Question

2-Methylisoborneol (MIB), a metabolite of algal production, is a common taste- and odor-causing compound in surface waters. Adsorption on activated carbon is one treatment option. A series of batch adsorption equilibrium tests were performed using powdered activated carbon (PAC) as the sorbent. Plot the data according to the Langmuir isotherm. The water of the foul smelling Reservoir has an MIB concentration of 1.5 mg/L. The treated water is to have a MIB concentration of 0.030 mg/L.

Flask No.

Initial MIB conc. (Co) (m g/L)

Equilibrium MIB conc. (Co) (m g/L)

PAC Dosage (Do) (mg/L)

1	1.0	0.01	20
2	1.0	0.05	10
3	1.0	0.10	7
4	1.0	0.50	2
5	5.0	1.0	10
6	5.0	2.0	6
7	5.0	3.0	3

Determine if the desired effluent quality can be achieved by adsorption.

Determine the adsorptive capacity (q_e) of the carbon at this level of effluent quality.

Determine the dose of PAC required to treat a demand of 0.15 m³/s of this water.

Answer 1

a)The desired effluent efficiency of 0.03 mg/L can be acheived since a lower value of 0.01 mg/L has been acheived as reflected in the data for flask 1

b) A linear fit of the Langmuir isotherm i.e a plot of 1/qe vs 1/ce, as shown above gives the following equation:

y = 0.0002x + 0.0036

For x = 1/ce =1/ 0.03 mg/L, the corresponding value of y = 1/qe is as follows:

1/qe = 0.0002*1/0.03 + 0.0036 = 0.01027

qe = 97.371 mg MIB/g activated carbon