Chromate ion exchange mechanism for cooling water

Journal Article · Thu May 01 04:00:00 EDT 1986 · Ind. Eng. Chem. Fundam.; (United States)

DOI:https://doi.org/10.1021/i100022a012· OSTI ID:5459309

Sengupta, A K; Clifford, D

The chromate ion exchange recovery process for cooling tower blowdown is unique due to the early, gradual breakthrough of highly preferred Cr(VI) from fixed-bed columns for all types of anion-exchange resins. It is shown that the early Cr(VI) breakthrough is not due to poor column kinetics but is predictable from an equilibrium model by using the appropriate exchange reaction involving both HCrO/sub 4//sup -/ and Cr/sub 2/O/sub 7//sup 2 -/. At acidic pH, HCrO/sub 4//sup -/ is practically the only Cr(VI) species in the aqueous phase, while in the exchanger phase both HCrO/sub 4//sup -/ and Cr/sub 2/O/sub 7//sup 2 -/ exist. The presence of Cr/sub 2/O/sub 7//sup 2 -/ in the exchanger's solid phase causes a positively cured (concave upward) isotherm at relatively low Cr(VI) loading of the resin, and this equilibrium property is primarily responsible for the unusual, gradual breakthrough of Cr(VI). The presence of Cr/sub 2/O/sub 7//sup -/ in the solid phase may be viewed as the dimerization of HCrO/sub 4//sup -/, according to the Donnan equilibrium principle.

• Research Organization: Univ. of Houston-University Park, Houston, TX 77004
• OSTI ID: 5459309
• Journal Information: Ind. Eng. Chem. Fundam.; (United States), Journal Name: Ind. Eng. Chem. Fundam.; (United States) Vol. 25:2; ISSN IECFA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ANIONS
AQUEOUS SOLUTIONS
BLOWDOWN
CHARGED PARTICLES
CHEMICAL REACTIONS
CHROMATES
CHROMIUM COMPLEXES
CHROMIUM COMPOUNDS
COMPLEXES
COOLING TOWERS
DIMERIZATION
DISPERSIONS
DONNAN THEORY
EQUILIBRIUM
HYDROGEN COMPOUNDS
ION EXCHANGE
ION EXCHANGE MATERIALS
IONS
ISOTHERMS
MATERIALS
MECHANICAL STRUCTURES
MIXTURES
ORGANIC COMPOUNDS
ORGANIC POLYMERS
OXYGEN COMPOUNDS
PACKED BED
PETROCHEMICALS
PETROLEUM PRODUCTS
PH VALUE
POLYMERIZATION
POLYMERS
RESINS
SOLUTIONS
TOWERS
TRANSITION ELEMENT COMPLEXES
TRANSITION ELEMENT COMPOUNDS
WATER