title: Abatement of aqueous anionic contaminants by thermo-responsive nanocomposites: (poly(N-isopropylacrylamide))-co-silylanized magnesium/aluminun layered double hydroxides.
abstract: A series of novel thermo-responsive composite sorbents, were prepared by free-radical co-polymerization of N-isopropylacrylamide (NIPAm) and the silylanized Mg/Al layered double hydroxides (SiLDHs), named as PNIPAm-co-SiLDHs. For keeping the high affinity of Mg/Al layered double hydroxides towards anions, the layered structure of LDHs was assumed to be reserved in PNIPAm-co-SiLDHs by the silanization of the wet LDH plates as evidenced by the X-ray powder diffraction. The sorption capacity of PNIPAm-co-SiLDH (13.5 mg/g) for Orange-II from water was found to be seven times higher than that of PNIPAm (2.0mg/g), and the sorption capacities of arsenate onto PNIPAm-co-SiLDH are also greater than that onto PNIPAm, for both As(III) and As(V). These sorption results suggest that reserved LDH structure played a significant role in enhancing the sorption capacities. NO3(-) intercalated LDHs composite showed the stronger sorption capacity for Orange-II than that of CO3(2-). After sorption, the PNIPAm-co-SiLDH may be removed from water because of its gel-like nature, and may be easily regenerated contributing to the accelerated desorption of anionic contaminants from PNIPAm-co-SiLDHs by the unique phase-transfer feature through slightly heating (to 40 °C). These recyclable and regeneratable properties of thermo-responsive nanocomposites facilitate its potential application in the in-situ remediation of organic and inorganic anions from contaminated water.
authors.affiliation: School of Environmental and Chemical Engineering, Shanghai University, No. 99 Shangda Road, Shanghai 200444, PR China.
authors.forename: Hua
authors.initials: H
authors.lastname: Chen
authors.affiliation: School of Environmental and Chemical Engineering, Shanghai University, No. 99 Shangda Road, Shanghai 200444, PR China.
authors.forename: Guangren
authors.initials: G
authors.lastname: Qian
authors.affiliation: School of Environmental and Chemical Engineering, Shanghai University, No. 99 Shangda Road, Shanghai 200444, PR China; School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia. Electronic address: ruanxiuxiu@shu.edu.cn.
authors.forename: Xiuxiu
authors.initials: X
authors.lastname: Ruan
authors.affiliation: School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia. Electronic address: r.frost@qut.edu.au.
authors.forename: Ray L
authors.initials: RL
authors.lastname: Frost
keywords: Anionic contaminants; Layered double hydroxides (LDHs); PNIPAm; Regeneration; Sorption; Thermo-responsive