Removal of formaldehyde from the air with a suspended growth bioreactor.

In the present study, the root zone of Canna flaccida Salisb. was selected as the biological component. We found that the adsorption rate of formaldehyde (FA) by C. flaccida was initially low, before increasing substantially. ¹³CNMR analysis indicated that C. flaccida can metabolize H¹³CHO and the major metabolic products were organic acid and amino acids. On this basis, we had designed a suspended growth bioreactor (SGB) to remove FA. An SGB was tested under a series of different conditions and the results showed that FA removal efficiency was strongly influenced by water volume, root zone weight, and gas flow rate. More than 52% of the FA was removed in 1 h and the maximum elimination capacity reached 35.112 mg m⁻³ h⁻¹. After 24 h, no FA remained in the SGB. Running for 15 days, the concentration of FA in the lab space decreased from 1.12 to 0.82 mg m⁻³, and the concentration of FA in the SGB reached a low level. These results confirmed that SGB is an effective way to remove FA. Article Highlights: Kinetics of FA uptake by Canna roots in FA solutions was established. Canna roots could metabolize FA was confirmed. FA removal efficiency significantly affected by a series of different conditions. The performance evaluation of the SGB in short- term and long-term treatment. [ABSTRACT FROM AUTHOR]