title: Mechanisms of simultaneous hydrogen production and estrogenic activity removal from secondary effluent though solar photocatalysis.
abstract: The mechanisms of simultaneous photocatalytic hydrogen production and estrogenic activity (EA) removal from secondary effluent were investigated by evaluating the effects of initial dissolved oxygen (DO), organic matter, and inorganic ions on the process. The photocatalytic process was enhanced and can be divided into two phases according to the availability of DO. In aerobic phase, the humic/fulvic-like compounds in hydrophilic substances fraction were preferentially decomposed by aerobic photo-formed reactive oxygen species (i.e. O2(-), h(+), and OH) with generation of electron donors (i.e. formaldehyde, acetaldehyde, acetate, and formate). Approximately 41% of dissolved organic carbon and 90% of EA were reduced in the aerobic phase. In the following anoxic phase, the hydrogen production was significantly improved (apparent photonic efficiency 3.04 × 10(-3)) by the generated electron donors and accompanied with completely EA removal by the anoxic photo-formed OH. Hydrogen production was enhanced with the presence of low concentrations of HPO4(2-) (below 0.1 mmol/L) and HCO(3-) (below 0.2 mmol/L) through accelerating electrons accumulation while it was inhibited at high concentrations since the formed ion-radicals could not decompose humic/fulvic-like compounds. EA removal was inhibited by HPO4(2-) and HCO(3-) through scavenging h(+)/$OH. The presence of NO(3-) (below 1 mmol/L) only resulted in minor impacts since NO(3-) was almost unreactive toward electronor OH in neutral conditions.
authors.affiliation: Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, PR China.
authors.forename: Wenlong
authors.initials: W
authors.lastname: Zhang
authors.forename: Yi
authors.initials: Y
authors.lastname: Li
authors.forename: Chao
authors.initials: C
authors.lastname: Wang
authors.forename: Peifang
authors.initials: P
authors.lastname: Wang
authors.forename: Qing
authors.initials: Q
authors.lastname: Wang
authors.forename: Dawei
authors.initials: D
authors.lastname: Wang
mesh_terms: D002384:Catalysis / Q000528:radiation effects; D004967:Estrogens / Q000302:isolation & purification*; D006859:Hydrogen / Q000032:analysis*; D007477:Ions; D009930:Organic Chemicals / Q000302:isolation & purification; D010100:Oxygen / Q000032:analysis; D010984:Platinum / Q000737:chemistry; D017382:Reactive Oxygen Species / Q000032:analysis; D012995:Solubility; D013050:Spectrometry, Fluorescence; D013472:Sunlight; D014025:Titanium / Q000737:chemistry; D014865:Waste Disposal, Fluid; D014874:Water Pollutants, Chemical / Q000302:isolation & purification
chemical_list: D004967:Estrogens; D007477:Ions; D009930:Organic Chemicals; D017382:Reactive Oxygen Species; D014874:Water Pollutants, Chemical; C009495:titanium dioxide; D010984:Platinum; D006859:Hydrogen; D014025:Titanium; D010100:Oxygen