Volume Changes in an Aqueous Suspension of Amorphous Iron(III) Hydroxide Due to the Adsorption of Phosphates (H2PO−4)

✍ Scribed by Noriko Yamaguchi; Takusei Hashitani; Masanori Okazaki; Toru Takeda

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 94 KB
• Volume: 183
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.1996.0544

✦ Synopsis

complex (2). There are no water molecules between the

Volume changes on H 2 PO 0 4 adsorption with amorphous adsorbed ion and the adsorbent of the innersphere surface iron ( III ) hydroxide were determined in a mixture of aqueous complex. Consequently, some water molecules hydrated on solutions of phosphates ( NaH 2 PO 4 ) and suspended amorphous ions and adsorbent must be released during adsorption. Howiron ( III ) hydroxide at an initial pH of 5.50 or 4.50, at 298 K. ever, this had not been identified experimentally until this Volume changes were determined by a dilatometer after the mixstudy, in which the release of hydrated water molecules was ing of phosphate solutions and suspended amorphous iron ( III ) observed as volume changes. hydroxide solutions. The increased volumes of the systems after Volume changes of the systems were determined using a the mixing of H 2 PO 0 4 solutions and suspended amorphous dilatometer designed by Hashitani (3). This dilatometer has iron ( III ) hydroxide suggested that H 2 PO 0 4 adsorption was accompanied by dehydration of aqueous H 2 PO 0 4 ions and sus-two optically flat discs for separating two solutions. When pended amorphous iron ( III ) hydroxide in water. The estimated two solutions (or suspensions) were mixed in the dilatomevolume changes per mole of H 2 PO 0 4 adsorption were about /15 ter, volume changes were measured as changes in water level cm 3 .