The effect of weak chelating agents on the removal of heavy metals by precipitation processes
Particle size distributions and heavy metal removals are presented for hydroxide precipitation and sulfide precipitation of zinc and cadmium in the presence of several weak complexing agents, namely citrate, tartrate, and ammonia. The pH was held constant at pH 10.0 in these experiments. The presence of these weak complexing agents had little effect on the chemical equilibrium for both the hydroxide and sulfide systems due to their weak complexing ability with metal ions. The presence of the complexing agents does affect the particle size distribution, generally forming smaller particles. Particle size distributions are presented for the Zn(OH)/sub 2/, ZnS, Cd(OH)/sub 2/, and CdS systems (at pH 10.0) in the presence of the chelating agents citrate, tartrate, and ammonia. Sulfide precipitation exhibits a better particle size distribution and settling characteristics than the corresponding metal hydroxide precipitation for both zinc and cadmium.
- Research Organization:
- Environmental Engineering, School of Civil Engineering, Purdue Univ., West Lafayette, IN 47907
- OSTI ID:
- 7032233
- Journal Information:
- Environ. Prof.; (United States), Journal Name: Environ. Prof.; (United States) Vol. 5:3; ISSN EPROD
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201* -- Chemical & Physicochemical Properties
AMMONIA
CADMIUM
CADMIUM COMPOUNDS
CADMIUM HYDROXIDES
CADMIUM SULFIDES
CARBOXYLIC ACID SALTS
CHALCOGENIDES
CHELATING AGENTS
CITRATES
ELEMENTS
EQUILIBRIUM
HYDRIDES
HYDROGEN COMPOUNDS
HYDROXIDES
INORGANIC PHOSPHORS
METALS
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
OXYGEN COMPOUNDS
PARTICLE SIZE
PH VALUE
PHOSPHORS
PRECIPITATION
REMOVAL
SEPARATION PROCESSES
SIZE
SULFIDES
SULFUR COMPOUNDS
TARTRATES
ZINC
ZINC COMPOUNDS
ZINC HYDROXIDES
ZINC SULFIDES