title: Preliminary study on the photoproduction of hydroxyl radicals in aqueous solution with Aldrich humic acid, algae and Fe(III) under high-pressure mercury lamp irradiation.
abstract: Under a high-pressure mercury lamp (HPML) and using an exposure time of 4 h, the photoproduction of hydroxyl radicals (*OH) could be induced in an aqueous solution containing humic acid (HA). Hydroxyl radicals were determined by high-performance liquid chromatography using benzene as a probe. The results showed that *OH photoproduction increased from 1.80 to 2.74 microM by increasing the HA concentration from 10 to 40 mg L(-1) at an exposure time of 4 h (pH 6.5). Hydroxyl radical photoproduction in aqueous solutions of HA containing algae was greater than that in the aqueous solutions of HA without algae. The photoproduction of *OH in the HA solution with Fe(III) was greater than that of the solution without Fe(III) at pH ranging from 4.0 to 8.0. The photoproduction of *OH in HA solution with algae with or without Fe(III) under a 250 W HPML was greater than that under a 125 W HPML. The photoproduction of *OH in irradiated samples was influenced by the pH. The results showed that HPML exposure for 4 h in the 4-8 pH range led to the highest *OH photoproduction at pH 4.0.
authors.affiliation: Department of Environmental Science, Wuhan University, Wuhan, People's Republic of China.
authors.forename: Xianli
authors.initials: X
authors.lastname: Liu
authors.forename: Dong
authors.initials: D
authors.lastname: Xu
authors.forename: Feng
authors.initials: F
authors.lastname: Wu
authors.forename: Zhenhuan
authors.initials: Z
authors.lastname: Liao
authors.forename: Jiantong
authors.initials: J
authors.lastname: Liu
authors.forename: Nansheng
authors.initials: N
authors.lastname: Deng
mesh_terms: D001554:Benzene / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D056890:Eukaryota; D005290:Ferric Compounds / Q000737:chemistry*; D006812:Humic Substances / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D017665:Hydroxyl Radical / Q000032:analysis / Q000737:chemistry*; D008027:Light; D008628:Mercury; D010636:Phenols / Q000032:analysis / Q000737:chemistry; D010782:Photolysis; D012996:Solutions; D013053:Spectrophotometry; D013997:Time Factors; D014867:Water / Q000737:chemistry*; D014873:Water Pollutants / Q000032:analysis
chemical_list: D005290:Ferric Compounds; D006812:Humic Substances; D010636:Phenols; D012996:Solutions; D014873:Water Pollutants; D014867:Water; D017665:Hydroxyl Radical; D008628:Mercury; D001554:Benzene