Adsorption of phenol on activated carbon

aim

Determination of the sorption process rate and adsorptive balance of phenol on activated carbon. Determination of sorption capacity in the column.
Batch sorption experiment
1. Prepare 2 x 40 mL of phenol solutionwith different concentration (given by supervisor) in 0.05 M phosphate buffer at pH 7.0.

2. Add 40 g of activated carbon to 40 ml of the phenol solution pre-incubated at 50 °C and monitor the change in phenol concentration over time. For the first 3 minutes, take the samples fprevery 0.5 min, and then every 2 minutes, until the equilibrium is established.

3.In the meantime of the process in the stirred tank reactor, the activated carbon undergoes breakdown and in this case the collected samples should be centrifuged in closed tubes for 5 minutes at 4 500 rpm.

4. Measurement of phenol concentration is performed by spectrophotometric method at wavelength λ = 272 nm against buffer solution.

5. Standard curve for phenol Abs272 = 15.73*c [g/L]; range of the curve is up to 0.12 g/L.

6. ATTENTION !!! The un-diluted samples are returned to the reactor.

7. Measurement of the current concentration of phenol is done until the concentration in the solution is stable.

Sorption In flow conditions

  1. Prepare 1 liter of the phenol solution at the given concentration (given by supervisor) in 0.05 M phosphate buffer pH 7.0. Determine the prepared concentration of phenol by measuring the absorbance at 272 nm and correlating with standard curve.
  2. Weigh the activated carbon and pack inside a column.
  3. Add slowly the phenol solution to the column and simultaneously monitor the concentration at the outlet until the column is pierced. Measure the volume of the purified solution.

Data processing (for calculating points 2 and 3 - data should be collected from all subgroups)

1. Plot changes in phenol concentration during the sorption process [Cphenol=f(t)].
2. Determine the initial phenol mass flow as a function of the initial concentration of phenol in tested solutions; indicate a dependence.
3. Determine the Freundlich equation coefficients.
4. Analyze of the column's work and determine the sorption capacity of the adsorbent.

Freundlichisotherm

Fig. 1. FreundlichAdsorptionequation in Logarithmic form

Issues of atest
1. Basic definitions related to the sorption process.
2. Classification of adsorbents and adsorbates depending on the nature of intermolecular interactions.
3. Chemisorption.
4. The adsorption equilibrium.
5. Freundlichand Langmuirisotherm equations.
6. Sorption in flow conditions. Sorption capacity.
7. Examples of adsorption and absorption process applications.

References

1. Sarbak Z., Adsorpcja i adsorbenty. Teoria i zastosowanie, Wyd. Nauk. UAM, Poznań 2000.

2. Lecturesfrom Bioproductsseparation and purification.