title: Investigation of heavy metal (Cu, Pb, Cd, and Cr) stabilization in river sediment by nano-zero-valent iron/activated carbon composite.
abstract: Nano-zero-valent iron/activated carbon (nZVI/AC) composite was evaluated for its effectiveness in the stabilization of Cu, Pb, Cd, and Cr in dredged river sediment. Synthetic precipitation leaching procedure (SPLP) and toxicity characteristic leaching procedure (TCLP) were adopted to compare the effects of nZVI/AC dosage, particle size, time duration, and temperature on heavy metal leachability. The results show that leachability dropped considerably with the addition of nZVI/AC and powdered particles in the size of 0.075-0.18 mm was more effective in stabilization than granular ones. Stabilization effect was stable in long-term and robust against changes in temperature. Tessier sequential extraction revealed that heavy metals were associated with solid particle, inorganic or organic matters in sediment. The addition of nZVI/AC was able to convert relatively weakly bound heavy metals into more strongly bound species and thus reduce the bioavailability and toxicity. Also, the standard potential of heavy metals may decide the mechanism of stabilization process.
authors.affiliation: School of Environment and Architecture, University of Shanghai for Science and Technology, 516 Jungong Rd., Shanghai, 200093, China. chenweifang@tsinghua.org.cn.
authors.forename: Wei-fang
authors.initials: WF
authors.lastname: Chen
authors.affiliation: School of Environment and Architecture, University of Shanghai for Science and Technology, 516 Jungong Rd., Shanghai, 200093, China.
authors.forename: Jinghui
authors.initials: J
authors.lastname: Zhang
authors.affiliation: School of Environment and Architecture, University of Shanghai for Science and Technology, 516 Jungong Rd., Shanghai, 200093, China.
authors.forename: Xiaomao
authors.initials: X
authors.lastname: Zhang
authors.affiliation: School of Environment and Architecture, University of Shanghai for Science and Technology, 516 Jungong Rd., Shanghai, 200093, China.
authors.forename: Weiya
authors.initials: W
authors.lastname: Wang
authors.affiliation: School of Environment and Architecture, University of Shanghai for Science and Technology, 516 Jungong Rd., Shanghai, 200093, China.
authors.forename: Yuxiang
authors.initials: Y
authors.lastname: Li
mesh_terms: D002104:Cadmium / Q000737:chemistry*; D002606:Charcoal / Q000737:chemistry*; D002857:Chromium / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D019015:Geologic Sediments / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D007854:Lead / Q000737:chemistry*; D019216:Metals, Heavy / Q000737:chemistry; D045483:Rivers / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D019216:Metals, Heavy; D014874:Water Pollutants, Chemical; D002104:Cadmium; D002857:Chromium; D002606:Charcoal; D007854:Lead; D003300:Copper; D007501:Iron
keywords: Heavy metal stabilization; Leaching; Nano-zero-valent iron/activated carbon; River sediment; Sequential extraction