Formaldehyde Removal Performance Research Articles

Modeling and simulation of an activated carbon-based botanical air filtration system for improving indoor air quality

A numerical model for simulating the performance of a dynamic botanical filtration system has been developed for the first time. The model accounts for the various transport and storage processes including air and contaminant convection, adsorption of non-water soluble compound by activated carbon, absorption of water soluble compound by water, bio-degradation of chemicals by microbes in the root bed as well as the automatically controlled irrigation system for the root bed. The model was built upon an existing Coupled Heat, Air, Moisture and Pollutant Simulation for Building Envelope System (CHAMPS-BES) model with the addition of bio-degradation process and the irrigation system. Model parameters were estimated from the experiments. The simulation results showed that the model could describe the pressure drop and airflow relationship well by using the air permeability as a model parameter. The water source added in the model also led to the similar bed moisture content and outlet air RH as that in real test case. The simulation results also showed that the developed model worked well in analyzing the effect of different parameters. It was also found that the critical bio-degradation rate constant was 1×10−5s−1 in this study, below which the dynamic botanical filtration system would not be able to sustain the formaldehyde removal performance. The bio-degradation rate constant of the reduced scale filter system tested was estimated to be in the range of 0.8–1.5×10−4s−1.

Development of carbon-supported hybrid catalyst for clean removal of formaldehyde indoors

A novel hybrid catalyst for a clean removal of formaldehyde indoors with a long lifetime was developed via a deposition of manganese oxide (MnOx) catalysts on a polyacrylonitril-based activated carbon nanofiber (PAN-ACNF) support. The combination of MnOx with PAN-ACNF induced synergic effects on the formaldehyde removal performance; twofold performance improvements were obtained as compared with PAN-ACNF alone not only in dry condition but also in the extremely humid condition at room temperature without an irradiation of the UV light. The two-staged removal process, the adsorption of formaldehyde in the PAN-ACNF micropores followed by the oxidative decomposition by the deposited MnOx nanoparticles, was found to afford the superior formaldehyde removal performance of the developed hybrid catalyst, MnOx@PAN-ACNF.

家庭用空気清浄機のホルムアルデヒド除去性能の劣化性に関する研究

家庭用空気清浄機のホルムアルデヒド除去性能の劣化性に関する研究

Influence of fins on formaldehyde removal in annular photocatalytic reactors

The influence of fins on formaldehyde removal in annular photocatalytic reactors was theoretically, numerically and experimentally studied. The simulated and experimental results agreed well. It was found that mass transfer tends to be the bottleneck of formaldehyde removal in conventional annular photocatalytic oxidation (PCO) reactors. When using fins coated with titania in a PCO reactor, the reaction area is greatly increased and the convective mass transfer is, therefore, obviously enhanced. The reaction coefficient may, however, be reduced. On the whole, the formaldehyde removal performance in an annular PCO reactor can be obviously improved by adding fins to the reactor. This analysis is helpful for annular PCO reactor design, and for performance optimization.