Catalyst based on bentonite clay modified with sodium metasilicate for heterogeneous Fenton-Raff type process

Natural bentonite clay with a montmorillonite content of 98 %, modified with a solution of sodium metasilicate, has high catalytic activity in the reaction of oxidative degradation of organic azo dyes with hydrogen peroxide by the Fenton-Ruff mechanism in a neutral medium. The activity is due to the presence of iron cations contained in the structure of montmorillonite, as well as protonated silanol and aluminol groups on the surface of the edges of aluminosilicate layers, which are the acid centers of Brensted. The degree of conversion of azo dye from cinema blue with an initial concentration in a solution of 20 mg/l was 99 % in 4 – 6 minutes of contact, at room temperature. The resulting material is well filtered and can be recommended for wastewater treatment from organic substances.