title: Highly efficient removal of chromium(VI) by Fe/Ni bimetallic nanoparticles in an ultrasound-assisted system.
abstract: Highly active Fe/Ni bimetallic nanocomposites were prepared by using the liquid-phase reduction method, and they were proven to be effective for Cr(VI) removal coupled with US irradiation. The US-assisted Fe/Ni bimetallic system could maintain a good performance for Cr(VI) removal at a wide pH range of 3-9. Based on the characterization of the Fe/Ni nanoparticles before and after reaction, the high efficiency of the mixed system could attribute to the synergistic effects of the catalysis of Ni(0) and US cavitation. Ni(0) could facilitate the Cr(VI) reduction through electron transfer and catalytic hydrogenation. Meanwhile, US could fluidize the Fe/Ni nanoparticles to increase the actual reactive surface area and clean off the co-precipitated Fe(III)-Cr(III) hydroxides to maintain the active sites on the surface of the Fe/Ni nanoparticles. Thus, compared with shaking, the US-assisted Fe/Ni system was more efficient on Cr(VI) removal, which achieved 94.7% removal efficiency of Cr(VI) within 10 min. The pseudo-first-order rate constant (kobs) in US-assisted Fe/Ni system (0.5075 min(-1)) was over 5 times higher than that under shaking (0.0972 min(-1)). Moreover, the Fe/Ni nanoparticles still have a good performance under US irradiation after 26 days aging as well as regeneration.
authors.affiliation: College of Chemical Engineering, Huaqiao University, Xiamen 361021, China.
authors.forename: Xiaobin
authors.initials: X
authors.lastname: Zhou
authors.affiliation: College of Chemical Engineering, Huaqiao University, Xiamen 361021, China. Electronic address: zhoujing@hqu.edu.cn.
authors.forename: Guohua
authors.initials: G
authors.lastname: Jing
authors.affiliation: College of Chemical Engineering, Huaqiao University, Xiamen 361021, China.
authors.forename: Bihong
authors.initials: B
authors.lastname: Lv
authors.affiliation: College of Chemical Engineering, Huaqiao University, Xiamen 361021, China.
authors.forename: Zuoming
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: Guangdong Provincial Key Laboratory of Mineral Physics and Materials, Guangzhou 510640, China.
authors.forename: Runliang
authors.initials: R
authors.lastname: Zhu
mesh_terms: D002384:Catalysis; D002857:Chromium / Q000032:analysis* / Q000737:chemistry; D007501:Iron / Q000737:chemistry*; D008962:Models, Theoretical; D053758:Nanoparticles / Q000737:chemistry*; D009532:Nickel / Q000737:chemistry*; D010084:Oxidation-Reduction; D013499:Surface Properties; D000069453:Ultrasonic Waves; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry; D018508:Water Purification / Q000379:methods*
chemical_list: D014874:Water Pollutants, Chemical; D002857:Chromium; C074702:chromium hexavalent ion; D009532:Nickel; D007501:Iron
keywords: Cr(VI) removal; Fe/Ni bimetallic nanoparticles; Mechanism; Ultrasound