Thermal catalytic oxidation performance study of SWTCO system for the degradation of indoor formaldehyde: Kinetics and feasibility analysis

This article proposes a novel application combining the thermal catalytic oxidation with solar-collected wall (SWTCO) in buildings without auxiliary energy. Thermal catalyst MnOx-CeO2 was prepared by the method of modified coprecipitation. The performance and kinetics of MnOx-CeO2 for catalytic oxidation of indoor formaldehyde were investigated. Once-through experiments at different concentrations of 300 -4300 ppb and temperatures 20-100 degrees C were conducted. Moreover, formaldehyde conversion experiments in SWTCO system at several typical indoor concentrations (289 ppb, 587 ppb and 1374 ppb) were performed. Furthermore, a simple system model predicting the degradation of indoor formaldehyde versus the time in SWTCO system was built. Results were as follows: (1) The reaction rate expression considering two parameters i.e. concentration and temperature based on modified L-H model fit the experimental data well; (2) System model calculation results showed initial formaldehyde concentration was an important factor to the formaldehyde degradation capability; (3) SWTCO system could realize high pollutant-removal efficiency and low energy costs simultaneously under higher temperature compared with the system using electrical heating; (4) The purification time constant increased with the horizontal solar radiation and the influence of concentration in typical indoor formaldehyde concentration on it could be neglected. (C) 2016 Elsevier Ltd. All rights reserved.