Lead(II) immobilization in kaolinite at near-neutral pH conditions using titanium-based compounds. Issue 4 (August 2017)

• Record Type: Journal Article
• Authors: Suzuki, Tasuma; Kakoyama, Satoshi; Nomura, Takeshi; Fukuoka, Chihiro; Niinae, Masakazu
• Is Part Of: Journal of environmental chemical engineering. Volume 5:Issue 4(2017:Dec.)
• Page Start: 3129
• Page End: 3135
• Publication Date: 2017-08
• Subjects: Soil contamination -- Lead -- Immobilization -- Anatase -- Layered protonated titanate; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2017.06.002
• Languages: English
• ISSNs: 2213-2929

Abstract

Graphical abstract: Highlights: Ti-based adsorbents were evaluated as Pb(II) immobilization agents in kaolinite. Layered protonated titanate (LPT) showed excellent Pb(II) adsorption capability. LPT not only effectively adsorbs Pb(II) but also entraps Pb(II) in the interlayer. LPT effectively immobilizes Pb(II) at near-neutral pH conditions. The LPT effectiveness lasts for 200 years under the exposure to acid rain. Abstract: Anatase and layered protonated titanate (LPT) were chosen as potential Pb(II) immobilization agents for a series of batch adsorption/desorption and immobilization experiments. Batch adsorption experiments demonstrated that adsorption of Pb(II) onto anatase and LPT were both favored at higher pH, and LPT exhibited significantly higher Pb(II) adsorption capability than anatase and the two commercially available Ti-based adsorbents. In addition, Pb(II) adsorption induces structural deformation of the LPT layer structure, which results in irreversible adsorption; this trend was not observed for anatase. Based on these favorable LPT adsorption/desorption characteristics as a Pb(II) immobilization agent, Pb(II) in artificially contaminated kaolinite was immobilized using LPT. Leaching test results demonstrated that LPT effectively immobilized Pb(II) below the permissible level in Japan (0.01 mg/L). At the dosage of 75 mg/4 g-kaolinite or above, this LPT immobilization capacity was maintained even when the leaching solution pH was 2.5, equivalent to 200 years of soil exposure to acid rain. These experimental data demonstrated that LPT is an effective Pb(II) immobilization agent that can immobilize Pb(II) at near-neutral pH conditions, and its effectiveness lasts for a long time.