Concentration of trace metals by complexation with dithiocarbamate and sorption onto C-18 bonded silica gel

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:6410224

Shah, N K

Adsorption of metal complexes on C-18 bonded silica gel is an efficient and rapid method of separating and concentrating trace elements from natural waters. The adsorption characteristics of some metal dithiocarbamate complexes on C-18 bonded silica gel are described. At pH 2, Au, Pd, Pt, U and W form stable pyrrolidinecarbodithioate (PCDT) complexes which can be quantitatively recovered by C-18 bonded silica gel. Simultaneous determination of the adsorbed metals on C-18 bonded silica gel at parts per billion (ppb) levels can be achieved by instrumental neutron activation analysis (INAA). Concentrations of trivalent and pentavalent arsenic and antimony species were studied by complexation with PCDT and adsorbing its metal complexes on C-18 bonded silica gel. The adsorbed metal complexes were eluted with acetonitrile, evaporated to dryness, and dissolved in nitric acid for neutron activation analysis (NAA). The redox potentials were also calculated for As and Sb species with PCDT to study the nature of complex formation. Both Sb(III) and Sb(V) can form stable complexes with PCDT. The reducing nature of dithiocarbamate causes Sb(V) to be readily reduced to Sb(III). X-ray diffraction studies indicate that the crystal structures of the SB(III) and Sb(V) complexes with PCDT are indeed identical with a metal-to-ligand ratio of 1:3. The pentavalent species is apparently reduced to Sb(III) by PCDT. Preconcentration and separation of trace metal ions chelated with bis(2-hydroxyethyl)dithiocarbamate (HEDDC) have been studied by the C-18 bonded silica gel adsorption method. The hydroxy groups present in HEDDC cause its metal complexes to be soluble in water at low concentrations. The stability constant for lead bis(2-hydroxyethyl)dithiocarbamate was evaluated using competition reactions and the C-18 bonded silica adsorption method.

• Research Organization: Idaho Univ., Moscow, ID (USA)
• OSTI ID: 6410224
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400101 -- Activation
Nuclear Reaction
Radiometric & Radiochemical Procedures
400105* -- Separation Procedures
54 ENVIRONMENTAL SCIENCES
540320 -- Environment
Aquatic-- Chemicals Monitoring & Transport-- (1990-)
540330 -- Environment
Aquatic-- Radioactive Materials Monitoring & Transport-- (1990-)
ACTINIDE COMPLEXES
ACTINIDES
ACTIVATION ANALYSIS
ADSORBENTS
ADSORPTION
AMINES
ANTIMONY
ANTIMONY COMPLEXES
ARSENIC
ARSENIC COMPLEXES
AZOLES
CARBAMATES
CARBONIC ACID DERIVATIVES
CARBOXYLIC ACID SALTS
CHEMICAL ANALYSIS
CHEMICAL REACTIONS
COHERENT SCATTERING
COMPLEXES
CRYSTAL STRUCTURE
DIFFRACTION
ELEMENTS
GOLD
GOLD COMPLEXES
GROUND WATER
HETEROCYCLIC COMPOUNDS
HYDROGEN COMPOUNDS
LEAD
LEAD COMPLEXES
METALS
NEUTRON ACTIVATION ANALYSIS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
OXYGEN COMPOUNDS
PALLADIUM
PALLADIUM COMPLEXES
PH VALUE
PLATINUM
PLATINUM COMPLEXES
PLATINUM METALS
PYRROLES
PYRROLIDINES
REDOX POTENTIAL
REDUCTION
SCATTERING
SEMIMETALS
SEPARATION PROCESSES
SILICA GEL
SORPTION
SURFACE WATERS
TRACE AMOUNTS
TRANSITION ELEMENT COMPLEXES
TRANSITION ELEMENTS
TUNGSTEN
TUNGSTEN COMPLEXES
URANIUM
URANIUM COMPLEXES
WATER
X-RAY DIFFRACTION