CALCIUM Analysis | Carbon Capture & Storage Process Technologies | Free Carbon Dioxide Determination in Waste Water

Calcium determination:

Outlines of the method:
The liquid samples are titrated against the EDTA solution using the Murexide indicator. This chemical analysis is suitable for the range of 0 to 250 mg/l of calcium content.

1. sodium hydroxide solution – 4N
2. Murexide indicator solution  – mix 0.20 g of Murexide and 100g of sodium chloride and grind to a fine powder.
3. Std EDTA solution (0.02N) –  3.72g of disodium ethylenediamine tetra amine dihydrate is dissolved in a 1-liter solution distilled water solution.  One milliliter of this solution is equal to 1mg of CaCO3
4. Std HCl – 0.02N
5. Triethanolamine – 20 percent (v/v)

Producer: Measure 100ml of the sample into a porcelain basin; neutralize it by adding Std HCl acid in a quantity equivalent to the alkalinity of methyl orange. Add 1ml of Std NaOH solution and allow to stand for 5min. Add 5ml of triethanolamine and about 50mg of Murexide indicator and titrate the solution with Std EDTA solution until the color changes from pink to purple.

Calcium (as CaCO3), mg/l = 1000 V1/V2
V1 = volume in ml of EDTA sol required for titration
V2 = volume of sample in ml

Carbon Capture & Storage Process Technologies

Techniques developed for carbon capture are:

  • By absorption and desorption column by alkanolamine-based solutions.
  • Flue gas scrubbing by MEA (monoethanolamine)
  • Membrane separation
  • Cryogenic fractionation
  • Absorption by molecular sieves
  • Adsorption on a solid surface
  • Clathrate Hydrates

Carbon storage also considers carbon dioxide capture from the atmosphere and from the flue gases produced at industries by means of chemical absorption and other unit operation techniques. Membrane separation techniques are being recognized as new technology and unit operations that performer completely unique tasks. They promise effective separation of compounds and utilize energy with minimal loss. These techniques are being studied and developed for more applications.

Free Carbon Dioxide Determination in Waste Water


Industrial wastewater containing carbon dioxide can be found by titrating the sample with a Std sodium carbonate solution using a phenolphthalein indicator.


1. Phenolphthalein indicator solution

2. Std sodium carbonate


Take 100ml of the unfiltered sample in a measuring cylinder avoiding agitation. Add 10 drops of phenolphthalein indicator, and run in Std sodium carbonate solution 0.5ml at a time, stirring the sample gently but thoroughly by raising and lowering a glass rod. The endpoint is reached when a definite pink color persists for 5 min.


Free carbon dioxide as (CO2), mg/l = 4.4 V


V= volume in ml of Std sodium carbonate sol consumed.

Free carbon dioxide is the amount of carbon dioxide dissolved in water and wastewater. The quantity of free carbon dioxide shows the acidic nature of the sample water caused by carbonic acid, which is formed by the reaction of carbon dioxide and water.

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