Ecofriendly Reduction of Methylene Blue with Polyurethane Catalyst

Figure 4

UV-Vis absorption spectra recorded for the progress in reduction of MB dye: (a) 2.5 mL of MB () solution and 2.5 mL of fresh Psidium guajava extract, (b) 2.5 mL of MB () solution and 2.5 mL of fresh Psidium guajava extract with 0.25 g of CPUF, and (c) 2.5 mL of MB () solution, Psidium guajava extract, and ascorbic acid (50 : 50) with 0.25 g of CPUF.

(a)

(b)

(c)