Effects of Methane Fermentation on Spectral Properties of Fulvic Acid Extracted from Peat through Liquid Acid Precipitation

Figure 6

(a) Fluorescence spectrum of fulvic acid. Fluorescence spectrum of fulvic acid by (b) sulfuric acid precipitation, (c) nitric acid precipitation, (d) hydrochloric acid precipitation, and (e) phosphoric acid precipitation.

(a)

(b)

(c)

(d)

(e)