title: A novel method for remediation of nickel containing wastewater at neutral conditions.
abstract: Heavy metals contained in wastewater are generally removed by adding antalkaline to increase the pH, and Ni is commonly precipitated as Ni-hydroxides at pH 10. However, a more sustainable remediation method of treatment at neutral conditions would be attractive due to the high cost of chemical reagents and inefficient treatment at present. Based on natural attenuation, the method of adding Al ions has been used in wastewater treatment to precipitate layered double hydroxides (LDH). Here, we investigated the use of Al ion addition in the Ni containing wastewater treatment, experimentally and thermodynamically. By co-precipitation experiments adding Al ions to Ni-containing water, Ni was selectively incorporated into the structure of LDH, and the removal efficiency of Ni was close to 100% even in pH 7 and 8 samples (lower pH than conventional methods) with initial Ni concentrations of 200-10,000mg/L. Geochemical modeling results replicate the experimental results well when the Al/Ni ratio of LDH is assumed to be 0.33. This model makes it possible to estimate the amount of Al ions and additive agents necessary for use in treatment of wastewater containing different Ni concentrations.
authors.affiliation: Graduate School of Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo 060-8628, Japan.
authors.forename: Haruko
authors.initials: H
authors.lastname: Hase
authors.affiliation: Graduate School of Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo 060-8628, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Nishiuchi
authors.affiliation: Faculty of Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo 060-8628, Japan. Electronic address: tomsato@eng.hokudai.ac.jp.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Sato
authors.affiliation: Faculty of Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo 060-8628, Japan.
authors.forename: Tsubasa
authors.initials: T
authors.lastname: Otake
authors.affiliation: Materials Sciences Research Center, Japan Atomic Energy Agency, 1-1-1 Koto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Yaita
authors.affiliation: Materials Sciences Research Center, Japan Atomic Energy Agency, 1-1-1 Koto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan.
authors.forename: Tohru
authors.initials: T
authors.lastname: Kobayashi
authors.affiliation: Faculty of Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo 060-8628, Japan.
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Yoneda
keywords: Aluminum; Geochemical modeling; Layered double hydroxide; Nickel; Wastewater treatment