Nb2O5 monolith as an efficient and reusable catalyst for textile wastewater treatment

Abstract

Abstract In this work, the degradation of methylene blue (MB) in aqueous solution by a heterogeneous Fenton-like process was studied. Nb 2 O 5 supported on an anodized aluminum monolith was used as catalyst. The Nb 2 O 5 coating generated during the catalyst synthesis was uniform and porous, with a thickness of 7 μm. Response surface methodology was used to study the relationship between process variables and MB degradation and chemical oxygen demand (COD) reduction. The optimal operating conditions were: initial MB concentration of 45 mg L − 1 , initial H 2 O 2 concentration in the reaction medium of 40 mM, catalyst loading of 7.85 $$ {\mathrm{kg}}_{{\mathrm{Nb}}_2{\mathrm{O}}_5} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>kg</mml:mi> <mml:mrow> <mml:msub> <mml:mi>Nb</mml:mi> <mml:mn>2</mml:mn> </mml:msub> <mml:msub> <mml:mi>O</mml:mi> <mml:mn>5</mml:mn> </mml:msub> </mml:mrow> </mml:msub> </mml:math> m − 3 , and pH 4, reaching a MB degradation of 98% and a COD reduction of 79% at 150 min. The high activity of the Nb 2 O 5 monolith catalyst remained constant after 10 catalytic tests.