Degradation of methyl blue using Fe-tourmaline as a novel photocatalyst.

This study investigated the photocatalytic activity of tourmaline by itself. Under irradiation of a 13 W, 254 nm UV lamp, 50% of methyl blue disappeared in the presence of 130 mg·L⁻¹ tourmaline. The reaction was inhibited by the addition of ethanol, Cl⁻, SO₄²⁻ and Cu²⁺, and promoted a little by addition of 50 mg/L Mg²⁺, which supports the inference of involvement of •OH radicals. This is the first proposal of tourmaline as a single photocatalyst without the need to add any artificial chemical products. Results from this study might contribute to the broadened usage of this mineral to approach the goals of saving energy and eliminate direct or indirect environmental pollution.