title: Removal of anionic metals by amino-organoclay for water treatment.
abstract: We describe a facile and simple one-pot synthesis of water-soluble amino-organoclay under ambient conditions. The clay was used to successfully remove environmentally toxic anionic metals, such as arsenate, chromate, and ferricyanide. The electrostatic interactions between the anionic metals and the protonated amino (ammonium) groups of the amino-organoclay resulted in rapid precipitation, within 3 min, with a high removal capacity. The maximum removal capacities (in units of mg metal per g organoclay) of the amino-organoclay clay toward HAsO(4)(2-), CrO(4)(2-), or Fe(CN)(6)(3-) were, 30.73 mg/g, 34.67 mg/g, or 218.88 mg/g in case of 0.02 g, 0.03 g, and 0.005 g of the amino-organoclay, respectively. The removal efficiencies of 0.07 g, 0.09 g, and 0.03 g of the amino-organoclay whose dosage of clay was at the highest removal efficiency (%) for arsenate, chromate, and ferricyanide, respectively, presented 59.79%, 89.54%, and 97.43%. Furthermore, humic acid that ubiquitous in the organic matter present in water or soil environments, inhibited the removal rate of anionic metals, and thus the removal efficiencies toward all anionic metals were markedly reduced. Humic acid preferentially precipitated with the interaction of amino-organoclay prior to the anionic metals.
authors.affiliation: Department of Chemical and Biomolecular Engineering (BK21 Program), KAIST, 335 Gwahak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea.
authors.forename: Young-Chul
authors.initials: YC
authors.lastname: Lee
authors.forename: Won-Kun
authors.initials: WK
authors.lastname: Park
authors.forename: Ji-Won
authors.initials: JW
authors.lastname: Yang
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry*; D000588:Amines / Q000737:chemistry*; D000838:Anions; D011232:Chemical Precipitation; D000077215:Clay; D006812:Humic Substances; D008670:Metals / Q000302:isolation & purification*; D012995:Solubility; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods*
chemical_list: D000538:Aluminum Silicates; D000588:Amines; D000838:Anions; D006812:Humic Substances; D008670:Metals; D014874:Water Pollutants, Chemical; D000077215:Clay