Abstract
A new, simple and accurate method is introduced for determining H 2CO3* alkalinity in fresh waters dominated by the carbonate weak-acid system. The method relies on a single H3PO4 dosage and two pH readings (acidic pH value target: pH∼4.0). The computation algorithm is based on the concept that the overall alkalinity mass of a solution does not change upon the addition of a non-proton-accepting species. The accuracy of the new method was assessed batch-wise with both synthetic and actual tap waters and the results were compared to those obtained from two widely used alkalinity analysis methods (titration to pH∼4.5 and the Gran titration method). The experimental results, which were deliberately obtained with simple laboratory equipment (glass buret, general-purpose pH electrode, magnetic stirrer) proved the method to be as accurate as the conventional methods at a wide range of alkalinity values (20-400 mg L-1 as CaCO3). Analysis of the relative error attained in the proposed method as a function of the target (acidic) pH showed that at the range 4.0<pH<4.5 the error was minimal. A suggested experimental setup for continuous alkalinity measurement is also described.
Original language | English |
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Pages (from-to) | 12-20 |
Number of pages | 9 |
Journal | Talanta |
Volume | 100 |
DOIs | |
State | Published - 15 Oct 2012 |
Externally published | Yes |
Keywords
- Alkalinity analysis
- Carbonate alkalinity
- Fresh water
- Single titration