efficient Generation Of Hydroxyl Radicals Based On Bromate Detection

The application of conventional oxidants in drinking water disinfection and seawater treatment will produce a large number of disinfection by-products,which seriously threaten human health and marine ecological safety.As a kind of green strong oxidant,hydroxyl radical(·OH)can react with bromine ions(Br-)to produce HBrO/BrO-.But HBrO/BrO-can react again to produce Br-,and the reaction rate constant is as high as 109 L mol-1·s-1.So BrO3-will not be formed when Br'ions are oxidized by ·OH alone,which is safe for drinking water disinfection and seawater treatment.High concentration oxygen active species are produced by atmospheric pressure ionization discharge,and·OH is efficiently prepared in pipeline by water jet cavitation.Bro3-will not be formed when bromide ions are oxidized by·OH alone,but BrO3-will be formed when bromide ions are oxidized by oznoe(O3).Therefore,the efficient generation of ·OH can be verified by detecting BrO3-.In addition,BrO3-is a 2B carcinogen with carcinogenicity and genotoxicity.So the determination of BrO3-formation can also evaluate the safety of preparing ·OH by strong ionization discharge for water treatment.The main results are as follows:(1)In pure water,·OH was efficiently generated by strong ionization discharge combined with hydrodynamic cavitation by detecting BrO3-.The concentration of gradient total rective oxidant TRO was 0.5,1.0 and 2.5 mg/L,respectively.No BrO3-was formed when Br-was oxidized by ·OH in the pipeline.After 24 hours of reaction outside the pipeline,when TRO was 2.5 mg/L,the BrO3-production was only 8.63?g/L.Under the same experimental conditions,the BrO3-concentration produced by 24 h ozonation of Br-was 17.67,29.72 and 55.35?g/L,respectively.(2)In seawater,·OH was efficiently generated by strong ionization discharge·combined with hydraulic cavitation by detecting BrO3-.The concentration of gradient total rective oxidant TRO was 0.5,1.0 and 2.5 mg/L,respectively.No BrO3-was produced in the treated seawater by ·OH in the pipeline.After 48 hours of reaction outside the pipeline,when TRO was 2.5 mg/L,the BrO3-production was only 4.14 ?g/L.(3)·OH can efficiently treat the water of Jinxiu Lake without producing disinfection by-products BrO3-and THMs,and can effectively kill algae,improve the dissolved oxygen,reduce turbidity and CODMn,and improve water quality.In conclusion,the efficient generation of ·OH in pure water and seawater in the process of strong ionization discharge combined with hydraulic cavitation was verified by detecting BrO3-.In this paper,an efficient generation ·OH experimental device was constructed to treat lake water without producing disinfection by-products BrO3--and THMs.At the same time,it can effectively kill algae and improve water quality,which proved that ·OH treatment was safe for lake water and can be applied to emergency treatment of lake water when algae outbreak occurs.