title: Temperature effect on phosphate sorption by iron hydroxide.
abstract: The ion exchange sorption of phosphate on Fe(OH)3 is studied as a function of temperature (25-55 degrees C) and concentration (1.49-3.23 mmol l(-1)). The mechanism of sorption is observed to be the exchange of OH- anions from the adsorbent surface by those of H2PO4- and HPO4(2-) from the aqueous solution. An equation developed in the Langmuir formalism is used to explain the ion exchange sorption of phosphate on Fe(OH)3. The isosteric heat of sorption illustrates that the uptake of phosphate on Fe(OH)3 takes place through an anion exchange process, involving both the phosphate anions H2PO4- and HPO4(2-). Further, at higher temperature the solid prefers the HPO4(2-) anions forming a binuclear bridging complex.
authors.affiliation: National Centre of Excellence in Physical Chemistry, University of Peshawar, Peshawar, Pakistan.
authors.forename: S
authors.initials: S
authors.lastname: Mustafa
authors.forename: G
authors.initials: G
authors.lastname: Nawab
authors.forename: A
authors.initials: A
authors.lastname: Naeem
authors.forename: N
authors.initials: N
authors.lastname: Rehana
authors.forename: B
authors.initials: B
authors.lastname: Dilara
mesh_terms: D000327:Adsorption; D005290:Ferric Compounds / Q000737:chemistry*; D007474:Ion Exchange; D008962:Models, Theoretical; D010710:Phosphates / Q000737:chemistry* / Q000302:isolation & purification*; D013696:Temperature; D014873:Water Pollutants / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods*
chemical_list: D005290:Ferric Compounds; D010710:Phosphates; D014873:Water Pollutants; C021024:ferric hydroxide