A novel advanced oxidation process to degrade organic pollutants inwastewater: Microwave-activated persulfate oxidation
YANG Shiying , WANG Ping , YANG Xin , WEI Guang , ZHANG Wenyi , SHAN Liang
DOI:
Received November 21, 2008,Revised January 03, 2009, Accepted , Available online
Volume 21,2009,Pages 1175-1180
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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 e ciency maintains at 50% byMWenergy 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 SO4
.?? 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.
