A novel advanced oxidation process to degrade organic pollutants in wastewater:Microwave-activated persulfate oxidation

摘要

This article,for the first time,provides a novel advanced oxidation process based on sulfate radical(SO4. -) to degrade organic pollutants in wastewater:microwave(MW)-activated persulfate oxidation(APO)with or without active carbon(AC).Azo dye acid Orange 7(AO7)is used as a model compound to investigate the high reactivity of MW-APO.It is found that AO7(up to 1000 mg/L)is completely decolorized within 5-7 min under an 800 W MW furnace assisted-APO.In the presence of chloride ion(up to 0.50 mol/L),the decolorization is still 100%completed,though delayed for about 1-2 min.Experiments are made to examine the enhancement by AC.It is exciting to find that the 100%decolorization of AO7(500 mg/L)is achieved within 3 min by MW-APO using 1.0 g/L AC as catalyst,while the degradation effciency maintains at 50%by MW energy without persulfate after about 5 min.Besides the destruction of visible light chromophore band of AO7(484 nm),during MW-APO,two bands in the ultraviolet region(228 nm and 310 nm)are rapidly broken down.The removal of COD is about 83%-95%for 500 mg/L AO7.SO4. -is identified with quenching studies using specific alcohols.Both SO4. -and.OH could degrade AO7,but SO 4 .-plays the dominant role.In a word,MW-APO AC is a new catalytic combustion technology for destruction of organic contamination even for high concentration.