Development of PdCu Structured Catalysts Based on ZrO₂–CeO₂ Materials Supported on Cordierite Monoliths for Water Remediation: Removal of Hazardous Oxyanions

Abstract

The elimination of hazardous oxyanions NO 3 − , NO 2 − , and BrO 3 − from synthetic and real water samples using novel PdCu/10ZrCe (10 wt % ZrO 2 on CeO 2 ) structured catalysts supported on cordierite monoliths was studied in order to avoid loss of the catalytic material during water treatment. The monoliths were coated with different suspensions of the 10ZrCe support. Particle sizes, suspension concentration of 10ZrCe, and pH effects were evaluated. The structured catalyst was tested in a fixed-bed reactor at different flow rates for the elimination of the selected anions. Good results in terms of activity and selectivity to the products of interest (S N 2 : 0.99 and S Br − :1) were obtained in synthetic water. The structured catalyst was reused three times, maintaining its activity and selectivity. It was evaluated in a real water sample but the activity was lower probably due to competition for active sites by different ions present in the sample. The structured catalyst prepared is promising for the development of a system for water remediation, based on PdCu/ZrO 2 −CeO 2 materials.

Catalytic Hydrogenation of Nitrate over Immobilized Nanocatalysts in a Multi-Phase Continuous Reaction System: System Performance, Characterization and Optimization

“…One of the first studies was conducted by Pintar et al [33], who studied the catalytic hydrogenation of NO 3 − in fixed-bed reactors, showing that NO 3 − conversion and selectivity were strongly influenced by liquid and gas flow maldistribution associated with the use of compact material beds. To avoid this type of problem, monolithic reactors emerged as interesting supports for the powder catalysts allowing immobilization of the powdered materials on structured supports and their application in heterogeneous catalytic continuous systems [34][35][36][37]. These types of structures have been widely studied over the past few years as efficient solutions to perform the catalyst immobilization for their application at the industrial level [38,39].…”

“…However, to create an efficient system for NO 3 − conversion using a monolithic reactor, it is still required to optimize all the parameters that influence the catalytic reaction. This approach has not been adequately studied yet, since most of the studies in continuous systems are focused on fixed-bed reactors and there are very few studies on the application of monolithic reactors as support for the catalyst (macrostructured catalysts); also, most of these studies are more related to the synthesis of stable and active macrostructured catalysts and not to the optimization of reaction parameters that drive the reaction [37]. Thus, as important as the catalyst design, there is a need to understand what variables of the continuous system operation mostly contribute to the efficiency of the process using macrostructured catalysts.…”

Coating Process of Honeycomb Cordierite Support with Ni/Boehmite Gels

“…Commercial cylinders of cordierite with square-shaped cross sections were used. Cordierite material (2Al 2 O 3 •2MgO•5SiO 2 ) is commonly used as a monolith support in the catalyst field [14][15][16][17].…”