IonExchange Separation and Spectrophotometric Determination of Nickel and

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Ion-Exchange Separation and Spectrophotometric Determination of Nickel and Cobalt By Doan-Phuong Dao

Ion-Exchange Separation and Spectrophotometric Determination of Nickel and Cobalt By Doan-Phuong Dao

Background information This experiment had two major steps: 1)Separation of Ni and Co in

Background information This experiment had two major steps: 1)Separation of Ni and Co in the unknown sample by using an ion-exchange chromatography column with a strong base anion exchanger 2) Determination of the concentrations of Ni and Co in the unknown sample by using standard spectrophotometric procedures l

Ion exchange chromatography In ion-exchange chromatography, retention is based on the attraction between solute

Ion exchange chromatography In ion-exchange chromatography, retention is based on the attraction between solute ions and the charged sites bound to the stationary phase. l In anion exchangers, positive charged groups on the stationary phase attract solute anions l Cation exchangers contain covalently bound, negatively charged sites that attract solute cations l This experiment used a strong base anion exchanger l

l In solution containing a large concentration of hydrochloric acid, Co was converted into

l In solution containing a large concentration of hydrochloric acid, Co was converted into complex anions (chlorides) Co. Cl 4 2 -, and was adsorbed by an anion resin. Ni was not converted into complex anions so that it was not adsorbed by such a resin. The separation of Nickel from Cobalt was easily effected. The cobalt is removed by washing the resin with 1 M HCl.

After separating from the mixture, Nickel was oxidized with bromine in ammonia solution and

After separating from the mixture, Nickel was oxidized with bromine in ammonia solution and then treated with dimethylglyoxime. A wine-red or brown complex is formed. Cobalt was determined by conversion of the metal to the blue complex cobalt thiocyanate, Co(CNS)42 -. l 95% ethanol solution was used because both complexes were somewhat dissociated in water l The concentrations of Ni and Co were determined by measuring the absorbance at 455 nm (for Ni), and at 625 nm (for Co) with a spectrophotometer. l

The graphs of concentration vs. absorbance of Ni and Co standard solution were plotted

The graphs of concentration vs. absorbance of Ni and Co standard solution were plotted to determine the line equations. l From the line equations , the absorbance of the Ni and Co in the unknown were plugged in to calculate the concentration of each metal in the sample l

Question l What is required when it comes to separating Nickel and Cobalt in

Question l What is required when it comes to separating Nickel and Cobalt in the column?

Answer l Need 9 M HCl to bind to Cobalt and release Nickel l

Answer l Need 9 M HCl to bind to Cobalt and release Nickel l Need 1 M HCl to release the Cobalt from the column.

Spectrophotometric Determination of Iron Quantitative spectrophotometric analysis willSpectrophotometric Determination of Iron Quantitative spectrophotometric analysis will
Nickel Ni Nickel Symbol Ni Nickel is aNickel Ni Nickel Symbol Ni Nickel is a
Separation Process Separation Methods Separation Methods 1 SeparationSeparation Process Separation Methods Separation Methods 1 Separation
Spectrophotometric Analysis Spectrophotometric techniques are used to measureSpectrophotometric Analysis Spectrophotometric techniques are used to measure
Chemistry SEPARATION TECHNIQUES Separation Techniques Involve the separationChemistry SEPARATION TECHNIQUES Separation Techniques Involve the separation
Separation Zone Inshore Traffic Zone Separation Line SeparationSeparation Zone Inshore Traffic Zone Separation Line Separation
Common Color Table Nickel Black Nickel Gold AntiGoldCommon Color Table Nickel Black Nickel Gold AntiGold