title: New method of treating dilute mineral acids using magnesium-aluminum oxide.
abstract: Mineral acids, such as H(3)PO(4), H(2)SO(4), HCl, and HNO(3,) were treated with magnesium-aluminum oxide (Mg-Al oxide), which behaved as a neutralizer and fixative of anions. Anion removal increased with increasing Mg-Al oxide quantity, time, Mg/Al molar ratio, and initial acid concentration. Up to 95% removal of anions was achieved in 0.5 N acids using a stoichiometric quantity of Mg(0.80)Al(0.20)O(1.10) for H(3)PO(4), 1.75 stoichiometric quantities for H(2)SO(4), or 2.5 stoichiometric quantities for HCl or HNO(3) at 20 degrees C over a period of 6 h. The final solutions were found to have a pH in the range of 8-12. Selectivity of acid removal was found to follow the following order: H(3)PO(4) > H(2)SO(4) > HCl > HNO(3). The equivalent of acid removal per 1 g of Mg-Al oxide decreased as the Mg/Al molar ratio of Mg-Al oxide increased.
authors.affiliation: Dapartment of Applied Chemistry, Graduate School of Engineering, Tohoku University, Aoba 07, Aoba-ku, Sendai 980-8579, Japan. kameda@tagen.tohoku.ac.jp
authors.forename: Tomohito
authors.initials: T
authors.lastname: Kameda
authors.forename: Fumiko
authors.initials: F
authors.lastname: Yabuuchi
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Yoshioka
authors.forename: Miho
authors.initials: M
authors.lastname: Uchida
authors.forename: Akitsugu
authors.initials: A
authors.lastname: Okuwaki
mesh_terms: D000148:Acids, Noncarboxylic / Q000737:chemistry*; D000537:Aluminum Oxide / Q000737:chemistry*; D000838:Anions; D006863:Hydrogen-Ion Concentration; D008274:Magnesium / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D000148:Acids, Noncarboxylic; D000838:Anions; D008274:Magnesium; D000537:Aluminum Oxide