Natural diatomites: Efficient green catalyst for Fenton-like oxidationof Orange II

INCHAURRONDO N.; FONT J; RAMOS C; HAURE P.

APPLIED CATALYSIS B-ENVIRONMENTAL

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2016 vol. 181 p. 481 - 494

0926-3373

The Fenton-like oxidation of the anionic azo-dye Orange II (100?500 mg/L) was batchwise performed using commercial grade diatomites (3.5% Fe content) thermally treated. Solid samples were thoroughly characterized by several techniques. Peroxidation experiments were performed varying the diatomite calcination temperature (500, 700, 1000◦C), reaction temperature (50,60, 70, 80◦C), catalyst load (0.47, 0.94, 1.89 and 3.78 g), H2O2 concentration (11.0, 13.7, 20.6 mmol/L) and dosing, pH (2?3.5) and initial dye concentration (0.28, 0.57, 1.43 mmol/L). The influence of NaCl andoxalic acid on the catalytic performance and stability was also addressed. The best results were obtained with samples calcined at 700◦C, with initial pH 3, at 70◦C and using the stoichiometric amount of H2O2, since complete decoloration, TOC reduction close to 67% and negligible Fe leaching were achieved. The stability of the catalyst maintains after 20 h of usage, with a final Fe loss of 2.25%. An average of 0.88 mg/L of iron leached after each run, which is below the discharge limit.