Determination of Hexavalent Chromium (Cr(VI)) Concentrations via Ion Chromatography and UV-Vis Spectrophotometry in Samples Collected from Nacogdoches Wastewater Treatment Plant, East Texas (USA)

Figure 5

((a)–(d)) UV-Vis spectra of samples spiked with 5, 10, and 15 mL of 0.5 ppm Cr(VI) standard solution from the four treatment stages: aeration, clarifier, chlorination chamber, and sulfur dioxide chamber.

(a) Aeration chamber

(b) Clarifier

(c) Chlorination chamber

(d) SO₂ chamber