title: Regeneration of acid orange 7-exhausted granular activated carbons with microwave irradiation.
abstract: An investigation was performed for the regeneration of three granular activated carbons (GACs) exhausted with acid orange 7 (AO7). The three GACs were made from different materials, i.e. coconut shells, almond nucleus and coal. The AO7 adsorption process was carried out in a continuous-flow adsorption column. After adsorption, the AO7-saturated GAC was dried at 120 degrees C, then regenerated in a quartz reactor by 2450 MHz microwave (MW) irradiation at 850 W for 5 min. The efficacy of this procedure was analyzed by determining the rates and amounts of AO7 adsorbed in successive adsorption-MW regeneration cycles. Effects of this regeneration on the structural properties, surface chemistry and the AO7 adsorption capacities of GAC samples were examined. It was found that after several adsorption-MW regeneration cycles, the adsorption rates and capacities of GACs could maintain relatively high levels, even higher than those of virgin GACs, as indicated by AO7 breakthrough curves and adsorption isotherms. The improvement of GAC adsorption properties resulted from the modification of pore size distribution and surface chemistry by MW irradiation.
authors.affiliation: School of Environmental and Biological Science and Technology, Dalian University of Technology, 2 Linggong Road, Dalian 116024, China.
authors.forename: Xie
authors.initials: X
authors.lastname: Quan
authors.forename: Xitao
authors.initials: X
authors.lastname: Liu
authors.forename: Longli
authors.initials: L
authors.lastname: Bo
authors.forename: Shuo
authors.initials: S
authors.lastname: Chen
authors.forename: Yazhi
authors.initials: Y
authors.lastname: Zhao
authors.forename: Xinyi
authors.initials: X
authors.lastname: Cui
mesh_terms: D000327:Adsorption; D001391:Azo Compounds / Q000737:chemistry* / Q000302:isolation & purification; D001557:Benzenesulfonates; D002244:Carbon / Q000737:chemistry*; D003031:Coal; D003247:Conservation of Natural Resources; D008872:Microwaves; D009754:Nuts; D016062:Porosity; D013696:Temperature; D018508:Water Purification / Q000379:methods*
chemical_list: D001391:Azo Compounds; D001557:Benzenesulfonates; D003031:Coal; D002244:Carbon; C014722:2-naphthol orange