title: [Activated carbon catalyzed persulfate oxidation of azo dye acid orange 7 in aqueous solution].
abstract: Persulfate oxidation is a recently emerging advanced oxidation process for the pollution control. Persulfate (PS) degradation of azo dye acid orange 7 (AO7) in an aqueous solution was studied in the presence of suspended granular activated carbon (GAC) at ambient temperature (e. g., 25 degrees C). It was observed that in the GAC/PS combined system AO7 was not only a good decolorization as well as a good mineralization. The AO7 decolorization ratio, the removal efficiency of the naphthalene ring and the removal of TOC were 80%, 50% and 48%, respectively, at PS/AO7 molar ratio of 100: 1, GAC dosage of 1.0 g/L in 5 h reaction time. As a catalyst, GAC can be reused for several times. For each reuse cycle, AO7 removal efficiencies gradually decreased, however, with the oxidant concentration increased, the extent of the deactivation of GAC decreased. The removal efficiencies of AO7 for each reuse cycle hardly changed, and were all above 90% at PS/AO7 molar ratio of 500: 1, GAC dosage of 1.0 g/L in 5 h reaction time. The adsorption capacity of reused GAC decreased as the reuse time increased. The results of surface oxygen function groups, scanning electron microscopy (SEM) and energy disperse spectroscopy (EDS) analysis of reused GAC changed slightly. Therefore, the reason leading to deactivation of GAC could be that adsorption took up the active sites, thus reducing PS's opportunities to contact with the surface of GAC.
authors.affiliation: Key Laboratory of Marine Environment & Ecology, Ministry of Education, Qingdao 266100, China. yangxin-008.2005@163.com
authors.forename: Xin
authors.initials: X
authors.lastname: Yang
authors.forename: Shi-Ying
authors.initials: SY
authors.lastname: Yang
authors.forename: Lei-Lei
authors.initials: LL
authors.lastname: Wang
authors.forename: Xue-Ting
authors.initials: XT
authors.lastname: Shao
authors.forename: Rui
authors.initials: R
authors.lastname: Niu
authors.forename: Liang
authors.initials: L
authors.lastname: Shan
authors.forename: Wen-Yi
authors.initials: WY
authors.lastname: Zhang
mesh_terms: D001391:Azo Compounds / Q000737:chemistry / Q000302:isolation & purification*; D001557:Benzenesulfonates / Q000737:chemistry / Q000302:isolation & purification*; D002384:Catalysis; D002606:Charcoal / Q000737:chemistry*; D010084:Oxidation-Reduction; D013440:Sulfides / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000302:isolation & purification*
chemical_list: D001391:Azo Compounds; D001557:Benzenesulfonates; D013440:Sulfides; D014874:Water Pollutants, Chemical; C051552:persulfides; D002606:Charcoal; C014722:2-naphthol orange