title: Synthesis of buoyant metal-coated fly ash cenosphere and its excellent catalytic performance in dye degradation.
abstract: In this work, Ag(+) and Ag(0) were absorbed onto the surface of 3-mercaptopropyltriethoxysilane modified fly ash cenospheres (FACs) in two Ag activation processes. The activation methods, avoiding traditional surface sensitization by SnCl2, successfully initiated electroless copper particles deposition for the preparation of buoyant Cu-FAC and CuAg-FAC composites. The CuAg-FAC had a much more uniform morphology than the Cu-FAC. The catalytic performance of the Cu-FAC and CuAg-FAC was examined by the reduction of Orange IV azo dye with the presence of NaBH4. 98.4% of Orange IV was rapidly reduced within 25 min by the CuAg-FAC, whereas 76.4% of Orange IV was removed by the Cu-FAC. The results reveal that the degradation processes matched well with the pseudo-first-order kinetics model, and rate constants of 0.057 and 0.186 min(-1) were obtained for the Cu-FAC and CuAg-FAC, respectively. Moreover, two other dyes of Orange II and Reactive Black 5 were also efficiently reduced by the CuAg-FAC which could be easily recycled and stably reused at least four times. These buoyant metal-coated FAC composites would be very useful in various catalytic reductions.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, and School of the Environment, Nanjing University, Nanjing 210023, China; Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, 398 Ruoshui Road, Suzhou Industrial Park, Jiangsu 215123, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, and School of the Environment, Nanjing University, Nanjing 210023, China.
authors.forename: Jianping
authors.initials: J
authors.lastname: Zhai
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, and School of the Environment, Nanjing University, Nanjing 210023, China. Electronic address: qli@nju.edu.cn.
authors.forename: Qin
authors.initials: Q
authors.lastname: Li
keywords: 3-Mercaptopropyltriethoxysilane; Aze dye; Catalytic degradation; Electroless Cu plating; Fly ash cenospheres