The LXT-SMS220 Sulfide Measurement System is an all in one analyzer for the continuous measurement of sulfide ions in aqueous media. Sulfide is present in well water, municipal waste water and waste waters from refineries, tanneries, chemical plants and pulp and paper facilities. Hydrogen sulfide (H2S) exists in acidic water as a dissolved gas and at pH values above 7, bisulfide ions (HS-) are the predominate form and at very high pH values, < pH 13, sulfide ions (S-2) are predominate.
Sulfide Ion Selective Electrode (ISE)
The LXT-SMS220 uses a sulfide ion selective electrode (ISE) to measure the total amount of sulfide present in samples with a high pH level. In order to raise the pH of the given sample, Potassium Hydroxide (KOH) is added. The KOH raises the sample to around pH 13 while a pH electrode measures the actual pH level in the sample. This pH measurement infers what percent of the total sulfide was measured while the sulfide ISE measures the amount of sulfide present. The LXT-220 then calculates and displays the total sulfide that was present. Lastly, the highly caustic sample is neutralized with HCl and the pH is measured and displayed to verify the neutralization. The neutralization of KOH with HCl produces potassium chloride salt (KCl) and water. The neutralized sample can be disposed as waste or returned to the water supply.
Sequential Sampling
The LXT-SMS220 is a sequential sampling analyzer. It is set to run 6 minute analysis cycles but can easily be programmed to run 12 or 30 minute cycles. Each cycle uses about 1 ml of caustic and 1 ml of acid. When running continuously, the usage of each reagent are as follows:
10 cycles per hour - 7.2 liters per month
5 cycles per hour - 3.6 liters per month
2 cycles per hour - less than 1.5 liters per month
The Enclosure
The enclosure provides IP66 protection and is NEMA-4x rated. The base is made of gray hot-molded fiberglass reinforced polyester and the cover is made of transparent polycarbonate with non-metallic hinges.
