Sensor to measure a concentration of alkali alcoholate
View Patent ↗A sodium sensor to measure a concentration of sodium methylate in methanol. The sensor assembly includes a solid alkali ion conducting membrane, a reference electrode, and a measurement electrode. The solid alkali ion conducting membrane transports ions between two alkali-containing solutions, including an aqueous solution and a non-aqueous solution. The reference electrode is at least partially within an alkali halide solution of a known alkali concentration on a first side of the solid alkali ion conducting membrane. The measurement electrode is on a second side of the solid alkali ion conducting membrane. The measurement electrode exhibits a measurable electrical characteristic corresponding to a measured alkali concentration within the non-aqueous solution, to which the measurement electrode is exposed.
1. A method for measuring a concentration of an alkali-based compound within a non-aqueous solution, the method comprising:
exposing a reference electrode to an alkali halide in an aqueous solution of a known alkali concentration;
exposing a measurement electrode to an alkali alcoholate in a non-aqueous solution;
exchanging alkali ions between the aqueous and non-aqueous solutions via a solid alkali ion conducting membrane;
measuring an electrical characteristic of at least one of the reference and measurement electrodes, wherein the electrical characteristic is dependent on the concentration of the alkali alcoholate in the non-aqueous solution; and
determining the concentration of the alkali alcoholate in the non-aqueous solution from the measured electrical characteristic.
2. The method of claim 1 , wherein measuring the electrical characteristic comprises measuring an open circuit voltage between the reference and measurement electrodes.
3. The method of claim 1 , wherein measuring the electrical characteristic comprises measuring a current between the reference and measurement electrodes.
4. The method of claim 1 , wherein exchanging the alkali ions between the aqueous and non-aqueous solution comprises exchanging the alkali ions through a solid alkali ion conducting membrane.
5. The method of claim 4 , wherein the solid alkali ion conducting membrane is selected from a group consisting of:
a sodium super ionic conductor (NaSICON) membrane;
a sodium Nafion (Na-Nafion) membrane; and
a sodium glass membrane.
6. The method of claim 1 , wherein exposing the reference electrode to the alkali halide in the aqueous solution comprises exposing the reference electrode to a saturated solution of sodium chloride (NaCl).
7. The method of claim 6 , wherein exposing the reference electrode to the alkali halide in the aqueous solution comprises exposing a silver/silver-chloride (Ag/AgCl) electrode to the saturated solution of sodium chloride (NaCl).
8. The method of claim 1 , wherein exposing the measurement electrode to the alkali alcoholate in the non-aqueous solution comprises exposing the measurement electrode to sodium methylate (NaOCH 3 ) in methanol (CH 3 OH).
9. The method of claim 8 , wherein exposing the measurement electrode to the alkali alcoholate in the non-aqueous solution comprises exposing a platinum (Pt) electrode to the sodium methylate (NaOCH 3 ) in the methanol (CH 3 OH).